[Federal Register Volume 59, Number 249 (Thursday, December 29, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-32086]


[[Page Unknown]]

[Federal Register: December 29, 1994]


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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-352 and 50-353]

 

In the Matter of Philadelphia Electric Company (Limerick 
Generating Station, Units 1 and 2); Exemption

I

    Philadelphia Electric Company (the licensee), is the holder of 
Facility Operating License Nos. NPF-39 and NPF-85, which authorize 
operation of the Limerick Generating Station (LGS), Units 1 and 2. The 
licenses provide, among other things, that the licensee is subject to 
all rules, regulations, and orders of the Nuclear Regulatory Commission 
(the Commission) now and hereafter in effect.
    The facilities consist of two boiling water reactors located in 
Montgomery County, Pennsylvania.

II

    Section 50.54(o) of 10 CFR Part 50 requires that primary reactor 
containment for water cooled power reactors be subject to the 
requirements of Appendix J to 10 CFR Part 50. Appendix J contains the 
leakage test requirements, schedules, and acceptance criteria for tests 
of the leak tight integrity of the primary reactor containment and 
systems and components which penetrate the containment. Section 
III.D.2(a) of Appendix J to 10 CFR Part 50 requires that Type B leak 
rate tests, except for air locks, be performed during reactor shutdown 
for refueling, or other convenient intervals, but in no case at 
intervals greater than 2 years. Type B tests are intended to detect 
local leaks and to measure leakage across each pressure-containing or 
leakage-limiting boundary for certain reactor containment penetrations.
    Section III.D.3 of Appendix J to 10 CFR Part 50 requires that Type 
C leak rate tests be performed during each reactor shutdown for 
refueling but in no case at intervals greater than 2 years. Type C 
tests are intended to measure containment isolation valve leakage rates 
for certain containment isolation valves.

III

    By letter dated July 22, 1994, the licensee requested a one-time 
exemption from the Commission's regulations. The subject exemption is 
from the requirements of 10 CFR Part 50, Appendix J, ``Primary Reactor 
Containment Leakage Testing for Water-Cooled Power Reactors,'' Sections 
III.D.2(a) and III.D.3, to allow the two-year interval to be exceeded 
by no more than 26 days for the 68 leak tests. In its request, the 
licensee provided a list of the affected penetrations and associated 
plant-specific leak test procedures, and the dates when the current 
leak tests will expire.
    This exemption is being requested in order to avoid an early 
reactor shutdown to comply with the 2-year testing interval, and to 
allow for shutdown scheduling flexibility following the third, Unit 2, 
operating cycle. Currently, LGS Unit 2 is using a new core design which 
allows the intervals between reactor shutdowns for refueling to extend 
beyond the maximum-allowable, two-year testing period. Prior to the 
current operating cycle, local leak rate tests were performed in 
conjunction with an 18-month refueling cycle. The use of the extended-
cycle core designs has been recognized as a growing trend in the 
industry as discussed in Generic Letter 91-04, ``Changes in Technical 
Specification Surveillance Intervals to Accommodate a 24-Month Fuel 
Cycle,'' dated April 2, 1991.
    The licensee has divided the affected leak tests into the 
categories: 1) those that will expire prior to the scheduled outage 
beginning on January 28, 1995, and 2) those that will expire during the 
period that follows, up to February 19, 1995. There are 22 leak rate 
tests which are listed in Table 1 of the licensee's July 22, 1994 
request in the first category, and 46 additional tests, listed in 
Tables 2, 3 and 4 of the licensee's request in the second category. The 
earliest of these tests falls due on January 24, 1995, 4 days prior to 
the scheduled shutdown. The licensee has requested an exemption for up 
to 26 days which will allow the unit to operate until the beginning of 
the planned outage without shutting down to perform leak tests, and to 
allow for flexibility in planning the leak tests during the outage. The 
licensee has stated that all of the leak rate tests will be performed 
prior to February 19, 1995.
    The licensee has presented information in support of their request 
for a 26-day extension of the Type B and C test intervals. The Unit 2, 
as-left, minimum pathway leak rate (i.e., maximum allowable leakage 
rate for maintaining primary containment), following the second Unit 2 
refueling outage, was .13La (maximum allowable pathway leakage) or 
20,625 standard cubic centimeters per minute (sccm), including 
contributions from the Main Steam Isolation Valves (MSIV); with a 
maximum pathway leak rate of .27La or 42,502 sccm, excluding MSIV 
leakage, in accordance with LGS's current Appendix J exemption. These 
as-left leak rates represent a significant margin to the maximum 
allowable pathway leakage of 158,273 sccm.
    The licensee has stated that the 26-day extension of the leak test 
interval is not likely to decrease the margin between as-found leak 
rates and the maximum allowable pathway leakage. Also, the licensee has 
stated that extending the testing interval by 26 days will not 
significantly impact the integrity of the containment boundary, and 
therefore, will not significantly impact the consequences of an 
accident or transient in the unlikely occurrence of an event during the 
26 days of power operation.
    For the reasons set forth above, the NRC staff concludes there is 
reasonable assurance that the containment leakage-limiting function 
will be maintained and that a forced outage to perform Type B and C 
tests is not necessary. Therefore, the staff finds the requested one-
time exemption, to allow the Type B and C tests listed in the 
licensee's July 22, 1994, submittal to be extended up to 26 days, but 
not to exceed February 19, 1995, to be acceptable.

IV

    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 and 
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 rule 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. The 2-year maximum interval was 
originally expected to bound the typical operating cycle, including a 
limited amount of mid-cycle outage time. The advent of advance fuel 
types has made it possible to operate the facility for a 2-year maximum 
interval. Based on the as-left leak rates for LGS, Units 1 and 2, we 
find that application of the regulation is not necessary to meet the 
underlying purpose of the rule in that, taking into consideration the 
26-day extension, the components that comprise the primary containment 
boundary will still be tested at a frequency that is appropriate to 
those components and their application. In addition, the 26-day 
extension represents a minimal increase in the existing 2-year interval 
required by the rule.

V

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
Part 50.12, an exemption is authorized by law and will not present an 
undue risk to the public health and safety, and that there are special 
circumstances present, as specified in 10 CFR 50.12(a)(2). An exemption 
is hereby granted from the requirements of Sections III.D.2(a) and 
III.D.3 of Appendix J to 10 CFR Part 50, which requires that Type B and 
C tests be performed during each reactor shutdown for refueling but in 
no case at intervals greater than 2 years, for a period of up to 26 
days (not to exceed February 19, 1995) from the expiration of the 
current leak test for the affected penetrations.
    Pursuant to 10 CFR 51.32, the Commission has determined that the 
granting of this exemption will have no significant impact on the 
quality of the human environment (59 FR 65808).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 22nd 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. 94-32086 Filed 12-28-94; 8:45 am]
BILLING CODE 7590-01-M