ML20067C480
| ML20067C480 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 02/04/1991 |
| From: | Skolds J SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20067C482 | List: |
| References | |
| TAC-76977, TSP-900003-2, NUDOCS 9102120081 | |
| Download: ML20067C480 (2) | |
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Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555 Gentlemen:
Subject:
VIRGIL C. SUMMER NUCLEAR STATION DOCKET NO. 50/395 OPERATING LICENSE NO. NPF-12 TECHNICAL SPEClflCATIONS CHANGE PEQUEST: REQUIRED SHUTOOWN MARGIN CURVE (TSP 900003-2) (TAC NO. 76977)
In a letter dated May 3, 1990. South Carolina Electric & Gas Company (SCE&G) informed the Nuclear Regulatory Commission (NRC) that the boron worths for Modes 3 and 4 in the Virgil C. Summer Nuclear Station (VCSNS) Cycle 6 core are more negative than the boron worths assumed in the existina Boron Dilution Accident Analysis. As a result, the Required Shutdr aargin curve (figure 3.1-3, " Required Shutdown Margin (Modes 3, 4, cnd 5).
in tae VCSNS Technical Specifications) will not e.sure that the operator has sufficient time (previously accepted as 13.4 minutes for Mode 3 and 13.6 minutes for Mode 4) from receipt of an alarm to terminate a bornn dilution event prior to a loss of shutdown margin, in the subject letter, SCE&G committed to administrative 1y control ocerations to abide by a more restrictive Required Shutdown Margin curve which incorporates the ad.usted boron worths for Modes 3 and 4 Additionally, SCE&G committed to expet itiously process and submit a Technical Specifications Change Request (TSCR) la replace the errant figure 3.1-3 with the more restrictive curve.
During subsequent conversations with J. J. Ha3es Jr. and O. B. Fieno (both of the NRC) SCE&G 1 earned that approval had been granted, for at least one plant, to remove the Required Shutdown Margin curve from Technical Specifications and place it in the Core Operating Limits Report (COLR).
After discussing this with J. J. Hayes Jr. and L. P. Modenos (VCSNS Resident inspector)
SCE&G decided to request approval for placing figure 3.1-3 in the COLR. VCSNS submitted this TSCR in a July 18, 1990, letter to the Document Control Desk.
As stated in the July submittal, SCE&G maintains that required shutdown margin limits are cycle specific, making the Required Shutdown Margin curve a candidate for inclusion in the COLR. Because boron worths may vary with each reload cycle, b0unding values of the parameter must be chosen for future cycles when compiling the data points for Figure 3.1-3.
This necessity to bound future cycles can place undue restrictions on operations during earlier cycles.
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Document Control Desk TSP _900003-2 Page 2 of 2 In a recent conversation, G. F. Wunder of the NRC informeo SCE&G that the TSCR for relocating the Required Shutdown Margin curve to the COLR will be denied. The reason delineated for the impending anial is the NRC position that required shutdown margin limits are not CV.2 specific parameters.
I SCE&G still maintains the position that the subject limits are cycle specific. 'However, SCE&G wishes to withdraw the. July 18, 1990, request and submit, in its place, the attached TSCR to revise figure 3.1-3 to incorporate
-the more negative baron worths-in Modes-3 and 4.
The proposed changes to the Technical Specifications r e provided as Attachment 1. provides the required safety evaluation. Attachment 3 contains the proposed curve superimposed on the current Figure 3.1-3 in the VCSNS Technical.
Specifications. The proposed no significant hazards evaluation is provided as Attachment 4.
Additionally.-an administrative change is included in the attached TSCR to revise Basis 3/4.2-1, " Axial Flux Difference," to refer to the COLR rather thtn the Peaking factor Limits Report (PFLR). Amendment No. 88 to the VCSNS Operating License replaced the PFLR with the COLR.
This request has been reviewed and approved by the Plant Safety Review Committee and the Nuclear Safety Revie>v Committee. SCE&G requests the NRC to
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review and approve this-TSCR by May 15, 1991.
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I declare that the statements and matters set forth herein are true and correct to the best of my knowledge, information, and belief. Should you have any questions, please call at your convenience.
Very truly yours, John L. Skolds EWR:JLS: led Attachments c:
- 0. W. Dixon Jr. (w/o attachments)
R. R. Mahan R. J. White.
J. B. Knotts Jr.
S. C. Ebneter H. 3. Shealy-G. F. Wunder D. O. Warner General Managers RTS l TSP 900003)
NRC Resident Inspector File (l'13.20)
NUCLEAR EXCELLENCE - A SUM ER TRADITION!
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