ML19282B126
| ML19282B126 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 02/16/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Koester G KANSAS GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7903090048 | |
| Download: ML19282B126 (1) | |
Text
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UNITED STATES o
NUCLEAR REGULATORY COMMISSION
[N REGION IV n
2
..I 611 RYAN PLAZA DRIVE, SulTE 1000
%,**m /[
ARLINGTON, TEXAS 76011 o
February 16, 1979 In Reply Refer To:
RIV Docket No.
STil 50-482/IE Information Notice No. 79-04 Kansas Gas & Electric Co.
Attn: Mr. Glenn L. Koester Vice President-0perations Post Office Box 208 Wichita, Kansas 67201 Gentlemen:
This Infomation flotice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the information for possible apolicability to their facilities.
No specific action or response is requested at this time.
If further fiRC evaluations so indicate, an IE Circular, Bulletin or NRR Generic Letter will be issued to recommend or request specific licensee action.
If you have questions regarding this matter, please contact the Director of the appropriate flRC Regional Office.
Sincerely, 7
qjt Karl V. Seyfrit [!
j Director
Enclosures:
1.
IE Information t;otice fio. 79-04 2.
List of IE Information Notices Issued in 1979 cc: w/ enclosures Messrs.
Nicholas A. Petrick, SNUPPS D. T. McPhee, Kansas City Power and Lighc Company Gerald Charnoff, Shaw, Pittman, Potts & Trowbridge E. W. Creel, Kensas Gas and Electric Company 790309009%
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION Afl0 ENFORCEMENT WASHINGTON, D.C.
20555 IE Information Notice No. 79-04 Date:
February 16, 1979 Page 1 of 5 DEGRADATION OF ENGINEERED SAFETY FEATURES Summary:
On September 16, 1978, an unusual sequence of events occurred at Arkansas Nuclear One, Units 1 and 2.
The events involved the electrical power sources and culminated in the spurious activation and degraded operation of Unit 2 Engineered Safety Features (ESF).
Analysis of the course of the incident has identified three safety concerns in the electrical distribution system operation and design.
(1) The offsite power supply for AN0 Unit 1 Engineered Safety Feature loads was deficient in that degraded voltage could have resulted in the unavailability of ESF equipment, if it were to be' needed.
(2) The design of the ANO site electrical system that provides offsite power to Units 1 and 2 did not fully meet the Commission's Regula-tions,10 CFR 50, Appendix A, General Design Criterion 17, because in certain circumstances a loss of one of the two offsite power circuits would also result in a loss of the other such circuit.
(3)
Deficiencies existed in the operation of the Unit 2 inverters that convert DC to AC power for the uninterruptable 120 volt vital AC buses.
Description of Circumstances:
Initially Unit I was operating at 100 percent power; Unit 2 was in hot standby performing hot functional testing in preparation for initial criticality and power operation ]f.
Unit 1 auxiliary electrical loads were being supplied from the Unit 1 main generator via the unit auxiliary transformer.
Unit 2 auxiliary electrical loads were being fed from the offsite grid through Startup Transformer No. 3.
The normal operating status was interrupted by the failure of the Unit 1 Loop "A" Main Steam Line Isolation Valve (MSIV) air operator solenoid causing the MSIV to close as designed. The Unit 1 Reactor Protection System sensed conditions requiring reactor shutdown and tripped the reactor. The 1/ The Unit 2 Operating License did not permit criticality of power operation at the time of the incident.
DMd 7903020383