ML19256D004
| ML19256D004 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 06/14/1979 |
| From: | Bryan S, Klingler G, Nolan F NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| PNO-79-162, NUDOCS 7910150838 | |
| Download: ML19256D004 (1) | |
Text
PRELIMINARY NOTIFICATION June 14, 1979 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-79-162 This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance.
The information presented is as initially received without verification or evaluation and is basically all that is known by IE staff on this date.
FACILITY: Arkansas Power and Light, ANO - Unit 2 (Docket No. 50-368)
SUBJECT:
Loss of Off-Site Power Caused by Faults in Unit 2 High Voltage Distribution System.
On June 13, 1979, ANO - Unit 2 was engaged in startup testing at the 20 perceat power level. The unit auxiliary power was being supplied from off-site pow r through startup (SU) transformer No. 3.
At 3:43 pm hours the SU No. 3 trar sformer lockout relay energized on differential overcurrent on two phases, causing Unit 2 to suffer a loss of off-site power.
Water being used in a clean up operation in the viciatity of the high voltage switchgear apparently seeped into the bus ductwork and caused the above event.
In addition, a short section of one side of the bus ductwork for the Unit 2 auxiliary transformer was blown out.
Both diesel generators started and accepted all automatically actuated loads on the engineered safety features busses.
The emergency feedwater system was manually initiated. The operators observed a minimum delta T accross the core of 30 F and a minimum margin to saturation of 75 F.
By 4:43 pm hours the equipment necessary for a normal cool-down of the reactor primary system had been energized through the backup power supply SU transformer No. 2 and reactor cooldown was commented.
The licensee is continuing his investigation of the event and will submit an event report.
The licensee expects to be down about seven (7) days to inspect and repair the high voltage ductwerk.
The site residert inspector will follow the licensee's investigation and repairs.
The Regional Office plans no press release; however, the licensee plans to make a press release.
The Region IV duty officer was notified of the above event by the site resident inspector, who was present during the event, on June 13, 1979.
Contact:
GKlingler IE, x28019; FNolan IE, x28019; SBryan IE, 28019 TransmittedHStf.*dd Distribution:
Chairman Hendrie Commissioner Bradford S. J. Chilk, SECY Commissioner Kennedy Commissioner Ahearne C. C. Kammerer, CA Commissioner Gilinsk ACRS (For Distribution)
Transmitted: MNBB
.dM P. Bldg V. Stello. IE L. V. Gossick, EDO H. R. Denton, NRR Region H. L. Ornstein, EDO R. C. DeYoung, NRR
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J. J. Fouchard, PA R. J. Mattson, NRR N. M. Haller, MPA NRR (MAIL)
R. S. Boyd, / C -
J. J. Cummings, OIA SS Bldg A J R. G. Ryan, OSP H. K. Shapar, ELD W. J. Dircks, NMSS R. Minogue, SD S. Levineu JS _
J. Dircks. NMS L R
PRELIMINARY NOTIFICATION 791015U h M
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1450 315