|River Bend Station - Unit 1|
|Reporting criterion:||10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications|
|4582017001R00 - NRC Website|
|Person / Time|
|From:||Maguire W F|
Document Control Desk, Office of Nuclear Reactor Regulation
|Download: ML17101A614 (5)|
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 I nfocollects Resource@nrc gov, and to the Desk Officer, Office of Information and Regulatory Affairs, 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- River Bend Station - Unit 1 458
During a refueling outage that commenced on January 28, 2017, there were occasions during which maintenance was performed without taking the required actions to comply with the applicable Technical Specifications. Specifically, , operations with a potential to drain the reactor vessel (OPDRVs) were conducted without establishing primary containment integrity, and the provisions of NRC Enforcement Guidance Memorandum (EGM) 11-003, Rev. 3, were invoked instead.
The first such operation was commenced on January 31, and the final OPDRV was completed on March 4. This condition is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B) as operations prohibited by Technical Specifications.
As explained in the EGM, certain safety systems must be operable during OPDRV activities to mitigate draindown events, and to provide protection against untreated fission product release in the event that the reactor pressure vessel (RPV) water level drops and uncovers irradiated fuel. BWR Technical Specifications do not define the term OPDRV or identify specific plant actions that constitute OPDRV activities. Because a definition is not provided, the NRC staff expects the licensee to use the plain language meaning of OPDRV for determining applicable TS requirements. This means that any activity that could potentially result in draining or siphoning the RPV water level below the top of active fuel (TAF), without taking credit for mitigating measures, would be an OPDRV activity. The EGM contains extensive prerequisites for commencements of OPDRVs.
1. Flushing certain sections of the reactor coolant piping to reduce radiation dose to workers.
2. Replacement of the "A" reactor recirculation system pump and motor.
3. Replacement of the "B" reactor recirculation pump seal.
4. Reactor control rod drive mechanism replacements.
5. Repair to valves in the control rod drive hydraulic system.
OPDRVs were completed on March 4 with no complications regarding pool water level control.
PREVIOUS OCCURRENCE EVALUATION
On April 18, 2013, RBS submitted Licensee Event Report 050-458 / 2013-001-00 to report a similar occurrence. At the time of that event, Revision 1 of the EGM was in effect and formed the basis upon with RBS conducted OPDRVs during a refueling outage.
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(See NUREG-1022, R 3 for instruction and guidance for completing this form http://www nrc gov/reaciing_rm/doc-coliectionsLnureg5/staff/sr1022/r3..() APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (1-5 F53), U S Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NE013-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means 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- River Bend Station - Unit 1 458
CORRECTIVE ACTION TO PREVENT RECURRENCE
On December 20, 2016, NRC approved a generic Technical Specification amendment that can be used by licensees to reconcile this condition. It is required by the EGM that applicable licensees (including River Bend Station) must submit a request for this amendment by December 20, 2017.
During all OPDRVs, the following prerequisites were enforced:
2. The high pressure core spray system was maintained available for inventory makeup 3. The size of the allowable drainage path was minimized to maintain time-to-draindown at greater than24 hours
All activities were completed with no transients in reactor cavity water level having occurred. This event was, thus, of minimal safety significance with regard to the health and safety of the public.