ML20054G129
| ML20054G129 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 06/07/1982 |
| 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 8206210144 | |
| Download: ML20054G129 (2) | |
Text
TENNESSEE VALLEY AUTHC)RQY CHATTANOOGA TENNESSEE 74o'I*74
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400 Chestnut Street er II June 7 198 A O,+ 2 I BLRD-50-438/81-76 BLRD-50-439/81-75 U.S. Nuclear Regulatory Consnission 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 - VIKING FLOW CONTROL VALVES IN FIRE PROTECTION SYSTEM - BLRD-50-438/81-76, BLRD-50-439/81 THIRD INTERIM REPORT The subject deficiency was initially reported to NRC-0IE Inspector R. V. Crlenjak on November 24, 1981 in accordance with 10 CFR 50.55(e) as NCR BLN MEB 8103 This was followed by our interim reports dated December 22, 1981 and March 1, 1982. Enclosed is our third interim report. We expect to submit our next report by October 6,1982. We consider 10 CFR Part 21 applicable to this deficiency.
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 D S l'emp L. M. Mills, Manager Nuclear Licensing Enclosure cc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 1
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8206210144 820607 PDR ADOCK 05000438 S
PDR An Equal Opportunity Employer
~o an ENCLOSURE
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BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 VIKING FLOW CONTROL VALVES IN FIRE PROTECTION SYSTEM BLRD-50-438/81-76, BLRD-50-439/81-75 HCR BLN MEB 8103 10 CFR 50.55(e)
THIRD INTERIM REPORT Description of Deficiency i
The Viking model G-1 and G-2 flow control valves which are used in preacgion sprinkler systems will not regulate outlet pressure to 25 lb/in as required by the acceptance criteria in Preoperational Test PT-RF-01.
Severe system vibrations occur when attempts are made to regulate the valves under the high inlet pressure and low flow conditions established by the Preoperational Test. These conditions are equivalent to those that would result if water was flowing from a single sprinkler head.
The model G-1 and G-2 flow control valves are manufactured by Viking Corporation of Hastings, Michigan. The manufacturer's catalog literature indicgtes that the valves will regulate outlet pressure as low as 25 lb/in. However, the literature did not indicate that the valves would not regulate properly under the conditions TVA is establishing during preoperational testing.
Interim Progress TVA has tried to eliminate the vibration problems by changing pressure regulators, flow restricting orifice sizes, and valve trim configurations. To date, none of the modifications have been effective at regulating pressure under low flow conditions. We have therefore decided to remove the pressure control capability from all Viking flow control valves used on the sprinkler systems at Bellefonte. This will involve changing the valve trim to a configuration used on Viking model D-4 and D-5 deluge valves and removing a spring located between the valve disk and bonnet. The valves will then function identically to the Viking deluge valves which open fully on actuation. Such valves have operated satisfactorily in preaction sprinkler systems at other TVA power plants under operating conditions that are similar to those existing at Bellefonte.
The removal of the pressure control capability will not affect system operation during a fire if a large number of sprinkler heads open.
Friction losses from the resulting high flow would reduce system pressures to this design range for the sprinkler heads. A small fire on the other hand would not open many heads, and the sprinkler system pressure would be higher. All system components are designed to withstand the higher pressures. However, higher sprinkler head nozzle pressures will result in smaller water droplet sizes and less than optimum fire plume penetration. The degrading of system performance because of a small droplet size is not considered significant by TVA as compared to the potential damage caused by severe vibrations.
TVA will provide a schedule for implementation of corrective actions and necessary actions to prevent recurrence in our next report.