ML20092D980
| ML20092D980 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 06/15/1984 |
| From: | Tucker H DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| TAC-59005, TAC-59006, NUDOCS 8406220235 | |
| Download: ML20092D980 (2) | |
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DUKE POWER COMPANY P.O. HOx 33180 CHAMLOTTE, N.C. 28242
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Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Connission Washington, D. C. 20555 Attention: Ms. E. G. Adensam, Chief Licensing Branch No. 4 Re:
Catawba Nuclear Station Docket No. 50-413
Dear Mr. Denton:
On June 8,1984, Duke Power telephoned Mr. Kerry Landis at Region II to notify the NRC of a potentially reportable item relating to recent infonnation concerning the analysis performed by Duke Power for a Main Steam Line Break (MSLB) in the Catawba Nuclear Station doghouses. Based upon the original Westinghouse analysis for an in-containment MSLB which considered a saturated steam condition in the steam generators, Duke Power also had assumed a saturated steam condition for a MSLB in the doghouses which are located outside containment. The results of this analysis served as a basis for doghouse design, including resulting environ-mental parameters to be employed for equipment qualification in this area of the plant. Westinghouse has since detennined that a MSLB can cause steam generator tubes to uncover, allowing superheated steam to form, generating higher steam line exit temperatures. Based upon this new, preliminary mass / energy release datum from Westinghouse, revised Duke Power environmental analysis indicates an increase in doghouse temperature greater than the previous design basis of 3300F.
Currently, the doghouse equipment qualification documentation is based upon the 3300F parameter.
To date, Duke Power's review of this problem has determined that some of the essential components that must function to mitigate the consequences of this event are located in the doghouses, but we have not yet fully determined if any design modifications or revision to equipment qualification documentation will be necessary.
Duke Power has reviewed this situation with respect to the pending request to load fuel and perform pre-critical testing for Catawba Unit 1.
It was concluded that the consequences would be less severe than analyzed in FSAR Section 15.1.5 -
for the following reasons:
- 1) Prior to initial criticality, there would be no fission product inventory in the core.
- 2) The moderator temperature coefficient at beginning-of-life (BOL) is slightly positive. Therefore, the core would not go critical as a result of a MSLB accident.
8406220235 840615 Ol DR ADOCK 0500041.;
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~Mr. Harold R.,Denton, Director June 15,'1984
- Page 2.
' Our present' action plan for resolving this problem is to complete our review of the effects of this overtemperature condition, detennine if any plant modifications or revisions to equipment' qualification documentation are necessary.
--schedule for their implementation (should the final analysis indicate that-modifications are required), and submit a report by July 9,1984. This report of Duke Power's finding / conclusions will be sent to Region-II and to NRR.
Duke Power will continue to keep you advised as to any other major items of concern should they occur as our review progresses.
In the interim, please let me know if you have any questions concerning this matter.
Very truly yours,
>$ hQ '/ ~l" Hal B. Tucker ROS/php cc: Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 NRC Resident Inspector Catawba Nuclear Station Mr. Robert Guild, Esq.
Attorney-at-Law P. 0.' Box 12097 Charleston, South Carolina 29412 Palmetto Alliance 21356 Devine Street Columbia, South Carolina 29205
- Mr. Jesse L. Riley Carolina Environmental Study Group
' 854 Henley. Place
. Charlotte, North Carolina 28207 l
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