[Federal Register Volume 64, Number 69 (Monday, April 12, 1999)]
[Notices]
[Pages 17690-17695]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-9036]


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NUCLEAR REGULATORY COMMISSION


Draft Guidance on the Benchmark Dose Modeling for the 
Radiological Criteria for License Termination of Uranium Recovery 
Facilities

AGENCY: Nuclear Regulatory Commission.

ACTION: Notice of availability; opportunity for comment.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is soliciting 
comments on draft guidance for the radium benchmark dose approach, 
associated with the final rule, ``Radiological Criteria for License

[[Page 17691]]

Termination of Uranium Recovery Facilities,'' that is in this 
publication. The guidance will be incorporated into the NRC final 
Standard Review Plan (SRP) for the Review of Reclamation Plans for Mill 
Tailings Sites and the SRP for In-Situ Leach Uranium Extraction License 
Applications. Public comments should be submitted within sixty (60) 
days of publication of this Notice.

SUPPLEMENTARY INFORMATION:

Background

    In 10 CFR 40.4, uranium milling is defined as any activity 
resulting in byproduct material. 1 Therefore, Part 40, 
Appendix A, applies to in situ leach (ISL), heap leach, and ion-
exchange facilities (i.e., uranium recovery (UR) facilities) that 
produce byproduct material, as well as to conventional uranium and 
thorium mills. The draft guidance only addresses UR facilities because 
there are no currently licensed or planned thorium mills.
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    \1\ Byproduct material means the tailings or waste produced by 
the extraction or concentration of uranium or thorium from any ore 
processed primarily for its source material content, including 
discrete surface wastes resulting from uranium solution extraction 
processes.
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    Decommissioning of ISLs and mills are similar in that the type of 
soil and building contamination is the same, consisting mainly of 
residual radium (Ra-226) and uranium (U-nat). The applicable cleanup 
standards for soil radium in Criterion 6(6) address the main 
contaminant at uranium mills in the large areas (hundreds of acres) 
where windblown contamination from the tailings pile has occurred, and 
at ISLs in holding/settling ponds and process solution spills. In other 
mill and ISL site areas proximate to locations where radium 
contamination exists (e.g., under the mill or process building or in a 
yellowcake storage area), uranium would be the radionuclide of concern. 
Thorium (Th-230, the parent of Ra-226) would be the radionuclide of 
concern at some mill raffinate evaporation ponds.
    Because Part 40, Appendix A, provides only decommissioning soil 
radium 2 and ground-water protection criteria, Criterion 6 
(6) was amended to address criteria for residual radionuclides, other 
than radium in soil, for decommissioning of lands and structures at UR 
facilities. The final rule, ``Radiological Criteria for License 
Termination of Uranium Recovery Facilities,'' added a paragraph after 
the radium in soil criteria in Criterion 6(6), to read:

    \2\ The concentration of radium, as a result of byproduct 
material, averaged over areas of 100 square meters, should not 
exceed the background level by more than 5 pCi/g (0.19 Bq/g) in the 
first 15 cm (6 inches) of soil, and 15 pCi/g (0.56 Bq/g) for every 
subsequent 15 cm (6 inch) layer.

    Byproduct material containing concentrations of radionuclides 
other than radium in soil, and surface activity on remaining 
structures, must not result in a total effective dose equivalent 
(TEDE) exceeding the dose from cleanup of radium contaminated soil 
to the above standard (benchmark dose), and must be at levels which 
are as low as is reasonably achievable.
    If more than one residual radionuclide is present in the same 
100-square-meter area, the sum of the ratios for each radionuclide, 
of concentration present to the concentration limit, will not exceed 
``1'' (unity). A calculation of the peak potential annual TEDE 
within 1000 years to the average member of the critical group that 
would result from applying the radium standard (not including radon) 
on the site, must be submitted for approval. If the benchmark dose, 
before application of ALARA, exceeds 100 mrem/yr, the staff will 
consult the Commission before approving the decommissioning plan. 
This requirement for dose criteria does not apply to sites that have 
decommissioning plans for soil and structures approved before the 
effective date of this rule.

    The final rule, ``Radiological Criteria for License Termination of 
Uranium Recovery Facilities,'' requires the use of the soil radium 
standard to develop a site-specific dose benchmark for the cleanup of 
residual radionuclides, other than radium, at UR sites. The radium 
benchmark approach ensures that the dose limit across the UR site will 
be equal for all radionuclides (other than radon).
    The NRC-licensed sites subject to the new rule currently include 
four uranium mills (one operating, others in stand-by status), seven in 
situ leach (ISL) facilities, and any new UR facility licensed by NRC 
after promulgation of the rule (two ISL license applications are under 
review at NRC, also in the Agreement States, several ISLs in Texas 
could be affected by the rule). These sites are located in semi-arid 
(7-15 inches (18-39 cm) of precipitation), high evapo-transpiration, 
sparsely populated (1-5 people per sq. mile (0.4-3 per sq. km)) areas 
of New Mexico, Utah, Wyoming, and Nebraska. The land use around these 
facilities is predominately mining and ranching, and the potable water 
aquifer is usually 100-200 feet deep. Also, many of the sites have 
natural (in situ) uranium and/or radium deposits or mine pits that 
create a wide range of radium, thorium and uranium background values. 
Because of these unique properties and the specific regulations in 10 
CFR Part 40, Appendix A, the UR facilities are exempt from the 
decommissioning criteria in Part 20 Subpart E, as specified in Section 
20.1401(a).
    The benchmark dose applies to surface cleanup (buildings or the top 
15 cm (6 inches) of soil) of radionuclides other than radium and it is 
the estimated dose resulting from cleanup of areas to 5 pCi/g (0.19 Bq/
g) Ra-226 at that site. For the small areas requiring the use of the 
radium subsurface soil standard, the estimated dose resulting from 15 
pCi/g (0.56 Bq/g) Ra-226 at that site and for those areas, would be 
used. The same concept of regulation (using a Ra-228 benchmark dose) 
would be applicable to thorium mills, if any are licensed in the 
future.
    The draft guidance on dose modeling and implementation of the 
radium benchmark approach was developed in conjunction with the final 
rule and the SRPs under development for uranium mill site reclamation 
and ISL licensing. The draft SRPs have already been published for 
comment as NUREG-1569 (NRC, 1997) and NUREG-1620 (NRC, 1999). After 
review of the comments received on the draft guidance, the final 
benchmark dose guidance will be incorporated into the final SRPs for UR 
facilities.

Draft Guidance: Standard Review Plan--Chapter 6

6.0  Decommissioning Plan for Soil and Buildings--The Radium 
Benchmark Dose Approach

    A mill reclamation plan, required for licensing or license renewal, 
generally focuses on the tailings disposal cell and contains only brief 
mention of anticipated decommissioning activities. The licensee submits 
a detailed mill or ISL decommissioning plan and a soil cleanup/
verification plan for NRC approval at least six months before 
decommissioning is to begin. The general requirements for a 
decommissioning plan, and the remediation and verification of soil Ra-
226 contamination cleanup are addressed in Chapter 5 of the Standard 
Review Plan (SRP). This chapter discusses the evaluation of the radium 
benchmark dose approach for the cleanup of thorium and uranium, 
specifically dose modeling and its application to site cleanup 
activities that should be addressed in the decommissioning plan.
    This chapter applies to those uranium recovery (UR) facilities 
licensed by the NRC and subject to the new requirements for cleanup of 
contaminated soil and buildings under 10 CFR Part 40, Appendix A, 
Criterion 6(6) (as amended in 1999). The facilities that did not have 
an approved

[[Page 17692]]

decommissioning plan at the time the rule became final are required to 
reduce residual radioactivity, i.e., byproduct material, as defined by 
Part 40, to levels based on the potential dose, excluding radon, 
resulting from the application of the radium (Ra-226) standard at the 
site. This is referred to as the radium benchmark dose approach.
    This chapter would also apply to any future thorium processing 
facilities and uranium heap leach operations, because Part 40 defines 
uranium milling as any activity resulting in byproduct material. This 
chapter also applies to any revised decommissioning plan submitted for 
NRC review and approval, after the final rule is effective. However, if 
a subject licensee can demonstrate that no contaminated buildings will 
remain, and that soil thorium or total uranium levels are not 
discernable from background, radium benchmark dose modeling is not 
required. Other aspects of decommissioning are addressed in Chapter 5 
of this SRP.
    In order for NRC staff to evaluate the radium benchmark dose 
modeling and the implementation of the modeling results, as proposed in 
the building and soil decommissioning plan, an understanding of the 
site conditions and site operations is essential. The required site 
information should be provided by the licensee, or relevant portions of 
previously submitted documents (e.g., environmental assessments, 
license renewal, reclamation plan, and characterization report) should 
be summarized and referenced. The information should include: (1) 
processes used at the facility; (2) type and location of possible 
contamination; (3) geologic and climatic data; and (4) surrounding land 
use information (also see Section 3 of Inspection Procedure 87654).

6.1  Radium Benchmark Dose Modeling

6.1.1  Areas of Review

    In implementing the radium benchmark approach, the licensee 
calculates the peak potential dose for the site resulting from the 5 
pCi/g (0.19 Bq/g) concentration of radium in the surface (top 15 cm (6 
inches)) soil. The dose from the 15 pCi/g (0.56 Bq/g) subsurface radium 
limit would be calculated for any area that may require subsurface 
cleanup. The dose modeling review involves examination of the computer 
code or other calculations employed for the dose estimates, the code or 
calculation input values and assumptions, and the modeling results 
(data presentation).

6.1.2  Review Procedures

    The radium benchmark dose modeling review consists of ascertaining 
that an acceptable dose modeling computer code or other type of 
calculation has been used; that input parameter values appropriate 
(reasonable considering long-term conditions and representative of the 
application) for the site have been used in the modeling; that a 
realistic (overly conservative is not acceptable as it would result in 
higher allowable levels of uranium or thorium which would not be ALARA) 
dose estimate is provided; and that the data presentation is clear and 
complete.

6.1.3  Acceptance Criteria

    The radium benchmark dose modeling results will be acceptable if 
the dose assessment (modeling) meets the following criteria:
(1) Dose Modeling Codes and Calculations
    The assumptions are considered reasonable for the site analysis and 
the calculations employed are adequate. Reference to documentation 
concerning the code or calculations is provided (for example, the 
RESRAD Handbook and Manual (Argonne, 1993a and b)).
    The RESRAD code developed by the U.S. Department of Energy (version 
5.82, 1998) (see website www.ead.anl.gov/resrad/html), may be 
acceptable for dose calculations because, while the RESRAD ground-water 
calculations have limitations, this does not impact the UR sites that 
have deep aquifers (ground-water exposure pathway is insignificant). 
The DandD code developed by the NRC (version 1.0, August 1998, see 
website ftp://nwerftp.nwer.sandia.gov/nrc/DandD/; also see the website 
at http://techconf.llnl.gov/radcri/dose-top.html) provides conservative 
default values, but does not allow for modeling subsurface soil 
contamination, and does not allow calculation of source removal due to 
soil erosion. Neither the RESRAD nor the DandD code would be adequate 
to model the dose from off-site contamination, but codes such as GenII 
would be considered.
    If the code or calculation's assumptions are not acceptable for 
site conditions, adjustments have been made in the input to adequately 
modify these assumptions.
    The RESRAD code assumes a circular contaminated zone. The shape 
factor (external gamma, screen R017) must be adjusted for a non-
circular-shaped area.
    The code or calculation provides an annual dose (total effective 
dose equivalent (TEDE)) estimate (mrem/yr).
    The DandD code provides the annual dose, but RESRAD calculates the 
highest instantaneous dose. However, RESRAD results are acceptable for 
long-lived radionuclides that do not move rapidly out of surface soils.
(2) Input Parameter Values
    The code/calculation input data are appropriate for the site and 
represent current or long-term conditions, whichever is more applicable 
to the time of maximum dose. When code default values are used, they 
are justified as appropriate (representative) for the site. Excessive 
conservatism (i.e., upper bound value) is not used as this would result 
in a higher dose and thus higher levels of uranium and thorium would be 
allowed to remain on site.
    Previously approved MILDOS code input parameter values may not be 
appropriate, because derived operational doses in the restricted area 
may be an order of magnitude higher than acceptable doses for areas to 
be released for unrestricted use.
    Site-specific input values are demonstrated to be average values of 
an adequate sample size. Confidence limits are provided for important 
parameters so that the level of uncertainty can be estimated for that 
input value. Alteration of input values considers that some values are 
inter-related (see draft NUREG-1549, Appendix C) (NRC, 1998a) and 
relevant parameters are modified accordingly. The preponderance of 
important parameter values are based on site measurements and not 
conservative estimates. One or more models consider the annual average 
range of parameter values likely to occur within the next 200-year time 
period, for important parameters that can reasonably be estimated. Some 
other considerations for the input parameter values are as follows:
a. Exposure Pathways and Scenarios for the Critical Group
    The scenario(s) chosen to model the potential dose to the average 
member of the critical group\3\ from residual radionuclides at the site 
reflects reasonable probable future land use. The licensee has 
considered ranching, mining, home-based business, light industry, and 
residential farmer scenarios, and has justified the scenarios modeled.
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    \3\ As defined in 10 CFR Part 20, ``the group of individuals 
reasonably expected to receive the greatest exposure to residual 
radioactivity for any applicable set of circumstances.''
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    Based on one or more of these projected (within 200 years is 
reasonably foreseeable) land uses to define the critical group(s), the 
licensee

[[Page 17693]]

has determined and justified what exposure pathways are probable for 
potential exposure of the critical group to residual radionuclides at 
the site.
    Dairies are not likely to be established in the area of former UR 
facilities, and even if some milk cows were to graze in contaminated 
areas, the milk would probably be sent for processing (thus diluted), 
and not be consumed at the site. Therefore, milk consumption is not a 
likely ingestion exposure pathway. Also, a pond in the contaminated 
area providing a significant quantity of fish in the resident's diet is 
not likely, so the aquatic exposure pathway may not have to be modeled. 
However, the external gamma, plant ingestion, and inhalation pathways 
are likely to be important.
    The radon pathway is excluded from the benchmark dose calculation 
as defined in Criterion 6(6) of Appendix A, to 10 CFR Part 40. This 
also reflects the approach in the main decommissioning rule 
(radiological criteria for license termination, Part 20 subpart E).
b. Source Term
    If the RESRAD code is used, the input includes Pb-210 at the same 
input value as for Ra-226. The other radium progeny are automatically 
included in the code calculations. The chemical form of the 
contamination in the environment is considered in determining input 
values related to transport, or inhalation class (solubility in the 
lung) for dose conversion factors.
c. Time Periods
    The time periods for calculation of the dose from soil Ra-226 
include the 1000-year time frame. The calculated maximum annual dose 
and the year of occurrence is provided in the results.
d. Cover and Contaminated Zone
    A cover depth of zero is used in the surface contamination model 
and a depth of at least 15 cm (6 inches) for the subsurface model. The 
values for area and depth of contamination are derived from site 
characterization data. The erosion rate value for the contaminated zone 
is less than the RESRAD default value because in regions drier than 
normal, the erosion rate is less, as discussed in the RESRAD Data 
Collection Handbook (Argonne, 1993a), and the value is justified. The 
soil properties are based on site data (sandy loam or sandy silty loam 
are typical for UR sites) and other input parameters are based on this 
demonstration of site soil type (see RESRAD Handbook pages, 23, 29, 77, 
and 105).
    The evapo-transpiration coefficient for the semi-arid UR sites is 
between 0.6 and 0.99. The precipitation value is based on annual values 
averaged over at least 20 years, obtained from the site or a nearby 
meteorological station.
    The irrigation rate value may be zero, or less than a code's 
default value, if supported by data on county or regional irrigation 
practices (e.g., irrigation water is obtained from a river not a well). 
The runoff coefficient value is based on the site's soil type, expected 
land use, and morphology of the region.
 e. Saturated Zone
    The dry bulk density, porosity, ``b'' parameter, and hydraulic 
conductivity values are based on local soil properties. The hydraulic 
gradient for an unconfined aquifer is approximately the slope of the 
water table. For a confined aquifer, it represents the difference in 
potentiometric surfaces over a unit distance.
    If the RESRAD code is used, the nondispersion model parameter is 
chosen for areas greater than 1000 sq. meters (screen R014), and the 
well pump rate is based on irrigation, stock, or drinking water well 
pump rates in the area.
f. Uncontaminated and Unsaturated Strata
    The thickness value represents the typical distance from the soil 
contamination to the saturated zone. Since the upper aquifer at UR 
sites is often of poor quality and quantity, the depth of the most 
shallow well used for irrigation or stock water in the region is chosen 
for the unsaturated zone thickness. A value of 18 meters (60 feet) is 
typical for most sites and 15 meters (50 feet) for the Nebraska site, 
but regional data are provided for justification. The density, 
porosity, and ``b'' parameter values are similar to those for the 
saturated zone or any changes are justified.
g. Distribution Coefficients and Leach Rates
    The distribution coefficient (Kd) is based on the site's soil 
physical and chemical characteristics. The leach rate value of zero in 
the RESRAD code is acceptable as it allows calculation of the value. If 
a value greater than zero is provided, justification for the value is 
also provided.
h. Inhalation
    An average inhalation rate value of approximately 8,395 
m3/yr is used for the activity assumed for the rancher or 
farmer scenario (based on Draft Letter Report, Sandia, 1998a). The mass 
loading for inhalation (air dust loading factor) value is justified 
based on the average level of airborne dust in the local region for 
similar activities as assumed in the model.
i. External Gamma
    The shielding factor for gamma is in the range of 0.33 to 0.55 (PG-
8-08, NRC 1994; DandD code screening default value), based mainly on 
the type (foundation, materials) of the house likely to be built on the 
site.
    The time fractions for indoor and outdoor occupancy are similar to 
default values in RESRAD and draft guidance developed for the main 
decommissioning rule (NUREG/CR-5512, Volume 3, NRC, 1996b). For 
example, the staff would consider fraction values approximating 0.7 
indoors and 0.15 outdoors for a resident working at home, and 0.5 
outdoors and 0.25 indoors for the farmer scenario.
    The site specific wind speed value is based on adequate site data 
(the average annual wind speed for the UR sites varies from 7 to 13 mph 
(3.1 to 5.5 meters/sec)). The maximum and annual average wind speed are 
also considered when justifying/evaluating proposed erosion rates.
j. Ingestion
    Average consumption values (g/yr) for the various types of foods 
are based on average values as discussed in NUREG 5512, Volume 3, or 
the Sandia Draft Letter Reports (1998a and b), or are otherwise 
justified. Livestock ingestion parameters are default values, or are 
otherwise justified.
    For sites with over 25 acres of contamination, the fraction of diet 
from the contaminated area is assumed to be 0.25 for the farmer 
scenario (Sandia 1998a), or is otherwise justified based on current or 
anticipated regional consumption practices for home-grown food. Because 
of the low level of precipitation in the UR facilities regions, 
extensive gardens or dense animal grazing are not likely, so the 
percentage of the diet from contaminated areas is likely to be lower 
than the code default value.
    Note that the default plant mass loading factor in the DandD code 
can reasonably be reduced to 1 percent (Sandia, Draft Report, 1998c). 
The depth of roots is an important parameter for UR licensees using the 
RESRAD code. The value is justified based on the type of crops likely 
to be grown on the site in the future. For vegetable gardens, a value 
of 0.3 is more appropriate than the RESRAD default value of 0.9 meters 
that is reasonable for alfalfa or a similar deep-rooted plant.

[[Page 17694]]

(3) Presentation of Modeling Results
    The radium benchmark dose modeling section of the decommissioning 
plan includes the code or calculation results as the maximum annual 
dose (TEDE) in mrem/yr, the year that this dose would occur, and the 
major exposure pathways by percentage of total dose. The modeling 
section also includes discussion of the likelihood of the various land 
use scenarios (reflecting the probable critical groups) modeled, and 
provides the variations in dose (dose distribution) created by changing 
key parameter values to reflect the range of dose values that are 
likely to occur on the site. The section also contains the results of a 
sensitivity analysis (RESRAD code can provide a sensitivity analysis 
via the graphics function) to identify the important parameters for 
each scenario.

    Note: As indicated in Criterion 6(6), if a licensee submits a 
radium benchmark dose result that is 100 mrem/yr or higher, the 
staff will consult with the Commission before approving the 
decommissioning plan based on this value.

6.1.4  Evaluation Findings

    If the staff review, as described in this section, results in the 
acceptance of the radium benchmark dose modeling, the following 
conclusions may be presented in the technical evaluation report (TER).
    The staff has completed its review of the site benchmark dose 
modeling for the ________________ uranium recovery facility. This 
review included an evaluation using the review procedures in the Title 
II SRP (NRC, 1999), Section 6.1.2, and the acceptance criteria outlined 
in SRP Section 6.1.3.
    The applicant has provided an acceptable radium benchmark dose 
model and staff evaluation determines that: (1) the computer code or 
set of calculations used to model the benchmark dose is appropriate for 
the site; (2) input parameter values used in each model are site-
specific or reasonably estimates; (3) the dose modeling information 
includes adequate estimates of dose uncertainty.

6.2  Implementation of the Benchmark Dose

6.2.1  Areas of Review

    The results of the radium benchmark dose calculations are used to 
establish a surface and subsurface soil dose limit for residual 
radionuclides other than radium, as well as a limit for surface 
activity on structures that will remain after decommissioning. The 
staff reviews the licensee's conversion of the benchmark dose limit to 
soil concentration (pCi/g) or surface activity levels (dpm/100 cm \2\) 
as a first step to provide cleanup levels. Alternatively, the licensee 
can derive the estimated dose from the uranium or thorium contamination 
(as discussed in Section 6.1.3) and compare this to the radium 
benchmark dose.
    The cleanup levels adequately consider the ALARA principle and the 
unity rule to demonstrate that the Part 40.42 (k) requirements (the 
premises are suitable for release and reasonable effort has been made 
to eliminate residual radioactive contamination) can be met.

6.2.2  Review Procedures

    The decommissioning plan section on cleanup criteria will be 
evaluated for appropriate conversion of the radium standard benchmark 
dose to cleanup limits for soil uranium and thorium and/or surface 
activity concentration. The plan will also be examined to ensure 
reasonable application of the ALARA principle to the cleanup guideline 
values.

6.2.3  Acceptance Criteria

    (1) The soil concentration limit is derived from the site radium 
dose estimate. The modeling performed to estimate mrem/year per pCi/g 
of Th-230 and/or U-nat follows the criteria listed in Section 6.1.3. In 
addition, the U-nat source term is represented as percent activity by 
49.14% U-238, 49.14% U-234, and 0.71% U-235, or is based on analyses of 
the ore processed. For a soil uranium criterion, the chemical toxicity 
is considered in deriving a soil concentration limit if soluble forms 
of uranium are present.
    Detailed justification for the inhalation pathway parameters is 
provided, such as the determination of the chemical form in the 
environment, to support the inhalation class.
    The derived Th-230 soil limit will not cause any 100 square meter 
(m \2\) area to exceed the Ra-226 limit at 1000 years (i.e., current 
concentrations of 14 pCi/g Th-230 surface and 43 pCi/g subsurface, if 
Ra-226 is at approximately background levels).
    (2) In conjunction with the activity limit, the ALARA principle is 
considered in setting cleanup levels (derived concentration guideline 
levels). The ALARA guidance in draft Regulatory Guide 4006 is 
considered.
    In recent practice at mill sites, ALARA is implemented by removing 
at least two more inches (5 cm) of soil than is estimated to achieve 
the radium standard. (reduce any possible excess or borderline 
contamination). At mills, it is generally cheaper to remove more soil 
than to do sampling and testing that may indicate failure and require 
additional soil removal plus additional testing.
    (3) The unity rule is applied to the cleanup if more than one 
residual radionuclide is present in a soil verification grid (100 m 
\2\). This means that the sum of the ratios for each radionuclide of 
the concentration present/concentration limit may not exceed ``1'' 
(i.e., unity).
    (4) The subsurface soil standard, if it is to be used, is applied 
to small areas of deep excavation where at least 15 cm (6 inches) of 
compacted clean fill is to be placed on the surface.
    (5) The surface activity limit for remaining structures is 
appropriately derived using an approved code or calculation.
    If the DandD code is used, data is provided to support that 10% or 
less of the activity is removable; otherwise the resuspension factor is 
scaled to reflect the site-specific removable fraction. Note that this 
code assumes that the contamination is only on the floor, which can be 
overly conservative. If the RESRAD-Build code is used, the modeled 
distribution of contamination on walls vs. floor is justified.

6.2.4  Evaluation Findings

    If the staff review, as described in this section, results in the 
acceptance of the application of the radium benchmark dose modeling to 
the site cleanup criteria, the following conclusions may be presented 
in the technical evaluation report.
    The staff has completed its review of the proposed implementation 
of the benchmark dose modeling results for the ________________ uranium 
recovery facility. This review included an evaluation using the review 
procedures in the Title II SRP, Section 6.2.2, and the acceptance 
criteria outlined in SRP Section 6.2.3.
    The licensee has provided an acceptable implementation of the 
benchmark dose modeling results to the proposed site cleanup activities 
and staff evaluation determines that: (1) The cleanup criteria will 
allow the licensee to meet Part 40.42(k) and Part 40, Appendix A, 
criterion 6(6) requirements; (2) the soil and structures of the 
decommissioned site will permit termination of the license because 
public health and the environment will not be adversely affected by any 
residual radionuclides.

6.3  References

Argonne National Laboratory (for the U.S. Department of Energy), 
``Data Collection Handbook to Support Modeling the Impacts of 
Radioactive Material in Soil,'' ANL/EAIS-8, April 1993a.

[[Page 17695]]

Argonne National Laboratory (for the U.S. Department of Energy), 
``Manual for Implementing Residual Radioactive Material Guidelines 
Using RESRAD, Version 5.0,'' ANL/EAD/LD-2, September 1993b.
Sandia National Laboratories, ``Review of Parameter Data for the 
NUREG-5512 Residential Farmer Scenario and Probability Distributions 
for the DandD Parameter Analysis,'' Draft Letter Report, January 30, 
1998a.
Sandia National Laboratories, ``Review of Parameter Data for the 
NUREG-5512 Building Occupancy Scenario and Probability Distributions 
for the DandD Parameter Analysis,'' Draft Letter Report, January 30, 
1998b.
Sandia National Laboratories, ``Comparison of the Models and 
Assumptions Used in the DandD 1.0, RESRAD 5.61, and RESRAD-Build 
Computer Codes with Respect to the Residential Farmer and Industrial 
Occupant Scenarios Provided in NUREG/CR5512.'' Draft Report, October 
15, 1998c.
U. S. Nuclear Regulatory Commission, ``Residual Radioactive 
Contamination from Decommissioning,'' NUREG/CR-5512, PNL-7994, Vol. 
1, 1992.
U.S. Nuclear Regulatory Commission, Office of Nuclear Material 
Safety and Safeguards, Division of Waste Management, Policy and 
Guidance Directive PG-8-08, ``Scenarios for Assessing Potential 
Doses Associated with Residual Radioactivity,'' May 1994.
U. S. Nuclear Regulatory Commission, ``Residual Radioactive 
Contamination from Decommissioning--User's Manual,'' NUREG/CR-5512, 
Vol. 2, October 1996a.
U. S. Nuclear Regulatory Commission, ``Residual Radioactive 
Contamination from Decommissioning--Parameter Analysis,'' (DRAFT FOR 
REVIEW), NUREG/CR-5512, Vol. 3, April 1996b.
U.S. Nuclear Regulatory Commission, Office of Nuclear Material 
Safety and Safeguards, ``Draft Standard Review Plan for In Situ 
Leach Uranium Extraction License Applications,'' NUREG-1569, October 
1997.
U.S. Nuclear Regulatory Commission, ``Decision Methods for Dose 
Assessment to Comply With Radiological Criteria for License 
Termination,'' Draft NUREG-1549, July 1998a.
U.S. Nuclear Regulatory Commission, Draft Regulatory Guide-4006, 
``Demonstrating Compliance With the Radiological Criteria for 
License Termination,'' August 1998b.
U.S. Nuclear Regulatory Commission, Office of Nuclear Material 
Safety and Safeguards, ``Draft Standard Review Plan for the Review 
of a Reclamation Plan for Mill Tailings Sites Under Title II of the 
Uranium Mill Tailings Radiation Control Act,'' NUREG-1620, January 
1999.

Notice of Opportunity To Provide Comments

    The Commission hereby provides notice of opportunity for public 
comment on the draft guidance addressing the radium benchmark approach 
for decommissioning UR facilities. Written comments should be sent, 
within sixty (60) days from the date of publication of this Federal 
Register Notice (FRN), to the Chief, Rule and Directives Branch, U.S. 
Nuclear Regulatory Commission, Washington, DC 20555-0001. Comments may 
also be provided electronically on the NRC Uranium Recovery Branch 
website and the final rule FRN may also be viewed (http://www.nrc.gov/
NRC/NMSS/URANIUM/guidance.htm).

FOR FURTHER INFORMATION CONTACT: Ms. Elaine S. Brummett, Uranium 
Recovery and Low-Level Waste Branch, Mail Stop T7-J9, Division of Waste 
Management, Office of Nuclear Material Safety and Safeguards, U.S. 
Nuclear Regulatory Commission, Washington, D.C. 20555-0001. Telephone 
301/415-6606.

    Dated at Rockville, Maryland, this 1st day of April 1999.

    For the Nuclear Regulatory Commission.
N. King Stablein,
Acting Chief, Uranium Recovery and Low-Level Waste Branch, Division of 
Waste Management, Office of Nuclear Material Safety and Safeguards.
[FR Doc. 99-9036 Filed 4-9-99; 8:45 am]
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