[Federal Register Volume 61, Number 21 (Wednesday, January 31, 1996)]
[Notices]
[Pages 3511-3512]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-1868]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-352]
Philadelphia Electric Company (Limerick Generating Station, Unit
1)
Exemption
I
The Philadelphia Electric Company (the licensee) is the holder of
Facility Operating License No. NPF-39, which authorizes operation of
the Limerick Generating Station (LGS), Unit 1. The license provides,
among other things, that the licensee is subject to all rules,
regulations, and orders of the Nuclear Regulatory Commission (the
Commission) now or hereafter in effect.
The LGS, Unit 1 facility consists of a boiling water reactor,
located in Chester and Montgomery Counties, Pennsylvania.
II
Section III.D.1.(a) of 10 CFR Part 50, Appendix J (hereafter
referred to as Appendix J) requires the performance of three Type A
containment integrated leakage rate tests (ILRTs), 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
inservice inspection (ISI).
III
By a June 20, 1995 letter, the licensee requested a one-time
exemption 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 a one-time interval extension of
the third Type A test and would permit the third Type A test of the
first 10-year ISI period to not correspond with the end of the current
American Society of Mechanical Engineers Boiler and Pressure Vessel
Code (ASME Code) inservice inspection interval and to be performed in
the seventh refueling outage. The proposed action is requested to allow
the licensee to realize cost savings and reduced worker radiation.
Subsequent to the licensee's submittal, a rulemaking was completed
on Appendix J (60 FR 49495, September 26, 1995) which allows the Type A
test to be performed at intervals up to once every 10 years. However,
because the licensee's outage is scheduled to begin in January 1996,
there is insufficient time for the licensee to implement the amended
rule prior to the start of the outage.
The licensee was previously granted a similar exemption on February
16, 1994 (59 FR 9257). This 1994 exemption and the related license
amendment (Amendment No. 67) allowed the licensee to perform its third
Type A test during the 10-year plant ISI refueling outage by extending
the test interval between the second and third test to approximately 65
months.
The licensee's request cites the special circumstances of 10 CFR
50.12, paragraph (a)(2), as the basis for the exemption. The licensee
also stated 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. Data,
supplied by the licensee, from the first (August 1989) and second
(November 1990) ILRTs at LGS, Unit 1, indicate that most of the
measured leakage is from the containment penetrations and not from the
containment barrier. The ``as-left'' leakage rate was well below the 10
CFR Part 50, Appendix J limit. Appendix J requires the leakage rate to
be less than 75% of La to allow for deterioration in leakage paths
between tests. The allowable leakage rate, La, is 0.5 wt.%/day.
Therefore, the established acceptable limit is <0.375 wt.%/day.="" the="" as-="" left="" leakage="" rates="" for="" the="" first="" two="" ilrts="" were="" 0.178="" and="" 0.334="" wt.%/="" day,="" which="" are="" below="" the="" acceptable="" limit.="" the="" type="" b="" and="" c="" test="" (local="" leakage="" rate="" test="" or="" llrt)="" program="" also="" provides="" assurance="" that="" containment="" integrity="" has="" been="" maintained.="" llrts="" demonstrate="" operability="" of="" components="" and="" penetrations="" by="" measuring="" penetration="" and="" valve="" leakage.="" iv="" 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;="" 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="" rule="" is="" to="" ensure="" that="" any="" potential="" leakage="" pathways="" through="" the="" containment="" boundary="" are="" identified="" such="" that="" leakage="" will="" not="" exceed="" allowable="" leakage="" rate="" values.="" the="" nrc="" staff="" has="" reviewed="" the="" basis="" and="" supporting="" information="" provided="" by="" the="" licensee="" in="" its="" exemption="" request.="" the="" nrc="" staff="" notes="" that="" the="" first="" and="" second="" ilrts="" of="" the="" set="" of="" three="" tests="" for="" the="" first="" 10-year="" service="" period="" were="" conducted="" in="" august="" 1987="" and="" november="" 1990.="" the="" third="" ilrt="" will="" be="" scheduled="" for="" refueling="" outage="" 7,="" projected="" to="" start="" in="" april="" 1998.="" in="" a="" september="" 29,="" 1995="" phone="" call,="" the="" licensee="" stated="" to="" the="" nrc="" staff="" 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="" regulatory="" guide="" (i.e.,="" regulatory="" guide="" 1.163)="" accompanying="" appendix="" j="" option="" b="" specifies="" that="" the="" containment="" inspections="" be="" performed="" more="" often="" than="" the="" type="" a="" tests.="" the="" nrc="" staff="" has="" also="" made="" use="" of="" the="" information="" supporting="" the="" revised="" appendix="" j,="" including="" nureg-1493,="" which="" provides="" the="" technical="" justification="" for="" the="" 10-year="" test="" interval="" for="" type="" a="" tests.="" the="" 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="" type="" b="" and="" c="" testing.="" 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="" that="" llrt="" could="" not="" detect.="" this="" is="" 3%="" of="" all="" failures.="" this="" study="" agrees="" 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="" called="" 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="">a. Of these, only nine were not due to Type B or C
leakage penalties. The NEI data also added another perspective. The NEI
data shows that in about one-third of the cases exceeding allowable
leakage, the as-found leakage was lessthan 2La; in one case the
leakage was
[[Page 3512]]
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. KFor about half of
the failed ILRTs, the as-found leakage was not quantified. These data
show that, for those ILRTs for which 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 another cycle for the performance of the Appendix
J, Type A test at LGS Unit 1 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 schedule extension of an additional one cycle, to
the seventh refueling outage, for the performance of the Appendix J,
Type A test, provided the general containment inspection is performed
in the sixth refueling outage, to be acceptable.
Pursuant to 10 CFR 51.32, the Commission has determined that
granting this exemption will have no significant effect on the quality
of the human environment (60 FR 57604).
This exemption is effective upon issuance, shall supersede the
exemption dated February 16, 1994 and shall expire at the completion of
the 1998 refueling outage.
Dated at Rockville, Maryland this 25th day of January 1996.
For the Nuclear Regulatory Commission.
Steven A. Varga,
Director, Division of Reactor Projects--I/II, Office of Nuclear Reactor
Regulation.
[FR Doc. 96-1868 Filed 1-30-96; 8:45 am]
BILLING CODE 7590-01-P
