ML17339B129

LER 80-011/01T-0:on 800527,util Was Notified by NSSS Vendor That Nonconservative Error Had Been Discovered in Computer Inputs Used in Feb 1979 10CFR50.46 App K LOCA Analysis. Caused by Personnel Error

ML17339B129
Person / Time
Site:	Turkey Point
Issue date:	06/10/1980
From:	Schoppman M FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML17339B128	List: ML17339B127 ML17339B129
References
LER-80-011-01T, LER-80-11-1T, NUDOCS 8006230564
Download: ML17339B129 (2)

Text

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l Additional Cause Descri tion and Corrective Actions:

On Tuesday, May 27, 1980, Florida Power & Light Company (FPL) was notified by the NSSS vendor that a non-conservative error had been discovered in the computer inputs used in February 1979 to calculate the heat flux hot channel factor, F(q), for the fifteen by fifteen assemblies, used at Turkey Point Plant., The error involved not accounting for the presence of flow holes in the upper guide tubes in the analysis, and thus predicted an upper head water temperature which was cooler and allowed more cooling during the blowdown phase of a LOCA.

This occurrence was a personnel error, traced to a particular analyst and a particular analysis. The error was discovered by a Quality Assurance Audit requested of the NSSS vendor by FPL.

Reanalysis using the proper inputs for Unit No. 3 indicates that the allowable F(q) has decreased from 1.99 to 1.93, with the maximum predicted for the fuel cycle being 1.96. Augmented surveillance of core parameters has been instituted above 98 % power. in accordance with Technical Specification requirements. Unit No. 4'imits will be established by reanalysis prior to startup following the current outage.