ML20063J215
| ML20063J215 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 08/27/1982 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-82 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8209020338 | |
| Download: ML20063J215 (2) | |
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V TENNESSEE VALLEY AUTHORITY '.f p n.
CH ATTANOOGA. TENNESSEE 374of 400 Chestnut Street Tower II l? t orp 30 August 27, 198I2
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/t S, 7 g U.S. Nuclear Regulatory Commission Region II Attn:
Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - FAILURE OF MAIN STEAM LINES BECAUSE OF MAIN FEEDWATER OVERFILL - NCR BLN NEB 8004 - SEVENTH INTERIM REPORT On March 19, 1980, Bruce Cochran, NRC-0IE Region II, was informed that the subject nonconformance was determined to be reportable in accordance with 10 CFR 50.55(e). This was followed by our interim reports dated April 17, September 23, and December 29, 1980, June 25 and December 28, 1981, and March 31, 1982. Enclosed is our seventh interim report. We expect to submit our next report by November 19, 1982. We consider 10 CFR Part 21 to be applicable to this nonconformance.
If you have any questions concerning this matter, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY Ch L. M. Mills, Manager Nuclear Licensing Enclosure cc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Comission Washington, DC 20555 Mr. James McFarland (Enclosure)
Senior Project Manager Babcock & Wilcox Company P.O. Box 1260 Lynchburg, Virginia 24505 gG?
8209020338 820827 A.e PDR ADOCK 05000438 S
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ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 FAILURE OF MAIN STEAM LINES BECAUSE OF MAIN FEEDWATER OVERFILL NCR BLN NEB 8004 10 CFR 50.55(e)
SEVENTH INTERIM REPORT Description of Deficiency A preliminary safety concern, PSC 35-79, was initiated within B&W, Lynchburg, Virginia, which presents the concern that a potential exists for overfilling steam generators by excessive addition of main feedwater (MFW) or auxiliary feedwater ( AFW).
Excessive feedwater addition, as used here, is defined as a condition which would exist if feedwater (main or auxiliary) is continually added to the steam generators in an unplanned fashion at a rate greater than the core heat generation capability for converting it to steam. Overfill, the condition addressed in this preliminary safety concern, may be defined as a limiting case of excessive feedwater addition which allows liquid spillage into the steam lines.
It is estimated that the time to overfill the integral economizer once-through steam generators (IE0TSG) provided on the Bellefonte Nuclear Plant is approximately 2 to 4 minutes with MFW and between 7 to 15 minutes with AFW.
Potential results of overfill could be:
1.
Steam line deformation and failure due to water accumulation.
2.
Steam generator blowdown because of steam line failure with the potential for core return to power from a safe shutdown condition, excessive steam generator tube stress, exceeding reactor vessel NDT limits, or containment overpressurization.
Interim Progress TVA and B&W met on July 1, 1982, at B&W, Lynchburg, Virginia, to discuss the main feedwater (MFW) concern. B&W had previously given TVA the additional data needed to enable TVA to evaluate B&W's mini-report on MFW overfill. TVA did evaluate the report and used input from the report to do pipe force calculations to determine if the main steam lines (MSL) could withstand the forces generated by the MFW overfill. TVA's preliminary results indicate that the MSL appear to be able to withstand the MFW overfill event. Further detailed calculations are needed, however, before a final conclusion can be reached. TVA is working on these detailed calculations and will provide additional information in the next report.