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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