ML19225C898
| ML19225C898 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 07/30/1979 |
| From: | Moody D YANKEE ATOMIC ELECTRIC CO. |
| To: | Grier G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| RO-50-29-79-18, NUDOCS 7908030204 | |
| Download: ML19225C898 (2) | |
Text
.
Telephone 617 366-9011 Flo - 3 9 0.o 7 3 3 YANKEE ATOMIC ELECTRIC COMPANY
,Yamnu,$
4 1 20 Turnpike Road Westborough, Massachusetts 01581 s
' '---~~*
July 30, 1979 Mr. B. H. Grier, Director U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region 1 631 Park Avenue King of Prussia, PA 19406
Subject:
Licensee Event Report 50-29/79-18 Exxon Fuel Rod Pre-Pressurization Error
Dear dr. Grier:
Pursuant to the requirements of Technical Specification Section 6.9.4.a.(8) the following is reported as Reportable Occurrence 59-29/79-18. The occurrence involves " errors discovered in the transient or accident analysis or in the methods used for such analysis as described in the FHSR or in the Bases for the Tech-nical Specifications that have or could have permitted reactor operation in a manner less conservative than assumed in the ana-lysis."
Yankee Atomic Electric Company was informed about a deviat!on in the fuel pin pressure from its specified value by its fuel manufacturer, Exxon Nuclear, Inc.
The nominal value of the pin pressure is 125 1 5 psig, but a refined measurement of the archieved pins showed a pressure of up to a maximum value of 143.1 psig.
The pin pressure impacts LOCA calculations in two ways:
(1) the average fuel temp-erature at operating conditions may change and (2) the swelling and rupture response during the accident may alter.
To assess the impact, CAPCON-THERMAL-2 ccmputer calculation was per-formed for the high (as-built) and low (design) prepressurization levels.
It is predicted that at the present operating core average burnup condition of 6867 MWD /MT, the as-built fuel average tempera-ture is about 73 F (3.1%) lower than that of the design case and the pressure is about 1. 7 psi or 0.2% higher.
It is also predicted that at the end-o f-cycle conditions, the as-built fuel average temperature is about 117 F (-6.1%) lower than that of the design case and the pressure is about 74 psi or -6.6T. lower.
Hence, it is concluded that the pin pressure increase from its specified value of 125 i 408 172 7 9 08 0 3 0 2C) f
v Licensee Event Report 50-29/79-18 Exxon Fuel Rod Pre-Pressurization Error Page two 5 psig should have no adverse affect on Peak Clad Temperature experienced as a result of a LOCA and that the plant may continue to operate without adversely impacting the health and safety of the public.
Ve ry t ruly you rs,
YMIKEE ATOMIC ELECTRIC COMPMiY
~$
1:1 1
D.
E. Moody Fbnager of Oper..tions JKT/sec cc: Director, Of fice of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D.
C.
20555 Director, Of fice of Management Information & Program Control U. S. Nuclear Regulatory Commission Washington, D.
C.
20555 408 173
.