ML052080170
| ML052080170 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 07/25/2005 |
| From: | Scherer A Southern California Edison Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-04-002, TAC MC4714, TAC MC4715 | |
| Download: ML052080170 (3) | |
Text
SOUTHIERN CALIFORNIA EDISON' An E DISON INTIERN'ITIONAI!
Comnpany A. Edward Shcerer Manager of Nuclear Regulatory Affairs July 25, 2005 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
Subject:
San Onofre Nuclear Generating Station Units 2 and 3 Docket Nos. 50-361 and 50-362 NRC Generic Letter 2004-02 Response To NRC Request For Additional Information
References:
- 1. Letter from A. E. Scherer (SCE) to the Document Control Desk (NRC) dated March 7, 2005;
Subject:
San Onofre Nuclear Generating Station Units 2 and 3, Docket Nos. 50-361 and 50-362, 60-Day Response to NRC Bulletin 2003-01, "Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors"
- 2. Letter from Bo M. Pham (NRC) to H. B. Ray (SCE) dated June 2, 2005;
Subject:
San Onofre Nuclear Generating Station, Units 2 and 3 - Request for Additional Information (RAI) Related To Generic Letter 2004-02, 'Potential Impact Of Debris Blockage On Emergency Sump Recirculation At Pressurized-Water Reactors" (TAC Nos. MC4714 and MC4715)
Dear Sir or Madam:
By Reference 1, Southern California Edison (SCE) submitted a 90-day response to NRC Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors." By Reference 2, the NRC staff has requested additional information, to be provided within 45 days of receipt of Reference 2. SCE received Reference 2 on June 10, 2005.
P.O. Box 128 San Clemcntc, CA 92672 949-368-7501 Fax 949-368-7575 IIY
Document Control Desk July 25, 2005 The pertinent part of the staffs request is as follows:
Question:
As a result of the review of the 90-day responses for all licensees and recent discussions with industry, the staff is concerned that some licensees may be delaying the evaluation of chemical and downstream effects until after the September 1, 2005, due date for the next response to the GL. This would result in an incomplete response and is not in accordance with the schedule in the GL.
Your 90 day response indicated that your analysis will be completed by September 1, 2005, but did not discuss the evaluation of chemical and downstream effects. Although the GL did not specifically request that the evaluation of chemical and downstream effects be discussed in the 90-day response, please discuss your plans and schedule for evaluating chemical and downstream effects and verify whether your September 1, 2005, response will include an evaluation of these effects.
Response
SCE will perform a downstream effects evaluation in support of the September 1, 2005 submittal. Specifically, blockage and wear evaluations will be performed for Emergency Core Cooling System and Containment Spray System heat exchangers, orifices, spray nozzles, instrumentation tubing, pumps, and valves. Additionally, blockage evaluations will be performed for the Reactor Vessel and the fuel.
Our current plans for evaluating the chemical effects are the following: (1) SCE will include a conservative margin in the debris head loss calculation prepared in support of the September 1, 2005 submittal, specifically allocated for chemical effects based on the preliminary results of the Integrated Chemical Effects Testing (ICET) Program; and (2) SCE will validate this margin, as necessary, through follow-on testing and/or analysis.
SONGS uses Trisodium Phosphate (TSP) as a buffering agent in the post-Loss Of Coolant Accident core cooling. As a result of the preliminary debris generation and transport studies, pertinent SONGS debris loads are primarily fibrous insulation (Mineral Wool). These two primary test parameters (TSP and Fiber) would indicate that ICET Test No. 2 is generally applicable. Since ICET Test No. 2 was conducted with fiberglass insulation, however, SCE will address the impact of Mineral Wool (in lieu of fiberglass) on the chemical reactions products. A more detailed discussion of these activities will be included in the September 1, 2005 GL 2004-02 response.
-t.
Document Control Desk July 25, 2005 If you have any questions or require any additional information, please contact Mr. Jack Rainsberry at (949) 368-7420.
Sincerely, cc: B. S. Mallett, NRC Region IV, Regional Administrator B. M. Pham, NRC Project Manager, San Onofre Units 2 and 3 C. C. Osterholtz, NRC Senior Resident Inspector, San Onofre Units 2 and 3