ML20205L661

Final Deficiency Rept Re Incorrect Installation of Pressure Relief & Safety Valves.Initially Reported on 820305.Relief Valve Piping Will Be Redesigned to Provide Adequate Vent Area

ML20205L661
Person / Time
Site:	Bellefonte
Issue date:	03/24/1986
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8604140205
Download: ML20205L661 (3)

Text

~ -. . _

') ~,

TENNESSEE VALLEY. AUTHORITY CHATTANOOGA. TENNESSEE 37401 SN 1578 Lookout Place N har 24, 986 BLRD-50-438/82-25 BLRD-50-439/82-22 U.S. Nuclear Regulatory Commission Region II- .

Attn: Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street, NH, Suite 2900 i

Atlanta, Georgia 30323

Dear Dr. Grace:

i BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - INCORRECT INSTALLATION OF PRESSURE l RELIEF AND SAFETY VALVES - BLRD-50-438/82-25, BLRD-50-439/82 FINAL REPORT i

The subject deficiency was initially reported to NRC-01E Inspector Don Quick on March 5,1982 in accordance with 10 CFR 50.55(e) as NCR BLN BLP 8210. Enclosed is our final report.

4

! If you have any questions, please get in touch with R. H. Shell at j FTS 858-2688.

Very truly yours,

) TENNESSE VALLEY AUTHORITY f..A./L. Gridley Manager of Licensing Enclosure I

cc: Mr. James Taylor, Director (Enclosure)

Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 1 Washington, D.C. 20555 Records Center (Enclosure)

Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Sulte 1500 j Atlanta, Georgia 30339 ts609190205 860324 PDR ADOCK 05000438

S PDR I

g An Equal Opportunity Employer

'] .

ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 INCORRECT INSTALLATION OF PRESSURE RELIEF AND SAFETY VALVES BLRD-50-438/82-25 AND BLRD-50-439/82-22 NCR BLN BLP 8210 10 CFR 50.55(e)

FINAL REPORT Description of Deficiency Condition I: Six-inch relief Valves 1KC-VRBC-166 and -172 on unit I and

! 2KC-VRBC-166 and -172 on unit 2 -- in the component cooling water supply lines

to the shell side of the letdown coolers -- discharge into a common waste

! disposal drain header. The waste disposal header is not sized to accommodate both relief valves. Also, there are several other smaller component cooling water relief valves discharging into this same waste disposal header. This condition applies to units 1 and 2.

Condition II: Relief valves IKC-VRAC-176 and 1KC-VRFC-183 -- on the component cooling water piping for the coolers to reactor coolant pump PlAl -- discharge into a common line that is sized too small to accommodate both relief valves.

This condition applies to unit 1 only.

These conditions violate ASME Code Section III, Division I, ND-3677.3d(2).

The cause of this deficiency was lack of attention to and knowledge of the applicable codes on the part of the design personnel. I Identification of the subject deficiency resulted from a generic review initiated as a result of the identification of similar deficiencies.

These deficiencies were documented as significant -- but nonreportable --

nonconformances BLN BLP 8127 (originally reportable but downgraded in final report) and BLN BLP 8204. The generation of these two nonconformances and BLN BLP 8210 represent the results of a comprehensive generic review of Bellefonte safety relief valve designs. This review, not incidentally, had the added benefit of alerting all Bellefonte mechanical design personnel to the ASME code requirements pertinent to safety relief valve design.

This deficiency was potentially applicable to other TVA plants; therefore, a generic review per Office of Engineering Procedure (0EP) 17 was initiated.

TVA's generic review revealed that Sequoyah and Watts Bar are not subject to I this deficiency. However, mechanical engineering personnel of Browns Ferry reported a similar concern and have issued significant condition report l BFN MEB 8210 to document the concern.

I

.' ('

Safety Implications Conditions I and II:

Combining the relief valve discharge lines into a common line that is undersized and activating all relief valves using the same discharge piping simultaneously will cause excessive back pressure in the relief valve discharge line. The excessive pressure could damage piping and components in the waste disposal system and will raise the relief valve set pressures, since the set pressure is dependent on the differential pressure across the valve.

The higher set pressure could overpressurize and damage the system or components being protected. Had this condition remained uncorrected, the safe operation of the plant could have been adversely affected.

Corrective Action Corrective action for deficient conditions I and II shall consist of redesign-Ing the relief valve piping to provide adequate vent area, placing it on the appropriate drawings, and installing it in the field.

In order to implement this disposition, TVA has outlined the following actions:

Condition I: The cited six-inch valves will be vented to the containment atmosphere; and 2 three-inch relief valves will be added, which will be set at a lower pressure and will exhaust into the waste disposal header.

Condition II: The size of the common drainline from the two relief valves has been increas'ed to accommodate the flow from both relief valves.

The component cooling water system was reviewed to ensure the rest of the system is in compilance with ASME Code Section III, Division I, ND-3677.3d(2) and was found to be in compliance.

In order to prevent recurrence of the identified deficiency, Bellefonte mechanical design personnel were notified of the failures to comply with ASME Code requirements and were instructed to review all safety relief valve designs. At the completion of the review, only one similar nonsignificant, nonreportable nonconformance was identified.

All action required to correct the deficient condition will be completed no later than six months prior to unit I and unit 2 fuel load dates respectively.

l 4

l i

I I

1