Headquarters Daily Report
APRIL 30, 2001
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REPORT NEGATIVE NO INPUT
ATTACHED INPUT RECEIVED RECEIVED
HEADQUARTERS X
REGION I X
REGION II X
REGION III X
REGION IV X
PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION I APRIL 30, 2001
Licensee/Facility: Notification:
Northeast Utilities MR Number: 1-01-0008
Millstone 2 Date: 04/29/01
Waterford,Connecticut
Dockets: 50-336
PWR/CE
Subject: AUTOMATIC REACTOR SHUTDOWN DUE TO PERSONNEL ERROR
Reportable Event Number: 37952
Discussion:
On April 29,2001, at 11:28 a.m., Millstone Unit 2 automatically shut down
(turbine and reactor trip) from 97.5% power. This resulted from a
partial loss of condenser vacuum. Personnel error caused an inadvertent
loss of the "C" circulating water (CW) pump during ongoing work
supporting the "D" CW pump outage. The error occurred when an
electrician disturbed a control circuit in the "D" CW pump breaker
cubicle that caused the "C" CW pump to trip.
Following the automatic reactor trip, all major equipment responded as
expected, which included actuation of emergency feedwater due to
post-trip steam generator level change. Operators stabilized the plant
condition in Mode 3, at normal operating pressure and temperature. In
addition, the steam line atmospheric relief valves lifted momentarily and
reseated as designed following the turbine trip due to the pressure
transient in the secondary plant. Contrary to the information in the
subject event notification report, the steam generator safety valves did
not lift during this event. The licensee is conducting maintenance on
selected plant systems which they expect to complete later today.
RI responded to site to review licensee actions.
Contact: R. Summers (610)337-5282
C. Cowgill (610)337-5233
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