05000335/LER-2001-002
| Docket Number | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3352001002R00 - NRC Website | |
Description of the Event
On April 3, 2001 St. Lucie Unit 1 was shutdown in Mode 4 operations during the beginning of the SL1-17 refueling outage. At 0440 hours0.00509 days <br />0.122 hours <br />7.275132e-4 weeks <br />1.6742e-4 months <br /> both the lA and 1B shutdown cooling (SDC) loops [EIIS:BP] were removed from service to repair relief valve, V3483. The 1A1 and 1A2 reactor coolant pumps (RCPs) were also inoperable at this time, leaving only one reactor coolant loop operable and in operation. At 0645 hours0.00747 days <br />0.179 hours <br />0.00107 weeks <br />2.454225e-4 months <br />, control room personnel identified this plant configuration and immediately initiated actions to restore the minimum required loops to operable status in accordance with the action statement for specification 3.4.1.3.A. The 1A1 RCP was restored to service at 1036 and the action statement for Technical Specification 3.4.1.3 was exited. Both the 1B1 and the 1B2 RCPs remained in service during the entire event.
Cause of the Event
The cause of this event was a personnel error on the part of control room supervision that authorized the implementation of an equipment clearance order that removed both of the shutdown cooling loops from service at the same time the "A" RCS loop was out of service.
There were several contributing factors to this event. The teamwork, communications, and peer checking that is relied upon to provide defense in depth was not effective between the control room and clearance center. Additional contributors to this event were the failure to properly enter out of service equipment in the chronological log and the equipment out of service (EGOS) log. Entries into these logs may have prompted one of the involved SROs to become aware of the technical specification implications of the planned evolutions.
Analysis of the Event
This event is reportable under 10 CFR 50.73(a)(2)(i)(B) as "Any operation or condition prohibited by the plant's Technical Specifications..." Contrary to the requirements of Technical Specification 3.4.1.3, St. Lucie Unit 1 inadvertently entered a condition where less than the required minimum RCS heat removal loops were operable and did not initiate actions to correct that condition within the allowed outage time.
Analysis of Safety Significance At 0745 hours0.00862 days <br />0.207 hours <br />0.00123 weeks <br />2.834725e-4 months <br /> on April 2, 2001, the 1A1 RCP was removed from service. At 1445 hours0.0167 days <br />0.401 hours <br />0.00239 weeks <br />5.498225e-4 months <br />, the 1A2 RCP was secured and later removed from service. Later that same day, during an attempt to place the lA SDC loop in service, the hot leg suction relief valve, V3483, lifted causing an unplanned loss of reactor coolant. Emergent plans were initiated to remove the relief valve and repair or replace it as needed. To safely clear the valve for maintenance, both trains of SDC had to be removed from service.
Mode 4 was entered at 1510 hours0.0175 days <br />0.419 hours <br />0.0025 weeks <br />5.74555e-4 months <br /> on April 2, 2001, at which time Technical Specification 3.4.1.3 became applicable. At 0440 hours0.00509 days <br />0.122 hours <br />7.275132e-4 weeks <br />1.6742e-4 months <br /> on April 3, 2001, the lA and 1B SDC loops were entered in the out of service log in preparation of hanging the emergent equipment clearance order (ECO)04-007. At 0446, the clearance for the SDC system was initiated and the "A" and "B" SDC loops became administratively inoperable. In fact, the "B" SDC loop remained immediately available for use until 0552 when the breaker for V3651 was placed in the OFF position and an ECO tag was affixed. At 0645 when it was realized that both SDC loops were disabled and only one FACILITY NAME (1)
DOCKET
LER NUMBER (6) RCS loop was in service, actions were taken to restore the minimum required cooling loops. At 1036 hours0.012 days <br />0.288 hours <br />0.00171 weeks <br />3.94198e-4 months <br /> on April 3, 2001, the 1A1 RCP was placed back in service restoring an additional RCS coolant loop to operable status. Throughout this event both the 1B1 and the 1B2 RCPs and associated steam generator remained in service.
Therefore, this event had no adverse impact on the health and safety of the public.
FPL addressed the potential generic implications (e.g., inadequate communication and coordination) by the corrective actions planned and put in place and the discussions that occurred during the operations stand down meetings that specifically focused on preventing additional events of this nature.
Corrective Actions
1. The 1A1 RCP was expeditiously returned to service to satisfy the requirements to have two operable heat removal loops.
2. Interim corrective actions were implemented, including Operations personnel turnover reviews of the stand down issues document that described this event; issuance of a night order that listed expectations for smooth and successful communications between the control room, EOOS coordinators, and clearance center personnel with regard to EOOS issues; and the development of a standard to accurately document, track and delineate responsibility when Technical Specification equipment is removed from service for the remainder of SL1-17 refueling outage.
3. The guidance that was developed for the SL1-17 refueling outage with regard to EOOS tracking will be incorporated in appropriate plant procedures such as ADM 09.08 "In-plant Equipment Clearance Orders" and 0-NOP-100.01 "Equipment Out Of Service.
Additional Information
Failed Components Identified None Similar Events None