05000354/LER-2013-006
| Hope Creek Generating Station | |
| Event date: | 10-31-2013 |
|---|---|
| Report date: | 12-24-2013 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3542013006R00 - NRC Website | |
PLANT AND SYSTEM IDENTIFICATION
General Electric — Boiling Water Reactor (BWR/4)* Reactor Pressure Vessel (AC) — EIIS Identifier {AC/RPV} Secondary Containment (NG) — EIIS Identifier {NG} *Energy Industry Identification System {EIIS} codes and component function identifier codes appear as {SS/CCC}
IDENTIFICATION OF EVENT
Event Dates: October 31, 2013 Discovery Date: October 31, 2013
CONDITIONS PRIOR TO EVENT
Hope Creek was shutdown for Refueling Outage H1R18 in Operational Condition (OPCON) 5- Refueling Operations. The reactor pressure vessel level was at the flange. The reactor cavity draining had been completed and the fuel pool gates were in place.
DESCRIPTION OF EVENT
On October 31, 2013, at approximately 09:30, Hope Creek Generating Station (HCGS) performed an operation with a potential to drain the reactor vessel (OPDRV) without having an operable secondary containment. During the refueling outage, the Reactor Water Cleanup (RWCU){CE} system was placed in letdown to radwaste to control reactor pressure vessel (RPV) inventory. Because the automatic isolation function was not available for either valve in the drain-down path, the guidance in Enforcement Guidance Memorandum (EGM) 11-003, Revision 1 could not be utilized. EGM 11-003, Revision 1 states: "The addition and removal of small volumes of water inventory from the RPV, for example control rod drive cooling water, is considered steady-state water level control and not an OPDRV provided the instrumentation and valves for automatic isolation of the drain-down path remain available." This placed the plant in an OPDRV. Technical Specification (TS) 3.6.5.1 requires secondary containment to be set if the plant is in an OPDRV. Secondary containment was not set; therefore, the plant was in a condition prohibited by Technical Specifications. In this condition, Hope Creek transitioned to OPCON*.
OPCON * is described in TS 3.6.5.1 as: "When recently irradiated fuel is being handled in the secondary containment and during operations with a potential for draining the reactor vessel." RPV level was being maintained at the flange by balancing input from the control rod drive system by using reactor water cleanup (RWCU) letdown to radwaste.
The Shift Manager (SM) identified the condition at 16:31, 6.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after placing RWCU in letdown to radwaste.
Once recognized, the functionality of the instrumentation and valve for automatic isolation of the drain-down path was restored at 17:21.
TS 3.6.5.1 requires secondary containment to be operable during OPDRV activities in OPCON *. The Action Statement with Secondary Containment inoperable in OPCON * is to suspend operations with a potential to drain the reactor vessel. The operators did not comply with this action. During this evolution the EGM guidance was not met and secondary containment should have been set.
This event is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as an operation or condition which was prohibited by the plant's Technical Specifications.
CAUSE OF EVENT
The cause of the event was the failure of the operating crew to recognize that the Level 2 isolation instrumentation to support the automatic isolation of the drain path was removed from service for refueling outage maintenance. Once the OPDRV was recognized, automatic isolation capability of one of the valves in the drain path was restored.
SAFETY CONSEQUENCES AND IMPLICATIONS
The safety consequences of this occurrence are minimal. The condition existed for only a short period of time (approximately 7.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />). Reactor inventory was maintained at a safe level, stable at the RPV flange, throughout the time that a RWCU valve would not have isolated automatically. Level indication and alarm functions remained available and the evolution was being constantly monitored. Additionally, an isolation valve was capable of being manually closed from the control room if required.
This event was determined not to be a Safety System Functional Failure (SSFF) as defined in NEI 99-02.
PREVIOUS EVENTS
A review of events at Hope Creek for the past three years was performed to determine if a similar event had occurred. No events involving unplanned OPDRVs were identified.
CORRECTIVE ACTIONS
The condition was corrected at 17:21 by restoring the automatic isolation capability of one of the valves in the drain path.
COMMITMENTS
This LER contains no regulatory commitments.