05000458/LER-2017-001

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LER-2017-001, Operations Prohibited by Technical Specifications (Conduct of Operations With a Potential to Drain the Reactor Vessel With Primary Containment Open)
River Bend Station - Unit 1
Event date: 01-31-2017
Report date: 04-03-2017
Reporting criterion: 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
4582017001R00 - NRC Website
LER 17-001-00 for River Bend Station, Unit 1, Regarding Operations Prohibited by Technical Specifications (Conduct of Operations With a Potential to Drain the Reactor Vessel With Primary Containment Open)
ML17101A614
Person / Time
Site: River Bend Entergy icon.png
Issue date: 04/03/2017
From: Maguire W F
Entergy Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
RBF1-17-0036, RBG-47745
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

REPORTED CONDITION

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.

BACKGROUND

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.

EVENT DESCRIPTION

The OPDRVs conducted in RBS' recent refueling outage included:

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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CONTINUATION SHEET

(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.

SAFETY SIGNIFICANCE

During all OPDRVs, the following prerequisites were enforced:

1. Refueling cavity water level was maintained greater than 23 feet above the reactor pressure vessel flange.

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 than

24 hours
2.777778e-4 days
0.00667 hours
3.968254e-5 weeks
9.132e-6 months

(to the RPV flange) 4. Two independent means of monitoring reactor cavity water level were maintained.

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.