ML18347A678
| ML18347A678 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 04/08/1976 |
| From: | Bixel D Consumers Power Co |
| To: | Purple R Office of Nuclear Reactor Regulation |
| References | |
| Download: ML18347A678 (2) | |
Text
{{#Wiki_filter:* April 8, 1976 Director of Nuclear Reactor Regulation Att: Mr Robert A. Purple, Chief Operating Reactor Branch No 1 US Nuclear Regulatory Commission Washington, DC 20555 consumers Power company This letter is written as a further response to Question 4.A.4 in your list of questions dated March 10, 1976. In our March 20, 1976 response, we indi-cated that the ECCS analysis (:XN-76-4) which had been submitted to you was acceptable although certain inconsistencies were present with regard to steam generator modeling. As a result of further discussion with your staff, a supplemental analysis which corrects these inconsistencies has been performed by Exxon Nuclear. This analysis examines a 1.0 DES/PD break in Loop 1 with Combustion Engineering Type D fuel. The result of this analysis is a peak-cladding temperature of 2146°F. ...,"~~§h,,;:;;~~i\\-'Z:-{i,Attached is a preliminary summary from Exxon Nuclear which describes the analy-. c?'*' *:"**~ -~,~-sii.s performed and the results obtained, A complete supplement to XN:._76-4 will be sent to you when it becomes available, David A. Bixel Assistant Nuclear Licensing Administrator CC: JGKeppler, USNRC 3572
OJI' '"\\....
1.0 INTRODUCTION
AND
SUMMARY
fiuiatonr Do~ket ~ XN-76.-4 Supplement 2 This report presents the results of a single supplemental LOCA-ECCS analysis requested by NRC and Consumers Power for the Palisades reactor. The LOCA-analytical models employed were the Exxon Nuclear Company WREM-Based Generic PWR ECCS Evaluation Model as detailed in XN-75-41.(l) Nodalization diagrams and analyti~al modeling for the Palisades reactor are as presented in XN-75-64.l2J A large break spectrum analysis for ENC fuel was presented in XN-76-4,(3) and supplemental analyses were reported in XN-76-4, Supplement
- 1. (4)
The case presented in this report is the 1.0 DES/PD break in Loop 1 with the Combustion Engineering (CE) Type D fuel. Steam generator volumes and flow areas were corrected to conform to the conservatively assumed number of steam generator tubes plugged. Steam generator A in Loop 1 assumed approximately 2,407 tubes plugged, steam generator Bat Loop 2 assumed 1,768 tubes plugged for a total of 4,175 tubes plugged. The assumed tube plugging is more than 400 tubes greater than expected to be plugged at the beginning of Cycle 2. Loop 1 flow was determined to be 16,774 lb/sand Loop 2 was 17,670 lb/s for a total of 34,444 lb/s or 124. x 106 lb/h. The RELAP4-EM/BLOWDOWN program initializes with small residuals for these values. The analysis for the 1.0 DES/PD Loop 1 break with Combustion Engineering Type D fuel yielded a peak-cladding temperature of 2146°F. Previous analyses gave a PCT of 2125°F for the 1,0 DES/PD Loop 2 break with CE Type D fuel, and indicated a PCT approximately 14°F higher for Loop 1 breaks compared to Loop 2 breaks with ENC fuel. Hence, the PCT of 2146°F is very close to the value expected when the CE Type D fuel analysis is combined with the adverse Loop 1 break. The results also indicate that the other changes did not significantly affect the calculated results. The supplemental analysis shows that the 1.0 DES/PD break in Loop 1 for Combustion Engineering Type D fuel remains the worst case with a calculated PCT of 2146°F. The emergency core cooling system is shown to meet the acceptance criteria as presented in 10 CFR 50.46.(5J An acceptably conservative number of steam gener-ator tubes plugged has been assumed for the analysis.}}