ML20034F493
| ML20034F493 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 03/01/1993 |
| From: | Ray H SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20034F495 | List: |
| References | |
| NUDOCS 9303030313 | |
| Download: ML20034F493 (2) | |
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23 PARKER STREET IRVINE, CALIFORNIA 92718 HAROLD B RAY TELEPHONE St seeOm vaca pet s.OE est he458-*a00 March 1, 1993 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C.
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Gentlemen:
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Subject:
Docket Nos. 50-361 and 50-362 Amendment Application Nos. 131 and 115 Change to the Technical Specification 3.3.3.2, " Instrumentation Incore Detectors" San Onofre Nuclear Generating Station Units 2 and 3.
Enclosed are Amendment Application Nos. 131 and 115 to Facility Operating Licenses NPF-10 and NPF-15, respectively, for San Onofre Nuclear Generating Station Units 2 and 3.
These Amendment Applications consist of Proposed Change Number (PCN) 420. PCN-420 requests a change to Technical Specification j
(TS) 3.3.3.2, " Instrumentation Incore Detectors."
The proposed change to TS 3.3.3.2 would redefine an operable incore detector string (location) such that a string would be considered operable when at l
least three out of five rhodium detectors are operable (as opposed to the existing TS which requires a minimum of four out of five detectors operable).
l To limit the total number of detector failures allowed, a requirement that at least '75% of all detectors be operable will be added.
To ensure that all parts of the core are instrumented, at least one operable detector in each quadrant at each level will be required.
In addition, the proposed change strengthens the provision related to quadrant symmetric locations by explicitly stating that at least six tilt estimates are required, with at least one tilt estimate at each of three levels. This proposed change allows greater variance in failed detector patterns while remaining within the Core Operating Limit Supervisory System operating characteristics and safety i
l analysis.
With the present Unit 2 Incore Detector System status, as few as three additional detector failures (in selected, critical locations) would force the unit into a TS action statement required power reduction to approximately 90%;
notwithstanding that the core would still be adequately instrumented and the Incore Detector System still capable of performing its design function.
The priority of this amendment application is not immediate, as there is no immediate safety significance or impact to plant operations and we plan on repairing the existing failed detectors during the upcoming refueling outages.
However, in the event of additional detector failures it may become necessary to request an expedited review and approval of this application.
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Document Control Desk If you have any questions regarding this amendment application, please let me i
know.
Since aly, M
Enclosures l
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cc: J. B. Martin, Regional Administrator, NRC Region V M. B. Fields, NRC Project Manager, San Onofre Units 2 & 3 C. W. Caldwell, NRC Senior Resident Inspector, San Onofre Units 1, 2 & 3 l
H. Kocol, California Dqartment of Health Services
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