ML13330A307
| ML13330A307 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/15/1981 |
| From: | Baskin K Southern California Edison Co |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML13330A308 | List: |
| References | |
| NUDOCS 8104280456 | |
| Download: ML13330A307 (2) | |
Text
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD. CALIFORNIA 91770 K. P. BASKIN MANAGER, NUCLEAR ENGINEERING April 15, 1981 AND LICENSING Director, Office of Nuclear Reactor Regulation Attention: D. M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D,
-C-.20555 Gentlemen:
Subject:
Docket No. 50-206 Amendment No. 95 San Onofre Nuclear Generating Station Unit 1 By letter dated December 10, 1980, Amendment No. 95 to the San Onofre Unit 1 Operating License was submitted for NRC review and approval.
Amendment No. 95 consists of Proposed Change No. 100 to the Technical Specifications which revises the affected specifications to allow operation as described in the supporting report, "Reload Safety Evaluation, San Onofre Nuclear Generating Station, Unit 1, Cycle 8, Revision 1," dated October, 1980, (hereafter referred to as "RSE Rev. 1").
The nominal design parameters for Cycle 8 included in the RSE Rev. 1 are 1347 Mwt (100% rated core power), 2100 psia system pressure, nominal core inlet temperature of 551.5 0F, 4.64 kW/ft.
average linear fuel power density, and a 195,000 gpm RCS Thermal Design Flow (TDF) (93.4% of Cycle 7 TDF).
The reduced TDF of the RSE Rev. 1 accounts for up to an equivalent 20% steam generator tube plugging.
It is now projected that the final configuration of the steam generators, at the completion of the ongoing modifications, will result in a TDF consistent with an equivalent 15% steam generator tube plugging. In o
addition, as indicated in our letter dated April 10, 1981, it is now planned to return to power operation.with reduced core outlet temperature. The probable effect of the reduced temperature will be a reduction in the rate of tube degradation. Accordingly, a new set of analyses has been performed and documented in the report entitled, "Reload Safety Evaluation, San Onofre 1e Nuclear Generating Station, Unit 1, Cycle 8, Revision 2," dated April, 1980 (hereafter referred to as "RSE Rev. 2"), 40 copies of which are enclosed. The nominal design parameters for Cycle 8 included in the RSE Rev. 2 which differ from those of the RSE Rev. 1 are the nominal core inlet temperature of 528 0F and the 201,900 gpm RCS TDF (96.7% of cycle 7 TDF).
The reduced TDF of the RSE Rev. 2 accounts for up to an equivalent 15% steam generator tube plugging.
- 8 1o4 2-e85(
D.
April 15, 1981 It should be noted that the results of RSE Rev. 2 do not require any changes to the Technical Specifications resulting from RSE Rev. 1. The review and approval of Proposed Change No. 100 to the Technical Specifications should therefore proceed using the RSE Rev. 2 as additional basis. One item of Proposed Change No. 100 does require a correction for a typographical error on Page 1. In the section entitled "Proposed Specification," a change to Table 2.1, Item 4 is identified as:
"4. Variable Low Pressure 26.15 (0.984 AT + Tavg) -
14341".
This item should be:
"4. Variable Low Pressure 26.15 (0.894 AT + Tavg) -
14341".
The same typographical error appears on Page 8 of RSE Rev. 1.
It is requested that approval of Proposed Change No. 100 to the Technical Specifications be granted based on a review of both RSE Rev. 1 and Rev. 2. It is now planned to commence operation at or less than an equivalent 15% tube plugging and reduced core outlet temperature as analyzed in the RSE Rev. 2. Our decision to return the unit to service at a reduced core outlet temperature is based on our desire to determine to what extent such reduced temperature operation retards or eliminates corrosion of the steam generator tubes and is not based on safety considerations. Since the decision to operate at a reduced core outlet temperature is not based on safety considerations, the unit will be returned to operation at the original core outlet temperature at such time in the future as circumstances warrant such operation. As noted above, no change in the Technical Specifications will be needed to return to the original core outlet temperature and the analysis provided in the RSE Rev. 1 is bounding.
If you have any questions or desire additional information, please contact me.
Enclosures