[Federal Register Volume 60, Number 133 (Wednesday, July 12, 1995)]
[Notices]
[Pages 35968-35970]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-17028]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-272]
Public Service Electric and Gas Co., (Salem Nuclear Generating
Station, Unit 1; Exemption)
I
The Public Service Electric and Gas Company (the licensee) is the
holder of Facility Operating License No. DPR-70, which authorizes
operation of the Salem Nuclear Generating Station, Unit 1 (the
facility). The license provides, among
[[Page 35969]]
other things, that Salem, Unit 1 is subject to all rules, regulations,
and Orders of the U.S. Nuclear Regulatory Commission (the Commission or
NRC) now or thereafter in effect.
The facility is a pressurized water reactor, located at the
licensee's site in Salem, New Jersey.
II
Section III.D.1.(a) of Appendix J to 10 CFR Part 50 requires the
performance of three Type A containment integrated leakage rate tests
(CILRTs), at approximately equal intervals during each 10-year service
period. The third test of each set shall be conducted when the plant is
shutdown for the 10-year plant inservice inspection.
III
By letter dated April 4, 1995, the licensee requested relief from
the requirement to perform a set of three Type A tests at approximately
equal intervals during each 10-year service period. The requested
exemption would permit an interval extension for the second Type A test
and defer this test from the twelfth refueling outage, scheduled to
begin September 1995, to the thirteenth refueling outage, scheduled to
begin February 1997 and end no later than June 1997.
The licensee's request cites the special circumstances of 10 CFR
50.12, paragraph (a)(2)(ii), as the basis for the exemption. The
underlying purpose of the requirement to perform three Type A CILRTs,
at approximately equal intervals during each 10-year service period, is
to assure that any potential leakage pathways through the primary
reactor containment are identified within a time span that prevents
significant degradation from continuing or becoming unknown. The
licensee has stated that the existing Type B and C local leak rate test
(LLRT) programs are not being modified by this request, and will
continue to effectively detect containment leakage caused by the
degradation of active containment isolation components as well as
containment penetrations. It has been the consistent and uniform
experience at Salem during the four Type A tests conducted from 1979 to
date that any significant containment leakage paths are detected by the
Type B and C testing. The Type A test results have only been
confirmatory of the results of the Type B and C test results.
Therefore, consistent with 10 CFR 50.12, paragraph (a)(2)(ii),
application of the regulation in this particular circumstance is not
necessary to achieve the underlying purpose of the rule.
IV
Section III.D.1.(a) of Appendix J to 10 CFR Part 50 states that a
set of three Type A leakage rate tests shall be performed at
approximately equal intervals during each 10-year service period.
The licensee proposes an exemption to this section which would
provide an interval extension for the next Type A test. The Commission
has determined that pursuant to 10 CFR 50.12(a)(1) this exemption is
authorized by law, will not present an undue risk to the public health
and safety, and is consistent with the common defense and security. The
Commission further determines that special circumstances, as provided
in 10 CFR 50.12(a)(2)(ii), are present justifying the exemption;
namely, that application of the regulation in the particular
circumstances is not necessary to achieve the underlying purpose of the
rule.
The NRC staff has reviewed the basis and supporting information
provided by the licensee in the exemption request. The NRC staff has
noted that the licensee has a good record of ensuring a leak-tight
containment. All Type A tests were within the acceptance limits. The
only penetrations with a history of unacceptable, as found, leakage
have been the containment air lock shaft seals, and during the eleventh
refueling outage a new type shaft seal was installed. The licensee has
noted that the results of the Type A testing have been confirmatory of
the Type B and C tests, which will continue to be performed. The
licensee has stated to the NRC Project Manager that they will perform
the general containment inspection although it is only required by
Appendix J (Section V.A) to be performed in conjunction with Type A
tests. The NRC staff considers that these inspections and system
enhancements, though limited in scope, provide an important added level
of confidence in the continued integrity of the containment boundary.
The NRC staff has also made use of the information in a draft staff
report, NUREG-1493, which provides the technical justification for the
present Appendix J rulemaking effort which also includes a 10-year test
interval for Type A tests. The integrated leakage rate test, or Type A
test, measures overall containment leakage. However, operating
experience with all types of containments used in this country
demonstrates that essentially all containment leakage can be detected
by local leakage rate tests (Type B and C). According to results given
in NUREG-1493, out of 180 ILRT reports covering 110 individual reactors
and approximately 770 years of operating history, only about 3% of
leakage that exceeds current requirements is detectable only by CILRTs,
and those few failures were only marginally above prescribed limits.
This study agrees well with previous NRC staff studies which show that
Type B and C testing can detect a very large percentage of containment
leaks. The Salem experience has also been consistent with these
results.
The Nuclear Management and Resources Council (NUMARC), now the
Nuclear Energy Institute (NEI), collected and provided the NRC staff
with summaries of data to assist in the Appendix J rulemaking effort.
NUMARC collected results of 144 ILRTs from 33 units; 23 ILRTs exceeded
1.0La. Of these, only nine were not due to Type B or C leakage
penalties. The NEI data also added another perspective. The NEI data
show that in about one-third of the cases exceeding allowable leakage,
the as-found leakage was less than 2La; in one case the as-found
leakage was less than 3La; one case approached 10La; and in
one case the leakage was found to be approximately 21La. For about
half of the failed ILRTs the as-found leakage was not quantified. These
data show that, for those ILRTs for which the leakage was quantified,
the leakage values are small in comparison to the leakage value at
which the risk to the public starts to increase over the value of risk
corresponding to La (approximately 200La, as discussed in
NUREG-1493). Therefore, based on these considerations, it is unlikely
that an extension of one cycle for the performance of the Appendix J,
Type A test at Salem would result in a significant degradation of the
overall containment integrity. As a result, the application of the
regulation in these particular circumstances is not necessary to
achieve the underlying purpose of the rule.
Based on generic and plant specific data, the NRC staff finds the
basis for the licensee's proposed exemption to allow a one-time
exemption to permit a schedular extension of one cycle for the
performance of the Appendix J Type A test, provided that the general
containment inspection is performed, to be acceptable.
Pursuant to 10 CFR 51.32, the Commission has determined that
granting this Exemption will not have a significant impact on the
quality of the human environment (60 FR 34560).
This Exemption is effective upon issuance and shall expire at the
completion of the thirteenth refueling outage.
[[Page 35970]]
Dated at Rockville, Maryland this 5th day of July 1995.
For the Nuclear Regulatory Commission.
Steven A. Varga,
Director, Division of Reactor Projects--I/II, Office of Nuclear Reactor
Regulation.
[FR Doc. 95-17028 Filed 7-11-95; 8:45 am]
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