ML20214H186

Final Deficiency Rept Re Error in Seismic Data Used in Auxiliary Control Bldg Design.Initially Reported on 840406. Revised Fixed Damped Response Spectra for Auxiliary Control Bldg Generated

ML20214H186
Person / Time
Site:	Bellefonte
Issue date:	08/01/1986
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8608130025
Download: ML20214H186 (3)

Text

.

h /N b i

TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNCSSEE 374ot SN 157B Lookout Place

~ "i r 't , 'l t BLRD-50-438/84-31 AUG 011986 P];vp g, BLRD-50-439/84-29 U.S. Nuclear Regulatory Commission Region II Attn: Dr. J. Nelson Crace, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323

Dear Dr. Grace:

BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - ERROR IN SEISMIC DATA USED IN AUXILIARY-CONTROL BUILDING DESIGN - BLRD-50-438/84-31, BLRD-50-439/84 FINAL REPORT The subject deficiency was initially reported to NRC-OIE Inspector R. Carroll on April 6, 1984 in accordance with 10 CFR 50.55(e) as NCR BLN CEB 8404. 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, Director Nuclear Safet and Licensing Enclosure Mr. James Taylor, Director (Enclosure)

Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C. 20S55 Records Center (Encleaure)

Institute of Nuclear Power Operations I

1100 circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 8608130025 860801 PDR ADOCK 05000438 fi An Equal Opportunity Employer _ TE"%

- e[

, ,. ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 ERROR IN SEISMIC DATA USED IN AUXILIARTY-CONTROL BUILDING DESIGN BLRD-50-438/84-31, BLRD 50-439/84-29 NCR BLN CEB 8404 10 CFR 50.55(e)

FINAL REPORT Description of Deficiency TVA committed in BLN FSAR section 3.7.1.2, " Design Time History," to base the seismic design response spectra on three statistically independent artifical earthquake records, two horizontal records and one vertical record. We found during a review of main steam valve room B that the auxiliary-control building seismic analysis used only one of the horizontal time histories in both horizontal directions. When the auxiliary-control building spectra was reanalyzed using both horizontal time histories, the east-west peak acceleration, velocity, and displacement values significantly increased.

The cause of this oversight was that the engineers who performed and checked the spectra analysis did not review Design Criteria N4-50-D708 to verify analysis requirements. The engineer who performed the analysis had previously worked on SQN and WBN both of which did not have the requirement of three statistically independent earthquake records. The engineer that checked the analysis did not detect the error.

Review of other Bellefonte structures indicates statistically independent earthquakes were used in their seismic analyses.

Bellefonte Nuclear Plant is the only TVA plant to define three orthogonal statistically independent earthquakes as the design earthquake for all structures.

Safety Implications During a seismic event, a significant increase in the peak acceleration, velocity, and displacement values for the auxiliary-control building could adversely affect the integrity of safety-related piping and components located in the auxiliary-control building. This could adversely affect the safe operation of the plant.

Corrective Action To correct this deficiency, revised fixed damped response spectra for the auxiliary-control building was generated and included in revision 3 to TVA seismic analysis report CEB 80-33. This spectra increased over the erroneous spectra contained in revision level 2 of the same report. Additionally,

( variably damped response spectra has been generated and included in revision level 4 to the same report (CEB 80-33). Since the more recently generated 1

1 variably damped response spectra now used for piping analysis is enveloped by the erroneous fixed damped spectra of revision level 2, no further evaluations are required for piping under this NCR. The qualification of equipment and verification of structural design of building components, cable trays, conduits, and ducts will be completed 6 months before the fuel load for each unit.

In order to prevent this problem from recurring, section training on EN DES-EP 3.03 " Design calculations", was held on April 26, 1983. A section meeting was held on April 16, 1984, in which the section supervisor emphasized that checking requires a review of calculation methods and adherence to design criteria as well as checking the mathematics.

Additionally, training was conducted on OEP-06, " Design Input," OEP-07,

" Calculation," and OEP-08, " Design output" when theso documents replaced the old EN DES engineering procedures in June 1985.

l l

1

. _ _ _ _ ._ . - _ .