ML13317B222
| ML13317B222 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/27/1990 |
| From: | Nandy F SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML13317B223 | List: |
| References | |
| NUDOCS 9012030012 | |
| Download: ML13317B222 (3) | |
Text
Southern California Edison Company 23 PARKER STREET IRVINE, CALIFORNIA 92718 F. R. NANDY TELEPHONE MANAGER, NUCLEAR LICENSING (714) 454-4504 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 Small Break LOCA Model San Onofre Nuclear Generating Station, Unit 1 This letter provides information for your review and approval of the Westinghouse NOTRUMP Small Break Loss of Coolant Accident (SBLOCA)
Emergency Core Cooling System (ECCS) Evaluation Model for application to San Onofre Nuclear Generating Station, Unit 1 (SONGS 1).
NRC approval is requested by February 1, 1991.
Restart for Cycle 11 operation will be based on the results obtained using NOTRUMP for SBLOCAs. An early Updated Final Safety Analysis Report (UFSAR) update package reporting the results of the SBLOCA analysis will be provided by March 30, 1991.
Background
In a letter dated October 2, 1990, we informed you of our decision to modify the safety injection mode miniflow recirculation for the main feedwater pumps prior to restart from the current Cycle 11 refueling outage. This modification is being performed to increase the recirculation flow rate in accordance with the pump vendor recommendations for sustained operation at minimum delivery to the Reactor Coolant System (RCS).
The increase in miniflow rate was deemed necessary as a result of our review of comments provided by the NRC in a letter dated July 17, 1990 on SCE's response to NRC Bulletin 88-04.
Due to the increase in miniflow rate, less flow is available to the RCS.
during a SBLOCA. As discussed in the October 2, 1990 letter, the SBLOCA analysis must be performed using NOTRUMP. As agreed in the meeting between SCE and the NRC on November 3, 1990, SCE committed to submit for NRC approval the SONGS 1 specific Westinghouse NOTRUMP SBLOCA ECCS Evaluation Model.
612
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Document Control Desk 2
NOTRUMP SONGS 1 Scoping Calculations Scoping calculations were performed in order to demonstrate that NOTRUMP is capable of correctly modeling the thermal-hydraulic phenomena during a postulated SBLOCA for SONGS 1. The details of the scoping calculations are provided in Enclosures 1 and 2 (Enclosure 1 is a proprietary version of the report and Enclosure 2 is a non-proprietary version). This is a Westinghouse report titled "Applicability of NOTRUMP to the San Onofre Nuclear Generating Station Unit 1 (SONGS 1)."
Ten copies are provided for your use.
These calculations were performed by utilizing the NOTRUMP model for the Virgil Summer Plant which is a typical 3-loop Westinghouse plant. To obtain better similarity with SONGS 1, the model was modified as follows:
- 3. The accumulators were deactivated.
Overall, the phenomena observed in the scoping calculations were similar to those observed in the NOTRUMP generic results. The SONGS 1 design differences do not result in an RCS transient response which is substantially different from that obtained for other plants. Based on these observations it is concluded that the Westinghouse NOTRUMP SBLOCA ECCS Evaluation Model is applicable to SONGS 1.
Fuel Rod Cladding Properties The verification and validation of the properties for stainless steel fuel rod cladding have been completed. The generic NOTRUMP model contains properties of Zircaloy as fuel rod cladding material.
Since SONGS 1 fuel rod cladding is made of stainless steel, stainless steel properties have been incorporated into the NOTRUMP model for SONGS 1. The enclosed report provides the details of the fuel rod model for stainless steel cladding. The stainless steel properties included in the model are density, thermal conductivity, thermal capacity, radiation emissivity, and coefficient of thermal expansion.
Cladding swelling, rupture and oxidation are modeled as discussed in the enclosure.
Westinghouse Proprietary Information Also enclosed are Westinghouse authorization letter CAW-90-087 and accompanying affidavit (Enclosure 3), Proprietary Information Notice (Enclosure 4), and Copyright Notice (Enclosure 5).
As the enclosed reports contain information proprietary to Westinghouse Electric Corporation, they are supported by an affidavit signed by Westinghouse, the owner of the information. The affidavit sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.790 of the Commission's regulations.
S.
Document Control Desk 3
Accordingly, it is respectfully requested the information which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR Section 2.790 of the Commission's regulations.
Correspondence with respect to the copyright or proprietary aspects of the items listed above or the supporting Westinghouse Affidavit should reference CAW-90-087 and should be addressed to R. A. Wiesemann, Manager of Regulatory &
Legislative Affairs, Westinghouse Electric Corporation, P. 0. Box 355, Pittsburgh, Pennsylvania 15230-0355.
Conclusions The evaluation provided in the enclosed report demonstrates that the Westinghouse NOTRUMP SBLOCA ECCS Evaluation Model is applicable to SONGS 1. We therefore request NRC approval for plant-specific application of NOTRUMP to SONGS 1 SBLOCA analysis.
NRC approval is requested by February 1, 1991.
The results of the SBLOCA analysis will be used in support of restart for Cycle 11 operation. We plan to provide you with an early copy of the UFSAR update package reporting the SBLOCA results by March 30, 1991.
If you have any questions or comments, or if you would like additional information, please contact me.
Sincerely, Enclosures cc: J. B. Martin, Regional Administrator, NRC Region V C. W. Caldwell, NRC Senior Resident Inspector, SONGS 1, 2 and 3 C. D. Townsend, NRC Resident Inspector, San Onofre Unit 1