ML20069B873

Third Interim Rept Re Tornado Depressurization Design Deficiencies,Initially Reported 810402.Ventilation Opening Added in Exterior Door of Each Stairwell.Stairwell Doors to Main Bldg Will Be Pressure Doors.Next Rept by 821020

ML20069B873
Person / Time
Site:	Yellow Creek
Issue date:	01/22/1982
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8203080092
Download: ML20069B873 (2)

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TENNESSEE VALLEY AUTHCSRITY.

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400 Chestnut Street Tower II g Jgud)N, rd\ 1982 ' 6 YCRD-50-566/81-13 YCRD-50-567/81-11 g' 0)

O Mr. James P. O'Reilly, Director NECE;yED Office of Inspection and Enforcement [

J. it, U.S. Nuclear Regulatory Commission Region II - Suite 3100 i-t 151982A If I 101 Marietta Street  ?

Atlanta, Georgia 30303 tc.

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Dear Mr. O'Reilly:

YELLOW CREEK NUCLEAR PLANT UNITS 1 AND 2 - TChNADO DEPRESSURIZATION DESIGN DEFICIENCIES - YCRD-50-566/81-13, YCRD-50-567/81 THIRD INTERIM REPORT The subject deficiency was initially reported to NRC-OIE Inspector R. V. Crlenjak on April 2, 1981, in accordance with 10 CFR 50.55(e) as NCR YCN CDB 8101. This was followed by our interim reports dated May 4 and September 9, 1981. Enclosed is our third interim report. We expect to submit our next report by October 20, 1982.

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

Very truly yours, TENNESSEE VALLEY AUTHORITY

. M. Mills, Mahager Nuclear Regulation and Safety Enclosure cc: Mr. Richard C. DeYoung, Director (Enclosure)

Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 OFpjcIAL COFL 8203080092 820122 ## '#

PDR ADOCK 05000566 An Equal Opportunity Employer - ~"#

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ENCLOSURE YELLOW CREEK NUCLEAR PLANT UNITS 1 AND 2 TORNADO DEPRESSURIZATION DESIGN DEFICIENCIES YCRD-50-566/81-13, YCRD-50-567/81-11 10 CFR 50.55(e) -

THIRD INTERIM REPORT _

Description of Deficiency 3

While reviewing the tornado design of safety-related structures, design engineers discovered a discrepancy between drawings and design criteria for the Yellow Creek Nuclear Plant's Intake Pumping Station and ERCW Pumping Station concrete structures. Final structural design for these structures was completed in accordance with applicable design criteria (N8-9J-D701 and N8-K2-D701) that specify depressurization of the structures during a tornado. Construction drawings (8IE0311-K2 series and 8KE0320-K2 series) were icsued, but all parts of these structures were not vented sufficiently to ensure depressurization. Civil and mechanical engineers reviewing these drawings failed to ensure venting in accordance with the design criteria.

The deficiency does not extend to other structures at this or other nuclear plants. ,

Interim Progress The ventilation analysis for the ERCW Pumping Station identified the need for design changes in the stairwells. A ventilation opening was added in the exterior door of each stairwell. All doors connecting the stairwells with the main building will be pressure doors. Field Change Requests (FCRs)

C-1632 and C-1644 and Engineering Change Notice (ECN) 449 have been issued to revise the appropriate drawings. Design drawings and design criteria N8-MAD-740CR1 will document these changes. Three drawings have been issued, and the remaining drawings and criteria will be issued by August 1982. Supporting calculations have been added to calculation documents 93-K-C001 and 93-K-C002. Issuance of these remaining drawings

, will complete all design work for the ERCW Pumping Station related to this nonconformance report (NCR).

Last October structural design work for the Intake Pumping Station was halted because of NCR YCN EEB 8102. Resolution of this NCR may involve increasing the physical size of the building for additional electrical equipment. ECN 411 is being prepared and is expected to be issued by April 1982, at which time the structural design will resume. Another ventilation analysis will be required if the original building configuration is changed. All structural design is expected to be completed and the results included in the next report.

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