[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
