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Home NRC Library Document Collections Generic Communications Circulars 1980

IE Circular No. 80-08, BWR Technical Specification Inconsistency - RPS Response Time


                                                            SSINS No.: 6830 
                                                            Accession No.: 
                                                            8002280651

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF INSPECTION AND ENFORCEMENT
                           WASHINGTON, D.C.  20555

                               April 18, 1980

                                                         IE Circular No. 
80-08 

BWR TECHNICAL SPECIFICATION INCONSISTENCY - RPS RESPONSE TIME 

Description of Circumstances: 

On March 10, 1980, Vermont Yankee (VY) notified the NRC that the reactor 
protection system (RPS) response time of 100 milliseconds (from sensor 
contact opening to and including scram solenoid relay contact opening) 
specified in the Technical Specification is inconsistent with the value of 
50 milliseconds used in the safety analysis.  VY verified that actual 
response times have been below 50 milliseconds since initial plant operation 
and initiated Technical Specification change request and plant procedure 
changes.  VY reported that a letter from General Electric Company (GE) 
informed them of the inconsistency and that the problem may be generic. 

Our followup indicates that GE BWR facilities which have Technical 
Specifications similar to that discussed above may be affected.  Based on 
RPS design and test results, actual RPS response times are expected to be 
less than 50 milliseconds. 

For GE BWR's, we request that you take the following corrective action 
promptly after receipt of this Circular:  (1) verify that the actual RPS 
response time in the most recent test is less than the value specified in 
the safety analysis, (2) observe the RPS response time value specified in 
the safety analysis until a Technical Specification change (if necessary) is
approved, and (3) take appropriate actions to make Technical Specification 
on RPS response time consistent with the RPS response time used in the 
safety analysis.  If a value less than that currently in the Technical 
Specifications is proposed, the licensee will be expected to provide the 
basis for that value, including the validity of tests and methods. 

No written response to this Circular is required, however, IE will inspect 
licensee corrective action.  If you require additional information regarding
this matter, contact the Director of the appropriate NRC Regional Office.

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