[Federal Register Volume 59, Number 203 (Friday, October 21, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-26142]


[[Page Unknown]]

[Federal Register: October 21, 1994]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-336]

 

Northeast Nuclear Energy Company (Millstone Nuclear Power 
Station, Unit No. 2); Exemption

I

    The Northeast Nuclear Energy Company (NNECO, the licensee) is the 
holder of Facility Operating License No. DPR-65 which authorizes 
operation of Millstone Nuclear Power Station, Unit No. 2. The license 
provides, among other things, that Millstone Unit 2 is subject to all 
rules, regulations, and Orders of the Commission now or hereafter in 
effect.
    The plant is a pressurized water reactor located at the licensee's 
site in New London County, Connecticut.

II

    One of the conditions of all operating licenses for water-cooled 
power reactors, as specified in 10 CFR 50.54(o), is that primary 
reactor containments shall meet the containment leakage test 
requirements set forth in 10 CFR part 50, appendix J. More specifically 
the following sections require that:

10 CFR Part 50, Appendix J. Section III.D.2(a)

    Type B tests, except tests for air locks, shall be performed 
during reactor shutdown for refueling, or other convenient 
intervals, but in no case at intervals greater than 2 years.

10 CFR Part 50, Appendix J. Section III.D.3

    Type C tests shall be performed during each reactor shutdown for 
refueling but in no case at intervals greater than 2 years.

    By letter dated September 26, 1994, NNECO requested schedular 
exemptions from the above requirements. NNECO recently conducted a 
review of the Type B and Type C test data and on September 23, 1994, 
determined that a number of components, for which Type B and Type C 
testing is required, have exceeded their respective 24-month interval 
by up to approximately four months. Previously, Millstone Unit 2 
considered the Type B and Type C tests to constitute one group such 
that the 2-year surveillance window began after the last component test 
was completed during the refueling outage. A review of this rationale 
and discussions with industry counterparts and the NRC staff determined 
that this was not the appropriate interpretation. Rather, each Type B 
or C test of a penetration or valve should be considered unique, each 
with its own 2-year surveillance window. Using the appropriate 
interpretation, NNECO determined on September 23, 1994, that a number 
of Type B and Type C tests have exceeded their required 24-month test 
interval by up to approximately 4 months. The requirement to perform 
Type B and Type C local leak rate tests (LLRTs) on September 23, 1994, 
when NNECO discovered the misinterpretation of the requirement, would 
require an unscheduled plant shut down, given the current Millstone 
Unit 2 refueling outage schedule. The total schedular delay in testing 
components will accumulate to be as much as 4 months before the plant 
is shutdown for refueling.

III

    By letter dated September 26, 1994, NNECO requested an exemption to 
the requirements of Section III.D.2(a) and III.D.3 which require that 
Type B and C testing be performed during each reactor shutdown for 
refueling but in no case at intervals greater than 2 years. In their 
submittal and in a phone conference between the staff and NNECO on 
September 24, 1994, NNECO stated that they recently conducted a review 
of the Type B and Type C test data and on September 23, 1994, 
determined that a number of components, for which Type B and Type C 
testing is required, have exceeded their respective 24-month interval 
by up to approximately 4 months. The previously refueling was lengthy 
(approximately 7 months) due to the replacement of both steam 
generators. The LLRTs during the outage, were conducted from June 1992 
through December 1992. Previously, NNECO considered the Type B and Type 
C tests to constitute one group such that the 2-year surveillance 
window began after the last component test was completed during the 
refueling outage. A review of this rationale and discussions with 
industry counterparts and the NRC staff determined that this was not 
the appropriate interpretation. Rather, each Type B or C test of a 
penetration or valve should be considered unique, each with its own 2-
year surveillance window. Using the appropriate interpretation, NNECO 
determined on September 23, 1994, that a number of Type B and Type C 
tests have exceeded their required 24-month test interval by up to 
approximately 4 months. The requirement to perform Type B and Type C 
LLRTs on September 23, 1994, when NNECO discovered the 
misinterpretation of the requirement, would require an unscheduled 
plant shutdown, given the current Millstone Unit 2 refueling outage 
schedule. The total schedular delay in testing components will 
accumulate to be as much as 4 months before the plant is shutdown for 
refueling.
    NNECO stated in their submittal that they had completed the second 
Type A test for the present 10-year service period successfully on 
December 24, 1992. The ``As-Found'' and ``As-Left'' integrated leakage 
rate test ILRT results were 0.2809 weight percent per day and 0.2577 
weight percent per day respectively. Each ILRT result was below the 
Technical Specifications limit which demonstrates the overall leak-
tightness of the containment. In addition, as of December 1992, the 
total Type B and C ``As-Found'' and ``As-Left'' leakage results were 
0.049 weight percent per day and 0.008 weight percent per day. These 
values represent approximately 16.3% and 2.7% of the Technical 
Specification limit respectively. The results of these tests 
demonstrate that Millstone Unit 2 has maintained control of containment 
integrity by maintaining a conservative margin between the acceptance 
criterion and the ``As-Found'' and ``As-Left'' leakage rates. 
Subsequent to this ILRT, during Cycle 12, maintenance on several 
containment isolation valves was performed. The post-maintenance retest 
requirements were accomplished by successful performance of Type C 
test. Thus, the previously Type A, B and C tests and prior post-
maintenance retests of selected valves have demonstrated the leak-
tightness of the containment and the reliability of the penetrations/
valves.
    Based on the above evaluation, the staff finds 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 temporary 
exemption, to allow the Type B and C test intervals to be extended to 
the end of the 12th refueling outage which began on October 1, 1994, to 
be acceptable.

IV

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12(a), the requested 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. Further, the 
Commission finds that the special circumstances required by 10 CFR 
50.12(a)(2)(ii) are present. Application of the regulation in these 
particular circumstances is not necessary to achieve the underlying 
purpose of the rule in that, as discussed in Section III, the 
containment leakage-limiting function will be maintained.
    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 require 
that Type B and C tests be performed during each reactor shutdown for 
refueling but in no case at intervals greater than 2 years until end of 
the current refueling outage.
    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 50928).
    This Exemption is effective upon issuance.

    Dated at Rockville, Maryland this 12th day of October 1994.

    For the Nuclear Regulatory Commission.
Walter R. Butler,
Acting Director, Division of Reactor Projects--I/II, Office of Nuclear 
Reactor Regulation.
[FR Doc. 94-26142 Filed 10-20-94; 8:45 am]
BILLING CODE 7590-01-M