ML20249A648
| ML20249A648 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 06/12/1998 |
| From: | Nunn D SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20138K406 | List: |
| References | |
| NUDOCS 9806180042 | |
| Download: ML20249A648 (2) | |
Text
- --
soulmRN cAusoa.;%
S EDISON
" + " -
Vice President An LDISON IN7TRMTIOhAL" Company June 12, 1998 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington D.C. 20555 Gentlemen:
Subject:
Docket Nos. 50-361 and 50-362 Amendment Application Nos. 178 and 164 Turbine Missile Protection San Onofre Nuclear Generating Station Units 2 and 3 to this letter provides Amendment Application Nos.178 and 164 to Facility Operating Licenses NPF-10 and NPF-15, for the San Onofre Nuclear Generating Station (SONGS), Units 2 and 3, respectively.
The Amendment ApplicationsconsistofProposedChangeNumber494(PCN-494),whichisa request to revise the licensing basis as described in the Updated Final Safety i
Analysis Report (UFSAR) Section 3.5, " Missile Protection." This proposed change is in support of the turbine retrofit project, currently scheduled for i
the Units 2 and 3 Cycle 10 Refueling Outages.
l This proposed change to the licensing basis of SONGS 2 and 3 is to revise the turbine missile protection calculation methodology. The existing methodology assumes a missile generation probability, and provides specific analyses for the missile strike and damage probability. These values are used to calculate an overall prob:bility of damage to safety-related equipment due to turbine
/
l missile strikes. The revised methodology is consistent with the methodology that has been approved by the NRC for other plants since the early 1980s and
/
provides a value of missile generation probability that is supported by analysis, and assumes a value for missile strike and damage probability. This revised methodology continues to demonstrate that the probability of damage to
~
safety-related equipment is less than or equal to the overall acceptance 4
criteria. The acceptance criteria of 1 x 10 per unit year thus remains unchanged. to this letter provides an analysis from the turbine manufacturer, GEC-Alsthom, which demonstrates that with a ten-year inspection interval and monthly onload testing of the steam valves, the total annual probability of 4
failure (P ) at any. speed is less than 1 x 10 per unit year.
i 9906190042 990612 P
n s
PDR ADOCK 05000361!
, ;8 P
PDR P.O,Ika 128 San Clemente, CA 92674-0128 949 368-!480 Fad 443681490
1 l
lj Document Control Desk i This licensing basis change is necessary to support a return to. power operations following'the turbine rotor replacement scheduled for the Units 2 and 3 Cycle 10 refueling outages. The Unit 2 outage is currently scheduled to begin on January 2, 1999. Because the turbine rotor replacement has a major impact on outage scope, for planning purposes Southern California Edison requests NRC approval of this change by December 1,1998.
If you need additional information on this UFSAR change request, please let me know.
Sincerely,
}
N
(, %_
\\
Enclosures 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 1
J. W. Clifford, NRC Project Manager, San Onofre Units 2 and 3 S. Y. Hsu, Department of Health Services, Radiologic Health Branch i
l l
1 1
f 7,
-