[Federal Register Volume 59, Number 241 (Friday, December 16, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-30934]
[[Page Unknown]]
[Federal Register: December 16, 1994]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-327]
Tennessee Valley Authority (Sequoyah Nuclear Plant, Unit 1);
Exemption
I
The Tennessee Valley Authority (TVA) is the holder of Facility
Operating License No. DPR-77, which authorizes operation of the
Sequoyah Nuclear Plant, Unit 1 (the facility, Unit 1). The license
provides, among other things, that the facility is subject to all
rules, regulations, and orders of the Nuclear Regulatory Commission
(the Commission) now or hereafter in effect.
The facility consists of a pressurized water reactor located on
TVA's Sequoyah site in Soddy Daisy, Hamilton County, Tennessee.
II
Section III.D.3 of Appendix J to 10 CFR Part 50 requires that Type
C local leak rate tests (LLRTs) be performed during reactor shutdown
for refueling, or other convenient intervals, but in no case at
intervals greater than 2 years.
On March 2, 1993, SQN Unit 1 entered a forced outage and started
the Cycle 6 refueling outage. All Type B and Type C LLRTs were
preformed during the outage, which ended in December 1993. The unit
returned to service on April 20, 1994. Due to the length of the outage,
a number of LLRTs that were performed early in the outage were
reperformed prior to conducting the containment integrated leak rate
test (CILRT) in December 1993. LLRTs of values that were initially
tested between April 3 and July 19, 1993, however, were not retested
because of schedule restraints associated with the CILRT. Since the 2-
year time interval for the Type C value pentrations that were not
retested will expire starting in April 1995, Unit 1 would be forced to
shut down at that time to perform the tests unless a schedular
exemption is granted.
The next Unit 1 refueling outage is scheduled to start in September
1995. Therefore, the licensee has proposed an exemption to allow a one-
time deferment of the Appendix J interval requirement for the affected
Type C valve penetration tests from April 3, 1995, until October 1,
1995, a total of approximately 181 days for the first valve tested
during the Cycle 6 outage.
The extension would affect 126 isolation valves of 242 valves in
the leak rate test program and are listed in the submittal. They are
considered by the licensee to be leak tight and in good condition,
which was verified by the leak rate tests performed during the Cycle 5
refueling outage. Based on the present total integrated containment
leak rate that accounts for less than 93 percent of the 0.75 La limit,
the licensee believes that the remaining margin is sufficient to ensure
that any incremental increase in leakage because of the extension, will
not result in unacceptable as-found test results. Also, based on
historical data, the licensee believes that any incremental increase in
leakage from these valves because of the extension would be small. In
addition, the valves were included in the boundary for the Last Type A
test that was performed in December 1993, and have been subjected to
improved maintenance practices that provide increased assurance that
they will be capable of performing their intended safety function.
III
Pursuant to 10 CFR 50.12, the Commission may, upon application by
any interested person or upon its own initiative, grant exemptions from
the requirements of 10 CFR Part 50 when (1) the exemptions are
authorized by law, will not present an undue risk to public health or
safety, and are consistent with the common defense and security; and
(2) when special circumstances are present. Special circumstances are
present whenever, according to 10 CFR 50.12(a)(2)(ii), ``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. * * *''
The underlying purpose of the requirement to perform Type C
containment leak rate tests at intervals not to exceed 2 years, is to
ensure that any potential leakage pathways through the containment
boundary are identified within a time span that prevents significant
degradation from continuing or being unknown, and long enough to allow
the tests to be conducted during scheduled refueling outages. This
interval was originally published in Appendix J when refueling cycles
were conducted at approximately annual intervals and has not been
changed to reflect 18-month or 2-year operating cycles. It is not the
intent of the regulation to require a plant shutdown solely for the
purpose of conducting the periodic leak rate tests. Based on historical
data at SQN, any incremental increase in leakage because of the
extension would be small. Improved maintenance practices implemented
during the Unit 1 Cycle 5 outage, and continued in the Unit 1 Cycle 6
outage, provide increased assurance that these components will perform
their safety function. Therefore, since the maximum extension is
relatively short (approximately 181 days for the first valve tested
during the Cycle 6 outage) compared to the 2-year test interval
requirement, it is unlikely that substantial degradation of the valves
leading to the failure of the containment to perform its safety
function would occur. As a result, the application of the regulation in
the particular circumstances is not necessary to achieve the underlying
purpose of the rule.
IV
For the foregoing reasons, the NRC staff has concluded that the
licensee's proposed increase of the 2-year time interval for performing
the Type C Leak Rate Tests of the valves specified in the application
until the Cycle 7 refueling outage will not present an undue risk to
public health and safety and is consistent with the common defense and
security. The NRC staff has determined that there are special
circumstances present, as specified in 10 CFR 50.12(a)(2), such that
application of 10 CFR Part 50, Appendix J, Section III.D.3 is not
necessary in order to achieve the underlying purpose of this
regulation.
Accordingly, the Commission has determined that, pursuant to 10 CFR
50.12(a), the exemption is authorized by law, will not endanger life or
property or common defense and security, and is, otherwise, in the
public interest. Therefore, the Commission hereby grants the Tennessee
Valley Authority exemption from the requirements of Section III.D.3 of
Appendix J to 10 CFR Part 50 for Unit I as requested in the submittal.
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of this exemption will not result in any significant adverse
environmental impact (59 FR 63387).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 8th day of December 1994.
For the Nuclear Regulatory Commission.
Steven A. Varga,
Director, Division of Reactor Projects--I/II, Office of Nuclear Reactor
Regulation.
[FR Doc. 94-30934 Filed 12-15-94; 8:45 am]
BILLING CODE 7590-01-M
