05000272/LER-2014-006
| Salem Generating Station - Unit 1 | |
| Event date: | 10-19-2014 |
|---|---|
| Report date: | 04-08-2015 |
| 2722014006R01 - NRC Website | |
PLANT AND SYSTEM IDENTIFICATION
Westinghouse - Pressurized Water Reactor {PWR/4} Main Power Transformer {EL} Auxiliary Feedwater System {BA} Steam Generator {AB/SG} Energy Industry Identification System (EllS) codes and component function identifier codes appear as {SS/CCC}.
IDENTIFICATION OF OCCURRENCE
Event Date: October 19, 2014 Discovery Date: October 19, 2014
CONDITIONS PRIOR TO OCCURRENCE
Salem Unit 1 was in operational Mode 1, performing a unit shutdown in preparation for its twenty-third refueling outage. No additional structures, systems or components were inoperable at the time of discovery that contributed to this event.
DESCRIPTION OF OCCURRENCE
On October 19, 2014, at 1500, Salem Unit 1 commenced a power reduction to Hot Standby in preparation for a scheduled refueling outage.
At 1810, control room operators received a phase 2 Main Power Transformer (MPT){EL} trouble overhead annunciator. Local annunciation on the 1 B MPT panel indicated a low oil level condition in the 18 MPT.
I At 2027, operators entered the rapid load reduction procedure increasing power reduction rate from 20 percent per hour to 1 percent per minute.
I At 2048, the 1 B MPT trouble overhead annunciator reflashed. Local transformer annunciation indicated gas detection in the 1 B MPT.
I At 2051, at approximately 20 percent power, a manual reactor trip was initiated. All control rods fully inserted on the trip. All three auxiliary feedwater (AFW) pumps {BA/P} started as designed in response
CONTINUATION SHEET
2. DOCKET 6. LER NUMBER 3. PAGE APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 hours. Reported lessons learned are incorporated into the licensing process and fed back to Industry. Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an infonmation collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the infonmation collection.
to low Steam Generator (SG) {AB/SG} levels and decay heat was removed by the steam dumps to the main condenser. Operators entered the emergency operating procedures for the reactor trip and stabilized the plant in Hot Standby (Mode 3).
An eight hour NRC Emergency Notification System (ENS) notification was made on October 20, 2014 at 01 36 under the requirements of 1 0 CFR 50. 72(b )(3)(iv)(A), for automatic actuation of the AFW system. An update to this notification made on November 24, 2014, at 1 555, stated that the manual reactor trip met the criteria for four hour reporting in accordance with 1 0 CFR 50. 72(b )(2)(iv)(B), "Any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical. .. "
CAUSE OF EVENT
The cause of the unplanned manual reactor trip is attributed to weaknesses in behaviors and practices of Procedure Use and Adherence (PU&A) by the operating crew. Operators failed to recognize parameters on 1 B MPT which would have required them to enter an Adverse Condition Monitoring Plan. The Adverse Condition Monitoring Plan would have required them to initiate a fast load reduction and remove the main turbine from service at 40 percent power. Operators continued with a normal shutdown, then transitioned to their rapid load reduction procedure. Plant conditions were met in the rapid load reduction procedure to trip the turbine but a turbine trip was not performed. Operators manually tripped the reactor and transitioned from the rapid load reduction procedure to the emergency operating procedures.
The AFW pumps automatically started as designed on the unit trip due to low (14% Narrow Range) SG levels experienced after the reactor trip.
SAFETY CONSEQUENCES AND IMPLICATIONS
There were no safety consequences associated with this event. Operators responded appropriately to the manual reactor trip. All plant systems operated as designed.
SAFETY SYSTEM FUNCTIONAL FAILURE
A review of this event determined that a Safety System Functional Failure (SSFF) as defined in Nuclear Energy Institute (NEI) 99-02, Regulatory Assessment Performance Indicator Guideline, did not occur. This event did not prevent the ability of a system to fulfill its safety function to either shutdown the reactor, remove residual heat, control the release of radioactive material, or mitigate the consequences of an accident.
PREVIOUS OCCURRENCES
A review of Salem Unit 1 and 2 Licensee Event Reports for the previous three years identified no other similar manual reactor trip events.
CORRECTIVE ACTIONS
1 . The 1 B MPT leak was repaired and tested satisfactorily during the 1 R23 refueling outage.
2. A causal evaluation was performed to address the causes of this event.
3. Training and Operations will benchmark, implement and reinforce new PU&A standards and practices for Operations based on best industry criterion.
4. Analysis and training will be performed to address weaknesses in application of 1 0 CFR 50. 72 reportability requirements for licensed operators and Regulatory Assurance personnel.
COMMITMENTS
This LER contains no regulatory commitments.