05000327/LER-1981-102-01, /01T-0:on 810824,discovered That,In Accident Analysis of Containment Pressure Response,During Design Basis Events,Component Cooling Water Heat Exchanger Was Incorrectly Modeled.Caused by Incorrect Original Input

/01T-0:on 810824,discovered That,In Accident Analysis of Containment Pressure Response,During Design Basis Events,Component Cooling Water Heat Exchanger Was Incorrectly Modeled.Caused by Incorrect Original Input

ML20010F757
Person / Time
Site:	Sequoyah
Issue date:	09/04/1981
From:	Harding M, Kirk G TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20010F755	List: 05000327/LER-1981-102, Forwards LER 81-102/01T-0 05000327/LER-1981-102-01, /01T-0:on 810824,discovered That,In Accident Analysis of Containment Pressure Response,During Design Basis Events,Component Cooling Water Heat Exchanger Was Incorrectly Modeled.Caused by Incorrect Original Input
References
LER-81-102-01T, LER-81-102-1T, NUDOCS 8109110294
Download: ML20010F757 (2)

LER-1981-102, /01T-0:on 810824,discovered That,In Accident Analysis of Containment Pressure Response,During Design Basis Events,Component Cooling Water Heat Exchanger Was Incorrectly Modeled.Caused by Incorrect Original Input

Event date:
Report date:
3271981102R01 - NRC Website

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, Glenn B. Kirk /M. R. Harding Phone: (615) Bl.2-8317

.s of Pre" -er:

Sequoych Nuclocr Plant LER SUPPLEMENTAL INFORMATION SQRO-50-327/81102 Jechnical Specification Involved:

6.9.1.12.h Reported Under Technical Specification:

6.9.1.12.h Date of Occurrence: 08-24-81 Time of occurrence:

1445 CST Identification and Description of Occurrence:

In the accident analysis of the containment pressure response, during design basis events (LOCA, loss of offsite power, loss of two diesel generators of the same train, and loss of downstream dam) the component cooling water heat exchanger was incorrectly modeled. The heat exchanger was modeled as a counter-flow heat exchanger rather than a divided flow heat exchanger. Also, during the analysis, the component cooling water flow was reversed from the shell side to the tube side of the heat exchanger.

Conditions Prior to Occurrence:

Unit 1 in mode 1 at 100% reactor power. Unit 2 in mode 4 with RCS temperature and pressure at 339 F and 900 PSIG.

Apparent Cause of Occurrence:

The inputs into the original accident analysis incorrectly modeled the component cooling water heat exchanger.

Analysis of Occurrence:

This probably results in slightly less heat transfer capability which could result in a higher peak containment pressure than is now calculated in the accident analysis.

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Corrective Action

A preliminary evaluation using the present technical specifications' ice 6

condenser ice weight of 2.1 x 10 lbs, modeling the component cooling water I

heat exchanger correctly, modeling plugged tubes in the containment spray heat exchanger, and reducing the flow to the component cooling water heat exchanger to 4000 gpm has resulted in a containment pressure of less than design basis. A detailed analysis is underway to confirm the preliminary evaluation. If the detailed analysis shows the preliminary evaluation to l

be incorrect a revised report will be submitted and appropriate corrective actions will be taken.

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Flilure Data:

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