United States Nuclear Regulatory Commission - Protecting People and the Environment

Potential Inconsistency Between Plant Safety Analyses and Technical Specifications (Generic Letter No. 86-13)


                               UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                          WASHINGTON, D. C. 20555  

                               JULY 23, 1986  

TO:       ALL POWER REACTOR LICENSEES AND APPLICANTS WITH COMBUSTION 
          ENGINEERING AND BABCOCK AND WILCOX PRESSURIZED WATER REACTORS 

SUBJECT:  POTENTIAL INCONSISTENCY BETWEEN PLANT SAFETY ANALYSES AND 
          TECHNICAL SPECIFICATIONS (Generic Letter 86-13) 

The purpose of this letter is to advise you of a potential inconsistency 
between Technical Specifications and FSAR safety analyses. 

In June 1984, Westinghouse informed the staff that they had discovered a 
potential inconsistency between the Technical Specifications and the safety 
analyses when a plant is in Mode 3 of operation (hot standby). In a 
memorandum to the staff dated July 9, 1984, Westinghouse documented the 
inconsistency (NS-EPR-2935). When a plant is in Mode 3, the Technical 
Specifications may have required only one reactor coolant pump to be in 
operation whereas the safety analysis presented in the FSAR (which may have 
been presented only in terms of a bounding analysis in Mode 2) assumed that 
two or more reactor coolant pumps were in operation for Mode 3 events. 

When Westinghouse reanalyzed the affected events (i.e., steamline break, rod
ejection, and bank withdrawal from subcritical) in Mode 3 with only one 
reactor coolant pump in operation, they concluded that the FSAR analysis 
remained bounding except for the control rod bank withdrawal from 
subcritical conditions. For this event, they concluded that the DNBR 
criteria "may not be met when only one pump is in operation." The 
Westinghouse plants have evaluated this inconsistency and some plants have 
proposed Technical Specification revisions or analyzed for the event. 

We believe this situation may be equally applicable to CE and B&W designed 
plants. Representatives of both CE and B&W have notified the NRC that the 
safety analyses assume more than one reactor coolant pump to be operating, 
but that no analysis exists which demonstrates directly the adequacy of the 
current Technical Specifications. 

In view of the potential for an inconsistency we encourage you to review 
your FSAR and Technical Specifications for applicability of the problem for 
your plant(s). You may wish to examine your Technical Specifications, 
procedures or other administrative controls to determine if this 
inconsistency exists in Modes 4&5. Westinghouse plants which have determined 
that a discrepancy exists (Mode 3) have chosen to remedy this problem by: 
(1) proposing revised Technical Specifications to ensure that the plant 
remains within the analyzed limits of the FSAR, or (2) carrying out, and 
including in the next FSAR update, an analysis which bounds the single loop 
operation and shows that the applicable criteria are not violated. You might 
wish to consider this approach if the discrepancy exists for your facility. 


                                     -2- 

This generic letter is for information only and does not involve any 
reporting requirements. Therefore, no clearance from the Office of 
Management and Budget is required. 


                              Frank J. Miraglia, Director 
                              Division of PWR Licensing-B 
                              Office of Nuclear Reactor Regulation 
Page Last Reviewed/Updated Thursday, June 27, 2013