ML20198C978
| ML20198C978 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 10/01/1985 |
| From: | Hufham J TENNESSEE VALLEY AUTHORITY |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-85, REF-PT21-85-472-000 NCR-2086, NCR-2087, PT21-85-472, PT21-85-472-000, NUDOCS 8511120236 | |
| Download: ML20198C978 (3) | |
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4 TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 37401 400 Chestnut Street Tower II October 1, 1985 BLRD-50-438/82-80 m
BLRD-50-439/85-24
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co U.S. Nuclear Regulatory Connaission
.o Region II w
Attn:
Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street NW, Suite 2900 c;3 Atlanta, Georgia 30323 co
Dear Dr. Grace:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - RAW COOLING WATER CHILLER UNIT FLOW CONTROL VALVE DEFICIENCIES - BLRD-50-438/82-80 AND BLRD-50-439/85 FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector G. A. Belisle on November 26, 1982 in accordance with 10 CFR 50.55(e) as NCRs 2086, 2087, and 2088 for unit 1.
This was followed by our interim reports for unit I dated December 27, 1982 and March 21, July 27 and December 1,1983; March 22,1984 and April 18, 1985. Enclosed is our final report for units 1 and 2.
We consider 10 CFR Part 21 to be applicable to this deficiency.
If you have any questions concerning this matter, piense set in touch with R. H. Shell at FTS 858-2688.
Very truly yours.
TENNESSEE VALLEY AUTHORITY l
). h. AbomM VC. W. Hufham, Manager Licensing and Risk Protection Enclosure cct Mr. James Taylor, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Consnission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nuclear Power Operations 1100 circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 9511120236 951001 PDR ADOCM 05000438 8
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An Equal Opportunity Employer
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e ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 RAW COOLING WATER CHILLER UNIT FLOW CONTROL VALVE DEFICIENCIES BLRD-50-438/82-80, BLRD-50-439/85-24 NCRs 2086, 2087, AND 2088 10 CFR 50.55(e)
FINAL REPORT Description of Deficiency Two 6-inch freon-activated raw cooling water (RCW) flow control valves failed to operate upon activation. This resulted in a high-pressure trip of the heating, ventilating, and air-conditioning (HVAC) water chillers which are used to remove heat generated by components of the engineered safety features (ESF) system.
Investigation revealed that the failures were due to two separate conditions. One valve (serial No. 24867) failed due to a buildup of rust and scale on the valvo's pilot seat contact surfaces. This inhibited the movement of the valve stem. On both valves (included valve No. 24865),
the valve stem nut was completely detached. This allowed the valvo diaphragm to operate independently of the valve stem. These conditions degraded the valves' ability to perform their intended function.
In addition, the internal configuration of the valves supplied do not conform to the vendor's drawings. The drawings depict a two-way valve but the valves supplied are three-way valvon with one lower port blocked to make it a two-way valve. In addition, the drawings show a lower diaphragm, diaphragm spacer, and a diaphragm plate which are not on the valves supplied.
The valves in question are manufactured by Metrox Valve Corporation.
Glendora, California, and supplied as components on the water chillers fabricated by Dunham-Bush, West Hartford, Connecticut.
This deficiency is currently being investigated at other TVA nuclear plants. Sequoyah Nuclear plant (SQN) has identified the problem at their facility and significant condition report (SCR) SQN MEB 8504 has been written. Watts Bar (WBN) and Browns Ferry Nuclear Plants (BFN) are still evaluating the generic implication an1 problem identification report (PIR)/SCRs will be written as required.
Safety Impitentions A failure of the subject valves could result in a high-pressure trip of their related chiller units.
Should these chillers fail to remove the design heat load from the ESP components, the ability of the ESF system to perform its intended function could be degraded. This could adversely affect the ability to safely shut down the reactor and maintain it in the shutdown mode.
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Corrective Action TVA has received and approved a drawing from the vendor accurately depicting the internal configuration of the valves supplied to BLN.
I The original valve stem nut on all unit i valves has been replaced on the valve stem with a lock nut supplied by the vendor. The unit 2 valves are presently disassembled for reasons unrelated to this NCR and the original nuts have been replaced in the parts package by the new locking nuts.
Sequence control chart instructions have been written referencing the locking nuts' part number to ensure that the new nuts are used when the valves are reassembled.
In order to address the rust and scale buildup, a corrosion protective coating of 0.003-inch-thick minimum nickel plate was added to the surfaces of the upper diaphragm plate and the internal surf aces of the cover plate by Electroless Nickel of Dayton on contract 85KK4-836292.
The generic drawing TVA-3150-F1-2W, supplied by Metrix has been revised to show plated areas.
l To inhibit water chiller RCW flow control valves from rust and scale in the future, valves will be purchased with a rust preventive coating for water actuated valves. Valves with no corrosion protection would be limited to electric, hydraulic, or pneumatic actuated type. TVA will issue a standard specification, MEB-SS-24.1, by September 30, 1986, to ensure that this requirement is included in future procurement contracts.
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