Morning Report for May 23, 2000

                       Headquarters Daily Report

                         MAY 23, 2000

                    REPORT             NEGATIVE            NO INPUT
                    ATTACHED           INPUT RECEIVED      RECEIVED

HEADQUARTERS                           X
REGION I                               X
REGION II                              X
REGION III          X
REGION IV                              X

Licensee/Facility:                     Notification:

Commonwealth Edison Co.                MR Number: 3-00-0028
Quad Cities 2                          Date: 05/23/00
Cordova,Illinois                       ;VIA E-MAIL
Dockets: 50-265

Subject: Scram of Unit 2 Due to Steam Pressure Spike and Neutron High

Reportable Event Number: 37018


On May 22, 2000, with Unit 2 at 100 percent of rated power, operators
were returning the #1 turbine control valve to service. The valve opened
properly, but at about 50 percent of full open, operators received a high
APRM scram signal. Safety systems associated with response to the scram
responded properly. However, the Unit 2 emergency diesel generator
spuriously started and the 2 "A" feedwater regulating valve locked up.
These conditions did not have an adverse effect on operations, were
previously identified by the licensee, and will be addressed during
future system modifications. The licensee believed that as the #1 turbine
control valve opened, the remaining 3 turbine control valves closed in an
unsuccessful attempt to maintain turbine pressure. The resulting steam
pressure spike caused reactor power to spike to about 113 percent
resulting in a scram.

During the transient, an expected low reactor water level produced a
primary containment isolation signal (Group 2 and Group 3). A second low
reactor water signal caused another Group 2 and 3 isolation approximately
30 minutes later and was due to slow restoration of a reactor feed pump
to service.

The licensee planned to maintain the unit in Mode 3 pending results of
the root cause investigation into this event and to complete shutdown
maintenance items.

Regional Action:

The resident inspector responded to the site and monitored plant recovery

Contact:  M. RING                    (630)829-9703

Page Last Reviewed/Updated Wednesday, March 24, 2021