05000348/LER-2015-002
| Joseph M. Farley Nuclear Plant, Unit 1 | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown |
| 3482015002R00 - NRC Website | |
PLANT AND SYSTEM IDENTIFICATION
Westinghouse - Pressurized Water Reactor Energy Industry Identification Codes are identified in the text as [XX].
DESCRIPTION OF EVENT
At 0740 CDT on May 7, 2015, while at 27 percent power in Mode 1, the Unit 1 reactor was shut down per operating procedures and entered Mode 3. This shutdown was required by Technical Specification (T.S.) 3.4.4 Condition A which was entered at 0509 when the 1B Reactor Coolant Pump (RCP) tripped. The cause of the 1B RCP trip was a loss of the 1B electrical bus when the transfer of station loads from 1B Start Up Auxiliary Transformer (SAT) to the 1B Unit Auxiliary Transformer (UAT) failed due to jumpers having been inappropriately left in place during maintenance work associated with the installation of a new 1B UAT. The 1B Circulating Water pump also tripped when the 1B bus was de-energized. The plant also entered T.S. 3.4.2 condition A for Reactor Coolant System Minimum Temperature for Criticality due to the transient in loop temperature caused by the loss of the 1B RCP. This condition was exited after 15 minutes.
In 2006 a new transformer for the 1B UAT was partially installed in the Low Voltage Switchyard (LVSY). It remained on a storage pad in the LVSY since that time. Factory installed jumpers were in place to protect the current transformers. During the Unit 1 refueling outage in April and May of 2015 the design package to complete the installation was implemented as a station reliability enhancement initiative. While ascending in power from 1R26, the operating crew was transferring station loads from the 1B SAT to the 1B UAT when an unexpected actuation of the 1B UAT protective relaying occurred resulting in the loss of the 1B bus and subsequently the 1B RCP due to the jumpers having not been removed prior to energizing the 1B UAT.
CAUSE OF EVENT
The cause of this event was that jumpers were inappropriately left in place because of a failure to adhere to station standards during the project management process for the 1B UAT design change. Lapses in standards occurred at various levels of the organization in project oversight, work planning preparation and review, and proper post modification testing.
The causal analysis for this event is still in progress. This LER will be supplemented if information in this LER is affected by the final approved causal analysis.
REPORTABILITY ANALYSIS AND SAFETY ASSESSMENT
This event is reportable as required by 10 CFR 1 50.73(a)(2)(i)(A) due to a Unit 1 shutdown required by Technical Specifications. Technical Specification 3.4.4 Condition A was entered at 0509 when the 1B RCP tripped. The abnormal operating procedure was entered for loss of reactor coolant flow. The reactor was shut down at 0740 and mode 3 was entered to complete the required TS action. All safety related equipment operated as designed in association with this event. There was no loss of safety function and no radioactive release associated with this event. There was no actual consequence detrimental to the health and safety of the public.
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 NRC FORM 366A Estimated burden per response to comp l with this mandatory collector request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.
Reported lessons learned are incorporated into the licensing process and tad back to industry.
Send comments regarding burden estimate to the FOIA, Pnvacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by intemet e-mail to Infocollects.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 information collechon 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 information collection.
CONTINUATION SHEET
CORRECTIVE ACTION
Immediate actions were the removal of the jumpers and the completion of extensive post modification testing.
Additional corrective actions will be taken to reinforce planning and project management standards and strengthen post modification testing development guidance.
ADDITIONAL INFORMATION
Other system affected: No systems other than those mentioned in this report were affected by this event.
Commitment Information: This report does not create any licensing commitments Previous Similar Events: None