Southern California Edison Company (San Onofre Nuclear Generating Station, Unit 1); Exemption

NUCLEAR REGULATORY COMMISSION

[Docket No. 50-206]

Southern California Edison Company (San Onofre Nuclear Generating

Station, Unit 1); Exemption

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 November 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 Regulations, Sec. 140.11(a)(4) (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, 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 interested period 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 140.11(a)(4).

III

The Justification presented by the licensee for the request is that

the 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 10 CFR 140.11(a)(4) are no

longer applicable to SONGS 1, and there is no credible risk of an

accident at SONGS 1 with damages exceeding the $200 million primary

coverage which will remain in effect at the SCE site. SCE asserts that

because SONGS 1 will not benefit from secondary coverage it should not

be obligated to extend such coverage. Additionally, exclusion of 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.

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 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 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 deg.). 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 stainless steel

fuel cladding can support a self-sustaining oxidation 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 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.

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 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.

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 in the public interest. Therefore, the Commission grants

an exemption from the requirements of 10 CFR 140.11(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).

This exemption is effective upon issuance.

Dated at Rockville, Maryland this 4th day of May 1994.

For the Nuclear Regulatory Commission.

Brian K. Grimes,

Director, Division of Operating Reactor Support, Office of Nuclear

Reactor Regulation.

[FR Doc. 94-11227 Filed 5-9-94; 8:45 am]

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