ML20217J939
| ML20217J939 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/17/1997 |
| From: | Nunn D SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20217J945 | List: |
| References | |
| NUDOCS 9710220309 | |
| Download: ML20217J939 (3) | |
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[-j EDISON An EDISON INTERN ATION AL Company b
i October 17, 1997 I
U.S. Nuclear Regulatory Commission Attention: Document Control Desk If Washington, D.C.
20b55 h
Gentlemer:
Subject:
Docket Nos. 50-361 and 50-362 Proposed Change Number NPF-10/15-459 i
Radiation Monitoring System Digital Upgrade 3
San Onofre Nuclear Generating Station Units 2 and 3 j m
Reference:
Letter, SCE to NRC, " Docket Nos. 50-361 and 50-362 Radiation l
Monitoring System Digital Upgrade San Onofre Nuclear Generating Station Units 2 and 3," July 14, 1997 1
- ll Provided as Enclosure 1 to this letter, are Amendment Application Number 171 to Facility Operating License NPF-10, and Amendment Application Number 157 to Facility Operating License NPF-15, for the San Onofre Nuclear Generating U
Station (SONGS), Units 2and3;.respectively.
The Amendment Applications
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consistofProposedChangeNumberNPF-10/15-459(PCN-459).
j The Amendment Application is required to permit digital rarliation monitor d
installation for both trains supplying the Containment Purge Isolation Signal
' [
(CPIS), and permit digital radiation monitor installation for both trains i
supplying the Control Room Isolation Signal (CRIS). Approval of this
[
amendment will permit completion of Design Change Package 2&3-6926.01SJ, J
" Obsolete Equipment: Radiation Monitoring System Replacement Project." This i
amendment does r.ot require revision of the Technical Specifications for SONGS Unit 2 or Unit 3.
The evaluation of the use of common software in redundant channels resulted in an unreviewed safety question during performance of the 10 CFR 50.59 Safety Evaluation for this design change. The unreviewed safety question only would exist when both trains of CRIS and CPIS radiation monitors are upgraded to the digital system.
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Calculations J-SPA-289, "ESFAS Radiation Monitor Sof tware Common Mode Failure Evaluation," and N-0720-014. " Control Room and Offsite Doses Should CPIS, CRIS i
9710220309 971017 P.O.Ika 128 s%":3ab gi,\\l%I@N
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Document Control Desk 2-and FHIS Fail," have been performed to evaluate the consequences of a coninon mode failure of the-Fuel Handling Isolation Signal (FHIS), CPIS, and CRIS radiation monitors. -The basic software structure including its complexity and size have also been analyzed in J-SPA-?89. The calculations are provided as Enclosure' 2 to this letter.
If you would like additional information regarding this Amendment Application
- please let me know.
Sincerely, j
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Enclosure cc:
E. W. Merschoff, Regional Administrator, NRC Region IV K. E. Perkins, Jr., Director, Walnut Creek Field Office, NRC Region IV J. A. Sloan, NRC Senior Resident Inspector, San Onofre Units 2 & 3 M. B. Fields, NRC Project Manager, San Onofre Units 2 and 3 S. Y. Hsu, Department of Health Services, Radiological Health Branch
_____...___.__J
Proposed Change Number NPF-10/15-459 Radiation Monitoring System Digital Upgrade San Onofre Nuclear Generating Station Units 2 and 3 i
.-