Omaha Public Power District Independent Spent Fuel Storage Installation; Environmental Assessment and Finding of No Significant Impact, 41058-41061 [E6-11408]

Agencies

• NUCLEAR REGULATORY COMMISSION

[Federal Register Volume 71, Number 138 (Wednesday, July 19, 2006)]
[Notices]
[Pages 41058-41061]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E6-11408]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 72-54]


Omaha Public Power District Independent Spent Fuel Storage 
Installation; Environmental Assessment and Finding of No Significant 
Impact

AGENCY: Nuclear Regulatory Commission.

ACTION: Issuance of an Environmental Assessment and Finding of No 
Significant Impact.

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FOR FURTHER INFORMATION CONTACT: Joseph M. Sebrosky, Senior Project 
Manager, Spent Fuel Project Office, Office of Nuclear Material Safety 
and Safeguards, U.S. Nuclear Regulatory Commission, Washington, DC 
20555. Telephone: (301) 415-1132; Fax number: (301) 415-8555; E-mail: 
jms3@nrc.gov.

SUPPLEMENTARY INFORMATION: The U.S. Nuclear Regulatory Commission (NRC 
or Commission) is considering issuance of an exemption to Omaha Public 
Power District (OPPD) pursuant to 10 CFR 72.7, from specific provisions 
of 10 CFR 72.48(c)(2)(viii), 72.212(a)(2), 72.212(b)(2)(i)(A), 
72.212(b)(7), and 72.214. The licensee wants to use the Transnuclear, 
Inc. (TN) Standardized NUHOMS[supreg] Storage System, Certificate of 
Compliance No. 1004 (CoC or Certificate) Amendment No. 8 (32PT dry 
shielded canister), to store spent nuclear fuel under a general license 
in an Independent Spent Fuel Storage Installation (ISFSI) associated 
with the operation of the Fort Calhoun Station (FCS), located in 
Washington County, Nebraska. OPPD is requesting an exemption from CoC 
No. 1004 and NRC regulations to allow changes to the transfer cask (TC) 
dose rate measurements, an earlier start time for vacuum drying and use 
of a method of thermal analysis that is a departure from the 
methodology described in the Standardized NUHOMS[supreg] updated final 
safety analysis report (FSAR).

Environmental Assessment (EA)

    Identification of Proposed Action: The proposed action would exempt 
OPPD from the requirements of 10 CFR 72.48(c)(2)(viii), 72.212(a)(2), 
72.212(b)(2)(i)(A), 72.212(b)(7), and 72.214 and enable OPPD to use a 
light weight TC and allow the use of an earlier start time for vacuum 
drying in conjunction with the Standardized NUHOMS[supreg] Storage 
System, CoC 1004, at the FCS. Sections 10 CFR 72.212(a)(2), 
72.212(b)(2)(i)(A), 72.212(b)(7), and 72.214 specifically require 
storage in casks approved under the provisions of 10 CFR part 72 and 
compliance with the conditions set forth in the CoC for each dry spent 
fuel storage cask used by an ISFSI general licensee. The TN 
NUHOMS[supreg] CoC provides requirements, conditions, and operating 
limits in Attachment A, Technical Specifications (TSs). The proposed 
action would exempt OPPD from the requirements of 10 CFR 10 CFR

[[Page 41059]]

72.212(a)(2), 10 CFR 72.212(b)(2)(i)(A), 10 CFR 72.212(b)(7) and 10 CFR 
72.214 in order to permit changes from TSs in Amendment 8 to CoC No. 
1004 which would allow changes to the TC dose rate measurements, and 
allow an earlier start time for vacuum drying. Specifically, the 
exemption would be from CoC No. 1004 Attachment A, TSs, 1.2.1, ``Fuel 
Specification,'' 1.2.11, ``Transfer Cask Dose Rates with a Loaded 24P, 
52B, 61BT, or 32PT Dry Shielded Canister,'' and 1.2.17a, ``32PT Dry 
Shielded Canister Vacuum Drying Duration Limit.'' In addition, the 
proposed action would exempt OPPD from requirements of 10 CFR 
72.48(c)(2)(viii), which requires that a general licensee request that 
the certificate holder obtain a CoC amendment prior to implementing a 
change that would result in a departure from a method of evaluation 
described in the FSAR for the design. The method of evaluation for 
which OPPD is seeking an exemption involves the thermal analysis 
associated with the TC while it is inside the transfer trailer 
radiological shielding.
    OPPD committed in its June 9, 2006, submittal to a maximum decay 
heat load per dry shielded canister (DSC) of 11 kilowatts (kW). This is 
less than the CoC No. 1004 Attachment A, Technical Specification, Table 
1-1e maximum decay heat limit of 24 kW per DSC. In addition, in its 
July 3, 2006, supplement OPPD indicated that the minimum cooling time 
for the fuel that it intended to load is 16.2 years. This time is 
greater than the minimum amount of time specified in TS Table 1-1e.
    The NRC has determined that the exemption, if granted, will contain 
the following four conditions: (1) OPPD will be limited to loading a 
total of four 32PT DSCs, (2) OPPD shall limit the decay heat level per 
DSC to 11 kW to ensure cask loadings are bounded by the analyses 
supporting the TN CoC No. 1004, Amendment No. 8, (3) OPPD shall limit 
the cooling time of the fuel that it intends to load to a minimum of 
16.2 years to ensure that the radiological source term for fuel that is 
loaded in the light weight TC is kept as low as reasonably achievable, 
and (4) the TS 1.2.11 dose rate limit/specification are substituted 
with the limit of 170 mrem/hr in the axial direction and 110 mrem/hr in 
the radial direction. The axial dose rate limit of 170 mrem/hr is to be 
taken under the conditions in Table 1 below. The radial dose rate limit 
of 110 mrem/hr is to be taken under the conditions in Table 2 below.

           Table 1.--Axial Dose Rate Measurement Configuration
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32PT DSC inside the OS197L inside the decon sleeve/bell
Water drained from the DSC
TC/DSC annulus full (within approximately 1 foot of the top)
TC neutron shield full
Top shield plug in place and included in axial shielding
Inner top cover plate in place and included in axial shielding
Automated welding system (AWS) with integral shield in place and
 included in axial shielding
Measurement taken at vertical centerline of DSC, 3 feet from AWS shield
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          Table 2.--Radial Dose Rate Measurement Configuration
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32PT DSC inside OS197L inside decon sleeve/bell
water drained from the DSC
TC/DSC annulus full (within approximately 1 foot of the top)
TC neutron shield full
6 inch nominal thickness carbon steel decon sleeve/bell in place and
 included in radial shielding
measurement taken at outside surface (contact) of decon sleeve/bell
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    The proposed action is in accordance with the licensee's request 
for exemption dated June 9, 2006, as supplemented July 3, 2006, July 7, 
2006, and July 12, 2006.
    Need for the Proposed Action: The proposed action is needed because 
the FCS will lose full core offload after the 2006 refueling outage. 
During this refueling outage, major components of the reactor coolant 
system will be replaced including two steam generators, the reactor 
vessel head and the pressurizer. The large amount of reactor coolant 
system components being replaced during the outage raises the 
likelihood that foreign material could be introduced into the reactor 
vessel and potentially deposited under the core support plate. This 
scenario would require the core to be offloaded to the spent fuel pool 
and the reactor core barrel to be removed to allow removal of the 
foreign material. In addition, allowing four DSCs to be loaded prior to 
the beginning of the refueling outage would allow better management of 
decay heat loads within the spent fuel pool (including minimization of 
fuel handling activities) and would also allow the receipt and storage 
of new fuel prior to the refueling outage. Regarding receipt and 
storage of the new fuel, OPPD intends to inspect 44 new fuel assemblies 
and 49 new control rods to support the 2006 refueling outage. Once 
inspections are complete the assemblies are transferred from the new 
fuel storage rack into the spent fuel pool. This fuel handling 
operation requires more resources, presents more radiological 
challenges, and is more complicated than normal intra-spent fuel pool 
fuel movements. Consequently, it is OPPD's practice to perform these 
operations prior to a refueling outage before the spent fuel from the 
core is offloaded into the spent fuel pool.
    The proposed action is necessary because the NRC has not received 
an amendment to CoC No. 1004 to allow changes to the TC dose rate 
measurements, an earlier start time for vacuum drying and the use of a 
method of thermal analysis that is a departure from the methodology 
described in the Standardized NUHOMS[supreg] updated FSAR. The staff 
would have to review such an amendment request and only after making 
the appropriate findings would the staff initiate a 10 CFR 72.214 
rulemaking to implement the change. This process typically takes at 
least 10 months from the receipt of the amendment request for simple 
license amendments. Complex license amendments can take over 30 months. 
Therefore, an amendment to allow changes to the TC dose rate 
measurements, an earlier start time for vacuum drying and the use of a 
method of thermal analysis that is a departure from the methodology 
described in the Standardized NUHOMS[supreg] updated FSAR can not be 
completed in time to support OPPD's stated needs.
    Environmental Impacts of the Proposed Action: The NRC has completed 
its evaluation of the proposed action and concludes that there will be 
no significant environmental impact if the exemption is granted. The 
staff has determined that the proposed action would not endanger life 
or property. The potential environmental impact of using the 
NUHOMS[supreg] system was initially presented in the Environmental 
Assessment (EA) for the Final Rule to add the TN Standardized 
NUHOMS[supreg] Horizontal Modular Storage System for Irradiated Nuclear 
Fuel to the list of approved spent fuel storage casks in 10 CFR 72.214 
(59 FR 65898, dated December 22, 1994).
    The staff performed a safety evaluation of the proposed exemption. 
The staff has determined that the exemption to allow changes to the TC 
dose rate measurements, an earlier start time for vacuum drying and the 
use of a method of thermal analysis that is a departure from the 
methodology described in the Standardized

[[Page 41060]]

NUHOMS[supreg] updated FSAR meets the requirements of 10 CFR part 72 
for granting an exemption. Regarding the changes to the TC dose rate 
measurements, OPPD is seeking an exemption from TS 1.2.1, and 1.2.11. 
The exemption from TS 1.2.1 and 1.2.11 relate to the wording in these 
TSs for the TC dose rates. OPPD proposes to use a light weight TC that 
has reduced shielding including the elimination of all the lead 
shielding from previous versions of the TC. The reduced shielding 
results in a lower weight for the TC. The OS197L TC was developed by TN 
to be used at plants with reduced spent fuel pool building crane 
capacity. The OS197L TC is intended for plants that are limited to a 75 
ton spent fuel pool building crane capacity. The TC that the OS197L TC 
replaces (which TN designates as the OS197 TC) requires a 100 ton spent 
fuel pool building crane capacity. Because the OS197L TC has less 
shielding (including the elimination of all the lead shielding) than 
the OS-197, the OS197L TC surface dose rates are higher than the OS197 
TC with lead shielding. To reduce personnel doses, crane operations 
associated with the OS197L TC are done remotely and supplemental 
shielding is provided in the decontamination area where the DSC is 
welded and on the transfer trailer that is used to transport the OS197L 
TC to the horizontal storage module. The TS 1.2.1 and TS 1.2.11 
exemptions involve the use of supplemental shielding in addition to the 
shielding provided by the OS917L TC to meet the intent of the TSs. TS 
1.2.11 involves the measurement of the TC surface dose rates in the 
axial and radial direction. The objective of taking these dose rate 
measurements is to ensure that the DSC has not been inadvertently 
loaded with fuel not meeting specification (i.e., a fuel misload), and 
to maintain dose rates ALARA.
    In the safety evaluation report (SER) the staff provides the 
following reasons for granting the exemptions to TS 1.2.1 and 1.2.11: 
(1) Use of fuel with a minimum cooling time of 16.2 years ensures that 
the OS197L TC surface dose rate will be significantly lower than it 
would be for bounding type fuel, (2) appropriate ALARA precautions are 
being taken at the FCS given the use of the OS197L TC, and (3) use of 
the OS197L TC is limited to four DSCs and is found to be acceptable at 
the FCS due to the extenuating circumstances that are described in 
OPPD's exemption request (e.g., limited to use of a 75 ton crane, loss 
of full core offload capability, allow receipt and storage of new fuel, 
and allow better management of decay heat loads within the spent fuel 
pool). Additional reasons cited in the SER for granting the exemption 
to TS 1.2.11 include: (1) OPPD calculated TS limits specifically for 
the axial and radial directions and the calculations in the radial 
direction included the supplemental shielding, (2) OPPD's calculated 
values are consistent with the TS 1.2.11 values, and (3) the applicant 
demonstrated that the appropriate procedures will be in place to 
identify a fuel misloading and maintain doses ALARA. Based on the 
technical information provided in the exemption request, and the 
reasons provided above, the staff finds that there is reasonable 
assurance the applicant meets the shielding and dose requirements of 10 
CFR part 72 and 10 CFR part 20.
    Regarding an earlier start time for vacuum drying, the staff 
reviewed OPPD's request to change TS 1.2.17a. OPPD will start the time 
limit for completing vacuum drying earlier in the loading sequence and 
will use helium as the backfill gas. In the current FSAR, draining up 
to 750 gallons of water from the DSC prior to it leaving the spent fuel 
pool is allowed to reduce the weight on the crane. The DSC is then 
placed in the decontamination area where the inner top cover plate is 
welded. During the welding process approximately 750 gallons of water 
remains in the DSC. After the welding is completed and the weld 
examinations are successfully performed, the remaining water in the DSC 
is removed and vacuum drying is started. Unlike what is currently 
described in the FSAR, OPPD plans to remove the majority of the water 
from the DSC prior to it leaving the spent fuel pool. OPPD plans to 
perform the welding of the DSC inner top cover plate with the DSC in 
the drained condition. To support draining the DSC earlier in the 
process than currently described in the FSAR, OPPD proposes to start 
the time limit associated with completing vacuum drying at the time 
that the initial 750 gallon drain down from the canister is achieved, 
which is prior to movement of the cask/canister to the decontamination 
area.
    The time limits of TS 1.2.17a were selected to ensure that the 
maximum cladding temperature is within the acceptable limit of 752 
[deg]F during vacuum drying. These time limits also ensure that the 
cladding temperature meets the thermal cycling criteria of 117 [deg]F 
during drying, helium backfilling, and transfer operations. The staff's 
basis for concluding that the exemption is appropriate, as documented 
in the staff's SER, is that starting the time limit for vacuum drying 
earlier in the loading sequence is bounded by the thermal analysis 
previously performed. Therefore, based on its review of the 
representations and information supplied by the applicant the staff 
concludes that the change to the sequence to drain the DSC earlier in 
the process and the corresponding change to the start of the vacuum 
drying time has been adequately described and evaluated by the 
applicant, and finds reasonable assurance that these changes meet the 
thermal requirements of 10 CFR part 72.
    Regarding the change in method of evaluation related to the 
modeling of the heat transfer for the OS197L TC while it is inside the 
transfer trailer temporary shielding, OPPD intends to limit the loading 
of the DSCs to a total heat load of 11 kW. The supplemental shielding 
on the transfer trailer causes an impediment to heat transfer. Limiting 
the heat load of the DSC to 11 kW ensures that this configuration is 
bounded by the design basis fuel assemblies thermal analysis previously 
evaluated by the staff. The 11 kW limit is less than the CoC No. 1004 
Attachment A, Technical Specification, Table 1-1e maximum decay heat 
limit of 24 kW and is therefore bounding. Based on its review of the 
representations and information supplied by the applicant the staff 
concludes that the thermal design for the TC inside the transfer 
trailer has been adequately described and evaluated by the applicant, 
and finds reasonable assurance that by limiting the heat load to 11 kW 
the thermal requirements of 10 CFR part 72 are met.
    The proposed action to allow changes to the TC dose rate 
measurements, an earlier start time for vacuum drying and the use of a 
method of thermal analysis that is a departure from the methodology 
described in the Standardized NUHOMS[supreg] FSAR do not increase the 
probability or consequences of accidents, and no changes are being made 
in the types of any effluents that may be released offsite. 
Occupational exposures will not increase adversely because of the use 
of remote handling techniques for the OS197L TC and the additional 
supplemental shielding provided in the decontamination area and on the 
transfer trailer. Likewise public radiation exposure will not increase 
adversely due to the additional shielding provided on the transfer 
trailer. For an accident condition a complete loss of the OS197L TC 
neutron shield and the transfer trailer supplemental shielding was 
postulated. The dose rate at the site boundary assuming bounding fuel 
in a 32PT

[[Page 41061]]

canister and a 100 meter site boundary is approximately 13 mrem/hour. 
This equates to a 104 mrem dose at the site boundary assuming an 8 hour 
recovery period. This dose is well below the 10 CFR 72.106 regulatory 
limit of 5000 mrem for accident conditions. Therefore, there are no 
significant radiological environmental impacts associated with the 
proposed action.
    The exemption only affects the requirements associated with TC dose 
rate measurements, an earlier start time for vacuum drying, and the use 
of a different thermal analysis of the TC on the transfer trailer and 
does not affect non-radiological plant effluents or any other aspects 
of the environment. Therefore, there are no significant non-
radiological impacts associated with the proposed action.
    Accordingly, the Commission concludes that there are no significant 
environmental impacts associated with the proposed action.
    Alternative to the Proposed Action: Because there is no significant 
environmental impact associated with the proposed action, alternatives 
with equal or greater environmental impact were not evaluated. As an 
alternative to the proposed action, the staff considered denial of the 
proposed action. Denial of the exemption would result in no change in 
the current environmental impact.
    Agencies and Persons Consulted: This exemption request was 
discussed with Julia Schmitt of the Nebraska Health and Human Services 
Regulation and Licensure Radiation Control Program Office on July 5, 
2006. The State official had no comments regarding the environmental 
impact of the proposed action. The NRC staff has determined that a 
consultation under Section 7 of the Endangered Species Act is not 
required because the proposed action will not affect listed species or 
critical habitat. The NRC staff has also determined that the proposed 
action is not a type of activity having the potential to cause effects 
on historic properties. Therefore, no further consultation is required 
under Section 106 of the National Historic Preservation Act.
    Conclusion: The staff has reviewed the exemption request submitted 
by OPPD. Allowing changes to the TS TC dose rate measurements, an 
earlier start time for vacuum drying, and a different method of thermal 
analysis of the TC on the transfer trailer would have no significant 
impact on the environment.

Finding of No Significant Impact

    The environmental impacts of the proposed action have been reviewed 
in accordance with the requirements set forth in 10 CFR part 51. Based 
upon the foregoing Environmental Assessment, the Commission finds that 
the proposed action of granting the exemption from specific provisions 
of 10 CFR 72.48(c)(2)(viii), 72.212(a)(2), 72.212(b)(2)(i)(A), 
72.212(b)(7), and 72.214 to allow OPPD to make changes to the TS TC 
dose rate measurements, an earlier start time for vacuum drying, and a 
different method of thermal analysis of the TC on the transfer trailer, 
subject to conditions, will not significantly impact the quality of the 
human environment. Accordingly, the Commission has determined that an 
environmental impact statement for the proposed exemption is not 
warranted.
    In accordance with 10 CFR 2.390 of NRC's ``Rules of Practice,'' 
final NRC records and documents regarding this proposed action are 
publically available in the records component of NRC's Agencywide 
Documents Access and Management System (ADAMS). The request for 
exemption dated June 9, 2006, and supplemented July 3, 2006, July 7, 
2006, and July 12, 2006, was docketed under 10 CFR part 72, Docket No. 
72-54. These documents may be inspected at NRC's Public Electronic 
Reading Room at https://www.nrc.gov/reading-rm/adams.html. These 
documents may also be viewed electronically on the public computers 
located at the NRC's Public Document Room (PDR), O1F21, One White Flint 
North, 11555 Rockville Pike, Rockville, MD 20852. The PDR reproduction 
contractor will copy documents for a fee. Persons who do not have 
access to ADAMS or who encounter problems in accessing the documents 
located in ADAMS, should contact the NRC PDR Reference staff by 
telephone at 1-800-397-4209 or (301) 415-4737, or by e-mail to 
pdr@nrc.gov.

    Dated at Rockville, Maryland, this 13th day of July, 2006.

    For the Nuclear Regulatory Commission.
Joseph M. Sebrosky,
Senior Project Manager, Spent Fuel Project Office, Office of Nuclear 
Material Safety and Safeguards.
 [FR Doc. E6-11408 Filed 7-18-06; 8:45 am]
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