ML13330B525
| ML13330B525 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 06/26/1991 |
| From: | Rosenblum R Southern California Edison Co |
| To: | NRC/IRM |
| References | |
| NUDOCS 9107020213 | |
| Download: ML13330B525 (2) | |
Text
I7 Southern California Edison Company 23 PARKER STREET IRVINE, CALIFORNIA 92718 R. M. ROSENBLUM TELEPHONE MANAGER OF (714) 454-4505 NUCLEAR REGULATORY AFFAIRS June 26, 1991 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 Reduced Reactor Coolant Average Temperature San Onofre Nuclear Generating Station, Unit 1
Reference:
Letter, R. M. Rosenblum (SCE) to NRC Document Control Desk, "Main Feedwater Line Break Analysis/Reduced Tavg Operation,"
February 15, 1991.
This letter documents our plans for development of a Technical Specification (TS) on Reactor Coolant System (RCS) average coolant temperature, Tays. We had previously planned to submit a TS change on this subject this month.
However, we have determined that the development of the T TS is more appropriately accomplished following our Chapter 15 reanalysis project and, therefore, we will submit the TS change by December 15, 1992. We have discussed the revised schedule with our NRC Project Manager, Mr. G. Kalman.
BACKGROUND SONGS 1 was originally designed to operate with a To of 575.1*F. However, operation has been limited to a reduced Tyg due to the discovery in the early 1980's of inter-granular attack of the steam generator tubes. Reload analyses for Cycles 8, 9, and 10 were performed to support plant operation with either the original Tavg or a reduced Tyg For the reasons discussed below, the reload analysis for Cycle 11 operation was performed only for reduced Tavg.
Administrative controls reflecting the reduced Tavg limit of 553.5*F were established prior to Cycle 11 operation.
As discussed in the above reference, credit for operation at reduced T was also taken for post-Cycle 10 operation as part of resolution of NUREG-UY37, Item II.D.1, which requires the pressurizer Power Operated Relief Valves (PORVs) and Safety Relief Valves and their associated piping to be evaluated for worst case loads. Operation at reduced Tavg prevents filling the pressurizer after certain design basis events, and therefore, precludes water discharge from the PORVs after an accident.
9107020213' 910626.
FDR ADOCK 05000206 P
P--
FDR
Document Control Desk
-2 Since the SONGS 1 Technical Specifications do not have a specification for Tav (either nominal or reduced Tavg),
we committed in the referenced letter to submit a new TS based on the "Standard Technical Specifications for Westinghouse Pressurized Water Reactors," NUREG-0452.
IMPACT OF CHAPTER 15 ANALYSIS SCE's current project to re-perform the Chapter 15 analyses makes it unproductive to submit a TS on Tayg at this time. There are two options for development of a T, TS.
The first is to submit a proposed TS based on the existing design basis analyses using generic Westinghouse values for certain inputs. The second option is to submit a proposed TS based on new design basis analyses using plant specific input values calculated with modern methods and practices. The plant specific value for Tayg computed for use with the Chapter 15 reanalysis project may be different than the Westinghouse generic value and may not be consistent with the existing design basis analyses. Rather than re-perform the existing design basis analyses using the new Ta 8, it is more productive to defer development of a proposed TS until after he new analyses are complete. Submitting a proposed change now that is based on the existing design basis analyses may require a resubmittal once the new analyses are complete. Therefore, it is not productive for us to submit, or for the NRC to review, a proposed TS change on Tay that is based on the existing analyses.
REVISED SUBMITTAL SCHEDULE During our recent discussion of the above circumstances with Mr. Kalman, we agreed to cancel our current plans and submit our TS after the Chapter 15 reanalysis is complete. Based upon our current schedule for that reanalysis, we will submit a proposed TS by December 15, 1992. In the interim, plant operation continues to be restricted to operation with a reduced Tavg Of 553.5*F.
Please contact me if you have any questions on this matter.
Very truly yours, cc:
George Kalman, NRC Senior Project Manager, San Onofre Unit 1 J. 0. Bradfute, NRC Project Manager, San Onofre Unit 1 J. B. Martin, Regional Administrator, NRC Region V C. W. Caldwell, NRC Senior Resident Inspector, San Onofre Units 1, 2 & 3