ML20212B200

Final Deficiency Rept Re Unconservative Flange Qualification Analysis.Initially Reported on 841207.Caused by Misinterpretation of ASME Code Section Iii,Subsection NC-3658.1 (S76)

ML20212B200
Person / Time
Site:	Bellefonte
Issue date:	07/18/1986
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8608060255
Download: ML20212B200 (2)

Text

e bcb TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 37401 l SN 157B Lookout Place BLRD-50-438/85-01 BLRD-50-439/85-01 U.S. Nuclear Regulatory Commission Region II Attn: 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 - UNCONSERVATIVE FLANGE QUALIFICATION ANALYSIS - BLRD-50-438/85-01, BLRD-50-439/85 FINAL REPORT The subject deficiency was initially reported to NRC-OIE Inspector S. Weise on December 7, 1984 in accordance with 10 CFR 50.55(e) as NCR BLN CEB 8420. This was followed by our interim reports dated January 7 and May 23, 1985. Enclosed is our final report.

If you have any questions, please get in touch with D. L. Terrill at FTS 858-2682.

Very truly yours, TENNESSEE VALLEY AUTHORITY R.L.Gridley,Dkrector Nuclear Safety and Licensing Enclosure Mr. James Taylor, Director (Enclosure) l 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 8608060255 860718 8 DR ADOCK 0500 4

An Equal Opportunity Employer

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• ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 UNCONSERVATIVE FLANGE QUALIFICATION ANALYSIS BLRD-50-438/85-01, BLRD-50-439/85-01 NCR BLN CEB 8420 10 CFR 50.55(e)

FINAL REPORT Description of Deficiency The Bellefonte Nuclear Plant (BLN) Rigorous Analysis Handbook BLN-RAH-302, attachment 302.2, indicated that a normal operating temperature, as opposed to an upset temperature, may be used to qualify a flange according to ASME Code Section III, subsection NC-3658 (S79). This interpretation was effective November 20, 1982. However, a recent study has indicated that this interpretation was in error and that upset (service level B) temperatures must be used in flange qualification per NC-3658.3 (1983 edition), equation 12.

Policy statement 15 to section BLN-RAN-302, issued November 5,1984, has corrected this section. BLN piping analysis problems issued between the above dates, which used this optional attachment, may have overloaded flanges.

The root couse of this deficiency is attributable to a misinterpretation of the ASME code section III subsection NC-3658.1 (S76) which was incorporated into the BLN RAM. TVA has determined that this deficiency is not applicable to any other TVA plant.

Safety Implications If a safety-related flange is exposed to a temperature in excess of the temperature used in the qualification analysis, the design margin of the subject flange is reduced and could result in loss of the pressure boundary of the affected safety-related system. This could adversely affect the safe operation of the plant.

Corrective Actions Eighteen problems from BLN units 1 and 2 were originally identified to be affected by this deficiency. However, only problem N4-ONM-N required reanalysis, and problem N4-lCF-B required documentation change. The remainder

'j of the problems were not adversely affected. The rework of the above two problems is complete. The associated support design work will be done under

.}a ECN-3296.

l All work associated with this defielency will be complete no later than six months before fuel load of the affected unit.

, The misinterpretation of the ASME code discussed in the description of defielency was an isolated case of erroneous engineering judgement for which no actions to prevent recurrence are required.

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