ML19330C748

Third Interim Deficiency Rept Re Improper Documentation & Utilization of Computer Program Inertia.Documentation Revised to Restrict Use to Closed Sections.New Structural Responses Supplied & Verified

ML19330C748
Person / Time
Site:	Yellow Creek
Issue date:	08/01/1980
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:
References
NCR-YCN-CEB-800, NUDOCS 8008110414
Download: ML19330C748 (2)

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8008110Y/[ S

S ENCLOSURE YELLOW CREEK NUCLEAR PL\NT UNITS 1 AND 2 IMPROPER DOCUMENTATION AND UTILIZATION OF COMPUTER PROGRAM " INERTIA" NCR YCN CEB 8004 (FORMERLY NCR CEB 80-17) 10 CFR 50. 55(e) .

THIRD INTERIM REPORT Description of Deficiency Improper documentation and utilization of the TVA computer program " INERTIA" have resulted in incorrect shear-related, cross-sectional property calcula-tions for the control building. The computer program incorrectly calculates the eccentricity of open sections. The dynamic structural response calcula-tions used for the building structural member and anchor rod designs have been determined to be nonconservative. The instructure response spectra

.are also affected.

In our investigation of the applicability of this problem to Watts Bar, Bellefonte, Hartsville, and Phipps Bend Nuclear Plants, it was discovered that " INERTIA" is used as a subroutine in a computer program known as "BIGDYNA." "BIGDYNA" is a structural analysis program that calculates the modal frequencies and mode shapes of a structure and determines the structural response to dynamic loads by the modal superposition method.

Interim Progress TVA has revised the computer program dccumentation to restrict its use to closed sections only.

TVA proceeded in two stages to correct the existing deficiency at Yellow Creek Nuclear Plant:

1. TVA Civil Engineering Branch has supplied the plant design project with new structural responses using the appropriate computer program for open sections.

2. The structural design has been verified and required changes have been made; the instructure response spectra have been recalculated.

A che'ck has been made of all other .BLA nuclear plants, and it has been determined that the computer program was properly utilized. TVA is still checking Yellow Creek Nuclear Plant for other areas where the program may have been improperly used.

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