Event Number: 40537
Facility: PEACH BOTTOM
Unit:  [ ] [ ]
RX Type:  GE-4, GE-4
NRC Notified By: BARRY HEDRICK
HQ OPS Officer: RICH LAURA
Notification Date: 02/22/2004
Notification Time: 18:42 [ET]
Event Date: 02/22/2004
Event Time: 15:10 [EST]
Last Update Date: 02/22/2004
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Person (Organization): PAMELA HENDERSON (R1)
SCRAM Code M/R
RX CRIT Y
Initial PWR 100
Initial RX Mode Power Operation
Current PWR 0
Current RX Mode Hot Shutdown
MANUAL SCRAM AT PEACH BOTTOM 2 DUE TO DECREASING CONDENSER VACUUM
"Peach Bottom Unit 2 reactor was manually scrammed due to degrading main condenser vacuum. The reactor was manually scrammed prior to reaching the automatic scram setpoint. All plant systems responded as expected with no significant issues noted. A Group II and Group III Primary Containment Isolation was received due to reactor water level passing through 1 inch. All isolation systems responded as required and repositioned to their expected positions." The licensee also indicated that all control rods properly inserted into the core. The method of decay heat removal was using the main condenser. The licensee initiated a post scram review to identify and correct the source of degrading vacuum. The licensee also indicated the manual scram was initiated at 25 inches and lowering of condenser vacuum.
The licensee notified the NRC Resident Inspector.
Mechanical problems caused Peach Bottom's Unit 2 reactor to be shut down Sunday.
By SEAN ADKINS York Daily Record
Wednesday, February 25, 2004
Operators manually shut down Peach Bottom Atomic Power Station's Unit 2 reactor Sunday after a series of mechanical problems.
Last week, control room workers monitored an air leak in the reactor's condenser - equipment used to turn steam into water.
The condenser pumps that water back to the reactor.
On Tuesday, plant officials determined the leak came from an expansion joint caused by routine wear and tear of the system, said Dana Melia, spokeswoman for Exelon Generation. Exelon co-owns and operates the power station.
"That type of wear and tear is typical of any steam plant," Melia said.
That leak caused a loss of vacuum - a piece of equipment found inside the condenser, she said.
The shutdown caused no threat to public health or the plant's ability to distribute electricity, Melia said.
Peach Bottom Atomic Power Station's Unit 3 was not affected by its neighbor's shutdown and continues to function at full power.
The second unit's reactor is designed to go into automatic shutdown if the vacuum level drops to a specific set point, Melia said.
On Sunday, operators elected to manually take the reactor offline and bring the unit to a cold shutdown.
"(A shutdown) is safer when it's manual rather than automatic," Melia said. "You have more control over it."
All equipment used to carry out the shutdown functioned as it should, Melia said.
"They did what they were supposed to do," said Diane Screnci, spokeswoman for the U.S. Nuclear Regulatory Commission. "The plant's systems responded as expected."
Soon after the 3:11 p.m. shutdown, the plant notified its resident NRC inspector of the unit's problems.
The commission is having its inspector look into the cause of the shutdown, Screnci said.
As for Exelon, officials are investigating the cause of the leakage and what steps are necessary to bring the plant's second reactor back online, Melia said.
"We are trying to determine why it happened," she said.
Plant officials will use the shutdown as an opportunity to conduct routine maintenance of the site such as the checking of valves.
While Melia did not say when the reactor would return to service, Screnci said the time frame is more "a matter of days rather than months."
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