05000397/LER-2015-003
| Columbia Generating Station | |
| Event date: | 05-13-2015 |
|---|---|
| Report date: | 07-07-2015 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3972015003R00 - NRC Website | |
EVENT DESCRIPTION
While in Mode 5, Refueling, OPDRVs were performed as part of Columbia's 22nd refueling outage (R22) without an operable secondary containment. Columbia used the provisions of EGM 11-003, Revision 2 to perform the activities which are listed as follows:
5/13/2015 0222 Pacific Daylight Time (PDT) - Commenced OPDRV activity to Secure residual heat removal pump RHR- P-2B.
5/13/15 0323 PDT - started pump RHR-P-2B and exited the OPDRV activity 5/15/15 1607 PDT - Commenced Control Rod Drive (CRD) removal and replacement OPDRV activity 5/17/15 0500 PDT - Commenced local power range monitor (LPRM) incore assembly removal and installation activity 5/18/15 1212 PDT - Commenced removal/replacement of dry tube for IRM-DET-2A 5/18/15 2200 PDT - Exited OPDRV window following completion of CRD, LPRM and IRM maintenance activities 5/25/15 0425 PDT - Commenced swap of shutdown cooling from Train A to Train B OPDRV activity 5/25/15 0447 PDT - Exited OPDVR for shutdown cooling train swap activity 5/25/15 2338 PDT - Commenced leak rate testing of valves RHR-V-41C, RHR-V-41B, and RHR-V-50B OPDRV activity 5/26/15 1102 PDT - Exited OPDRV window for leak rate testing of valves RHR-V-41C, RHR-V-41B, and RHR-V-50B 6/11/15 0635 PDT - Commenced reactor recirculation pump RRC-P-1A seal replacement OPDRV 6/13/15 1205 PDT - Declared Secondary Containment operable, EGM 11-003 no longer required for use to support OPDRVs 6/14/15 0325 PDT - Exited RRC-P-1A seal replacement OPDRV
CAUSE OF THE EVENT
Implementation of EGM 11-003, Revision 2 interim actions during Columbia R22 was a planned activity. As such, no cause determination was performed on these events.
ANALYSIS / SAFETY SIGNIFICANCE
This event is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as operations prohibited by Columbia TS 3.6.4.1, which prohibits activities identified as OPDRVS in Mode 5 while secondary containment is inoperable.
The OPDRV activities described in this report were accomplished using the interim actions provided by the NRC in EGM 11-003, Revision 2. Columbia adhered to the NRC plain language meaning of OPDRV activities that could potentially result in draining or siphoning the reactor pressure vessel water below the top of fuel. This included evolutions involving 26158A R3 aligning and realigning systems prior to achieving steady-state water level control, without taking credit for mitigating measures. Columbia also met the requirements which specify the minimum makeup flow rate and water inventory.
Further, an adequate defense in depth was maintained to minimize the potential for the release of fission products with secondary containment inoperable. Since these measures were implemented, an adequate level of safety was provided during the OPDRV activities described in this report.
CORRECTIVE ACTIONS
Columbia will submit a license amendment request following NRC approval of the Technical Specification Task Force (TSTF) traveler associated with generic resolution of this issue within the time constraints specified in EGM 11-003, Revision 2.
PREVIOUS SIMILAR EVENTS
(Mode 5), leakage past a closed isolation valve associated with one hydraulic unit on the control rod drive system was observed through a drain line which was not recognized as an OPDRV. The leakage persisted for 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> until the maintenance activity was completed. During this period, secondary containment was inoperable. Technical Specifications require that with secondary containment inoperable during OPDRV activities, action must be initiated immediately to suspend OPDRV. Contrary to this, action was not taken to suspend OPDRV. The corrective action was to revise procedural guidance. This event could not have prevented the condition reported in LER 2015-003-00 since this event uses EGM 11-003, Revision 2 which results in a condition prohibited by Technical Specifications.
26158A R3