[Federal Register Volume 59, Number 247 (Tuesday, December 27, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-31779]
[[Page Unknown]]
[Federal Register: December 27, 1994]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-220]
Niagara Mohawk Power Corporation; (Nine Mile Point Nuclear
Station Unit No. 1); Exemption
I
Niagara Mohawk Power Corporation (NMPC or the licensee) is the
holder of Facility Operating License No. DPR-63, which authorizes
operation of Nine Mile Point Nuclear Station Unit No. 1 (the facility
or NMP1), at a steady-state reactor power level not in excess of 1850
megawatts thermal. The facility is a boiling water reactor located at
the licensee's site in Oswego County, New York. The license provides
among other things, that it is subject to all rules, regulations, and
Orders of the U.S. Nuclear Regulatory Commission (the Commission or
NRC) now or hereafter in effect.
II
Section III.D.1.(a) of Appendix J to 10 CFR Part 50 requires the
performance of three Type A containment leakage rate tests, at
approximately equal intervals during each 10-year service period of the
primary containment. The third test of each set shall be conducted when
the plant is shutdown for the 10-year inservice inspection of the
primary containment.
III
By letter dated August 26, 1994, NMPC 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
extension of the second 10-year service period of approximately 24
months (from the 1995 refueling outage, currently scheduled to begin in
February 1995, to the 1997 refueling outage). The requested temporary
relief would permit the third test of the containment's second 10-year
inservice inspection period to correspond with the end of the current
American Society of Mechanical Engineers Boiler and Pressure Vessel
Code (ASME Code) inservice inspection interval.
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 requirement to perform a set of three Type A leakage rate tests
at approximately equal intervals during each 10-year containment
service period provides assurance that the containment is leak tight.
Type A leakage rate tests were performed as required by Appendix J
during the first 10-year containment service period (1974-1984). The
second 10-year containment service period is scheduled to end in
December 1994.
Due to a lengthy outage for the replacement of reactor
recirculation piping, the first ASME Code required Inservice Inspection
(ISI) 10-year interval was extended to June 1986. An extended refueling
outage (January 1987 to July 1990) resulted in the second 10-year ISI
interval being extended to December 1998. These extensions were made in
accordance with the provisions of Section XI of the ASME Code and have
resulted in the ISI intervals being decoupled from the Type A leakage
test intervals since Appendix J does not contain any provisions for
adjusting the 10-year intervals as does the ASME Code for extended
outages.
Two Type A tests have already been performed (May 1990 and April
1993) during the second 10-year containment service interval. Since
this second interval is scheduled to end in December 1994, the third
test would be required during the next refueling outage (February
1995). However, in an attempt to recouple the schedule for the Type A
tests with the ISI schedule and to avoid performing an additional Type
A test, the license has proposed to extend the third Type A test of the
second interval until the 1997 refueling outage and to perform the
final tests of the second ISI interval at that time. This action would
eliminate the need to perform an extra Type A test which could
otherwise be required (one test in 1995 and another in 1997) while
recoupling the Type A test schedule with the ISI schedule.
V
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 underlying purpose of Section III.D.1.(a) of
the Appendix J to 10 CFR Part 50 is to provide an interval short enough
to prevent serious deterioration from occurring between tests and long
enough to permit testing to be performed during regular plant outages.
The last Type A test was performed in April 1993. Performance of
another Type A test in February 1995 would result in a test interval of
only 22 months. Whereas if the 10-year interval was equally divided
into three intervals, each test interval would be 40 months. Delaying
the next Type A test until the 1997 refueling outage would result in a
test interval of approximately 46 months since NMP1 is currently
operating on a 24-month fuel cycle. The 46-month test interval would be
consistent with the NRC staff's current position (as reflected in the
NRC's Standard Technical Specifications) that Type A test intervals
should be 40 10 months. Furthermore, the licensee has
presented the following information which gives a high degree of
confidence that the containment will not degrade to an unacceptable
extent while this exemption is in effect:
1. The two most recent Type A test data show that the ``as left''
leakage rates (0.463% wt/day and 0.4634% wt/day, respectively) were
well within the acceptance limit of 0.75 Lt (0.892% wt/day).
2. There have been no permanent or temporary modifications to the
containment structure, liner, or penetrations since the last Type A
test that could adversely affect the Type A test results.
3. No modifications that require a Type A test are planned prior to
the 1997 refueling outage.
4. There have been no pressure or temperature excursions in the
containment which could have adversely affected containment integrity.
Pursuant to 10 CFR 51.32, the Commission has determined that
granting this Exemption will not have a significant impact on the
environment (59 FR 62752).
This Exemption is effective upon issuance and shall expire at the
completion of the 1997 refueling outage.
For the Nuclear Regulatory Commission.
Dated at Rockville, Maryland, this 20th day of December 1994.
Steven A. Varga,
Director, Division of Reactor Projects--I/II, Office of Nuclear Reactor
Regulation.
[FR Doc. 94-31779 Filed 12-23-94; 8:45 am]
BILLING CODE 7590-01-M
