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CALVERT CLIFFS 1 0% 09/10/00 Hot Standby
AUTOMATIC RX TRIP/TURBINE TRIP
DUE TO SPURIOUS ESFAS S/G
ISOLATION SIGNAL - SEE EVENT
#37303
-- spider (spider0@usa.net), September 11, 2000
Scroll down the page to:Event 37303
http://www.nrc.gov/NRR/DAILY/der.htm
EVENT TEXT +--------------------------------------------------------------------- ---------+ | AUTOMATIC REACTOR TRIP DUE TO CLOSURE OF MAIN STEAM ISOLATION VALVES | | | | An automatic reactor trip/turbine trip occurred due to the spurious closure | | of both main steam isolation valves (MSIVs). The spurious MSIV closure was | | the result of a failed logic module in the engineered safety features | | actuation system (ESFAS). All control rods inserted following the trip, and | | all systems functioned as expected. The auxiliary feedwater (AFW) system | | automatically started as designed following the trip. The unit is currently | | stable in Hot Standby with decay heat being removed through steam released | | via the steam generator atmospheric dump valves. Steam generator water | | levels are being maintained by the AFW system. | | | | The licensee anticipates that replacement of the logic module and | | establishment of decay heat removal via the main condenser will occur within | | the next few hours. The NRC resident inspector has been informed of this | | event by the licensee. The licensee reported that nearby residents have | | contacted emergency services regarding the noises caused by the steam | | release through the atmospheric dump valves. The licensee plans to make a | | press release regarding this event. | | | | * * * UPDATE 0428EDT ON 9/11/00 FROM ROBERT PACE TO S. SANDIN * * * | | | | The MSIVs were reopened and the main condenser placed back in service at | | 0420EDT for decay heat removal. Preparations are underway to restore one | | main feedwater pump and secure the AFW system. Notified R1DO (Dimitriadis). | +--------------------------------------------------------------------- ---------+
-- Tom Beckner (becknert@erols.com), September 11, 2000.