ML20136C631
| ML20136C631 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 12/20/1985 |
| From: | Hufham J TENNESSEE VALLEY AUTHORITY |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8601030375 | |
| Download: ML20136C631 (3) | |
Text
a, TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374ot SN 157B Lookout Place.
~ut.cyg,h*/4 December 20, 1985 BLRD-50-438/85-31 BLRD-50-439/65-29 U.S. Nuclear Regulatory Commission Region II Attention:
Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear Dr. Grace:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - UNDERSIZED ERCW PUMP DISCHARGE AIR RELEASE VALVE - BLRD-50-438/85-31, BLRD-50-439/85 FIRST INTERIM REPORT The subject deficiency was initially reported to NRC-0IE Inspector Al Ignatonis on November 20, 1985 in accordance with 10 CFR 50.55(e) as SCR BLN MEB 8508.
Enclosed is our first interim report. We expect to submit our next report on or about one year before fuel load of unit 1.
If there are any questions, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY
.J.h. Huf'am tager of Li censing i
Enclosure cc:
Mr. James Taylor, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nuclear Power Operations 1100 circle 75 Parkway, Suito 1500 Atlanta, Georgia 30339 8601030375 851220 PDR ADOCK 05000438 PDR s
I An Equal Opportunity Employer E.17
ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 UNDERSIZED ERCW PUMP DISCHARGE AIR RELEASE VALVE BLRD-50-438/85-31, BLRD-50-439/85-29 10CFR50.55(e)
SCR BLN MEB 8508 FIRST INTERIM REPORT
'D'escription of Deficiency The Bellefonte essential raw cooling water (ERCW) pump discharge air release valves may be significantly undersized. When an ERCW pump is started, most of the air in the pump discharge piping will be forced into the ERCW system instead of being vented. This could affect the performance of safety-related heat exchangers served by the ERCW system.
This deficiency may be attributed to a lack of design guidance available for sizing pump discharge vacuum / air release valves.
This. condition was identified in response to a potential generic condition review prompted by a similar nonconformance documented at Watts Bar Nuclear Plant (WBN) on NCR WBN MED 8524.
Safety Implications The valve could restrict airflow such that air could enter ERCW system piping during pump startup. Air entrainment might degrade the performance of safety-related heat exchangers served by the ERCW system which could affect their heat removal capacity under the worst condition of two-unit operation.
Failure to remove sufficient heat from safety-related components being served by the ERCW system could result in loss of equipment necessary for a safe shutdown and therefore could adversely affect safety of operations of the plant.
Interim Protress Several tasks outlined below will be performed to determine if unvented air in the ERCW system piping will affect the performance of the heat exchangers served by the ERCW system. TVA will:
1.
Identify high points in the system piping upstream of the heat exchangers where air is likely to collect.
2.
Calculate the maximum volume of air injected into the system for each pump start.
3.
Evaluate the potential for air to go back into solution due to system operating pressure.
4.
If necessary, resize the air release valve.
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, To prevent recurrence of this deficiency in future ERCW systems TVA will incorporate a procedure in the design guide on how to properly size air release valves for.this problem in the ERCW system. Mechanical design guide DG-M6.3.3 will be modified under the next revision to it.
TVA will provide a final report upon completion of corrective actions but at least no later than one year before, fuel load of unit 1.
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