|Columbia Generating Station|
|Reporting criterion:||10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications|
|LER closed by|
|IR 05000397/2017004 (5 February 2018)|
|3972017002R00 - NRC Website|
|Person / Time|
|From:||Hettel W G|
Document Control Desk, Office of Nuclear Reactor Regulation
|Download: ML17191B138 (4)|
comments regarding burden estimate to the FOiA, Privacy and information Collections Branch cr-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose an information collection 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.
05000- Columbia Generating Station 397
At the time of the event, the plant was in a scheduled refueling outage in Mode 5 with the reactor head de-tensioned.
From May 16, 2017 to June 15, 2017, during a scheduled refueling outage, planned operations with the potential to drain the reactor vessel (OPDRV) activities were performed without secondary containment operable while the plant was operating in Mode 5, contrary to the requirements of Technical Specification (TS) 184.108.40.206. Energy Northwest met the provisions of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3, to perform these activities. The event timeline for the planned activities is as follows:
5/17/17 0325 PDT — Exited OPDRV window.
5/20/17 0402 PDT — Commenced OPDRV window to support Control Rod Drive replacement.
5/21/17 0924 PDT — Exited OPDRV window.
5/29/17 0244 PDT — Commenced OPDRV window to support Reactor Recirculation System seal replacement.
5/31/17 1106 PDT — Exited OPDRV window.
6/1/17 0354 PDT — Exited OPDRV window.
6/8/17 1515 PDT — Commenced OPDRV window to perform the functional verification of Scram Discharge Volume instrumentation.
6/10/17 1430 PDT — Commenced OPDRV window in support of the Reactor Water Clean-Up system fill.
6/11/17 0103 PDT — Suspended OPDRV window to support the function test of the Balance of Plant Isolation Logic.
6/11/17 0227 PDT — Commenced OPDRV window in support of draining the reactor cavity.
6/11/17 0428 PDT — Exited OPDRV window.
comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose an information collection 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.
05000- NUMBER NO.
6/15/17 1017 PDT — Exited OPDRV window.
REPORTABILITY AND SAFETY ASSESSMENT
This event is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as an operation or condition prohibited by TS 220.127.116.11, which prohibits performing 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 EGM 11-003, Revision 3. In accordance with station procedures, Energy Northwest adhered to the Nuclear Regulatory Commission plain language definition of OPDRV activities that could potentially result in draining or siphoning the reactor pressure vessel water below the top of the fuel. During all OPDRV activities, the following prerequisites were met:
2. Two independent means of monitoring RPV water level were available.
3. At least one Emergency Core Cooling System pump was available and capable of injecting water equal to or greater than the maximum potential leakage rate from the RPV for a minimum of four hours.
4. The size of the allowable draining path was minimized to maintain drain down time to greater than24 hours
5. Movement of recently irradiated fuel was prohibited.
The required compensatory measures were properly implemented and adequate levels of safety were provided during the performance of the OPDRV activities described in this report. Based on this information, the performance of these OPDRV activities was determined to have very low safety significance.
CAUSE OF EVENT
Implementation of EGM 11-003, Revision 3, interim actions during Columbia's Refueling Outage R23 was a planned activity. As such, no cause determination was performed on this condition.
On July 7, 2015, Energy Northwest submitted LER 2015-003-00 to report a similar occurrence. During Columbia's Refueling Outage R22, EGM 11-003, Revision 2, was utilized for OPDRV activities while secondary containment was inoperable.
FURTHER CORRECTIVE ACTIONS
Consistent with the guidance provided in EGM 11-003, Revision 3, Energy Northwest will submit a license amendment request to adopt Technical Specification Task Force Traveler 542, Reactor Pressure Vessel Water Inventory Control, associated with generic resolution of this issue.