U.S. Nuclear Regulatory Commission

Office of Public Affairs, Region IV

611 Ryan Plaza Drive - Suite 400

Arlington, Texas 76011-8064

RIV: 96-33 FOR IMMEDIATE RELEASE

CONTACT: Breck Henderson May 22, 1996

OFFICE: 817/860-8128

PAGER: (800) 443-7243 (065477)

NRC SENDS AUGMENTED INSPECTION TEAM

TO ARKANSAS NUCLEAR FOLLOWING REACTOR TRIP

The U.S. Nuclear Regulatory Commission has sent an augmented

inspection team to the Arkansas Nuclear One, Unit 1, nuclear

power plant near Russellville, Arkansas.

The five-man team of inspectors, who arrived at the plant

today, will look into factors that caused an automatic shutdown

of the reactor Sunday, May 19, and the complications that ensued.

The series of events to be examined are as follows:

Unit 1 shut itself down at 3:12 a.m. May 19 while operating

at 100 percent power. The shutdown resulted when the operating

speed of a main feedwater pump suddenly decreased, reducing the

flow of feedwater. This pump supplies water to the plant's steam

generators, which cool the reactor and generate steam to drive

the electricity-producing main turbine. The reduced cooling

water flow was detected and the plant shutdown, or tripped, as

designed.

As expected, main steam safety valves designed to protect

the system from high pressure opened and vented non-radioactive

steam outside the plant. After relieving excess pressure the

safety valves are designed to close. However, one safety valve

serving one of the steam generators stuck open. To prevent

excess cooling of the reactor coolant system, the affected steam

generator was isolated and it subsequently boiled dry.

A Notice of Unusual Event, the NRC's lowest classification

for emergency events, was declared by plant operators at 3:30

a.m. By 4:30 a.m. the temperature in the shut-down plant was

stable at a normal temperature of 550 degrees F. About 9 a.m.

the dry steam generator was refilled with water, and the Notice

of Unusual Event was canceled at 1:04 p.m. No radiation was

released from the plant, and the safety of plant personnel and

the public was not threatened.

-More-
The special NRC inspection team will focus on understanding

the entire sequence of events and the cause of the initial

failure of the main feed pump. It also will review the response

of the main steam safety valves, including the cause of the

failure of one of the valves to close as designed.

Other factors to be reviewed include the impact of recent

plant modifications on equipment which affected plant response to

the event, the analysis of stresses induced in the steam

generator, and the ability of the steam generator to continue to

operate safely.

The team is tentatively scheduled to complete its work on

Friday, May 24, and a report documenting findings will be issued

in about three weeks. NRC will hold a meeting with Entergy

Operations, Inc., the licensee, to discuss preliminary inspection

findings some time after May 24. The meeting will be open for

public observation.

An NRC augmented inspection team is solely a fact-finding

body and will not determine if violations of NRC regulations

occurred. Violations, if any, will be determined by subsequent

NRC inspections.

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