[Federal Register Volume 60, Number 156 (Monday, August 14, 1995)]
[Notices]
[Pages 41903-41904]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-20027]
[[Page 41903]]
NUCLEAR REGULATORY COMMISSION
[Docket No. 50-382]
Entergy Operations, Inc. (Waterford Steam Electric Station, Unit
No. 3); Exemption
I
Entergy Operations, Inc., (the licensee) is the holder of Facility
Operating License No. NPF-38, which authorizes operation of Waterford
Steam Electric Station Unit No. 3 (the facility, Waterford 3). The
operating license provides among other things, that it is subject to
all rules, regulations, and orders of the Commission now or hereafter
in effect. The facility is a pressurized water reactor located at the
licensee's site in St. Charles Parish, Louisiana.
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
(ILRTs), at approximately equal intervals during each 10-year service
period of the primary containment.
III
By letter dated November 16, 1993, as supplemented by letters dated
August 19, 1994, March 30, and June 19, 1995, the licensee requested
temporary relief from the requirement to perform a set of three Type A
tests at approximately equal intervals during each 10-year service
period of the primary containment. The requested exemption would permit
a one-time interval extension of the third Type A test by approximately
18 months (from the 1995 refueling outage, currently scheduled to begin
in September 1995, to the 1997 refueling outage).
The licensee's request primarily cites the special circumstances of
10 CFR 50.12, paragraph (a)(2)(ii), as the basis for the exemption.
They point out that the existing Type B and C testing 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. The licensee
also indicated that the testing history, structural capability of the
containment, and the risk assessment has established that Waterford 3
has a low leakage containment, the structural integrity of the
containment is assured, and that there is a neglible risk impact in
changing the Type A test schedule. Therefore, application of the
regulation in this particular circumstance would not serve, nor is it
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 a one-time interval extension for the Type A test by
approximately 18 months. The Commission has determined, for the reasons
discussed below, 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 underlying purpose of the requirement to perform Type A
containment leak rate tests at intervals during the 10-year service
period, 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 becoming unknown. 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 have passed with significant margin and the licensee will
continue to perform the existing Type B and C testing to detect
containment leakage caused by the degradation of active containment
isolation components as well as containment penetrations. 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, 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 ``Performance-Based Containment Leak-Test Program,''
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 5 ILRT failures were
found which local leakage rate testing could not detect. This is 3% of
all failures. 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 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 leakage
was found to be approximately 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 Waterford 3 would result in 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
[[Page 41904]]
test to be acceptable provided the general containment inspection (10
CFR Part 50, Appendix J, Section V.A.) is performed.
Pursuant to 10 CFR 51.32, the Commission has determined that
granting this Exemption will not have a significant impact on the
environment (60 FR 39020).
This Exemption is effective upon issuance and shall expire after
March 31, 1997, or at the completion of the 1997 refueling outage
whichever comes first.
Dated at Rockville, Maryland, this 3rd day of August 1995.
For the Nuclear Regulatory Commission.
Elinor G. Adensam,
Deputy Director, Division of Reactor Projects III/IV, Office of Nuclear
Reactor Regulation.
[FR Doc. 95-20027 Filed 8-11-95; 8:45 am]
BILLING CODE 7590-01-P