ML20029D643
| ML20029D643 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 05/04/1994 |
| From: | Grimes B Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20029D640 | List: |
| References | |
| NUDOCS 9405090151 | |
| Download: ML20029D643 (7) | |
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1 UNITED STATES OF AMERIM NUCLEAR REGULATORY COMMISSION In the Matter of
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SOUTHERN CALIFORNIA EDISON COMPANY
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Docket No. 50-206
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(San Onofre Nuclear Generating
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Station, Unit 1)
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l EXEMPTION i
I.
Southern California Edison Company (SCE or the licensee) is the holder of Facility Operating License No. DPR-13, which authorizes possession and maintenance of the San Onofre Nuclear Generating Station, Unit 1 (SONGS 1).
The license provides, among other things, that the licensee is subject to all rules, regulations, and orders of the Commission now or hereafter in effect.
The facility consists of a permanently shutdown pressurized water reactor at the SCE site located in San Diego County, California.
SONGS 1 is co-located with San Onofre Nuclear Generating Station, Units 2 and 3, which remain operational.
II.
SONGS 1 was permanently shut down in h ser 1992, and defueling of the reactor completed in March 1993. Upon licensee certification of the defueling on March 9, 1993, Amendment No. 150 to Facility Operating License No. DPR-13.
modifying the license to preclude reactor operation, became effective.
Title 10 of the Code of Federal Reaulations, Section 140.ll(a)(4)
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(10-CFR 140.11(a)(4)), requires each licensee to have and maintain primary nuclear liability insurance in an amount equal to $200 million.
In addition, 6
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4 o each licensee is required to maintain secondary financial protection in the form of private liability insurance under an industry retrospective plan.
However,10 CFR 140.8 allows that the Commission may, upon application of any
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interested person or upon its own initiative, grant such exemptions from the requirements of Part 140 as it determines are authorized by law and are otherwise in the public interest.
By letter dated February 2, 1993, the licensee requested the elimination of the current requirement for SONGS 1 to participate in the industry retrospective rating plan for secondary level coverage as required in 10 CFR j
140.11(a)(4).
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III.
I The justification presented by the licensee for the request is that the i
secondary financial protection requirements imposed by 10 CFR 140.11(a)(4) are applicable only to a reactor that is licensed to operate and that is designed for the production of electrical energy and has a rated capacity of 100,000 electrical kilowatts or more. The licensee contends that the provisions of a
l 10 CFR 140.11(a)(4) are no longer applicable to SONGS 1, and there is no
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credible risk of an accident at SONGS I with damages exceeding the $200 l
million primary coverag ich will remain in effect at the SCE site.
SCE t
l asserts that because 5 1 will not benefit from secondary coverage it should not be obligated to extend such coverage. Additionally, exclusion of i
SONGS 1 from the secondary financial program will remove the potential liability (up to $75.5 million per event, but not more than $10 million per year per event) that must be reported on SCE financial statements.
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e The NRC staff independently evaluated the legal and technical issues associated with the application of the Price-Anderson Act to permanently shut down reactors in SECY-93-127, " Financial Protection Required of Licensees of Large Nuclear Power Plants During Decommissioning," May 10, 1993.
In this evaluation, the staff concluded that the Commission has discretionary authority to respond to licensee requests for reduction in the level of primary financial protection and withdrawal from participation in the industry retrospective rating plan. Depending on the plant-specific configuration and the time since permanent shutdown, the staff also concluded that potential hazards may exist at permanently shut down reactors for which financial protection is warranted. The staff also concluded that accidents and hazards ensured against under Price-Anderson go beyond design basis accidents and beyond those considered " credible" as that term is used in 10 CFR Part 100 and cases interpreting the application of that regulation. The Commission issued a staff requirements memorandum (SRM) addressing SECY-93-127 on July 13, 1993.
In the exercise of its discretionary authority, the Commission may, as long as a potential hazard exists at a permanently shutdown reactor, require the full amount of primary financial protection and full participation in the industry retrospective rating plan. At such time as the hazard is determined to no longer exist, the Commission may reduce the amount of primary financial protection and permit the licensee to withdraw from participation in the industry retrospective rating plan.
Since the legislative history does not explicitly consider the potential hazards that might exist after termination of operation, the staff generically evaluated the offsite consequences associated with normal and abnormal
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. operations, design basis accidents, and beyond design basis accidents for reactors that have been permanently defueled and shut down. With regard to SONGS 1, the staff concluded that in view of the time that has elapsed since plant shutdown, aside from the handling, storage, and transportation of spent fuel and radioactive materials, no reasonably conceivable potential accident exists that could cause significant offsite damage.
A severe transportation accident could potentially result in local contamination requiring cleanup and offsite liabilities resulting from traffic disruption and loss of use. This type of accident would warrant maintaining some level of liability insurance. The liabilities and indemnification requirements associated with the transfer of spent fuel from the licensee to the Department of Energy will be evaluated on a case-by-case basis at a future time when spent fuel is shipped to a repository.
Typically, the most significant accident sequence for a permanently defueled and shutdown reactor involves the complete loss of water from a light water reactor spent fuel pool. For a spent fuel pool that contains fuel clad with Zircaloy, this beyond-design-basis accident sequence could result in a Zircaloy fuel cladding fire that could propagate through the spent fuel storage pool and result in significant offsite consequences. Although such an accident is beyond the design bases, it may be considered " reasonably conceivable" and could warrant financial protection. Such an accident is f
possible during the first year after reactor shutdown for a low density spent fuel storage configuration and during the first two to three years after shutdown for spent fuel stored in certain high density configurations.
However, the likelihood of occurrence of a fuel cladding fire at SONGS 1 is
negated because stainless steel, rather than Zircaloy, cladding is used at SONGS 1.
Zircaloy is a pyrophoric material which can undergo spontaneous oxidation before it reaches its melting point.
Zircaloy fuel cladding can therefore oxidize by a self-sustaining reaction (at a temperature of approximately 1650 ).
Stainless steel, however, cannot attain self-sustaining oxidation before it reaches its melting point.
This is due to the presence of chromium which forms an impervious oxide film which prevents oxygen from reaching the metal surface.
Consequently, there is no temperature at which l
stainless steel fuel cladding can support a self-sustaining oxidation I
reaction. Therefore, the postulated cladding fire accident scenario is not possible at SONGS 1.
However, using the Zircaloy fuel cladding analysis conservatively bounds the time at which fuel clad melting and fission product l
release could occur at SONGS 1.
Once the requisite cooling period after reactor shutdown has elapsed, fuel clad melting after a postulated loss of water is no longer a concern since the fuel would air cool sufficiently.
Possible accident scenarios, after these cooling periods have elapsed, have greatly reduced consequences, but could result in small releases or precautionary evacuations which could. result in offsite liability.
J The staff considered liability coverage needs associated with decommissioning activities and transportation of radioactive materials. The staff recognizes that the potential hazards and consequences associated with a reactor which has been permanently shut down with no spent fuel are greatly reduced, that such a reactor does not contribute a level of risk to the participants in the secondary pool proportionate to that of an operating reactor and that relief from financial protection requirements would then be
. l warranted. The results of our evaluation, as embodied in the July 13, 1993, SRM on SECY-93-127, allow a reduction in the amount of financial protection required of licensees of large nuclear plants that have been prematurely shut down. Although the licensee presented an opinion regarding the application of the Price-Anderson Act and 10 CFR Part 140 to permanently shut down reactors, the staff did not concur with this licensee opinion.
Nonetheless, SCE meets the criterion established in SECY-93-127 for relief from secondary financial protection requirements for low density spent fuel storage.
Specifically, more than 16 months have elapsed since SONGS 1 was permanently shut down.
This time period is conservative for SONGS 1.
The one-year cooling period prescribed in SECY-93-127 was based on fuel with Zircaloy cladding; SONGS 1 fuel is fabricated with stainless steel cladding which negates the likelihood and consequences of the cladding fire sequence and shortens the time after shutdown when fuel clad melting could occur upon loss of pool water, as discussed above.
IV.
The staff, based on its independent evaluation as embodied in the July 13,1993, SRM on SECY-93-127 " Financial Protection Required of Licensees of Large Nuclear Power Plants During Decommissioning," has concluded that sufficient bases exist for our approval of relief from the financial protection requirements for the San Onofre Nuclear Generating Station, Unit 1.
The staff has also concluded that granting the proposed exemption does not increase the probability or consequences of any accidents or reduce the margin of safety at this facility.
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V.
Based on Sections III and IV above, the Commission has determined that, pursuant to 10 CFR 140.8, this exemption is authorized by law and is otherwise l
in the public interest. Therefore, the Commission grants an exemption from the requirements of 10 CFR 140.ll(a)(4) to the extent that exemption from participation in the industry retrospective rating plan (secondary level financial protection) is granted for the San Onofre Nuclear Generating Station, Unit 1.
Pursuant to 10 CFR 51.32, the Commission has determined that the granting of this exemption will not have a significant effect on the quality of the human environment (59 FR 22872, dated May 3, 1994).
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This exemption is effective upon issuance.
FOR THE NUCLEAR REGULATOR COMMISSION l
i Brian K. Grimes, Director Division of Operating Reactor Support Office of Nuclear Reactor Regulation Dated at Rockville, Maryland this 4th day of May 1994 1
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