[Federal Register Volume 64, Number 16 (Tuesday, January 26, 1999)]
[Notices]
[Pages 3988-3991]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-1702]



[[Page 3988]]

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NUCLEAR REGULATORY COMMISSION

[Docket No. 40-3453; License No. SEA-917]


Atlas Corporation; Director's Decision Under 10 CFR 2.206

SUMMARY: Notice is hereby given that a request for Hearing and Petition 
for Leave to Intervene (Petition) filed by the State of Utah (State) 
has been reviewed by the staff as a petition under 10 CFR 2.206, in 
accordance with 10 CFR 2.1205(l)(2). For reasons explained in 
Director's Decision DD-99-02, dated January 20, 1999, the Petition has 
been denied.
    On August 2, 1988, Atlas Corporation (Atlas) submitted an 
application for a license amendment to revise its site reclamation plan 
for uranium mill tailings at its site near Moab, Utah. On April 4, 
1994, notice of Receipt of Application and notice of Opportunity for 
Hearing on the application were published in the Federal Register. 59 
FR 16,665 (1994). On July 13, 1998, the State filed its Petition 
stating that if the Petition is found to be untimely that it be treated 
as a 10 CFR 2.206 petition in accordance with 10 CFR 2.1205(l)(2). The 
Petition was filed by Denise Chancellor, Assistant Attorney General on 
behalf of the State. By Memorandum and Order dated August 13, 1998, the 
Presiding Officer determined that the Petition was inexcusably late and 
would be treated as a petition under 10 CFR 2.206, in accordance with 
10 CFR 2.1205(l)(2). On October 22, 1998, notice of receipt of the 
Petition was published in the Federal Register. 63 FR 56667 (1998).
    In its Petition, the State asserted that if Atlas were to proceed 
with its reclamation plan as approved by the Nuclear Regulatory 
Commission, it would be in violation of 10 CFR Part 40, Appendix A. The 
Petition was referred to the Director of the Office of Nuclear Material 
Safety and Safeguards. As provided by Section 2.206 and discussed in 
the Federal Register notice, appropriate action was taken on this 
Petition. The staff reviewed the specific assertions made by the State 
and concluded that the Petition should be denied. The basis for the 
staff's conclusions are detailed in Director's Decision DD-99-02, dated 
January 20, 1999. A copy of the Director's Decision is available for 
inspection at the Commission's Public Document Room at 2120 L Street, 
N.W., Washington, DC 20555.

FOR FURTHER INFORMATION CONTACT: Myron Fliegel, Petition Manager, 
Telephone (301) 415-6629.

    Dated at Rockville, Maryland, this 20 day of January, 1999.

    For the Nuclear Regulatory Commission.
Carl J. Paperiello,
Director, Office of Nuclear Material Safety and Safeguards.

Director's Decision Under 10 CFR 2.206

I. Introduction

    On August 2, 1988, Atlas Corporation (Atlas or licensee) submitted 
an application for a license amendment to revise its site reclamation 
plan for uranium mill tailings at its site in Moab, Utah. On April 4, 
1994, notice of Receipt of Application and notice of Opportunity for 
Hearing on the application were published in the Federal Register. 59 
FR 16665 (1994). On July 13, 1998, the State of Utah (State or Utah) 
filed the State's Request for Hearing and Petition for Leave to 
Intervene (Petition). By Memorandum and Order dated August 13, 1998, 
the Atomic Safety and Licensing Board determined that the petition was 
inexcusably late and would be treated as a petition under 10 CFR 2.206, 
in accordance with 10 CFR 2.1205(l)(2).
    In its Petition, the State asserts that if Atlas were to proceed 
with its reclamation plan as approved by the U.S. Nuclear Regulatory 
Commission (NRC), it would not meet the requirements of 10 CFR Part 40, 
Appendix A. More specifically, the State asserts that the rock apron 
design (armoring the side slope and toe of the tailings pile) does not 
provide reasonable assurance against engineering failure at the Atlas 
Uranium Tailings Site, and thus does not satisfy Appendix A. As bases 
for its assertion it is stated that the unpredictability of flood 
events, erosion, and vegetation growth along the river banks makes 
computation of the probability of river migration extremely difficult 
and that, therefore, conservatism should be built into how the tailings 
pile is armored. The State, furthermore, references an April 2, 1998, 
memorandum from its Department of Environmental Quality, Division of 
Radiation Control (DRC), wherein it is stated that: (1) There are two 
different conceptual designs for the Atlas tailings pile apron--one 
presented by Atlas and accepted by NRC, and the second presented by the 
U.S. Army Corps of Engineers (ACE); (2) assumptions and inputs to the 
conceptual models result in the size, gradation, and volume of rock 
necessary to protect the tailings pile from erosion by the Colorado 
River; (3) the DRC staff has concluded that the ACE approach is more 
protective of the tailings pile side slopes; and (4) the DRC staff 
disagrees with the NRC conclusion that the Atlas design provides the 
necessary protection of the tailings pile in the event of river 
migration. A letter acknowledging receipt of the Petition and its 
status for consideration pursuant to 10 CFR 2.206 was sent to the State 
on September 26, 1998.

II. Background

    In 1997, the NRC staff issued NUREG-1532 ``Final Technical 
Evaluation Report for the Proposed Revised Reclamation Plan for the 
Atlas Corporation Moab Mill'' (TER), presenting its evaluation of 
technical issues related to Atlas Corporation's proposed reclamation 
plan for the uranium mill tailings pile. Among the issues considered 
was the ability of the proposed erosion protection design to prevent 
erosion from various flooding events over long periods of time. One of 
the features of the erosion protection design evaluated in the TER was 
the ability of the self-launching rock apron to prevent erosion of the 
tailings if the Colorado River were to migrate to the pile.
    In the TER, the staff concluded that the rock apron provided 
adequate protection for the reclaimed tailings pile, in the unlikely 
event that the Colorado River migrated several hundred feet and reached 
the toe of the pile. The adequacy of the apron design was questioned by 
the State and the Grand County Council (GCC). In addition, the GCC 
funded a report developed by the ACE that indicated that the rock apron 
had not been designed properly. The GCC also solicited the opinions of 
vegetation and geomorphic experts and provided those opinions to the 
State. These reports, questions, and comments were transmitted to the 
NRC staff by the State by letters dated November 10, 1997, and January 
9, 1998.
    Because the 1997 TER only summarized the NRC staff review of the 
rock apron, a supplemental report (SR) was developed to address in 
detail the questions and concerns raised by the DRC. The SR addressed 
specific aspects of the staff review and provided a detailed technical 
basis for the staff's conclusions on the adequacy of the rock apron. 
The SR also addressed issues raised by the GCC and the ACE. Specific 
topics that were addressed included: (1) Potential for erosion and 
migration of the Colorado River; (2) riprap size needed for the side 
slopes to protect from overland or overtopping flows; (3) riprap size 
needed to protect the side slope from velocities in the river; (4) rock 
volume needed; (5) river velocities; (6) vegetation/tamarisk growth and 
the

[[Page 3989]]

effects on river flow velocities; (7) ACE design procedures, including 
specific discussions of computations and analytical methods; (8) 
potential for cohesive soils to affect the performance of the rock 
apron; (9) reasonable assurance requirements, NRC staff review 
procedures, and other regulatory requirements; (10) post-licensing 
monitoring and maintenance; and (11) other conservatisms in the design. 
Each of these factors was discussed in a degree of detail that was not 
provided in the TER. In addition, specific contentions and questions 
raised by the GCC, ACE, and/or DRC were addressed.

III. Discussion

    As discussed in the TER, the staff considers that an adequate 
design has been provided for the rock apron to be placed at the toe of 
the Atlas tailings pile side slope near the Colorado River. This 
conclusion is based on many factors, including evaluation of design 
details that are very site-specific.
    For the Atlas site, the design of the rock apron is affected by 
three principal factors: (1) The velocity or shear stress that is used 
in various analytical methods to determine the rock size necessary to 
resist erosive forces; (2) the analytical methods that are used to 
determine rock size, layer thickness, and rock volume; and (3) the 
estimated scour depth that is used to determine volume of rock needed 
in the apron. For each of these factors, there may be several 
acceptable methods for estimating and calculating the parameters. For 
example, a designer could assume various combinations of values for 
velocity, shear stress, radius of curvature, or other inputs to a 
design method and arrive at different estimates of rock size and rock 
volume. Also, each parameter requires input data, based to a great 
extent on the assumed configuration of the river and other assumptions 
related to expected river velocities.
    It should also be emphasized that there are many procedures for 
determining the rock sizes necessary to resist erosion. Over the years, 
various Government agencies and individuals have developed procedures 
that best suit their needs, given the degree of conservatism necessary, 
the risk to public health and safety, and other factors, such as cost. 
Use of any specific one of those procedures, including the ACE 
procedure, for determining rock size, is not necessarily ``correct'' 
nor required. It should be recognized that different methods are used 
by different organizations and agencies. ACE's special need to protect 
embankments, where erosion or failure could immediately jeopardize many 
lives behind those structures, is not necessarily the needs of 
designers to provide reasonable assurance of tailings stability, or to 
meet the requirements of 10 CFR Part 40, Appendix A.
    The staff considers it important to use input parameter values that 
can be reasonably expected to affect the rock apron (if the river were 
to migrate), not values that are based on very conservative 
assumptions. For many situations where streambank erosion is imminent, 
a bank configuration can be easily determined, based on observed 
conditions. However, in this case, the main river channel is hundreds 
of feet away and not threatening the tailings pile, and the rock apron 
must be designed for some future unknown configuration of the river. 
Therefore, the staff assumed that the river would retain its principal 
characteristics, even though it had migrated. Recognizing that exact 
characteristics would be difficult to predict, the staff assumed that 
the river would retain the same width, depth, radius of curvature, and 
velocity. It is also possible that the river would migrate and develop 
characteristics such as increased width, decreased depth, decreased 
velocity, and increased radius of curvature; such assumptions would 
result in lesser rock apron designs being protective of the pile.
    In making assumptions such as those discussed above, the staff is 
required by 10 CFR Part 40, Appendix A, to have reasonable assurance of 
tailings stability. The staff is not required to make a determination 
with absolute certainty. Therefore, given the fact that river migration 
to the pile in itself is unlikely, the staff is required only to assume 
a reasonable configuration, not necessarily an extreme configuration 
that maximizes every design parameter or input to a riprap design 
method. Recognizing that a considerable amount of judgment is necessary 
to predict design conditions at this site , such as river configuration 
or river velocity, it is not the position of the NRC staff to assume 
the most critical value for every input parameter that is used in every 
calculation. Reasonable assurance only requires that input parameters 
be selected within a reasonably conservative range of values of the 
parameter.
    It should be emphasized that the staff does not consider the ACE 
analyses or design method to be incorrect or inappropriate. Rather, the 
staff considered that the input parameters selected for use in the 
analyses were overly conservative for this specific application and do 
not represent conditions that can reasonably be expected to occur if 
the river were to migrate to the rock apron. In the SR, the staff 
provided many reasons to support its conclusion that the licensee's 
design was adequate and provided extensive discussion to show that the 
ACE report overestimates the riprap sizes and quantity of rock required 
for the rock apron to provide reasonable assurance of tailings 
stability. In summary, based on independent analyses of the licensee's 
proposal and the information provided the DRC and ACE, the staff 
concludes that Atlas proposes to use a volume and size of rock that is 
larger than the volume and size computed by the staff.
    Each of the assertions made by the State in the Petition have been 
addressed previously by the staff. The staff provided its initial 
findings in its TER and provided further details of the staff analysis 
in its supplemental report that was transmitted to the State by letter 
dated February 26, 1998. The staff has provided detailed technical 
bases for its conclusion that the design of the rock apron meets the 
requirements of 10 CFR Part 40, Appendix A.
    The State was offered an opportunity to provide additional 
information to further address its assertions. The State indicated that 
no additional information would be provided for staff review or 
consideration.
    Each of the State's assertions is addressed in the following 
discussions. Each assertion is stated and a brief summary of the 
staff's analysis is provided. If additional details are needed, they 
may be found in the staff's SR.
    Assertion 1. The unpredictability of flood events, erosion, and 
vegetation growth along the river banks makes computation of the 
probability of river migration very difficult, and therefore 
conservatism should be built into the tailings pile design.
    The staff agrees that the computation of the probability of river 
migration is difficult. However, the staff has concluded that the 
potential for migration of the Colorado River to the tailings pile is 
very low and has provided several bases supporting that conclusion. The 
staff has also concluded that adequate conservatism has been provided 
by the apron design to demonstrate that Part 40 requirements have been 
met and has provided detailed analyses and technical bases supporting 
that conclusion.
    First, the staff examined aerial photographs of the Colorado River 
in this area, taken over a period of about 47 years. Those photographs 
verified

[[Page 3990]]

that very little erosion has occurred over that period of time.
    Second, the staff reviewed a report prepared by expert 
geomorphologists that addressed the river migration issue. In that 
report, it was concluded that river migration was unlikely and that 
lateral accretion, rather than erosion, has occurred in some areas near 
the pile. Those expert geomorphologists also examined aerial 
photographs and concluded that: ``Review of available historical 
photographs indicates that the right bank * * * has remained remarkably 
fixed spatially.'' (Emphasis added.)
    Third, the staff has visited the site several times and has 
determined that only some minor erosion of the river banks has occurred 
and that this can be attributed to sloughing, rather than erosion from 
river velocities. In fact, it was this minor erosion that led the staff 
to question the original conclusion of the licensee that the river 
would not erode.
    Fourth, despite the information available on channel stability, a 
conservative approach was taken by Atlas in its reclamation plan by 
assuming that the Colorado River would migrate to the tailings pile and 
by designing the erosion protection apron to account for that event. 
This approach eliminated the need for Atlas to conduct further detailed 
analyses of river migration and provided a design that exceeds the 
reasonable assurance requirements specified in Part 40, Appendix A.
    Fifth, the staff examined the effects of increased vegetation 
growth on the erosion potential of the Colorado River. The staff 
performed independent calculations and concluded that the potentially 
increased density of vegetation and tamarisks in the floodplains of the 
river will not significantly affect river velocities. Staff 
computations indicate that the maximum velocity will be only slightly 
increased in the river channel near the tailings pile. Based on staff 
experience with vegetated floodplains and the widespread use of 
vegetation to stabilize channel banks, it is also likely that increased 
vegetation density of the river will increase the erosion resistance of 
the channel banks and floodplain area near the tailings pile.
    Assertion 2. There are two different conceptual designs: one 
presented by Atlas and accepted by the staff; and the second presented 
by the ACE.
    The staff has recognized for some time that there are two designs 
and that the designs are different. In the SR, the staff addressed the 
ACE design and provided a detailed analysis of the ACE method and the 
use of various input parameters to the ACE method. The staff performed 
a detailed review of the analyses, provided in the ACE report, that 
were used to assess the rock requirements for the apron. The staff 
evaluated input parameters related to computation of scour depths, 
river velocities, increases in river velocities at channel bends, and 
factors of safety. The staff also examined the technical basis for the 
development of the ACE procedure, including the supporting laboratory 
data. The staff's analysis of the ACE report is also discussed in 
Assertion 3, below.
    Assertion 3. Assumptions and inputs to the conceptual models 
results in differences in the size, gradation, and volume of rock 
necessary to protect the tailings pile from erosion by the Colorado 
River.
    The staff has recognized that differences in input parameters can 
significantly affect the size and volume of rock required for the rock 
apron. Extensive discussion of the ACE report and the ACE design method 
were provided in the SR.
    Based on its review of the ACE report, the staff concluded that the 
design parameters selected for use in the ACE calculations of rock size 
were very conservative and did not reflect conditions that are likely 
to occur at the rock apron if the river migrated to the tailings pile. 
Velocities, radii of curvature, and scour depths were based on 
conditions that currently exist upstream, but do not exist in the 
vicinity of the apron. Velocities that would affect the apron will 
likely be smaller, and radii of curvature greater, than those that 
currently exist upstream of the site. In addition, the methods used by 
ACE to determine design velocities, increases in velocities in bends, 
and scour depths are conservative and incorporate large factors of 
safety that may not be necessary to provide reasonable assurance that 
Appendix A requirements are met. The staff, however, concluded that if 
reasonable and likely, values of channel velocity and channel curvature 
are used in the ACE method, the rock apron design proposed by Atlas is 
acceptable, even if all the other ACE safety factors are taken into 
account.
    Assertion 4. The DRC staff has concluded that the ACE approach is 
more protective of the tailings pile side slope.
    The staff agrees that the ACE design is more conservative than the 
design approved and would protect the pile under more severe conditions 
if such conditions were to occur. Use of the ACE approach to determine 
rock size and volume results in larger quantity of larger rock. 
However, the staff has concluded that the design proposed by Atlas is 
acceptable and that more and larger rock is not required to meet the 
requirements of Appendix A.
    In the SR, the staff provided an extensive discussion of how the 
reasonable assurance requirements are met by the proposed design. 
Further discussion was also provided on the use of standard review 
plans and design procedures that reflect an approach to tailings 
management that incorporates an appropriate level of safety.
    Of considerable importance in the NRC staff's assessment of Atlas' 
proposed design of the rock apron is the concept of ``reasonable 
assurance.'' NRC regulations require (Part 40, Appendix A, Criterion 6) 
``* * * a design which provides reasonable assurance of control of 
radiological hazards to * * * be effective for 1000 years* * * .'' This 
requirement comes directly from U.S. Environmental Protection Agency 
(EPA) requirements in 40 CFR Part 192. These standards do not require 
absolute nor even near certainty.
    Several reasons can be offered to justify the appropriateness of a 
``reasonable assurance'' requirement, rather than a more conservative 
requirement. Of primary importance is that exposure to uranium mill 
tailings do not pose an immediate acute risk to the health and safety 
of individuals. Rather, the risk posed by tailings is from continual 
exposure to low levels of radioactivity and is a long-term cumulative 
risk. If control of tailings were lost (for example, if an earthquake 
beyond the design basis were to damage the cover and expose tailings), 
actions could be taken to repair the damage, with little likelihood of 
endangering individuals.
    Additionally, uranium mill tailings disposal sites will be under 
perpetual government custodial care. If the features providing control 
of the tailings were damaged or compromised in the future, the 
government custodian could assess the situation and provide repairs. 
Although NRC standards require that the design for control of 
radiological hazards not rely on maintenance, the concept of 
``reasonable assurance'' does not preclude contemplation of government 
custodian actions in unusual or unlikely situations.
    Finally, the rock apron does not have to withstand a single, severe 
event that could occur without warning at any time. This is unlike the 
situation in designing protection from earthquakes or severe 
precipitation. For those events, the protective design may not be 
tested for decades or centuries and then, in a

[[Page 3991]]

very short time, have to perform with a design event. If the Colorado 
River were to migrate towards the tailings pile, it would occur over 
decades or centuries. There would be ample time to determine whether 
the assumptions used in the design of the rock apron (e.g., the scour 
depth, river curvature, river velocity, etc.) were correct or 
appropriate.
    In summary, NRC regulations and EPA standards do not require the 
degree of certainty about the potential future threats to the rock 
apron that would require an extremely conservative design, but rather 
``reasonable assurance'' that the design will protect the tailings 
pile.
    Assertion 5. The DRC disagrees with the NRC conclusion that the 
Atlas design provides the necessary protection of the tailings pile. 
DRC asserts that the apron design does not meet the requirements of 10 
CFR Part 40, Appendix A.
    As discussed in the TER and SR, the staff performed detailed 
evaluations of the proposed design. Based on those evaluations, the 
staff concludes that: (1) A conservative approach was taken by Atlas in 
its reclamation plan by assuming that the Colorado River would migrate 
to the tailings pile and by designing the erosion protection apron to 
account for that event; (2) the rock size of 11 inches proposed by 
Atlas for the rock apron is greater than the rock size of about 2.4 
inches required to resist velocities produced by the Colorado River on 
the collapsed rock apron, based on the most conservative calculated 
channel velocity and considering the effects of channel curvature and 
increased shear forces on the outside of channel bends; (3) the volume 
of rock provided for the apron is acceptable; (4) the maximum river 
velocity that should be used for the design of the rock apron for 
reasonable assurance is approximately 5.2 feet per second (ft/sec), 
rather than the 6.9 ft/sec used by ACE; (5) the potentially increased 
density of vegetation and tamarisks in the floodplains of the river 
will not significantly affect river velocities in the channel; (6) the 
design parameters selected for use in the ACE calculations of rock size 
are very conservative and are not likely to reflect conditions that 
will exist at the rock apron, if the river were to migrate to the pile 
in the future; (7) cohesive soils that could adversely affect the 
performance of the apron are not significantly present; (8) the 
requirement of reasonable assurance of site stability for a period of 
200-1000 years is met by the proposed apron design; (9) a post-
licensing monitoring and maintenance program will be implemented for 
this by the long-term custodian and will help to assure that 
requirements are continuously met and to assure that any unexpected 
problems occurring at the site will be promptly detected and mitigated; 
(10) the current design includes an over-designed volume of 5.3-inch 
rock on the side slope of the tailings pile that would be available to 
also launch into any gaps formed in the launched 11-sinch rock; (11) 
the riprap for the side slopes is designed for a precipitation 
intensity approaching the world record rainfall intensity; and (12) the 
riprap layer thickness exceeds the design criteria routinely accepted 
by the staff; and (13) the rock sizes that will actually be constructed 
will likely exceed the sizes proposed by Atlas.

IV. Conclusions and Recommendations

    The NRC staff has reviewed the concerns and issues raised in the 
State's Petition and has concluded that the rock apron design for the 
Atlas reclamation plan complies with 10 CFR Part 40, Appendix A. For 
the reasons discussed above, no basis exists for taking any action in 
response to the Petition. Accordingly, no action pursuant to Section 
2.206 is being taken.

    Dated at Rockville, Maryland, this 20th day of January, 1999.

    For the Nuclear Regulatory Commission.
Carl J. Paperiello,
Director, Office of Nuclear Material Safety and Safeguards.
[FR Doc. 99-1702 Filed 1-25-99; 8:45 am]
BILLING CODE 7590-01-P