ML20091M567
| ML20091M567 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 05/21/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NCR-2879, NUDOCS 8406110345 | |
| Download: ML20091M567 (3) | |
Text
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G-TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 37401 400 Chestaut Street Tower II b/ Pf.24 May 21, 1984
- BLRD-50-438/84-23 BLRD-50-439/84-22 U.S. Nuclear Regulatory Comission Region II
. Attn:
Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW,\\ Suite 2900 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - OVERPRESSURIZATION OF EMERGENCY RAW COOLING WATER PIPING BECAUSE OF TWO MECHANICAL FAILURES -
4 BLRD-50-438/84-23, BLRD-50-439/84 FINAL REPORT The subject deficiency was initially naported to NRC-0IE Inspector R. Carroll on March 1,1984 in accordance with 10 CFR 50.55(e) as NCR 2879.
This was followed by car interim report dated March 29, 1984. Enclosed is our flna1 report.
If you have any questions, please get in touch with R. H. Shell at FTS 858-2688.
Very truly.yours, TENNESSEE VALLEY AUTHORITY L. M. Mills,' Manager Nuclear Licensing Enclosure oc:
Mr. Richard C. DeYoung,. 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, Suite 1500 Atlanta, Georgia 30339 8406110345 840521 PDR ADOCK 05000438 PDR OFFICIALCOPY ~
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i1983-TVA 5OTHl ANNIVERSARY -
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~An Equal Opportunity Employer
ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 OVERPRESSURIZATION OF EMERGENCY RAW COOLING WATER PIPING BECAUSE OF TWO MECHANICAL MALFUNCTIONS BLRD-50-438/84-23, BLRD-50-439/84-22 NCR 2879 10 CFR 50.55(e)
FINAL REPORT Description of Deficiency During a hydrostatic test on February 16, 1984, a temporary pressure gauge snubber and relief valve failed and resulted in an overpressurization of a portion of the essential raw cooling water (ERCW) system. The pressure gauge had been calibrated on February 14, 1984, and was used to set the relief 2
valve at 235 lb/in g on the same date.
During the hydrostatic test, a smil double-acting, air-driven pump was used 2
to pressurize the system to 90 lb/in g.
The pressure was then raised to 2
100 lb/in g by several strokes of the pump and at this time the over-pressurized portion of the system was checked for leaks, with none occurring.
The valve was opened, and the pump was started. When the pressure was near 180 lb/in g, it was noted that the pressure was increasing at an excessive 2
rate. At that point, the pump was shut off, and the valve between the pump and test items was closed before the indicated pressure reached 230 2
lb/in g, 4
Due to a significant lag in the response of the pressure gauge the pressure-2 indication continued to increase (above 235 lb/in 8) and efforts were initiated to relieve the pressure (since the relief valve had apparently failed). The coupling on the relief valve was loosened and valve 1KE-VJDC-242-B was opened in the discharge side of the air handling unit '( AHU). By the time the pressure was relieved, the gauge had begun to level off at 2
approximately 480 lb/in g.
Althodgh the coils on AHU 1VA-MAHU-198-B and associated KE (ERCW) system piping between valves 1KE-VHAC-280 and 1KE-VJDC-2 242-B were subjected to a pressure estimated at 480 to.500 lb/in g, they 2
are only hydrostatically qualified to a pressure of 300 lb/in g, The valve and pressure gauge were purchased by TVA's Division of Construction as shelf items and are non-quality assurance items.
Safety Implications The AHU affected by this overpressurization provides cooling of the 590 elevation area in the Auxiliary Building where several safety-related pumps and associated electrical equipment are located. Severe overpressurization
o could haya damagcd tha coils to the point of failure although in this instinca, such damaga did not occur. A failure of the coils of this unit apd o resultant loss of the safety-related AHU could hcva occurred, resulting in -
a riss in temperature in the area and the leakage of cooling water from the coils. This could have adversely affected the safe operation of the plant.
Corrective Action Nonconformance report 2879 has been returned from TVA's Division of Engineering Design with the recommended correctivo action to "use-as-is." The relief valve involved in the deficiency has been destroyed and the pressure gauge snubber has been reworked. Hydrostatic test 1KE-H-53 (per Bellefonte Construction Test Procedure 7.6) was successfbily completed on April 26, 1984, and no visible damage was evident to the AHU coils as a result of the overpmssurization. The simultaneous malfunction of the pressure gauge and the relief valve appear to be an isolated occurrence.
It should be noted that both the relief valves and pressure gauges are checked for calibration both before,and after hydrostatic tests are performed. Therefore, no fbrther action to prevent mourrence is necessary.
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