NRC Generic Letter 83-27, Surveillance Intervals in Standard Technical Specifications

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WASHINGTON, D.C. 20555

July 6, 1983

TO ALL LICENSEES AND APPLICANTS FOR OPERATING POWER REACTORS AND HOLDERS OF CONSTRUCTION PERMITS FOR POWER REACTORS

Gentlemen:

Subject: Surveillance Intervals in Standard Technical Specifications (Generic Letter No. 83-27)

There appears to be a misunderstanding as to the basis for the surveillance intervals given in the Standard Technical Specifications (STS) and in some existing custom Technical Specifications in use by a number of licensees. We have received several requests recently from licensees converting to 18-month fuel cycles to increase the surveillance intervals for the 12-month and 18-month surveillance requirements in plant-specific Technical Specifications. The requests indicated that the increase in surveillance intervals would maintain the same contingency period beyond nominal fuel cycle periods that existed in their approved Technical Specifications for shorter fuel cycles. The nominal surveillance interval was not established to provide a fixed contingency period beyond nominal fuel cycle periods. The purpose of this letter is to reiterate the bases for the specified surveillance intervals and to advise licensees of our current practice with respect to requests to increase surveillance intervals.

The 18-month surveillance intervals contained in the STS were established during the original development of STS after consultations with various senior staff members and with the reactor and fuel vendors. The 18-month surveillance intervals were established based upon operating experience and the knowledge that some reactors would be utilizing 18-month fuel cycles. To provide the necessary operational flexibility which may be required due to scheduling and performance considerations, the STS, and most custom Technical Specifications, include a provision which permits any surveillance interval to be extended by 25% of the nominal interval provided that the total time interval does not exceed 3.25 times the specified surveillance interval over any three consecutive surveillance intervals.-2-

The effect of extended outages was also considered during our development and establishment of the 18-month surveillance interval. We presumed that if a plant incurs an extended outage during a fuel cycle, the licensee would perform the appropriate surveillances during the extended outage so that required surveillances will not become due before completion of the fuel cycle.

The 12-month surveillance intervals applicable to certain portions of the fire protection (fire water systems) Technical Specifications were based upon annual climatic conditions rather than on the length of a fuel cycle; therefore, these intervals should not be changed. As stated in the STS Bases for the snubbers, establishment of the snubber surveillance intervals was based upon maintaining a constant level of protection. The assumptions used for maintaining the constant level of protection would be invalidated if the surveillance intervals are changed.

We intend to retain the 18-month and 12-month surveillance intervals given in the STS and plant-specific Technical Specifications except that infrequent, one time only changes may be granted for plant-specific conditions where adequate justification is given.

Sincerely,

Darrell G. Eisenhut, Director Division of Licensing