[Federal Register Volume 64, Number 11 (Tuesday, January 19, 1999)]
[Notices]
[Pages 2920-2921]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-1075]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-309]
Maine Yankee Atomic Power Company (Maine Yankee Atomic Power
Station); Application of Exemption
Exemption
I
Maine Yankee Atomic Power Company is the holder of Facility
Operating License No. DPR-36, which authorizes the licensee to possess
the Maine Yankee Atomic Power Station (MYAPS). The license states,
among other things, that the facility is subject to all the rules,
regulations, and orders of the U.S. Nuclear Regulatory Commission (the
Commission or NRC) now or hereafter in effect. The facility consists of
a pressurized-water reactor located at the licensee's site in Lincoln
County, Maine. The facility is permanently shut down and defueled, and
the licensee is no longer authorized to operate or place fuel in the
reactor.
II
Section 50.54(w) of 10 CFR Part 50 requires power reactor licensees
to maintain onsite property damage insurance coverage in the amount of
$1.06 billion. Section 140.11(a)(4) of 10 CFR Part 140 requires a
reactor with a rated capacity of 100,000 electrical kilowatts or more
to maintain liability insurance of $200 million and to participate in a
secondary insurance pool.
NRC may grant exemptions from the requirements of 10 CFR Part 50 of
the regulations, which, pursuant to 10 CFR 50.12(a), (1) are authorized
by law, will not present an undue risk to public health and safety, and
are consistent with the common defense and security and (2) present
special circumstances. Special circumstances exist when (1) application
of the regulation in the particular circumstances would not serve the
underlying purpose of the rule or is not necessary to achieve the
underlying purpose of the rule (10 CFR 50.12(a)(2)(ii)) or (2)
compliance would result in undue hardship or costs that are
significantly in excess of those incurred by others similarly situated.
The underlying purpose of Section 50.54(w) is to provide sufficient
property damage insurance coverage to ensure funding for onsite post-
accident recovery stabilization and decontamination costs in the
unlikely event of an accident at a nuclear power plant.
NRC may grant exemptions from the requirements of 10 CFR Part 140
of the regulations, which, pursuant to 10 CFR 140.8, are authorized by
law and are otherwise in the public interest. The underlying purpose of
Section 140.11 is to provide sufficient liability insurance to ensure
funding for claims resulting from a nuclear incident or a precautionary
evacuation.
III
On January 20, 1998, the licensee requested exemption from the
financial protection requirement limits of 10 CFR 50.54(w) and 10 CFR
140.11. The licensee requested that the amount of insurance coverage it
must maintain be reduced to $50 million for onsite property damage and
$100 million for offsite financial protection. The licensee stated that
special circumstances exist because of the permanently shutdown and
defueled condition of MYAPS.
The financial protection limits of 10 CFR 50.54(w) and 10 CFR
140.11 were established to require a licensee to maintain sufficient
insurance to cover the costs of a nuclear accident at an operating
reactor. Those costs were derived from the consequences of a release of
radioactive material from the reactor. Although the risk of an accident
at an operating reactor is very low, the consequences can be large. In
an operating plant, the high temperature and pressure of the reactor
coolant system, as well as the inventory of relatively short-lived
radionuclides, contribute to both the risk and consequences of an
accident. In a permanently shutdown and defueled reactor facility, the
reactor coolant system will never again be operated, thus eliminating
the possibility of accidents involving the reactor. A further reduction
in risk occurs because decay heat from the spent fuel decreases over
time. This reduction in decay heat reduces the amount of energy
available to heat up the spent fuel to a temperature that could
compromise the ability of the fuel cladding to retain fission products.
Along with the reduction in risk, the consequences of a release
decline after a reactor permanently shuts down and defuels. The short-
lived radionuclides contained in the spent fuel, particularly volatile
components such as iodine-131 and most of the noble gases, decay away,
thereby reducing the inventory of radioactive materials that are
readily dispersible and transportable in air.
Although the risk and consequences of a radiological release
decline substantially after a plant permanently defuels its reactor,
they are not completely eliminated. There are potential onsite and
offsite radiological consequences that could be associated with the
onsite storage of the spent fuel in the spent fuel pool (SFP). In
addition, a site may contain a radioactive inventory of liquid
radwaste, activated reactor components, and contaminated structural
materials. For purposes of modifying the amount of insurance coverage
maintained by a power reactor licensee, the potential consequences,
despite very low risk, are an appropriate consideration.
To determine the insurance coverage sufficient for a permanently
defueled facility, the cost of recovery from potential accident
scenarios must be evaluated. At MYAPS, spent fuel is the largest source
term on the site. The spent fuel is stored in the SFP, which uses water
to cool the fuel. Wet storage of spent fuel possesses inherently large
safety margins because of the simplicity and robustness of the SFP
design. The
[[Page 2921]]
design basis includes the ability to withstand an earthquake and to
retain sufficient water to adequately cool and shield the stored spent
fuel. In the MYAPS Defueled Safety Analysis Report, the licensee
specifically states that the SFP structure is designed to Seismic Class
I requirements and is capable of performing its intended safety
function under the licensee's design-basis hypothetical earthquake with
a 0.1-g peak ground acceleration. The floor and walls of the SFP are
constructed of 6-ft thick reinforced concrete and are completely lined
with \1/4\-inch steel plates. To add to the robustness of the design,
the pool is founded on bedrock and is embedded 12.5 feet below grade
level. Since the analyses used in designing the capability of
structures, systems, and components (SSCs) to perform their safety
function under a hypothetical earthquake have significant margin in
them, it is expected that an SSC built to withstand the hypothetical
design-basis earthquake actually will be able to withstand a larger
earthquake. Thus, the loss of coolant from the Maine Yankee SFP, which
partially or completely uncovers the fuel, is a beyond-design-basis
event with a very low probability of occurrence.
The NRC staff has determined that a significant accident sequence
for a permanently shutdown reactor involves the loss of water from the
SFP and subsequent heatup of the fuel. If the decay heat is high
enough, oxidation of the zirconium fuel clad could become self-
sustaining, resulting in a zirconium clad fire. Although the zirconium
clad fire may not be included in the design basis of the facility, the
NRC staff considers it among those accidents that are ``reasonably
conceivable'' and that should be considered in determining whether
there is undue risk to the public from a permanently shutdown reactor
facility. Analysis sponsored by the NRC in the late 1980s identified
approximately 2 years after shutdown as the critical decay time
necessary for pressurized-water reactor fuel to reach a decay power
below the minimum decay power for self-sustaining oxidation. Additional
NRC-sponsored analysis completed in 1997 identified 17 months as the
critical decay time for pressurized-water reactors. On December 6,
1998, Maine Yankee had been shut down for 24 months. Because of the
robust design and construction of the SFP and the fuel's having
exceeded the critical decay time for the representative pressurized-
water reactor, the staff has determined that there is reasonable
assurance that rapid zirconium oxidation of the fuel cladding is no
longer possible. The staff has also concluded that the cost of
recovering from a loss of SFP water would be bounded by other accidents
that may occur at a permanently defueled site.
In SECY 96-256, ``Changes to the Financial Protection Requirements
for Permanently Shutdown Nuclear Power Reactors, 10 CFR 50.54(w) and 10
CFR 140.11,'' dated December 17, 1996, the staff estimated the onsite
cleanup costs of accidents considered to be the most costly at a
permanently defueled site with spent fuel stored in the SFP. The staff
found that the onsite recovery costs for a fuel-handling accident could
range up to $24 million. The estimated onsite cleanup costs to recover
from the rupture of a large liquid radwaste storage tank could range up
to $50 million. The licensee's proposed level of $50 million for onsite
property insurance is sufficient to cover these estimated cleanup
costs.
The offsite cleanup costs of the accident scenarios previously
discussed are estimated to be negligible in SECY 96-256. However, a
licensee's liability for offsite costs may be significant as a result
of lawsuits alleging damages from offsite releases. Experience at Three
Mile Island Unit 2 showed that significant judgments against a licensee
are possible despite negligible dose consequences from an offsite
release. An appropriate level of financial liability coverage is needed
to account for potential judgments and settlements and to protect the
Federal Government from indemnity claims. The licensee's proposed level
of $100 million in primary offsite liability coverage is sufficient for
this purpose.
The staff has determined that participation in the secondary
insurance pool for offsite financial protection is not required for a
permanently shutdown and defueled plant after the time that air cooling
of the spent fuel is sufficient to maintain the integrity of the fuel
cladding. As previously noted, the staff finds that sufficient time has
elapsed to ensure the integrity of the MYAPS spent fuel cladding.
IV
The NRC staff has completed its review of the licensee's request to
reduce financial protection limits to $50 million for onsite property
insurance and $100 million for offsite liability insurance. On the
basis of its review, the NRC staff finds that the spent fuel stored in
MYAPS's SFP is no longer susceptible to rapid zirconium oxidation. The
requested reductions are consistent with SECY 96-256. The Commission
informed the staff in a staff requirements memorandum dated January 28,
1997, that it did not object to the insurance reductions recommended in
SECY 96-256. The licensee's proposed financial protection limits will
provide sufficient insurance to recover from limiting hypothetical
events, if they occur. Thus, the underlying purposes of the regulations
will not be adversely affected by the reductions in insurance coverage.
Accordingly, the Commission has determined that, pursuant to 10 CFR
50.12(a), an exemption to reduce onsite property insurance to $50
million is authorized by law, will not present an undue risk to public
health and safety, and is consistent with the common defense and
security. Further, special circumstances are present, as set forth in
10 CFR 50.12(a)(2)(ii). Therefore the Commission hereby grants an
exemption from the requirements of 10 CFR 50.54(w).
In addition, the Commission has determined that, pursuant to 10 CFR
140.8, an exemption to reduce primary offsite liability insurance to
$100 million, accompanied by withdrawal from the secondary insurance
pool for offsite liability insurance, is authorized by law and is in
the public interest. Therefore, the Commission hereby grants an
exemption from the requirements of 10 CFR 140.11(a)(4).
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of these exemptions will not have a significant effect on the
quality of the human environment (63 FR 67943, printed December 9,
1998).
These exemptions are effective upon issuance.
Dated at Rockville, Maryland, this 7th day of January 1999.
For the Nuclear Regulatory Commission.
Samuel J. Collins,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 99-1075 Filed 1-15-99; 8:45 am]
BILLING CODE 7590-01-P
