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

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