IE Circular No. 80-08, BWR Technical Specification Inconsistency - RPS Response Time
SSINS No.: 6830
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
April 18, 1980
IE Circular No.
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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