[Federal Register Volume 62, Number 53 (Wednesday, March 19, 1997)]
[Notices]
[Pages 13176-13198]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-6884]
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NUCLEAR REGULATORY COMMISSION
Disposition of Cesium-137 Contaminated Emission Control Dust and
Other Incident-Related Material; Final Staff Technical Position
AGENCY: U.S. Nuclear Regulatory Commission.
ACTION: Notice: final staff technical position.
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SUMMARY: The U.S. Nuclear Regulatory Commission is issuing guidance, in
the form of a technical position, that may be used, in case-by-case
requests, by appropriate licensees, to dispose of a specific incident-
related mixed waste. Mixed waste is a waste that not only is
radioactive, but also is classified as hazardous under the Resource
Conservation and Recovery Act (RCRA). The specific mixed waste
addressed in this position is emission control dust from electric arc
furnaces (EAFs) or foundries that has been contaminated with cesium-137
(\137\Cs). The contamination results from the inadvertent melting of a
\137\Cs source that: (1) Has been improperly disposed of by an NRC or
Agreement State licensee; (2) has been commingled with the steel scrap
supply; (3) has not been detected as it progresses to the steel-
producing process; and (4) is volatilized in the production process and
thereby can and has contaminated large volumes of emission control dust
and the emission control systems at steel-producing facilities.
The position, which has been coordinated with the U.S.
Environmental Protection Agency (EPA), provides the possibility of a
public health-protective, environmentally sound, and cost-effective
alternative for the disposal of a large part of this mixed waste, much
of which contains \137\Cs in concentrations similar to values that
frequently occur in the environment. The position provides the bases
that, with the approval of appropriate regulatory authorities (e.g.,
State-permitting agencies) and others (e.g., disposal site operators),
and with possible public input, could be used to allow disposal of
stabilized waste at Subtitle C, RCRA-permitted, hazardous waste
disposal facilities. NRC believes that disposal, under the provisions
of the position or other acceptable alternatives, is preferable to
allowing this mixed waste to remain indefinitely at steel company
sites.
The position has been developed through an open public process in
which working draft documents have been routinely shared with EPA, and
also placed in NRC's Public Document Room to allow interested party
access. NRC published the proposed position in the Federal Register for
comment (61 FR 1608, dated January 22, 1996). NRC is now publishing the
entire final position, together with its responses to the comments
received.
FOR FURTHER INFORMATION CONTACT: Dominick A. Orlando, Division of Waste
Management, Office of Nuclear Material Safety and Safeguards, Mail Stop
TWFN 8F-37, U.S. Nuclear Regulatory Commission, Washington, DC 20555,
Telephone (301) 415-6749.
SUPPLEMENTARY INFORMATION:
Disposition of Cesium-137 Contaminated Emission Control Dust and Other
Incident-Related Materials; Branch Technical Position
A. Introduction
Emission control (baghouse) dust and other incident-related
materials (e.g., clean-up materials or recycle process streams)
contaminated with \137\Cs 1 are currently being stored as mixed
radioactive and hazardous waste at several steel company sites across
the country. At any single site, this material typically contains a
total \137\Cs quantity ranging downward from a little more than 1 curie
(Ci) or 37 gigabecquerels (GBq) of activity, distributed within several
hundred to a few thousand tons of iron/zinc-rich dust, as well as
within much smaller quantities of clean-up or dust-recycle, process-
stream materials. In current situations, most, but not all, of this
material would be classified as mixed waste and this technical position
is intended as a potential disposition alternative for this incident-
related material.2
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\1\ The byproduct material \137\Cs does not include the \137\
Cs, from global fallout, that exists in the environment from the
testing of nuclear explosive devices (see Footnote 3).
\2\ The term, ``incident-related material,'' is frequently used
in this position to refer to the total spectrum of \137\Cs-
contaminated materials resulting from an inadvertent melting event.
Because of its widespread use in radioactive devices and its
volatility when subjected to steel melting temperatures, the
position is directed solely at incident-related materials involving
this radioisotope.
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Typically, the radioactivity is not evenly distributed among the
incident-related materials. Rather, a small fraction (e.g., one-tenth)
of the material contains most (e.g., 95 percent) of the radioactivity.
Most of the material contains a small quantity of radioactivity at low
concentrations and makes up most of the mixed waste, incident-related
material volume. This material is classified as hazardous waste under
RCRA because it contains lead, cadmium, and chromium which are common
to the recycle metal supply. The \137\Cs contamination of this
hazardous waste results from a series of three principal events: (1)
The loss of control of a radioactive source by an NRC or an Agreement
State licensee; (2) the inclusion of the source within the recycle
metal scrap supply used by the steel producers; and (3) the inability
to screen out the radioactive source as it progresses along the typical
scrap collection-to-melt pathway (including radiation detectors used at
most furnaces, foundries and many ferrous metal recycling facilities).
Consequently, irrespective of the quantity or concentration of the
radioactivity, most of the current material is subject to joint
regulation as mixed waste under RCRA and the Atomic Energy Act of 1954,
as amended, or the equivalent law of an Agreement State.
[[Page 13177]]
The disposal options for these materials, specifically the large
volumes of material with the lower concentrations of \137\Cs, have been
limited because of their ``mixed-waste'' classification and the costs
associated with the disposition of large volumes of mixed or
radioactive waste. Long-term solutions addressing the control and
accountability of licensed radioactive sources are being considered by
NRC and Agreement States. Solutions addressing the disposition of mixed
wastes are being considered by various Federal and State regulatory
authorities and the U.S. Department of Energy. Nevertheless, the
Commission believes that, pending decisions on improved licensee
accountability and the ultimate disposition of mixed waste, appropriate
disposal of the existing incident-related, mixed-waste material is
preferable to indefinite onsite storage.
As a result, this technical position defines the bases that the NRC
staff would find acceptable for: (1) Authorizing a licensee, possessing
\137\Cs-contaminated emission control dust and other incident-related
materials (e.g., the steel company or its service contractor), to
transfer treated \137\Cs-contaminated material, below levels specified
in this position, to a Subtitle C, RCRA-permitted hazardous waste
disposal facility; and (2) not licensing the possession and disposal of
these incident-related materials by the RCRA-permitted disposal
facility. The position does not address disposal at a Subtitle D
facility. Because of its radioactivity (i.e., \137\Cs concentration
levels), some of the incident-related material may not be suitable for
disposal at a Subtitle C, RCRA-permitted disposal facility. This
material may be disposed of either: (a) at a licensed low-level
radioactive waste disposal facility after appropriate treatment of its
hazardous constituents; or (b) at a mixed-waste disposal facility, if
applicable acceptance criteria are met.
The regulatory basis for the action is found at 10 CFR
20.2001(a)(1) and 20.2002. The first paragraph authorizes a licensee to
dispose of licensed material as provided in the regulations in 10 CFR
Parts 30, 40, 60, 61, 70, or 72. Paragraph 30.41(b) states the
conditions under which licensees are allowed to transfer byproduct
material. Paragraph 30.41(b)(7) of Part 30 specifically provides that
licensees may transfer byproduct material if authorized by the
Commission, in writing. In the case of the \137\Cs-contaminated
material, the licensing action under 10 CFR 20.2002 would constitute
the written authorization required by paragraph 30.41(b)(7).
It should be noted that additional acceptance requirements, beyond
those covered in this NRC position for disposal of \137\Cs-contaminated
incident-related waste at a Subtitle C RCRA-permitted disposal
facility, may be established by: (1) An Agreement State; (2) the permit
conditions or policies of the RCRA-permitted disposal facility; (3) the
regulatory requirements of the RCRA disposal facility's permitting
agency; or (4) other authorized parties, including State and local
governments. These requirements may be more stringent than those
covered in the guidance described in this technical position. The
licensed entity transferring the \137\Cs-contaminated incident-related
materials must consult with these parties, and obtain all necessary
approvals, in addition to those of NRC and/or appropriate Agreement
States, for the transfers defined in this technical position. Nothing
in this position shall be or is intended to be construed as a waiver of
any RCRA permit condition or term, of any State or local statute or
regulation, or of any Federal RCRA regulation. The position applies to
both hazardous and non-hazardous incident-related waste as specifically
defined. In addition, the conditions established in this position
pertain to NRC staff and licensee actions. Therefore, in those
instances where an Agreement State is the sole regulatory authority for
the radioactive material, the Agreement State has the option of using
this guidance in reviewing requests for the disposal of the material.
B. Discussion
Over the past decade, there has been an increasing number of
instances in which radioactive material has been inadvertently
commingled with scrap metal that subsequently has entered the steel-
recycle production process. If this radioactive material is not removed
before the melting process, it could contaminate the finished metal
product, associated dust-recycle process streams, equipment
(principally air effluent treatment systems), and the dust generated
during the process. Some of the contaminant radioactivity is a result
of naturally occurring radionuclides that are deposited in oil and gas
transmission piping. Other radioactivity may be associated with
radioactive sources that are contained in industrial or medical
devices. In this latter case, the commingling of the radioactive source
with metal destined for recycling can occur if the regulatorily
required accountability of these sources fails and a radioactive source
is included within the metal scrap supply used by the steel producers.
In cases where the radionuclide is naturally occurring, or is already
present in the environment as a result of global fallout, the
inadvertent melting of a radioactive source could increase the
contaminant concentration above that caused by these background
environmental levels.3
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\3\ In a letter to William Guerry, Jr. from NRC's Executive
Director for Operations, James M. Taylor, dated May 25, 1993, NRC
made a preliminary determination that \137\Cs levels in baghouse
dust can reasonably be attributed to fallout from past nuclear
weapons testing, if concentrations are less than about 2 pCi/g
(0.074 Bq/g).
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Although many of the steel producers have installed equipment to
detect incoming radioactivity, this equipment cannot provide absolute
protection because of the shielding of radioactive emissions that may
be provided by uncontaminated scrap metal or the shielded ``pig'' that
contains the radioactive source. Of special concern, because of the
nature and magnitude of the involved radioactivity, are NRC- or
Agreement State-licensed sources containing \137\Cs.
When \137\Cs sources are inadvertently melted with a load of scrap
metal, a significant amount of the \137\Cs activity contaminates the
metal-rich dust that is collected in the highly efficient emission
control systems that steel mills have installed to comply with air
pollution regulations. Because of hazardous constituents--specifically
lead, cadmium, and chromium--EAF emission control dust is a listed
waste, KO61, which is subject to regulation under RCRA. If this dust
becomes contaminated with \137\Cs, the resulting material is classified
as a mixed waste. Emission control dust, generated immediately after
the melting of a \137\Cs source with the scrap metal, can contain
cesium concentrations in the range of hundreds or thousands of
picocuries per gram (pCi/g) or a few to a few tens of becquerels (Bq)
per gram of dust, above typical levels in dust caused by \137\Cs in the
environment (e.g., 2 pCi/g or 0.074 Bq/g). Several thousand cubic feet
(several tens of cubic meters) of dust could be contaminated at these
levels. Dust generated days or weeks after a melt of a source
(containing hundreds of millicuries or a few curies of \137\Cs
(37 GBq)) will contain reduced concentrations, typically
less than 100 pCi/g (3.7 Bq/g).
Even after extensive decontamination and remediation activities,
newly generated dust may still contain concentrations greater than 2
pCi/g (0.074 Bq/g) background levels, but generally less than 10 pCi/g
(0.37 Bq/g). When the melting of a source is not immediately detected,
materials related
[[Page 13178]]
to downstream processes have also been contaminated with relatively low
concentrations of \137\Cs (e.g., 10 pCi/g (0.37 Bq/g)). In addition,
materials used during decontamination may also be contaminated with
dust containing \137\Cs concentrations at similar levels above
background.
As the result of past inadvertent meltings of \137\Cs sources, a
number of steel producers possess a total of about 10,000 tons (9000
metric tons) of incident-related materials, most of which contains
\137\Cs concentrations of less than 100 pCi/g (3.7 Bq/g). This material
is typically being stored onsite because of the lack of disposal
options that are considered cost-effective by the steel
companies.4 It is the disposition of material at these
concentration levels that is the subject of this technical position.
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\4\ In April 1995, Envirocare of Utah, Inc., an operator of a
mixed-waste disposal site, received authorization from the State of
Utah and initiated operations to treat and dispose of \137\Cs-
contaminated incident-related (mixed-waste) materials at
concentrations not exceeding 560 pCi/g (20.7 Bq/g).
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C. Regulatory Position
General
Because of the ``incident-related'' origin of the \137\Cs-
contaminated materials, the Commission has approved a course of action
that includes: (1) Exploration of approaches to improve licensee
control and accountability to reduce the likelihood of sealed sources
entering the scrap metal supply; (2) cooperation with the steel
manufacturers and other appropriate organizations to identify the
magnitude and character of the problem (with particular emphasis on
improving the capability to detect sealed sources before their
inadvertent melting); and (3) development of interim guidelines for the
disposal of \137\Cs contaminated dust and other incident-related
materials (the subject of this technical position).
Specific
Bases for Allowing Transfer and Possession of 137Cs-Contaminated,
Incident-Related Material
The bases for allowing transfer and possession of \137\Cs-
contaminated emission control dust and other incident-related
materials, under the provisions of existing regulations, are as
follows: (1) Any person at a Subtitle C, RCRA-permitted disposal
facility involved with the receipt, movement, storage, or disposal of
contaminated materials should not receive an exposure greater than 1
millirem (mrem) or 10 microsievert (Sv) per year (i.e., one-
hundredth of the dose limit for individual members of the public as
defined at 10 CFR 20.1301(A)(1)), above natural background levels;
5; (2) members of the general public in the vicinity of storage or
disposal facilities should not receive exposures and no individual
member of the public should be likely to receive a dose greater than 1
mrem (10 Sv) per year above background as a result of any and
all transfers and disposals of contaminated materials; (3) handling or
processing of the contaminated materials, undertaken as a result of its
radioactivity, should not compromise the effectiveness of permitted
hazardous waste disposal operations; (4) treatment of contaminated
materials must be accomplished by persons operating under a licensee's
radiation protection program (note that the licensee can be the steel
facility or the entity that treats the incident-related material,
either on- or offsite); and (5) transportation of contaminated
materials will be subject to U.S. Department of Transportation (DOT)
regulations and, as applicable, transportation of contaminated,
hazardous materials must be performed by hazardous material employees,
as defined in DOT regulations (49 CFR Part 172, Subpart H).
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\5\ The use of 1 mrem/yr (10 Sv/yr) has no significance
or precedential value as a health and safety goal. It was selected
only for the purpose of analysis of the levels at which the
referenced materials could be partitioned to allow the bulk of the
material to be transferred to unlicensed persons. It does not
represent an NRC position on the generic acceptability of dose
levels. Such levels are established only by rule.
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Definition of Contaminated Materials and Initial Incident Response
A melting event generally necessitates extensive decontamination
and remediation operations at the EAF or foundry (e.g., replacing
refractory bricks and duct work). Subsequent operations include the
proper interim handling and management (e.g., accumulation and
containment) of emission control dust and other incident-related
contaminated materials. Based on a review of several recent incidents,
the dust may contain \137\Cs concentrations up to hundreds or thousands
of pCi/g (a few to a few tens of Bq/g), whereas the other generally
limited-volume, incident-related materials typically contain lower
concentrations. As a result, the initial clean-up and collection/
treatment/packaging of the contaminated emission control dust and other
materials at the EAF or foundry must be performed by an NRC or
Agreement State licensee operating under an approved radiation
protection program. The licensee is also responsible for compliance
with other regulatory requirements (e.g., those of the Occupational
Safety and Health Administration and RCRA Treatment Permitting
requirements).
Provisions for Disposal at a Subtitle C, RCRA-Permitted, Disposal
Facility
Once the decontamination/remediation and collection/treatment/
packaging activities have been completed, one of two paths may be
followed for the disposal of the incident-related materials, dependent
on \137\Cs-concentration levels and whether the final land disposal
operation involves the burial of packaged or unpackaged materials.
1. Packaged Disposal of Treated Waste
On this disposal path, contaminated materials must be treated
through stabilization to comply with all EPA and/or State waste
treatment requirements for land disposal of regulated hazardous
waste.6 The treatment operations must be undertaken by either: (i)
The owner/operator of the EAF or foundry (licensed by NRC or
appropriate Agreement State to possess, treat, and transfer \137\Cs-
contaminated, incident-related materials); or (ii) an NRC- or Agreement
State-licensed service contractor (operating either on- or offsite).
Based on the radiological impact assessment provided in Appendix A, the
licensee could be authorized by NRC or an Agreement State to transfer
the treated incident-related materials to a Subtitle C, RCRA-permitted,
disposal facility, provided that all the following conditions are met:
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\6\ For non-hazardous material covered by this position,
stabilization equivalent to that provided for hazardous waste would
be necessary.
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(a) The \137\Cs-contaminated emission control dust and other
incident-related materials are the result of an inadvertent melting of
a sealed source or device;
(b) The emission control dust and other incident-related materials
have been stabilized to meet requirements for land disposal of RCRA-
regulated waste, and have been stored (if applicable) and transferred
in compliance with a radiation protection program as specified at 10
CFR 20.1101;
(c) The total \137\Cs activity, contained in emission control dust
and other incident-related materials to be transferred to a Subtitle C,
RCRA-permitted, disposal facility, has been specifically approved by
NRC or the appropriate Agreement State(s) and does not exceed the total
activity associated with the inadvertent melting incident.
[[Page 13179]]
Moreover, NRC or the appropriate Agreement State will maintain a public
record of the total incident-related \137\Cs activity, received by the
facility over its operating life, to ensure that the total disposed of
\137\Cs activity does not exceed 1 curie (37 GBq); 7
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\7\ The 1-curie (37-GBq) value represents a reasonable maximum
bounding activity, associated with several incidents, that could be
transferred to an RCRA-permitted facility under the provisions of
this position. It also represents a quantity that would be less than
the activity disposed of over the operating life of the RCRA-
permitted facility if the facility routinely disposed of non-
incident-related emission control dust containing background
concentrations of \137\Cs.
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(d) The RCRA disposal facility operator has been notified in
writing of the impending transfer of the incident-related materials and
has agreed in writing to receive and dispose of the packaged materials;
8
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\8\ The NRC staff believes the contract between the licensed
facility and the RCRA facility operator is an appropriate vehicle
for complying with this provision, provided that the contract
specifies the volume of waste, the radionuclide and its average
concentration in the waste in picocuries per gram or becquerels per
gram, the total aggregated amount of radioactive material in the
shipment, the hazardous waste code of the waste, and the EPA
identification number of the RCRA disposal facility receiving the
waste. The NRC staff will evaluate requests for license amendments
to transfer incident-related material based upon the licensee
demonstrating that the RCRA disposal facility operator has agreed to
the transfer and has made provisions to retain the information about
the radioactive material in the waste, along with the information
that is required to be retained by the RCRA facility operator under
40 CFR 263.22.
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(e) The licensee providing the radiation protection program
required in paragraph (b), notifies, in writing, the Commission or
Agreement State(s) in which the transferor and transferee are located,
of the impending transfer, at least 30 days before the transfer;
(f) The stabilized material has been packaged for transportation
and disposal in non-bulk steel packagings as defined in DOT regulations
at 49 CFR 173.213. (Note that this is a condition established under
this technical position and is not a DOT requirement. Under DOT
regulations, material with concentrations of less than 2000 pCi/g (74
Bq/g) is not considered radioactive);
(g) In any package, the emission control dust and other incident-
related materials, that have been stabilized and packaged as defined in
(b) and (f) above, contain pretreatment average concentrations of
\137\Cs that did not exceed 130 pCi/g (4.8 Bq/g) of material; 9
and
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\9\ The 130 pCi/g (4.8 Bq/g) value is the concentration, based
on the analysis in the appendix and including a regulatory margin of
1.5, that would result in a calculated potential exposure of less
than 1 mrem (10 Sv). The disposal of incident-related
materials in packaged form allows compliance with this position to
be demonstrated through measurement of \137\Cs concentrations, as
well as direct radiation levels external to the package.
Notwithstanding the redundant approaches to ensure compliance with
the exposure criterion, the regulatory margin of 1.5 has been
included in determining the acceptable measurables defined in the
position.
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(h) The dose rate at 3.28 feet (1 meter) from the surface of any
package containing stabilized waste does not exceed 20 rem per
hour or 0.20 Sv per hour, above background.10
\10\ At this exposure rate, for the exposure period as defined
in the appendix, total exposure would not exceed 1 mrem (10
Sv) with a regulatory margin of 1.5.
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Note that, in defining the pretreatment \137\Cs-concentration value
stated in paragraph (1)(g), a factor of 1.5 has been included as a
regulatory margin. This factor adds further assurance to the certainty
in protection provided by the licensee's: (1) Sampling of \137\Cs
concentrations in contaminated materials; (2) measurements of dose rate
external to the disposal (and transportation) packagings; and (3) other
assumptions included in the radiological impacts assessment.
2. Disposal of Unpackaged (i.e., Bulk) Treated Waste
On this disposal path, contaminated materials must also be treated
through stabilization to comply with all EPA and State waste treatment
requirements for land disposal of RCRA-regulated hazardous
waste.11 The treatment operations must be undertaken by either (i)
the owner/operator of the EAF or foundry (licensed to possess, treat,
and transfer 137Cs-contaminated, incident-related materials), or
(ii) a licensed service contractor. Based on the radiological impact
assessment provided in the appendix, the licensee could be authorized
to transfer the stabilized incident-related materials to a Subtitle C,
RCRA-permitted, disposal facility, provided that all the following
conditions are met. (Note that conditions (a) through (e) are identical
to those applicable to packaged disposal of treated waste):
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\11\ See footnote 6.
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(a) The 137Cs-contaminated emission control dust and other
incident-related materials are the result of an inadvertent melting of
a sealed source or device;
(b) The emission control dust and other incident-related materials
have been stabilized to meet requirements for land disposal of RCRA-
regulated waste, and have been stored (if applicable), and transferred
in compliance with a radiation protection program as specified at 10
CFR 20.1101;
(c) The total 137Cs activity, contained in emission control
dust and other incident-related materials to be transferred to a
Subtitle C, RCRA-permitted, disposal facility, has been specifically
approved by NRC or the appropriate Agreement State(s) and does not
exceed the total activity associated with the inadvertent melting
incident. Moreover, NRC or the appropriate Agreement State will
maintain a public record of the total incident-related 137Cs
activity, received by the facility over its operating life, to ensure
that the total disposed of 137Cs activity does not exceed 1 curie
(37 GBq); 12
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\12\ See footnote 7.
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(d) The RCRA disposal facility operator has been notified in
writing of the impending transfer of the incident-related materials and
has agreed in writing to receive and dispose of these materials;
13
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\13\ The NRC staff believes the contract between the licensed
facility and the RCRA facility operator is an appropriate vehicle
for complying with this provision, provided that the contract
specifies the volume of waste, the radionuclide and its average
concentration in the waste in picocuries per gram or becquerels per
gram, the total aggregated amount of radioactive material in the
shipment, the hazardous waste code of the waste and the EPA
identification number of the RCRA disposal facility receiving the
waste. The NRC staff will evaluate requests for license amendments
to transfer incident-related material based upon the licensee
demonstrating that the RCRA disposal facility operator has agreed to
the transfer and has made provisions to retain the information about
the radioactive material in the waste along with the information
that is required to be retained by the RCRA facility operator under
40 CFR 263.22.
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(e) The licensee providing the radiation protection program
required in paragraph (b) notifies, in writing, the Commission or
Agreement State(s) in which the transferor and transferee are located,
of the impending transfer, at least 30 days before the transfer; and
(f) The emission control dust and other incident-related materials,
that have been stabilized as defined in (b) above, contain pretreatment
average concentrations of 137Cs that did not exceed 100 pCi/g (3.7
Bq/g) of material.14
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\14\ The 100 pCi/g (3.7 Bq/g) value is the concentration, based
on the analysis in the appendix and including a regulatory margin of
2, that would result in a calculated potential exposure of less than
1 mrem (10 Sv). The disposal of incident-related material
in unpackaged (bulk) form dictates that compliance with this
position would be demonstrated through measurement of 137Cs
concentrations. Without the redundant approach to ensure compliance
with the exposure criterion inherent with the packaged-disposal
approach (see footnote 8), the regulatory margin, included in
determining the acceptable measurables defined in the position, has
been increased to 2.0.
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Note that, in defining the pretreatment 137Cs-concentration value
in paragraph (2)(f), a factor of 2 has been included as a regulatory
margin. The factor adds further assurance to the certainty of
protection provided by the licensee's: (1) Sampling of 137Cs
concentrations in
[[Page 13180]]
contaminated materials; and (2) other assumptions included in the
radiological impacts assessment.
Treatment, Storage, and Transfer of Emission Control Dust or Other
Incident-Related Materials with 137Cs Concentrations
Indistinguishable From Background Levels (i.e., 2 pCi/g (0.074 Bq/g) or
Less)
The EAF or foundry licensed to possess and transfer 137Cs-
contaminated emission control dust, or a licensed service contractor,
is authorized to transfer emission control dust and other incident-
related materials as if they were not radioactive, provided that the
137Cs concentration within the emission control dust and other
incident-related materials is 2 pCi/g (0.074 Bq/g) of material or less.
The foundry or licensed service contractor must determine the
137Cs concentration using the sampling program discussed below.
Aggregation of 137Cs-Contaminated Emission Control Dust and Other
Incident-Related Materials
If applicable, aggregation of 137Cs-contaminated emission
control dust and other incident-related material, before stabilization
treatment, is acceptable if performed in compliance with a radiation
protection program, as described at 10 CFR 20.1101, and provided that:
(1) Aggregation involves the same characteristic or listed
hazardous waste and the wastes must be amenable to and undergo the same
appropriate treatment for land-disposal restricted waste;
(2) Aggregation does not increase the overall total volume nor the
radioactivity of the incident-related waste; and
(3) Materials, when aggregated, are subjected to a sampling
protocol that demonstrates compliance with 137Cs-concentration
criteria on a package-average 15 basis.
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\15\ The term package, as used here, refers to packages used by
the licensee to transfer the material to the disposal facility,
irrespective of whether this package is also the disposal container.
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Determination of 137Cs Concentrations and Radiation Measurements
137Cs concentrations may be determined by the licensee by
direct or indirect (e.g., external radiation) measurements, through an
NRC- or Agreement State-approved sampling program. The sampling program
must be sufficient to ensure that 137Cs contamination in the
stabilized emission control dust and in other incident-related
materials, on a package-average basis, is consistent with the
concentration criteria in this technical position. The sampling program
must provide assurance that the quantity of 137Cs in any package
(see footnote 15) does not exceed the product of the applicable
concentration criterion times the net weight of contaminated material
in a package.
Appendix A--Assessment of Radiological Impact of Disposal of
137Cs-Contaminated Emission Control Dust and Other Incident-
Related Materials at a Subtitle C RCRA-Permitted Disposal Facility
1. Background
In the normal process of producing recycled steel, scrap steel
is subjected to a melting process. In this process, most impurities
in the scrap steel are removed and generally contained within
process-generated slag or off-gas. Typically, the off-gas carries
dust, that can contain iron and zinc, together with certain heavy
metals, through an emission control system to a ``baghouse,'' where
the dust is captured in ``bag-type'' filters. Hazardous constituents
within the dust, principally lead, cadmium, and chromium, can cause
the U.S. Environmental Protection Agency (EPA) to designate the dust
as a hazardous waste, under the Resource Conservation and Recovery
Act (RCRA)--often as the listed waste K061.
Typically, when the scrap consists largely of junk automobiles,
the dust contains a high percentage (greater than 20 percent) of
zinc, which can be a valuable recovery product. Moreover, the zinc
recovery process produces slag and other byproducts that have
recycle potential. If economic (e.g., low zinc content) or process
considerations preclude these recycle options, the dust may be
treated and disposed of in a hazardous waste disposal facility. EPA
has specified treatment standards for the various hazardous
constituents of the dust in 40 CFR 268.40. Solidification is the
treatment process typically used to meet these standards. On the
other hand, dust from steel production at basic oxygen furnaces and
open hearth furnaces is excluded from regulation as hazardous waste
(40 CFR 261.4(b)(7)(xvii)).
Because the recycling of steel involves the addition of natural
materials (primarily lime and ferromanganese), very low levels of
radioactivity, ubiquitous in the environment, are involved in the
production process. One of these radionuclides is cesium-137
(\137\Cs) which now occurs in the environment as a result of global
fallout from past weapons-testing programs. \137\Cs has a 30-year
half-life (i.e., a quantity of this radionuclide and its associated
radioactivity will decrease by half every 30 years). The decay of
\137\Cs and its very short-lived daughter produces emissions of beta
particles and gamma rays.
The principal hazard from the beta particles can only be
realized when it enters the human body. The principal hazard from
the gamma rays is as an external source of penetrating radiation
similar to the type of exposure received from an X-ray. Because of
its volatility in the very high-temperature (typically 3000 degrees
fahrenheit or 1650 degrees celsius) steel-making
process, \137\Cs is volatilized and transported in the furnace off-
gas and, as it condenses, becomes a constituent of the emission
control (baghouse) dust. Normal background \137\Cs concentrations in
dust have been measured at picocurie per gram levels (0.024 to 1.23
pCi/g) 1 or thousandths of a becquerel per gram (Bq/g). This
concentration is consistent with the general range of background
levels measured in soils within the United States whereas
concentrations of 10 pCi/g (0.37 Bq/g) are relatively common in
drainage areas.2 As a result of this information, the U.S.
Nuclear Regulatory Commission has determined that \137\Cs
concentrations in emission control dust below 2 pCi/g (0.074 Bq/g)
can be attributed to fallout from past weapons testing.3
---------------------------------------------------------------------------
\1\ A picocurie is one-trillionth of a curie and represents a
decay rate of one disintegration every 27 seconds or 1/27 of a
becquerel.
\2\ Letter to William Lahs, U.S. Nuclear Regulatory Commission,
from Andrew Wallo III, U.S. Department of Energy, dated May 20,
1993.
\3\ Letter from James M. Taylor, NRC, to William Guerry, Jr.,
Collier, Shannon, Rill, and Scott, dated May 25, 1993.
---------------------------------------------------------------------------
2. Statement of Problem
The inadvertent melting of a licensed \137\Cs sealed source with
scrap steel at an electric arc furnace (EAF) or foundry typically
results in the contamination of the steel producer's emission
control system and the generation of potentially large quantities
(e.g., of the order of 1000 tons or 900 metric tons) of \137\Cs-
contaminated emission control dust. Facility cleanup operations will
produce an additional quantity of contaminated material and,
depending on the effectiveness of cleanup operations, further
generation of contaminated dust or cleanup-related materials can
occur. Furthermore, if the occurrence of the melting event is not
immediately detected, contamination can unknowingly be carried
forward with the dust into zinc-recovery process streams. In one
case, for example, this has led to \137\Cs contamination of the
zinc-rich, splash condenser dross residue, referred to as SCDR
material. In the incidents to date, total quantities of these
contaminated materials have not exceeded 2000 tons (1800 metric
tons) per event. The \137\Cs concentration in all these materials
can vary, but in typical past events, much of the material is
contaminated at levels ranging from 2 pCi/g (0.074 Bq/g) to a few
hundred pCi/g (most below approximately 100 pCi/g or 3.7 Bq/g).
Smaller volumes (typically less than 5 percent of the total volume)
have included concentrations at nanocurie/gram levels (thousands of
pCi/g or a few tens of Bq/g).
The intent of this analysis is to characterize the potential
radiological impacts associated with the alternative options for
disposal of \137\Cs-contaminated emission control dust and other
incident-related materials at a Subtitle C, RCRA-permitted facility.
Because RCRA hazardous wastes must be treated to comply with the
requirements for land disposal of restricted waste, the potential
radiological impacts associated with treatment processes required
consideration. To protect against these radiological impacts, the
position includes the provision that treatment of \137\Cs-
contaminated emission control dust and other incident-related
[[Page 13181]]
materials be performed by an NRC or Agreement State licensee. The
licensee would operate, either on- or offsite, under an approved
radiation protection program, as well as any required RCRA treatment
permit. Such controls are necessary because of the wide range of
contaminated materials and their physical forms, together with the
variability in EPA-approved treatment processes. Under this
decision, the Subtitle C, RCRA-permitted disposal facility would be
receiving the emission control dust and other incident-related
materials after their treatment to stabilize the incident-related
material. This stabilized material would be, or would be equivalent
to, the form necessary to stabilize the RCRA-hazardous constituents
(specifically, lead, cadmium, and chromium); that is, a non-
dispersible,4 solid (e.g., cement-type) form. As a result, the
potential radiological hazard from the ``treated'' (stabilized)
material during disposal operations is associated with its
characteristic as an external source of radiation.
---------------------------------------------------------------------------
\4\ In the context used, the term ``non-dispersible'' means that
any radiological impacts from resuspended material are
inconsequential in comparison to the impacts from direct external
exposures resulting from the emission of gamma radiation in the
\137\Cs decay process.
---------------------------------------------------------------------------
After disposal, \137\Cs could only become a hazard through water
pathways if a sufficient quantity and concentration of \137\Cs were
to: (1) Become available, (2) be leached from its solid form, (3) be
released from the disposal facility, and (4) enter a drinking water
supply. No significant radiological hazard would be expected to
result from inadvertent intrusion into the disposed of waste after
facility closure. Notwithstanding the hazard to the intruder from
the hazardous waste constituents, or other hazardous wastes,
constraints placed on the total \137\Cs activity and concentration,
and the waste form, can ensure that radiological exposures would not
exceed those that would be received from residing over commonly
measured background \137\Cs concentrations in the United States (see
discussion under ``Intruder Considerations'').
The following analyses will therefore be directed at an
evaluation of the potential direct, water pathway, and intruder
hazards and will provide a perspective on their significance.
3. Direct Exposure
After the inadvertent melting of a \137\Cs sealed source at an
EAF or foundry, the relatively volatile \137\Cs will leave the
furnace as an offgas and be commingled with the normal emission
control dust. As a result, concentrations of \137\Cs contained in
this dust (and other materials associated with furnace clean-up
operations or subsequent dust recycle process streams) will
increase. Thus, the rate of radiological exposure from this material
will be similar in type, but different in magnitude, than that
received from the typical background levels of \137\Cs. Any change
in magnitude of the exposures to workers at the disposal facility
from this contaminated material when compared to the exposure
received from typical emission control dust would depend on: (1)
Differences in \137\Cs concentrations; (2) variations in the
physical/chemical properties of the materials disposed of; and (3)
changes in worker time-integrated interactions with contaminated
materials.
The three key variables above are particularly important in the
development of this technical position. Of significance to all three
variables, the approach defined in the position calls for treatment
(stabilization) of incident-related materials (to comply with
requirements for land disposal of restricted waste) to take place
``under license,'' at the location where the material was generated,
or at the site of a service contractor who has been permitted for
stabilization treatment of the material either on or off the steel
company site. Complying with the ``Treatment Standards for Hazardous
Wastes,'' defined at 40 CFR 268.40, will result in a solid waste
form from which exposure rates will be smaller than those
originating from the hazardous waste form (e.g., dust) before
treatment. More importantly, treatment of the contaminated
materials, under license, will obviate the need to specifically
address potential treatment-related radiological exposures at
unlicensed, RCRA-permitted, treatment facilities. Thus, under the
approach of this technical position, any minimal exposure to workers
who have not been trained in radiation safety would be limited to
disposal operations.
Furthermore, because the origin of the \137\Cs-contaminated
materials is the result of a melting incident, upper-bound values
can be established for the volume, weight, radioactive material
concentration, and total activity of the contaminated material, on
an incident basis. The base case analysis in this appendix presumes
that the contaminated material involves a volume of 40,000 cubic
feet (1132 cubic meters), a weight of 2000 tons (1800 metric tons),
and a total activity content of less than a 1 curie (Ci) or 37 GBq
of \137\Cs. These values are generally consistent with the
particulars from the incidents that have occurred to date.
Within these constraints, the starting point in the direct
exposure calculation is to estimate the radiation dose rate at a
distance of 3.28 feet (1 meter) from the surface of a semi-infinite
volume (i.e., infinite in areal extent and depth from the point of
exposure) of solidified contaminated material.5 The
calculations assume that the initial \137\Cs contamination in all
untreated dust is 100 pCi/g (3.7 Bq/g). Direct exposure results
scale linearly for other concentration levels, if the waste
configuration is unchanged.
---------------------------------------------------------------------------
\5\ This assessment is generally consistent with the approach
employed in ``Risk Assessment of Options for Disposition of EAF Dust
Following a Meltdown Incident of a Radioactive Cesium Source in
Scrap Steel,'' SELA-9301, Stanley E. Logan, April 1993.
---------------------------------------------------------------------------
Stabilization treatment,6 conducted under a licensed
radiation protection program, is achieved by mixing moist dust with
additives (e.g., liquid reagent to adjust oxidation potential and
portland cement/ fly ash).7 These additives (typically presumed
to add 30 parts by weight to 100 parts of dust or contaminated
material) would result in a solidified product that would contain
\137\Cs concentrations at about 77 percent of initial concentrations
(e.g., 77 pCi/g (2.84 Bq/g)). Because of allowable variations in the
solidification processes (e.g., from the production of granularized
aggregate to solidified monoliths), the bulk density of the
solidified material can range from about 1.4 to 2.5 g/cm3. A
representative dose [rate] conversion factor 8 under these
conditions (calculated at a density of 1.5 g/cm3) would
typically be less than 49 microem/hour (rem/hr) or 0.49
microsieverts/hour (Sv/hr), at a distance of 3.28 feet (1
meter) from the surface of a hypothetical semi-infinite volume of
the solidified material.\9\
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\6\ In the context of this position, stabilized treatment does
not include either onsite or offsite high-temperature metals
recycling processes.
\7\ This treatment may include the addition of special
stabilization reagents, such as clays, or involve other RCRA-
approved stabilization technologies, that reduce the leachability of
\137\Cs, although the radiological impacts analysis indicates that
such processes are not necessary to protect public health and
safety, and the environment.
\8\ A dose conversion factor represents a value that allows a
radionuclide contamination level to be converted to an estimated
exposure rate.
\9\ The dose rates in this appendix have been calculated through
use of the Microshield computer program, Grove Engineering, Inc.,
version 4.2, 1995. The value of 49 rem (0.49Sv)/
hour represents 0.77 of the 62.9 value shown on Figure 1.
---------------------------------------------------------------------------
Because the quantities of treated dust and other incident-
related materials are not semi-infinite in volume, the actual dose
rate/distance relationships from finite volumes of contaminated
materials will be less. The reduction can be calculated for various
volumetric sources through the use of shape factors. Shape factors
have been calculated for several configurations that are likely to
occur during operations from the time the contaminated treated
material is received at the RCRA-permitted disposal facility through
its disposal. The shape factors can be determined from Figures 1
through 6 for various distances between a specific source
configuration and an exposed individual. Typically, at a distance of
3.28 feet (1 meter), these factors range from about 0.03 to 0.5
(Figures 1 through 5), and have been calculated without accounting
for the limited shielding provided by any packaging. As the distance
from the contaminated materials increases to 9.84 feet (3 meters),
the shape factors for these similar geometries become smaller,
ranging from about 0.004 to 0.2. The largest, likely dose rate
potentially experienced by an individual involved in the disposal
process, measured at 3.28 feet (1 meter), would be from the sides of
large containers or shipments of contaminated materials, and would
be expected to range from about 10 to less than 14 rem/hour
(0.14 Sv/hr) above background (typically 8 to
12rem/hr (0.08 to 0.12 Sv/hr).10 From an open
trench (Figure 4), filled with
[[Page 13182]]
contaminated materials, the calculated dose rate would also be
somewhat less than 13 rem/hr (0.13 Sv/hr) measured
directly over the trench at a 3.28 feet (1 meter) distance. Again,
these values represent 0.77 of the respective values indicated on
the figures because of solidification additives. Figures 6 and 7,
respectively, show the variation in dose rate with the width of the
trench and depth of the waste. Figure 8 is provided to show the
change in dose rate versus the distance offset from the side of the
trailer-type container considered in Figure 3.
---------------------------------------------------------------------------
\10\ The two-thirds loading of the 30-cubic yard box is related
to the typical maximum payload weight that can be transported by
truck without an overweight permit. If the boxes referred to in
Figures 1 and 2 were full, the dose rate would increase by less than
a factor of 1.5. Similarly, if the assumed additive weight percent
(i.e., 30 percent) is varied over a reasonable range from 20 to 40
percent, the resulting dose rate would change in an inversely
proportional manner.
---------------------------------------------------------------------------
A typical disposal rate at a trench within an RCRA-permitted
facility would generally exceed 500 tons (450 metric tons) per
shift.11 Assuming this disposal rate of 500 tons (450 metric
tons) per shift applies to the disposal of treated,137Cs-
contaminated, incident-related material (approximately 20 to 25
truckloads in 8 hours), it would require approximately 4 times this
period of time to dispose of 2000 tons (1800 metric tons). (Note
that the rate of arriving material would likely be dictated by
transportation arrangements, so that the 32 hours required to
dispose of the contaminated material could be spread over several
days or weeks.) Facility workers, therefore, would, on average, only
be exposed to finite volumes of contaminated material for a maximum
period of 32 worker-hours. Applying the highest likely dose rate
(approximately 13 rem/hr (0.13 Sv/hr) from the
side of a trailer containing the contaminated materials), and
presuming exposure at a 3.28-ft (1-meter) distance for the entire
32-hour period, a worker would receive a dose of less than 0.5 mrem
(5 Sv) above background.
---------------------------------------------------------------------------
\11\ Note that if treatment at an RCRA-permitted facility were
required, the limiting operational handling rate for the treated
materials may be limited to 100 to 200 tons (90 to 180 metric tons)
per shift.
---------------------------------------------------------------------------
Qualitatively descriptive time and motion data gathered from
three RCRA-permitted disposal facilities indicate that the above-
calculated dose is conservative for two principal reasons: (1) The
workers having the most significant exposure to materials, from
receipt to disposal, are effectively at greater distances than 3.28
feet (1 meter); and (2) their exposure, at this distance, is over
time periods significantly less than the assumed receipt through
disposal time period of 32 hours. As a result, actual exposures are
expected to be significantly less than 0.5 mrem (5 Sv).
This conservative estimate of potential exposure is based on the
aforementioned time-distance assumptions and is expected to bound
reasonable interactions of disposal facility workers with the
stabilized incident-related materials. For example, incident-related
material could be stored at the disposal site or samples of the
treated material could be subjected to sampling activities. In the
first case, if a 90-day storage period is presumed, the average
exposure distance over the entire period needed to ensure a dose
less than the position's exposure criteria would be on the order of
10 to 20 meters (see Figures 1 through 3, which illustrate the
decrease in dose rate as a function of distance from the source). In
the second case, the typical activity in a 100-g sample would be no
greater than about 10-2 Ci (370 Bq). The dose rate
from such a sample would be less than 0.1 rem/hr (0.001
Sv/hr) at a distance of 1 foot (0.3 meters).
To place the significance of this calculation into perspective,
an estimate can be made of worker exposure from the presumed
handling, treatment, and disposal of normal emission control dust
(i.e., dust that has not been contaminated with 137Cs from a
melted source). This dust would contain background levels of
137Cs (approximately 1 pCi/g (0.037 Bq/g)). Therefore, a worker
interacting with this material at an effective distance of 3.28 feet
(1 meter) over about 300 8-hour shifts (a little more than a working
year) would receive a total maximum exposure of about 0.5 mrem (5
Sv). The magnitude of this exposure is in the same range as
the exposure calculated for the disposal of the contaminated
materials from a single melting event. Moreover, the potential
exposure from the ``melting event'' was estimated under the
extremely conservative assumption that all materials were
contaminated at levels of 100 pCi/g (3.7 Bq/g).
The imposition of a 1-Ci (37-GBq) criterion on the total
incident-related activity that could be disposed of at any one
Subtitle C, RCRA facility (see following discussion on water-pathway
considerations) should further ensure that worker exposures from
137Cs-contaminated emission control dust and other incident-
related materials will not exceed 1 mrem/year (10 Sv/year)
integrated over the lifetime of the facility.
4. Water-Pathway Considerations
The proposed approach to manage 137Cs-contaminated emission
control dust and other incident-related materials presumes licensee
treatment of these materials to comply with requirements for land
disposal of restricted waste. Thus, the radiological, and
potentially hazardous chemical constituents of these materials, will
be incorporated into a stable, solid (e.g., cement-type) form,
similar to that required for routine RCRA-permitted disposal of
emission control dust. As a result, the possibility of 137Cs
presenting a hazard through a water pathway requires consideration
of: (1) the quantity of 137Cs available; (2) the degree to
which the 137Cs could be leached from its waste matrix; and (3)
the extent that any leached 137Cs could migrate into a water
supply.
The disposal of 137Cs in treated emission control dust and
other incident-related materials would be constrained by this policy
to a total activity of 1 Ci (37 GBq). In the previous reference-
basis analysis, an effective concentration, in the treated waste, of
77 pCi/g (2.84 Bq/g) was evaluated--the originally assumed
contaminated material concentration reduced by 30 percent as a
result of the added mass associated with treatment. Both the
quantity and position-defined concentration values place bounds on
any potential water pathway hazard. In the actual wastes that are
subject to potential disposal under the provisions of this position,
the concentration of 137 Cs averaged over all the treated waste
would typically be significantly less than the defined concentration
criteria.
Furthermore, because the 137Cs is contained in a solid
matrix and buried within a facility in which the amount of water
infiltration is minimized, any 137Cs removal from its final
disposal location would be limited while these conditions remain in
effect. The chemistry of any water interacting with the solidified,
137Cs-contaminated waste would also be expected to limit the
leaching process (e.g., avoidance of acidic environments), because
of the controlled nature of the Subtitle C, RCRA-permitted disposal
site and the types and nature (e.g., no liquids) of the wastes
accepted for disposal. Any water that leached 137Cs from the
waste would normally be collected in a leachate collection system at
volumetric concentrations expected to be far less than those
existing in the treated waste. The chemistry of the fill materials
used at the disposal site could also provide a sorbing medium if any
137 Cs leached from the solidified waste. Finally, the location
of Subtitle C, RCRA-permitted disposal sites is such that the source
of any water supply would typically be some distance from the
disposal site.
These chemistry and distance factors are also likely to be major
factors in delaying the arrival of 137Cs at a receptor well
because of retardation effects. This retardation, in terms of its
effect on the time required, under a worst-case scenario, for the
137Cs to reach a water supply, is such that significant
radioactive decay of the 137Cs inventory is likely (the
radioactive half-life of 137Cs is 30 years) before the
137Cs could potentially reach the water supply.
Although qualitative in nature, and based on considerations that
can vary among Subtitle C, RCRA-permitted disposal sites, the
previous discussion has focused on the factors that are likely to
prevent any significant water-pathway hazard. The following, more
quantitative assessment, is provided to conservatively bound any
water-pathway hazard that could potentially occur under extremely
unlikely conditions.
The leachability of 137Cs from any solid waste form that
complies with the land disposal restrictions for the waste's non-
radiological hazardous constituents is likely to be extremely
limited after initial waste placement. After the end of operations
and a post-closure care period of 30 years, a worst-case scenario
presumes that processes take place to degrade the site so that
infiltrating water from the surface passes unimpeded through the
contaminated waste. In predicting the dissolution of 137Cs
under these conditions, a critical process is the partitioning of
the 137Cs that takes place between the waste, soil, and
infiltrating water. Conservatively assuming that the partitioning
from the solid waste form is similar to that from the interstitial
backfill soil to water, an estimate can be made of the amount of
137Cs that can leach into the infiltrating water.
The most important parameter in estimating this transfer, as
well as the subsequent movement of the 137Cs in groundwater, is
the distribution coefficient, ``Kd.'' This parameter expresses
the ratio at equilibrium of 137Cs sorbed onto a given weight of
soil particles to the amount
[[Page 13183]]
remaining in a given volume of water. The higher the value of the
distribution coefficient, the greater the concentration of
137Cs remaining in the soil. The Kd value can be affected
by factors such as soil texture, pH, competing cation effects, soil
porewater concentration, and soil organic matter content.12 For
the non-acidic, sand/clay/soil environments presumed to represent
the RCRA-permitted disposal facilities, a Kd value of 270
milliliter (ml)/g was selected from the Footnote 12 reference as
being appropriate for the subsequent bounding, conservative
analysis.
---------------------------------------------------------------------------
\12\ ``Default Soil Solid/Liquid Partition Coefficients,
Kds, for Four Major Soil Types: A Compendium,'' M. Sheppard and
D. Thibault, Health Physics, Vol. 59, No. 4, October 1990, pp. 471-
482.
---------------------------------------------------------------------------
To model the potential groundwater impacts, the RESRAD 13
code was used. For the representative case, the bounding 40,000
cubic feet (ft \3\) or 1132 cubic meters (m3) of treated
material were presumed to be disposed of in a volume measuring 100-
ft (30.4-m) length x 20-ft (6.09-m) width x 20-ft (6.09-m)
depth. All this material was assumed to contain a 137Cs
concentration of 77 pCi/g (2.84 Bq/g). Notwithstanding the actual
layouts of Subtitle C, RCRA-permitted facilities, a well was
presumed to be located and centered at the downgradient edge of this
specific volume of waste. To maximize the hazard as calculated by
the RESRAD model, the hydraulic gradient was considered to be
parallel to the length of the disposed volume of material.
Infiltration representative of a humid site was presumed and a
minimal unsaturated zone thickness of 3.28 ft (1 m) was assumed to
separate the contaminated zone from the saturated zone. The value
assigned to Kd in the unsaturated zone was 270 ml/g.
Assessments beyond this representative case evaluation are
subsequently discussed.
---------------------------------------------------------------------------
\13\ RESRAD, Version 5.0, Argonne National Laboratory, September
1993.
---------------------------------------------------------------------------
The results from this bounding analysis indicate that drinking
water dose rate would be insignificant (e.g., far less than a
microrem (10-2 Sv) per year). This result is not
surprising because the retardation provided, even in the 3.28-ft (1-
m) deep unsaturated zone and the saturated zone, is sufficient to
preclude drinking water doses for almost 700 years. During this
period, the activity of 137Cs would decay (i.e., be reduced by
radioactive decay) by a factor of about 10 million.
Note that, although it is considered an unrealistic scenario,
the drinking of the leachate directly from the disposal trench after
a period of 30 years would only result in a calculated exposure of
about 7 mrem/year (70 Sv/year).14
---------------------------------------------------------------------------
\14\ This dose estimate is based on comparing leachate
concentrations with the water effluent concentration in 10 CFR Part
20, Appendix B.
---------------------------------------------------------------------------
To consider the effects of a range of parameters, including
other Kd values, on the results of this bounding analysis, the
following analyses are presented. Based on the typical existing
volumes and 137Cs concentrations of incident-related materials,
the imposition of a constraint on 137Cs concentration
effectively bounds the total activity that could be disposed of at a
Subtitle C, RCRA-permitted facility, from a single steel company
site, to a few tens of millicuries (a few GBq).15 Material at
higher concentrations would require disposal at either a mixed-waste
disposal facility or a licensed low-level waste disposal site. Thus,
for the potential disposals at the Subtitle C, RCRA-permitted site
to approach the 1-Ci (37-GBq) incident-related material constraint
in this position, disposals of materials from several incidents
would have to occur. The total volume of material, in this case,
would still represent only a small fraction of an RCRA-permitted
facility's disposal capacity. Repeating the RESRAD analysis
discussed above under these assumptions, but respectively
considering lower Kd values in the contaminated, unsaturated,
and saturated zones, would still result in drinking water doses of
less than 1 mrem (10 Sv) per year unless the Kd values
in all zones approach single-digit values. Even in these cases
(e.g., Kd equal to 2.7), separation of the hypothesized well
location from the disposed material by about 328 feet (100 meters)
would reduce dose rates below 1 mrem (10 Sv) per year
because of the decay of 137 Cs brought about by the increased
retardation times.
---------------------------------------------------------------------------
\15\ For example, the total activity contained in 2000 tons
(1800 metric tons) of material, contaminated at a level of 77 pCi/g
(2.84 Bq/g), would be about 0.14 curies (5.2 GBq). It would be
unlikely that all the material from a particular incident would be
at the maximum concentration defined in the technical position.
---------------------------------------------------------------------------
The concentration constraints in this position, coupled with the
limited number of inadvertent melting situations to which this
position could be applicable, and the case-by-case NRC or Agreement
State approval of the proposed material transfers, are believed to
provide a sufficient basis to ensure protection of public health and
safety, and the environment from water-pathway considerations.
Nevertheless, to provide further protection, should a single
Subtitle C, RCRA-permitted disposal facility accept incident-related
material from more than one incident, the position includes a total
incident-related 137 Cs activity constraint of 1 Ci (37 GBq).
The magnitude of this constraint is based on the typical bounding
activity associated with an inadvertent melting of 137 Cs
sources that have occurred to date at EAFs or foundries. In large
measure, it has been included to provide assurance that the position
is only directed at the ultimate disposition of radioactive material
that exists in the environment as a result of specific inadvertent
melting incidents. However, it also provides a constraint on the
extent of volumetric contamination as a function of concentration.
The practical effect, as previously alluded to, is to limit the
disposal volumes of incident-related contaminated materials to a
small fraction of total disposal site capacity for hazardous waste.
As a result of this volumetric limit, the constraint would further
ensure that any exposures occurring offsite over the operating life
of the Subtitle C, RCRA-permitted facility would be equal to or less
than 1 mrem/year (10 Sv/year), if integrated over the
facility's operating life.
Again, the activity constraint and the water pathway
considerations can be placed in perspective by evaluating the
potential normal disposal of EAF emission control dust at a Subtitle
C, RCRA-permitted facility. If this dust includes a background
137Cs concentration of 1 pCi/g (0.037 Bq/g), and the facility
can treat 200 tons (180 metric tons) of dust per day, the total
quantity of 137Cs disposed of annually would be about 50 mCi
(1.85 GBq). Thus, over a facility operating period of about 20
years, the total quantity of 137Cs disposed of could equal the
1-Ci (37 GBq) incident-related material activity constraint.
5. Intruder Considerations
In the development of its licensing requirements for land
disposal of radioactive waste in 10 CFR Part 61, NRC considered
protection for individuals who might inadvertently intrude into the
disposal site, occupy the site, and contact the waste. In the
context of this position, this possibility has been considered
although the greater risk to the intruder would likely result from
the non-radiological hazardous constituents at the site.
In the intruder scenarios applied in the development of NRC's
LLW standards, 16 an inadvertent intruder was assumed to dig a
3-m (9.9-ft) deep foundation hole for construction of a house. The
top 2 m (6.6 ft) of the foundation were assumed to be trench cover
material and the bottom 1 m (3.28 ft) was assumed to be waste. Based
on the details of the scenarios, which included these and other
considerations, the intruder interacted with material whose
concentration had been reduced from the waste concentration by a
factor of 10. Presuming similar scenarios and assuming intrusion
occurs immediately after a post-closure care period of 30 years, the
intruder would be exposed to a 137Cs concentration of about 4 pCi/g
(0.15 Bq/g); that is, 77 pCi/g (2.84 Bq/g) reduced by the factor of
10 and an additional factor of 2 to account for radioactive decay).
Even for this worst-case situation in which all the incident-related
waste was presumed to have initial 137Cs concentrations of 77 pCi/g
(2.84 Bq/g), the projected intruder exposure would range from 0.8 to
3.8 mrem (8 to 38 Sv/year).17 As noted above, the
average concentrations over large volumes of incident-related
material would be expected to be far less than 77 pCi/g (2.84 Bq/g).
---------------------------------------------------------------------------
\16\ See NUREG-0782, Vol. 4, Draft Environmental Impact
Statement on 10 CFR Part 61, ``Licensing Requirements for Land
Disposal of Radioactive Waste,'' September 1981.
\17\ These estimates are based on the concentration to dose
conversion values in NUREG-1500, ``Working Draft Regulatory Guide on
Release Criteria for Decommissioning: NRC Staff's Draft for
Comment,'' August 1994. Appropriate adjustments of the tabulated
information were made to reflect the occupancy and shielding
assumptions made in NUREG-0782 (see Footnote 16).
---------------------------------------------------------------------------
6. Conclusions
These bounding analyses indicate that some significant volume of
137Cs-contaminated emission control dust and other incident-
related materials from an inadvertent melting of a sealed source can
be disposed of at a Subtitle C, RCRA-permitted
[[Page 13184]]
facility with negligible impacts to public and worker health and
safety and the environment. This method for disposal, if implemented
according to the limitations stipulated in this position, is very
unlikely to cause worst-case exposures that exceed 1 mrem (10
Sv) to any worker at the disposal facility or to any member
of the public in the vicinity of the facility. The design,
operations, and post-closure activities that take place at Subtitle
C, RCRA-permitted facilities will ensure that radiological impacts
from 137Cs will also be negligible in future timeframes. Proper
disposal of these materials would protect public health and safety,
and the environment to a greater degree than the alternative of
indefinitely storing these materials at a steel company facility.
The calculated public health and safety and environmental impacts of
disposition of specified incident-related materials at a Subtitle C,
RCRA-permitted facility can also be used to determine an optimum
course for disposal, if disposition alternatives exist.
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BILLING CODE 7530-01-C
[[Page 13193]]
Analysis of and Response to Comments on Staff Technical Position
``Disposition of Cesium-137 Contaminated Emission Control Dust and
Other Incident-Related Material''
On January 22, 1996, the Nuclear Regulatory Commission published
a proposed technical position on the disposition of Cesium-137
(137Cs) contaminated emission control dust and other incident-
related materials in the Federal Register (61 FR 1608). Comments
were solicited and, in response, 22 comment letters were received.
These comment letters included: six from State nuclear safety, human
resources, environmental conservation, and health offices; five from
the steel industry (three from industry associations); four from
hazardous waste disposal facility operators; one from a mixed-waste
disposal facility operator; two from other industry associations;
two from environmental groups; one from a member of the public; and
one from a member of Congress. These letters raised a number of
issues ranging from policy and legal concerns to specific comments
on the conservatisms in the position's supporting radiological
assessments. The responses to these submitted comments have been
grouped into the following categories: (1) Position justification,
precedence, and relationship to ``below regulatory concern'' (BRC)
policy considerations and constraints; (2) regulatory approach
(i.e., rulemaking versus technical position) and the implementation
process; (3) legal considerations; (4) related health, safety, and
environmental concerns; (5) technical considerations; (6) other
issues; and (7) clarifications.
1. Justification, Precedence, and Relationship to BRC
a. Comment: The comments on the justification issue were
intertwined with several other issues. Basically, however, the
comments from the steel and other industries (associations), three
States, the Subtitle C, hazardous waste facility operators, and the
Congressman supported the disposal concept, proposed in the
position, as a necessary adjunct to a regulatory program that should
improve licensee control of the devices, whose inadvertent meltings
have caused the problem. They believe that the position is safe,
environmentally sound, and cost-effective, and a reasonable
alternative to disposal at the existing mixed-waste disposal
facility (available since April 1995 for disposal of the subject
waste). These commenters, plus those from the disposal facility
operators, expressed the view that there was a serious lack of
competition in the business of disposing of mixed waste, resulting
in unacceptably high disposal costs. Several of these commenters,
including one State, suggested that the disposal costs could affect
the financial viability of certain facilities.
Comments from two of the States, the environmental groups, the
member of the public, and the mixed-waste disposal facility operator
stated that the justification (or combined justification and
regulatory approach) for the position was weak, with most
emphasizing the conflict with the current policy on, and approach
to, mixed-waste disposal. One State and the mixed-waste disposal
facility operator noted that the time, effort, and resources
expended to effect mixed-waste disposal at the existing facility
will be undermined by the precedent being established in the
position. The disposal facility operator also believed that the
position relied on unsubstantiated economic assumptions and
assertions, which NRC had accepted at face value without any
independent investigation, and that the justification had changed
with position development from a public-health to a cost-effective
rationale. This commenter also stated the belief that the position
was not in the public's interest because of potential exposures to
transportation workers, members of the public, and Subtitle C
facility workers. One of the environmental group commenters stated
that saving a few cents per ton of steel may not be in the public's
best interests.
a. Response: Because the subject disposition option was being
proposed in the form of a ``permissive'' technical position (i.e.,
an option, likely requiring multiple approvals, that would be
initiated by a request from an NRC or Agreement State licensee on a
case-by-case basis) and not a rule, the broad policy justification,
stated in the Federal Register notice (61 FR 1609, column 1) was as
follows: ``NRC believes that disposal, under the provisions of the
position or other acceptable alternatives (emphasis added), is
preferable to allowing this mixed waste to remain indefinitely at
steel company sites.'' Another acceptable alternative referred to in
the Federal Register notice (61 FR 1610, column 3) is the mixed
waste disposal facility operated by Envirocare of Utah. As the
footnote indicated, this facility received authorization to accept
the subject waste at concentrations not exceeding 560 picocuries
(pCi)/gram (g) (20.7 becquerel (Bq)/g) during April 1995, after the
work on the technical position was initiated. With the availability
of this facility, the NRC staff believes its aforementioned public
health justification became enmeshed with cost considerations, as
described below.
Notwithstanding the availability of the mixed-waste disposal
facility option, which has been used by several steel facilities
with 137Cs-contaminated, incident-related material, other steel
companies did not consider this option cost-effective. Contrary to
the commenter's statement, NRC staff did contact the industry, as
well as the mixed-waste and Subtitle C disposal facility operators,
to comprehend the possible cost differentials of the disposal
alternatives. Although contractual privacy and market considerations
prevented exact determination, NRC staff concluded that the
differential costs between the mixed-waste and Subtitle C disposal
options could be significant. In fact, the comment letters from the
mixed-waste disposal facility operator and the Subtitle C facility
operators appear to confirm this assessment. But whatever the actual
cost differences may be for specific situations, the process, as
envisioned in the potential use of the position, would identify the
cost differentials, if any, in the environmental assessment that
would support any decision to implement the position's disposition
alternative (One State commenter stated that it should be made clear
that an environmental assessment, under the National Environmental
Policy Act, would be required for each disposal). The significance
of any cost differential could be judged by appropriate regulatory
authorities, in their selection of the most reasonable and proper
disposal alternative (e.g., whether saving a few cents per ton of
steel is in the public interest).
In its decision to pursue what, the Commission believes, is a
health-protective and environmentally sound disposition alternative,
the Commission also considered the origin of the radioactive source
melting problem (a problem being addressed under a separate NRC
program) and the significant efforts of the steel industry to detect
incoming radioactive material. In the Commission's view, these
factors provided further justification for its ongoing actions.
Thus, although the Commission is aware of the substantial efforts,
time, and resources expended by all parties involved in the
licensing of the mixed-waste disposal facility, the Commission's
primary focus is to achieve ultimate disposition of the incident-
related material. The Commission believes that the real or imagined
cost differentials, from lack of competition or other causes, may be
resolved through issuance of the position, and lead to a resolution
of the disposal problem. The Commission has coordinated its actions
with the U.S. Environmental Protection Agency (EPA) and believes it
has the support of EPA in the position, at this proposal stage.
The potential exposures to workers and members of the public are
addressed in the responses to comments 3.a. and 4.f.
b. Comment: Two State commenters, the mixed-waste disposal
facility operator, the environmental group commenters, and the
member of the public raised concerns about the precedent-setting
nature of the technical position. By establishing a ``default''
value for 137Cs in incident-related material, it was questioned
why a similar argument could not be made for 137Cs in soil, or
some other radionuclide in another medium. It was further pointed
out that the cumulative effect of similar actions would need to be
addressed. An environmental group commenter opposed the creation of
exemptions that could be used by others, specifically the Department
of Energy, as applicable or relevant and appropriate requirements,
in settings for which the drafters of the [position] did not intend
or anticipate. The member of the public claimed a possible
relationship to issues involving disposals from the U.S. Enrichment
Corporation.
Commenters from the steel and other industry associations
supported the position as a proper precedent, and suggested that
other circumstances could justify similar actions. It was pointed
out, for example, that although Basic Oxygen Furnaces (BOFs) also
process scrap and are subject to the same kinds of incidents as
Electric Arc Furnaces, BOF dust may be neither a listed hazardous
waste nor a characteristic hazardous waste. It was suggested that
the position be clarified regarding its applicability to the
potential
[[Page 13194]]
disposal of 137Cs-contaminated BOF material and incident-
related material that may not be classified as mixed waste. Another
industry commenter questioned whether the position would apply to a
steel producer who is not an NRC or Agreement State licensee. This
same commenter questioned what approach would be used for meltings
involving other radionuclides, and whether the position could not be
broadened to other industries that have large volumes of mixed
waste. In a broader sense, a few of these commenters applauded NRC
and EPA efforts to minimize dual regulation of mixed waste.
b. Response: The Commission strongly believes that broad-based
exemptions, or creation of specific positions outside of established
policies, should be implemented through the rulemaking process. In
fact, efforts to provide the technical analyses to support a broad
recycle rulemaking, that would include consideration of incident-
related material, are underway. However, under its specific
regulations, cited in the technical position, the Commission can,
and has, in case-by-case determinations, approved actions that it
believes are in the best interests of public health and safety and
protection of the environment. In the case of this ``permissive''
technical position, NRC is putting forward a disposition option,
whose implementation and approval can be considered by applicable
regulatory authorities and others. The advantages and disadvantages
of alternatives would be addressed in appropriate environmental
assessments that would accompany license amendment requests, and the
choice would require acceptance by various regulatory authorities
and others, and would be contingent on State laws and permit
conditions.
The Commission believes the precedent being suggested, in this
case, is reasonable and proper, based on the circumstances and the
justification, as described in 1.a. above. The disposition option,
however, applies only to disposals at Subtitle C facilities; only to
treated (stabilized) 137Cs-contaminated, incident-related
material (inclusive of material that may not be classified as mixed
waste) that constitutes the greatest part of the problem; and only
to companies, or their service contractors, that will treat the
incident-related material, under NRC or Agreement State license, to
meet the land disposal requirements that would apply if the material
contained hazardous constituents. This last provision was considered
necessary to avoid the difficult task of generically defining bounds
on the potential radiological exposures that could occur during
treatment or disposal, and could involve consideration of inhalation
and ingestion, as well as direct exposure pathways.
With regard to other possible situations for which this position
may be considered a precedent, such as the disposal of BOF material,
the Commission believes these situations should be judged on their
own merit. Any interactions among combined actions would require
consideration, as one of the State commenters pointed out. The staff
is also aware of EPA interests, identified in its proposed Hazardous
Waste Identification Rule, and has encouraged EPA efforts to
identify mixed wastes that may be regulated as low-level radioactive
waste (LLRW), outside of Resource Conservation and Recovery Act
(RCRA) regulations. The response to comment 2 is also pertinent to
the question of developing a broader technical position. The staff
has had no interactions with U.S. Enrichment Corporation issues that
affected development of this position.
c. Comment: Several commenters either requested clarification on
the relationship of this position to BRC policy or stated their
belief that the position contravenes public law.
c. Response: In 1992, in response to the Commission's
publication of a BRC policy statement in 1990, Congress, in Public
Law 102-486, Energy Policy Act of 1992, stated that the [BRC] policy
shall have no effect. The BRC policy basically stated the bases that
the Commission would apply to determine if broad practices should be
considered for exemption from regulatory control. The NRC staff does
not believe that the subject technical position is a BRC policy for
the following reasons: (1) The technical position is a
``permissive'' guidance statement, basically stating Commission
views on safe implementation of existing regulations on licensed
material disposal in 10 CFR Part 20; (2) the position specifically
``directs'' the disposal to a regulated disposal entity, and
includes approval, notification, and total activity provisions that,
the staff believes, are inconsistent with the concept of BRC; (3)
the position is narrow in scope (i.e., directed at specific
material, caused by specific circumstances); and (4) if implemented,
the actions under the position are consistent with other case-by-
case determinations made by the Commission.
2. Regulatory Approach and the Implementation Process
Comment: Although related to the BRC issue discussed above, a
State commenter questioned why, if the proposal is sound in
protecting public health and safety, the regulatory approach is a
technical position, as opposed to a rulemaking--the latter providing
a broader review process. Another State commenter believed NRC
should define the ``life expectancy'' of the guidelines in the
technical position. Industry comments generally supported the
technical position as the approach needed to address a real problem
in a timely manner, as opposed to a rulemaking that would be very
time-consuming. They believe the steel companies should not be put
in the middle of a political tug-of-war over appropriate
administrative procedures to follow, given that the position has
been made available for public scrutiny in a manner similar to a
proposed rule.
Response: As referred to in 1.b. above, NRC staff intends to re-
address the Subtitle C-disposal option, proposed in the technical
position, in conjunction with a broad recycle rulemaking. At that
time the need to broadly address disposal options will be revisited.
However, because this rulemaking is in an early development stage,
with finalization unlikely in the next couple of years, and because
of the desirability of properly disposing of specific incident-
related material in a timely manner, the Commission directed that
the staff should work with EPA to develop interim guidelines and
associated technical bases. This is the process that has been
followed to date. The guidelines proposed in the technical position
would be in effect until this rulemaking is finalized.
To address the concern of the State commenter regarding a
broader review process, the staff has not only worked with EPA, but
has made early versions of the position available directly to a
number of affected parties and States. The Commission's intentions
were openly discussed and the early versions of the position,
together with early exchanges of views, were placed in NRC's public
document room. The staff published the proposed technical position
in its entirety in the Federal Register to obtain the broader review
that the commenter suggests. Furthermore, contrary to interpretation
of one commenter, NRC is not asserting the adoption of the technical
position as a matter of Agreement State compatabilty. In fact,
recognizing the likely involvement of many parties, if the
position's alternative is implemented, the staff's intent was that
this wide review and approval could be helpful in gaining general
understanding and acceptance of the merits of the proposed
alternative. Case-by-case reviews and approvals of individual
applications to use the position's disposal approach will still be
necessary even with the final technical position in place.
3. Legal Considerations
a. Comment: In several comment letters from the States and a
Subtitle C disposal facility operator, and in staff discussions with
other Subtitle C disposal facility representatives, it was pointed
out that the legal applicability of the technical position's
disposal alternative, in specific States, could be determined by how
the incident-related material is defined. If the waste were defined
as LLRW, requiring disposal as specified in the Low-Level Waste
Policy Amendments Act of 1985, the disposal alternative described in
the position could be precluded, absent an appropriate change to
State law or regulations, or permit conditions. One State commenter
stated that, if the treated incident-related material is considered
contaminated ash, it would be subject to permit and manifesting
requirements.
Another State commenter pointed out that State LLRW regulations
require demonstration that design, operation, and closure of any
class of LLRW facility ensure protection against inadvertent
intrusion and provide for an institutional control period. There was
concern about States being open to lawsuits if the incident-related
material were considered LLRW and if the aforementioned provisions
were not addressed. The mixed-waste disposal facility operator
pointed out that Subtitle C facilities are not required to have
radiation training programs. Another State commenter questioned the
differences that would exist between the Subtitle C and mixed waste
disposal facility requirements and their rationale, in the context
of the position.
a. Response: In the ``Regulatory Position'' text in Section C,
the waste that could be
[[Page 13195]]
transferred to the Subtitle C disposal facility was described as
incident-related material, and was not referred to as low-level
radioactive waste. In developing the proposed position, this was not
a decision based on legal considerations, but the terminology
selected to best characterize the waste, in a technical position
whose principal purpose was to demonstrate, through a conservative
assessment, the minimal radiological significance of the proposed
disposal option. It was recognized, however, that State laws and
permit conditions would need to be satisfied, and that numerous
approvals may be required, including those of appropriate State
regulatory bodies and the disposal facility operator.
Among other provisions, implementation of the disposal option
proposed in the position: (1) Involves a licensee's request and
regulatory approvals on a case-by-case basis pursuant to 10 CFR
20.2002; (2) includes notification and disposal-site operator-
approval provisions; and (3) includes accounting of the single and
total incident-related material received at a Subtitle C disposal
site. As a result, the position does not allow a licensee to dispose
of the incident-related material as if it were not radioactive, a
concept that applies only to disposal of certain wastes defined in
NRC regulations at 10 CFR 20.2005(a). Instead, if the provisions of
the position are followed, including the specific provision for
disposal at a Subtitle C facility, the position provides a basis for
disposing of incident-related material at a site other than one
specifically licensed for disposal of low-level radioactive waste.
Furthermore, although not taking a position on what LLW disposal
requirements could be reasonably applied to the disposal of this
incident-related material at a Subtitle C hazardous waste disposal
facility, the staff did specifically address groundwater and
intruder considerations. Groundwater and intruder assessments were
provided to allow others to judge the significance of these
scenarios and the need for additional regulatory provisions
(including radiation protection training). NRC staff has concluded
that, with the constraints provided in the position, specific
regulatory actions (e.g., groundwater monitoring for \137\Cs,
intruder barriers, institutional controls beyond those applicable to
Subtitle C disposal facilities) directed at these scenarios are not
necessary.
The NRC staff has also concluded that the position's dose
criterion, and the conservative assessment of allowable \137\Cs
concentrations, obviates the need for radiation protection training
for the Subtitle C facility workers. In this regard, the staff would
point out that the material defined by the technical position would
not be considered radioactive, for transportation purposes, under
the U.S. Department of Transportation's (DOT's) regulations. In
fact, the concentration criteria in the position are a factor of
about 20 less than the value used by DOT to define radioactive
material.
b. Comment: Two State commenters pointed out that the position
does not address specific permitting provisions pertaining to dust
treatment to meet land disposal requirements for the dust's
hazardous constituents. One of these commenters stated that NRC
cannot assume sole jurisdiction for [hazardous] waste treatment, if
such treatment were conducted at the steel company sites.
b. Response: The commenter is correct. The position calls for
compliance with RCRA land disposal requirements. In the situations
being addressed, the NRC staff believes appropriate RCRA authorities
may approve various options for carrying out the treatment of the
incident-related material. Therefore, only a general statement of
compliance was included in the technical position. The staff
acknowledges and agrees with the comment regarding NRC's
jurisdiction over hazardous waste treatment, no matter where
conducted. This would be an issue for the State-permitting agencies
or EPA to decide. In essence, the presumption in the position is
that the Subtitle C disposal facility would be disposing of waste
that had been treated under applicable RCRA requirements.
4. Related Safety, Health, and Environmental Concerns
a. Comment: An environmental group, a State commenter, and the
member of the public suggested that the best approach to solve the
problem is a better accounting of the sources causing the incidents,
and more rigorous regulation appears warranted. The suggestion was
made that worker exposure at the foundries should be a principal NRC
concern. As indicated in the discussion in comment 1.a., the steel
industry commenters also strongly requested NRC action to improve
accountability.
a. Response: The Commission, in its directions to the staff on
October 18, 1994, approved several concurrent courses of action. One
of these has led to the development of the proposed position, while
another has led to an Agreement State-NRC Working Group that is
developing recommendations to address the accountability issue. The
Working Group has held several meetings and a workshop, and
recommendations were sent to the Commission in late 1996. The NRC
staff is in the process of evaluating the NRC/Agreement States
Working Group's recommendations for increased control over, and
accountability for, devices containing radioactive material. Once
the NRC staff completes its evaluation, it will submit an action
plan to the Commission outlining measures to improve control over,
and accountability for, devices. Thus, the Commission agrees with
the commenter's worker safety and ``front-end'' concerns but,
recognizing that incident-related material currently exists, and
future incidents may not be prevented with 100 percent confidence,
believes the ``back end'' of the problem also requires Commission
action.
b. Comment: A State and an environmental group commenter viewed
the policy, in its granting of a ``regulatory exemption'' for the
incident-related waste, as counterproductive to the desire to
improve detection capabilities at the steel facilities. Three
industry commenters, one who responded directly to the State view,
pointed out that the steel company facilities have installed state-
of-the-art radiation-detection capabilities at considerable expense,
not to meet any regulatory requirement, but to reduce the likelihood
of experiencing the consequences of inadvertent-melting events that
result in significant shutdown, cleanup, and disposal costs, as well
as the possibility of incident-related exposures to plant personnel.
Furthermore, these detection systems have been coupled with
comprehensive scrap inspection programs.
b. Response: Although the policy provisions may require NRC or
appropriate Agreement States to not require licensing of the
Subtitle C facility for the radioactive material, the main feature
of the policy is the NRC determination that the incident-related
material can be transferred, under existing regulations (10 CFR
20.2001 and 20.2002), from a licensed to an unlicensed entity. The
position not only provides a conservative NRC assessment of the
radiological impacts of the disposal alternative, but also evaluates
certain hypothetical situations to provide a frame of reference for
the calculated impacts. Contrary to the connotation, ``regulatory
exemption,'' used by the commenters, NRC staff does not consider the
proposed position to be an exemption action, but an assessment that
could allow case-by-case decisions on incident-related material
disposals under current regulations (also see response 1.c.).
The staff also believes that this policy has no impact on a
steel company's selection of ``source'' detection capabilities. The
costs associated with shutdown (downtime) and cleanup alone can
exceed millions of dollars, far in excess of the costs of effective
detection systems and programs.
c. Comment: The environmental group commenters and the mixed-
waste disposal facility operator suggested that the position could
lead the steel companies to continue operations after a melting for
the purpose of generating additional contaminated dust in sufficient
volume to meet the position's concentration criteria. A State
commenter stated that this issue should be addressed. The mixed-
waste disposal facility operator postulated other abuses (e.g., the
mixing of other regulated waste with [incident-related] material)
and asked whether prevention measures were being proposed.
c. Response: The staff believes that the cost disincentives
alone are sufficient to consider the former suggestion unreasonable.
For example, the dilution necessary at one of the facilities with
this material, such that all the contaminated material would comply
with the position's criteria, would be about a factor of 5. The
costs of disposing of this increased volume at a Subtitle C
facility, even with an optimistic estimate of disposal costs, could
reach millions of dollars. The staff would note that its development
of this position has been enmeshed with cost-effective
considerations because of the real or imagined excessive
differential costs of the disposal alternatives. Furthermore, based
on the operation of the steel facilities' emission control systems,
with their dust-collection systems, the staff can not conceive of a
scenario that would allow real time comprehension of the extent of
the contamination or total quantity of \137\Cs involved in an
incident.
[[Page 13196]]
With regard to the question of protective measures, the staff
believes the NRC, Agreement State(s), permitting agencies, or the
Subtitle C disposal facility operator could, if warranted, require
or strongly recommend testing requirements to address any concerns
on disposal of unauthorized radioactive material. The NRC staff
believes that a licensee's measurement and sampling program, as
approved by NRC or the Agreement State, will be sufficient to
preclude unauthorized radioactive material disposals.
d. Comment: An environmental group commenter stated that the
concentration criteria in the position appear to be inconsistent and
less strict than criteria imposed by EPA on mill tailings at 40 CFR
Part 192. The mixed-waste disposal facility commenter questioned the
position's comparisons with environmental 137Cs concentrations.
The member of the public claimed the proposal would exempt 10 times
the amount of material that would have been exempted under the BRC
policy.
d. Response: The staff presumes that reference is being made to
the 5 and 15
pCi/g or 135 and 405 Bq/g remedial action criterion for radium=226
(\226\ Ra) in soil. These are criteria that would apply to soil that
could be released for unrestricted use. The concentrations in the
position are those for material that would be disposed of at a
hazardous waste disposal facility. Because radium is about 2.5 times
more hazardous from a direct exposure standpoint than 137Cs,
the position's bounding 137Cs values for Subtitle C facility
disposal are only about 3 to 4 times a value that would be found
acceptable for unrestricted release. In fact, the typical incident-
related material at under 20 pCi/g (540 Bq/g) would be within the
criteria range cited and applicable to unrestricted release
situations. Note also that the position contains a total-quantity
criterion which is not a part of the 40 CFR Part 192 regulations.
The comparison referred to by the mixed-waste disposal facility
commenter was between ``much of the mixed waste'' that contains
concentrations below 20 pCi/g (540 Bq/g). This concentration was
being compared with actual environmentally measured concentrations
of 11 and
12 pCi/g (6300 Bq/g) and statistically-predicted concentrations (95
percent value of distribution) up to 19 pCi/g (513 Bq/g). The
reference in footnote 13 of the final technical position is the
source of these values.
The staff was not certain about the intended context of the
comment from the member of the public, but has presumed it is
related to other issues addressed in the response to this comment,
comment 1.a., 4.e., or 4.f..
e. Comment: The mixed-waste disposal facility operator, among
others, suggested that the position, if adopted, may have adverse
health, safety, and environmental consequences. One issue involved
the disposition of higher-activity material that would not be
covered by the position's criteria. The commenter cites an example
where the 137Cs concentration, if averaged over all the
incident-related material, could be 551 pCi/g (14,900 Bq/g)--[below
the acceptance criteria at the mixed waste facility]. If the
material with concentrations below the position's values is disposed
of under the position's provisions, the commenter asks what would be
the disposition of the higher concentration material and, if it
remains onsite, would this violate NRC's intent in promulgating the
position.
In a somewhat related comment, a State questioned whether
material delisted from hazardous material regulations, and meeting
the concentration values in the position, could be disposed of at a
Subtitle D facility.
e. Response: For incident-related material remaining after
``position-allowed-'' and economically feasible blending of
contaminated material, the staff is aware of only one disposition
option at this time (see 61 FR 1616, column 2). That option would
involve treatment and delisting of the material under hazardous
material regulations, and disposal of the material as LLW. In two
situations where incident-related material existed or currently
exists at steel facilities, about 90 percent of the activity was
contained in a few percent of the material volume. Given that, in
many cases, it may not be feasible to blend the 137Cs in this
small volume to concentrations acceptable at either the mixed waste
or the Subtitle C facility (under the provisions of the position),
treatment and delisting of this small volume may not be onerous. In
any event, the staff does not believe the uncertainty or current
feasibility of addressing a small percentage of the problem affects
the merits of the position, especially as it relates to the mixed-
waste or Subtitle C disposal alternatives.
In response to the State query, the position does not justify
disposal at a Subtitle D sanitary waste landfill because the
radiological assessment was based on a Subtitle C facility disposal.
Any such disposal, if justified, would have to address the
differences, if any, between facilities and their operations.
f. Comment: A series of comments from the mixed-waste disposal
facility operator questioned NRC's appreciation of the potential
effects of exposure to low levels of radiation. On the other hand,
most other commenters either considered the regulatory basis for the
position of 1 mrem (10 microsievert (Sv)) per year (yr) to
be reasonable or very conservative. Among several comments, one
commenter suggested a modest increase in the position's dose basis
from 1 mrem (10 Sv)/yr to 4 mrem
(40 Sv)/yr, corresponding to the value in EPA drinking
water standards.
f. Response: For a number of years, the Commission has used the
linear no-threshold hypothesis as providing a reasonable and prudent
basis to assess the radiological risk associated with its actions.
In essence, this hypothesis involves an extrapolation of the
statistically significant health effects that can be attributed to
high-level, short-duration exposures (e.g., the Japanese atomic bomb
survivors) to levels of exposure at or below what the earth's
population receives from background sources (e.g., cosmic radiation
and exposure to radiation emanating from naturally occurring
materials). Notwithstanding the scientific controversy regarding the
reality of these hypothetical risks, the Commission's radiation
protection standards are consistent with standards, recommended by
international and national advisory bodies, that reflect this
hypothesis.
In the case of the technical position, a dose rate of 1 mrem/yr
(one-hundredth of the public dose limit and about one three-
hundredth of the average exposure rate received year in and year out
by the population of the United States) was chosen as the regulatory
basis, because, in the staff's view, it was suitably conservative
and, from a practical standpoint, provided a disposition solution
for most of the incident-related material currently existing at
steel company sites. Footnote 5 of the final technical position
reflected this view.
With respect to the mixed waste disposal facility operator's
comments on the NRC staff's appreciation of the effects of low-level
radiation and the 1 mrem/yr (10 Sv/yr) regulatory basis,
the staff believes that the conservatisms in its selection of a dose
criterion, with appropriate regulatory margins, can be appropriate,
if the resulting position can lead to resolution of an outstanding
incident-related waste disposition problem. Although selection of 4
mrem (40 Sv)/yr could be justified, staff's view is that
selecting a drinking water standard for this position, which staff
believes does not present a drinking water issue, would create more
concern and confusion than the value selected, and its associated
basis.
5. Technical Considerations
a. Comment: A State commenter suggested that the position should
specify acceptable methods for averaging the waste within a
container.
a. Response: The staff recognizes that the incident-related
material in a particular container may not be homogeneous in terms
of 137Cs concentration. However, because the principal
radiological hazard being addressed is related to direct exposure,
complying with the concentration values, as determined on a
container average basis, is acceptable. The specifics of the
characterization program directed at defining treated-material
(137Cs concentrations) would be defined when approving the
licensee's request for transfer of the incident-related material.
The characteristics of the treated material, the decision to pursue
packaged or unpackaged disposal, the statistical confidence desired,
the regulatory margins provided in the position, and the views of
the approving parties would need to be considered. The response to
comment 7.c. could also be applicable in determining a
characterization program.
b. Comment: The mixed waste facility operator noted that if one
considered exposure to a plane source of 60 rem (0.6
Sv) per hour for 8 hours per day for over 4 weeks, the
result would be a total exposure exceeding EPA's maximum allowable
dose. An industry association commenter noted that the dose rate
limit applied to shipments of radioactive material is a factor 500
times higher than the value applied in the position to packaged
disposal.
[[Page 13197]]
b. Response: The staff does not believe this calculation is
pertinent. Although the staff is not certain what maximum allowable
dose is being referred to, the critical point in the calculation is
that it presumes continuous exposure at 1 meter (3 feet)
to a plane of material that is all at the maximum concentration
criterion. As a point of reference, exposure to ``normal'' dust
could be calculated to cause an exposure that would be a factor of
65 or lower, or presuming the possibility of greater exposure
periods associated with the greater volumes of material, equivalent
exposure would be reached over a period of about 5 years. The need
to consider the applicable exposure scenario on which a regulatory
position is based is brought out by the industry association
commenter. To make this point, the staff would note that under
similar assumptions, DOT's allowable exposure rate of 10 mrem (0.1
mSv) per hour at 1 meter (3 feet) could be translated
into a dose estimate of 1.6 rem (16 mSv).
c. Comment: An industrial association commenter suggested that
the 1-curie (Ci) or 3.7 x 10 \4\ MBecquerel (MBq) total activity
limit be modified to a per disposal cell basis (i.e., if the cell
were larger than 100,000 cubic meters (3.5 x 10 \6\ ft \3\)), on the
grounds that the proposed constraint may be too limiting if one
facility would accept the incident-related material from more than a
single event.
c. Response: Although this change could be justified, it has not
been accepted for the following reasons: (1) The procedural
difficulties for the NRC or Agreement State to require a particular
disposal constraint at an unlicensed facility, and (2) the belief
that individual incident disposals under the position's provisions
are, in most cases, unlikely to approach the quantity constraint
(one-tenth is expected to be more typical).
d. Comment: An industrial association commenter suggested that
the area/shape factors used by NRC were overly restrictive by a
factor of 2. d.
d. Response: NRC became aware of area/shape factor differences
between different codes. Staff has checked its calculations and does
not believe its estimates are in error.
e. Comment: A State commenter questioned whether a discrepancy
existed in NRC's source term assumption, in that dividing a 1-Ci
(3.7 x 10 \4\ MBq) source over 2000 tons (1814 metric tons) of
contaminated material would result in an average concentration of
551 pCi/g (1.49 x 10 \4\ Bq/g).
e. Response: The commenter's calculation is correct. However, in
actual events, a significant fraction of the activity is generally
contained in a small volume of incident-related material at high
concentrations. As discussed in the response to comment 4.e., the
disposition of this material will likely require treatment of its
hazardous properties, so that the material can be delisted and
disposed of at a licensed LLRW disposal facility. Although the
position's provisions do allow blending of contaminated material,
NRC staff recognized that providing the required reduction in
average concentration to meet the position's concentration criteria
would likely not be practical in all cases. Staff believed this was
reflected in the proposed position (e.g., see ``Introduction'' (61
FR 1609, column 3) and ``Discussion'' (61 FR 1610, columns 2 and
3)). This reality is why the activity that could be disposed of at
the Subtitle C facility, for the specific events that have taken
place to date, is unlikely to exceed 100 mCi (3.7 x 10 \3\ MBq).
f. Comment: A State commenter raised several questions about the
groundwater modeling and the input parameters.
f. Response: The commenter noted that these comments applied to
an earlier version of the position; however, a few still have
relevance to the proposed version. In the context of this position,
the staff was faced with the task of bounding a specific potential
radiological impact, that staff believed was relegated to a status
of insignificance by the position's defined concentration and
quantity criteria. Nevertheless, the approach taken in the position
was to perform simple bounding analyses and comparisons, so as to
provide a perspective on the specific hazard. For example, in
staff's view, a very conservative dose estimate was provided under
the hypothesis that an individual could and would drink trench
leachate. Contrary to the commenter's apparent view, staff considers
the very conservatively calculated 7-mrem (70-Sv) dose from
directly drinking trench leachate, with a bounding concentration of
radioactive material, to be a prima facie rationale for claiming
that EPA's drinking water standards would be met with significant
margin, not only at the ``tap,'' but at any point in the
groundwater.
6. Other Issues
Comment: A State commenter suggested that the position should
state whether NRC [would] allow import or export of incident-related
material for disposal.
Response: The position did not address the import/export issue.
To the extent that the position's assumptions remain valid, the
technical basis could be applied to export. However, any imports or
exports could involve decisions by responsible parties, beyond NRC,
including non-U.S. regulatory authorities. To the extent that
appropriate U.S. regulatory authorities agree, and determine that
they can legally support NRC's views that the treated incident-
related material is not LLRW, the material could be considered for
disposal under the provisions of the position, giving consideration
to its hazardous properties, if applicable. The staff does not
believe this issue needs to be addressed in the context of the
position itself.
7. Clarifications
a. Comment: A State commenter stated that the licensee
transferring the treated incident-related material should notify the
Agreement State Program or, in the case where an Agreement State
Program does not exist, the appropriate solid or hazardous waste
regulatory authority.
a. Response: The position's provisions are intended to ensure
such notifications. In the case of Agreement States, their approval
of the transfer is called for in the position's provisions, as is
written notification from the licensee at least 30 days before any
actual transfer. The position also calls for disposal facility
operator notification and acceptance, in writing. Thus, there are
two avenues through which the solid or hazardous waste regulatory
authorities would likely be apprised of actions to implement the
position. In non-Agreement States, NRC would be the initial, but
possibly not the only, radiological approving authority. In these
cases, State-permitting authorities may seek the advice and approval
of their respective State radiological or public health
organizations. NRC would work with these authorities and others to
determine if implementing the position's disposition alternative is
reasonable and prudent, and legally acceptable.
b. Comment: In the comments from one State, there appeared to be
some confusion on what entity would track the total quantity
constraint (i.e., 1 Ci or 3.7 x 10 \4\ MBq).
b. Response: Under the position's provisions, the total quantity
constraint would be tracked by NRC or the appropriate Agreement
State, although others could also track this inventory value.
c. Comment: A State commenter queried who would confirm that the
position's concentration constraints were being met. An
environmental group commenter suggested that accurate
characterization presents a considerable challenge.
c. Response: In the staff's view, NRC or the appropriate
Agreement State would have a significant incentive to provide some
independent verification of the concentration criteria. However, the
specifics of this verification would be addressed when approving the
licensee's request to make the transfer of incident-related material
under the provisions of the position. Other parties, including the
Subtitle C facility operator and the permitting agency, whose
approvals are required, could also dictate a specific confirmation
process. On this point, the staff would note the inclusion of
regulatory margins in the position that, staff believes, should be
considered in developing a reasonable confirmation program.
d. Comment: An industry association commenter requested
clarification regarding the shipment of pretreated incident-related
material to offsite licensed treatment facilities.
d. Response: Under the provisions of the position, NRC would
have no objection to incident-related material being transferred
offsite for permitted treatment by an NRC or Agreement State
licensed entity. The position only addresses the transfer of
incident-related material that has been properly treated, under a
Commission or Agreement State license, to a Subtitle C disposal
facility.
e. Comment: An industry group commenter suggested that the
position should provide allowance for licensed service contractors
to be brought in to supervise implementation operations. It was
further suggested that treatment should not be a prior condition to
transport.
e. Response: The position, and NRC regulations, allow the
possibility of service contractors operating under the contracting
entity's license. Treatment is only required before transport to an
unlicensed Subtitle C disposal facility. See the response to comment
7.d. above.
f. Comment: An industrial association commenter questioned the
accuracy of the
[[Page 13198]]
dose rates associated with the 55-gallon drum.
f. Response: The publication of the figures in the Federal
Register caused some blurring that has caused the commenter to
misread the indicated dose rate. Comparisons with the scale on the
ordinate indicate that the commenter's figure is high by a factor of
10.
Dated at Rockville, Maryland, this 13th day of March, 1997.
For the U.S. Nuclear Regulatory Commission
John W. N. Hickey,
Chief, Low-Level Waste and Decommissioning Projects Branch, Division of
Waste Management, Office of Nuclear Material Safety and Safeguards.
[FR Doc. 97-6884 Filed 3-18-97; 8:45 am]
BILLING CODE 7590-01-P