05000388/LER-2013-001
| Susquehanna Steam Electric Station Unit 2 | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3882013001R00 - NRC Website | |
EVENT DESCRIPTION
While in Mode 5, Refueling, OPDRVs were performed as part of the Unit 2 16th Refueling and Inspection Outage (U216R10) without an operable secondary containment. The event timeline is as follows:
4/16/2013 22:00 — Entered Unit 2 Limiting Condition for Operation (LCO) 3.6.4.1 due to Zone II Secondary Containment Isolated from the Recirculation Plenum and Relaxed in support of outage activities 4/17/2013 00:02 — Entered OPDRV mode of operation, provisions of EGM 11-003 in effect 4/17/2013 to 5/17/2013 — Performed OPDRV activities in support of U216R10 5/17/2013 22:00 — Cleared Unit 2 LCO 3.6.4.1 The station used the provisions of EGM 11-003, Revision 1 in order to perform the following U216R10 activities:
- Recirculation system drain and maintenance
- Reactor Water Clean Up (RWCU) system removal from service, maintenance, testing, and restoration
- Residual Heat Removal (RHR) system local leak rate test (LLRT), drain, maintenance, and testing
- Hydraulic Control Unit (HCU) replacement
- Local Power Range Monitor (LPRM) replacement
- Scram Discharge Volume (SDV) maintenance and testing
- Control Rod Drive (CRD) mechanism replacements
- Scram Pilot Solenoid Valve testing
- Reset of Reactor Scram
CAUSE OF THE EVENT
Implementation of EGM 11-003, Revision 1 interim actions during the U216R10 was a planned activity. As such, no cause determination was performed on the events.
ANALYSIS/SAFETY SIGNIFICANCE
This event is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as operations prohibited by SSES Unit 2 Technical Specification 3.6.4.1, which prohibits performing activities identified as OPDRVs in Mode 5 while secondary containment is inoperable.
With the exception noted below, OPDRVs discussed in this report were accomplished using interim actions provided by the NRC in EGM 11-003, Revision 1. In accordance with station procedures controlling OPDRVs (NDAP-QA-0326, OP- AD-325), Susquehanna adhered to the NRC plain language meaning of OPDRV activities that could potentially result in draining or siphoning the RPV water level below the top of the fuel. This included evolutions involving aligning and realigning plant systems prior to achieving steady-state water level control, without taking credit for mitigating measures.
Susquehanna 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 not operable. With the exception of TS 3.8.2, all other Mode 5 Technical Specifications requirements for OPDRV activities were followed. Since these compensatory measures were implemented and the exception of TS 3.8.2 was determined to be of low shutdown risk significance, an adequate level of safety was provided during the performance of the OPDRV activities described in this report.
The exception of TS 3.8.2 was due to an unrecognized condition prohibited by the TS when more than one required AC power source was inoperable during OPDRV activities. Specifically, required emergency diesel generators were rendered inoperable by the failure of an electrical synchronizing switch. The duration of the exception was approximately 75 hours8.680556e-4 days <br />0.0208 hours <br />1.240079e-4 weeks <br />2.85375e-5 months <br />.
Because the inoperable AC power sources were determined to have maintained their ability to perform their necessary shutdown risk function, the impact to OPDRV activities was determined to be of low shutdown risk significance. Details of the condition prohibited by TS 3.8.2 are planned to be reported in a separate LER.
CORRECTIVE ACTIONS
SSES will submit a license amendment following NRC approval of the Technical Specifications Task Force traveler associated with generic resolution of this issue within the time constraints given in EGM 11-003, Revision 1.
No regulatory commitments are associated with this report.
ADDITIONAL INFORMATION
Component Information: None Previous Similar Events: None