United States Nuclear Regulatory Commission - Protecting People and the Environment

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


                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                           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. 





8307060329 
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                                     -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 

Page Last Reviewed/Updated Wednesday, June 19, 2013