TENFtt VVAtL VA AUTHORITY 8A?$i4;NO

6 dAr"T-iwsCC 37401

400 Chestawt Street Tower II

83 JUL IS AI0: 28 July 13, 1983

ND-50-390/81489 Mi-50-391/81-83

uS. I•clear Regulatory CoIdsion Regio n ATTI: Jams P. O'Reilly, Regional Adinistrator 101 Marietta Street, IV Suit* 2900 Atlanta, Georgia 30303

Dear Mr. O'Reilly:

•TS BA I CLEAR PLAIT NITS 1 AND 2 - INCORRECT MODELING OF FDWATBR PIPING

VALtS - VIRD-50-390/81-89, HBRD-50-391/81-83 - FINAL REPORT FOR UNIT 1 AND SIXTH ITEMRI FOR UgIT 2

The subject deficiency was initially reported to NRC-OIE Inspector

8. V. Crlenjak on October 9, 1981 in accordance with 10 CFR 50.55(e) as NCR

BW CEB 8112. Interim reports were submitted on lovember 9, 1981 and

February 2, March 17, August 12, and lovember 18, 1982. Enolosed is our final

report for unit 1 and sixth interim report for unit 2. We expect to submit

our next report for unit 2 on or about September 17, 1984.

IRC-OIE Inspector Linda Watson was notified on June 21, 1983 concerning the

subject nonconformance and a new submittal date of July 15, 1983 was established.

If you have any questions, please get in touch with R. H. Shell at FTS 8582688.

Very truly yours,

TEINESSEE VALLEY AUTHORITY

L. M. Mills, nager Nuclear Licensing

Enolosure oo: See page 2

8307220554 830713 PDR ADOCK 05000390 S PDR An Equal Opportunity Employer i/l

-2

U.S. Nuolear Rugulatory Commission July 13, 1983

cc (Enclosure): Mr. Richard C. DeToung, Director Office of Inspection and Enforcement U.S. Nucolear Regulatory Commission Washington, D.C. 20555

Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339

EHCLOSURB

WATTS BAR NUCLEAR PLANT UNITS 1 AND 2 INCORRECT MODELING OF FEEDATER PIPING VALVES

VBRD-50-390/81-89, VBRD-50-391/81-83 10 CFR 50.55(e)

FINAL FRPORT FOR UNIT 1 AND SIXTH INTERI FOR UNIT 2

Description of Deficiency

The analytical models and weights of four valves (FCY3-236, 239, 242, and 245) on feedwater piping analysis 0600200-02-05, -06, -07, and -08 were ircorrect. These valves appear on the Watts Bar Nuolear Active Valve List. The previous model my have produced unconservative analysis results.

TVA provided an assumed valve weight and center of gravity for the subject valves to EDS Nuclear, Incorporated, to be incorporated in the analyses of 0600200-02-05, -06, -07, and -08. It does not appear that the subject valve drawing (contract 77K3-822950, drawing 717543030D) was issued until December 1977 after the subject analyses were completed (approximately November 1977). A followup on the valve weight and center of gravity data should have been performed in a more timely manner.

The vendor's valve drawing giving the valve weight and center of gravity data was not available to TVA at the time the analysis was being performed. An assumed valve length, weight, and center of gravity was used and documented in the analysis. However, when the valve data was transmitted to TVA the valve data was not sent to the piping analysis personnel for comparison to the assumed valves. The failure to verify the conservatism of the assumed valves was due to a lack of procedures controlling the design process.

Safety Implications

Pipe supports on the steam generator feedwater and feedwater bypass lines could be underdesigned due L, the use of incorrect bypass valve weights in the seismic model. This deficiency could result in failure of the supports and associated piping or valve inoperability which could adversely affect the safety of operations of the plant (these valves are on the WBN Active Valve List and are required to be operable for safe shutdown of the plant).

Corrective Actions

TVA has reanalyzed piping problems 0600200-02-05, -06, -07, and -08 using the correct valve data. TVA's Watts Bar Design Project (VBP) has modified unit 1 piping support designs under engineering change notice (ECN) 3078 as required to sesoically qualify the piping and associated equipment components. TVA's Division of Construction (CONST) reworked those supports requiring modification under ECNs 3210 and 3078. All rework required for unit 1 supports has been completed.

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On November 3, 1977, TVA issued the E DES-EP 4.25, Design Review and Interface Coordination of Detailed Construction and Proourement Drawings." (The deficient analyses were also issued in Rovember 1977.) The ImpleMmntation of N D8S-P 4.,25 vas intended to assure verification of accurate design input data. However, it should be noted that TVA bas identified deficiencies on the implementation of a DS-EP 4.25 in the Office of Engineering Design and Construction (OEDC) Audit M81-13, deficiency 5. TVA's disposition of this deficiency should assure that the design process includes verification of design parameters such as valve weights and centers of gravity. Consequently, implementation of the disposition of ODC Audit H81-13, deficiency 5, should preclude occurrence of the subject deficiency.

Interim Progress

Redesign of unit 2 supports is being performed under ECU 3748. TVA's Division of Engineering Design (EN DES) Special Engineering Procedure (SEP) 82-13 has been written which will require a 100-percent valve review during the NRC-OIE Bulletin 79-14 program. This will ensure that all valve data used in seismic analyses is correct.