ML20077B916
| ML20077B916 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 07/15/1983 |
| From: | Ray H SOUTHERN CALIFORNIA EDISON CO. |
| To: | Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| RO-83-073, RO-83-73, NUDOCS 8307250491 | |
| Download: ML20077B916 (2) | |
Text
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.11ECEIVED
.fac Southern California Edison Company C;CE I B3 JUL 18 PH 12: 22 S AN ONOFRE NUCLE AR GENER A TING ST A TION P.O. BOX 128 S A N C LEMEN T E. C A LIFORNI A 92672 H. 8. R A Y REGl0:1VIU O~.
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July 15, 1983 U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region V 1450 Maria Lane, Suite 210 Walnut Creek, California 94596-5368 Attention:
Mr. J. B. Martin, Regional Administrator
Dear Sir:
Subject:
Docket No. 50-361 Prompt Report Licensee Event Report No.83-073 San Onofre Nuclear Generating Station, Unit 2 Pursuant to Section 6.9.1.12.b of Appendix A, Technical Specifications to Facility Operating License NPF-10 for San Onofre Unit 2, this letter provides the prompt notification and written confirmation of a reportable occurrence involving the Core Protection Calculators (CPC).
During the recent outage of Unit 2 for replacement of reactor coolant pump seals and other work,-the 18-month interval CPC channel calibration and functional test was performed for Channels B, C, and D.
Unit 2 returned to Mode 2 on July 13, 1983, and entered Mode 1 on July 14.
During comparison of CPC Channels on July 14, 1983, at about 1630, with Unit 2 in Mode 1 at about 50 percent power, it was determined that Channels B and D contained certain CPC Addressable Constants which were nonconservative, contrary to Limiting Condition for Operation (LCO) 2.2.2 of the Technical Specifications.
Action was taken immediately to correct the 4'
constants using the Control Room Addressable Constants log.
This action was completed well within one hour of the initial determination.
B307250491 830715 PDR ADDCK 05000361 S
PDR E
ll -XX.
Mr. J. B. Martin July 15, 1983 Investigation of the event has determined that the Addressable Constants from the channel functional test data base were left in Channels B and D following the 18-month interval test and 30-day functional test performed during the outage whereas the currently approved Addressable Constants should have been re-entered, as was done correctly for Channel C.
Review of surveillance tests performed prior to achieving significant reactor power levels on day shift on July 14, 1983, indicates that acceptance criteria were met.
The CPC surveillance conducted on the July 14, 1983, day shift showed a deviation in DNBR margin between channels of greater than 0.4.
This deviation was initially attributed to the need to complete the ongoing calorimetric and to calibration of Reactor Coolant System RTD's during the outage.
Further review identified the incorrect Channel B and D Addressable Constants as described above.
3 In a letter dated July 15, 1983, Combustion Engineering, Inc.,
documented a' preliminary evaluation which concludes that use of the Addressable Constants from the channel functional test data base (i.e., " default" constants) in this case did not violate required safety margins.
Corrective action to prevent recurrence will be described in our 14-day follow-up report and Licensee Event Report (LER) No.83-073 to be submitted prior to July 29, 1983.
If there are any questions, please contact me.
Sincerely, f
cc:
A.E. Chaffee (USNRC Resident Inspector, Units 2 and 3)
J.P. Stewart (USNRC Resident Inspector, Units 2 and 3)
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