ML15324A086

Summary of Conference Call Confirming Staff Understanding of Basis for Closing Open Item in Grand Gulf Reevaluated Flood Hazard Staff Assessment of Response to 10 CFR 50.54(f) Information Request- Flood Causing Mechanism Reevaluation

ML15324A086
Person / Time
Site:	Grand Gulf
Issue date:	11/24/2015
From:	Marshall M Japan Lessons-Learned Division
To:	Mohamed Shams Japan Lessons-Learned Division
Marshall, Michael, NRR/JLD 415-2871
References
CAC MF1102
Download: ML15324A086 (6)

Text

November 24, 2015 MEMORANDUM TO: Mohamed K. Shams, Chief Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation FROM: Michael L. Marshall, Jr., Senior Project Manager /RA/

Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation

SUMMARY

OF CONFERENCE CALL CONFIRMING STAFF UNDERSTANDING OF BASIS FOR CLOSING OPEN ITEM IN THE GRAND GULF NUCLEAR STATION, UNIT 1 REEVALUATED FLOOD HAZARD STAFF ASSESSMENT OF RESPONSE TO 10 CFR 50.54(f) INFORMATION REQUEST -

FLOOD-CAUSING MECHANISM REEVALUATION (CAC NO.

MF1102)

On November 18, 2015, U.S. Nuclear Regulatory Commission (NRC) staff from the Japan Lessons-Learned Division in the Office of Nuclear Reactor Regulation and from the Division of Site Safety and Environmental Analysis in the Office of New Reactors spoke with representatives from Entergy Operations, Inc. (the licensee) to confirm the staffs understanding of activities by the licensee that would resolve an open item in staff assessment of the licensees reevaluation of the flooding hazard at Grand Gulf Nuclear Station, Unit 1 (Grand Gulf). Specifically, the open item concerned proposed blockage assumptions concerning 4-foot culverts and vehicle barrier openings. The participants in the conference call are listed in to this memorandum.

BACKGROUND By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340), the NRC issued a request for information pursuant to Title 10 of the Code of Federal Regulations, Section 50.54(f) (hereafter referred to as the 50.54(f) letter). The request was issued as part of implementing lessons learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 2 to the 50.54(f) letter requested licensees to reevaluate flood-causing mechanisms using present-day methodologies and guidance. By letter dated March 11, 2013 (ADAMS Accession No. ML13071A457), the licensee responded to this request for Grand Gulf Nuclear Station, Unit 1. In response to NRC staff questions, this response was supplemented by letter dated January 9, 2014 (ADAMS Accession No. ML14014A277). By letter dated November 25, 2014, the NRC staff sent the licensee a staff assessment of the information provided. However the staff assessment included three open items, including the following open item:

Justify the proposed blocking assumptions on the onsite drainage system (e.g.,

supported by proposed maintenance and flood protection measures implemented

M. Shams through emergency procedures or administrative controls) consistent with the Integrated Assessment interim staff guidance (NRC, 2012c). In particular, the licensee is requested to justify the assumed 50 percent blockage of the 4-foot culverts and 30 percent blockage for vehicle barrier openings.

Subsequent to issuance of the staff assessment, the NRC staff realized that the licensee likely had in place practices, which would be documented in procedures that would support the licensees blockage assumption. In order to confirm the basis for closing the open item, the NRC staff requested a telephone conference with the licensee to verify the staffs understanding of the practices in place that would support the licensees blocking assumptions.

DISCUSSION During the conference call the licensee confirmed the staffs understanding that inspections are included in procedures for verifying that culvert and vehicle barrier openings are clear of debris.

The visual inspections of the culverts are described in the licensees surveillance procedure 06-TE-1000-V-0001, Revision 101, CURVERT NO. 1 EMBANKMENT STABILITY/SURVEY (see ). The visual inspections of the vehicle barrier openings are described in the licensees off-normal event procedure 05-1-02-VI-2, Revision 128, HURRICANES, TORNADOES, AND SEVERE WEATHER (see Enclosure 2). Both of these procedures describe how the licensee will implement periodic surveillances, as well as surveillances before and after intense precipitation events.

In addition to confirming the NRC staffs prior understanding, the licensee described the immediate area around the culverts and vehicle barrier openings. In particular, the licensee clarified that security screens discussed in staffs issued staff assessment only pertain to the 15-ft diameter culverts, not the 4-ft diameter culverts. The licensee discussed how there is no historical evidence of blockage during past intense weather events, and that trees around several of the drainage canals had been cut-down and removed to further lessen the chance for leaf debris or fallen trees to block or clog the canals. The licensee, also, discussed how weather forecasts and alerts are transmitted to operators at the site. In addition to privately-operated weather services, the licensee discussed how they receive and monitor weather alerts issued by National Oceanic and Atmospheric Administrations National Weather Service.

M. Shams Based on the confirmation of the NRC staffs prior understanding, the NRC staff informed the licensee that it had sufficient information to now close the open item. The NRC staff informed the licensee that the NRC staff would document the closure of the open item in a supplement to the staff assessment.

Docket No. 50-416

Enclosures:

1. List of Conference Call Participants

2. Bentley, Donald E., Entergy Operations, Inc.,

email to Hall, Victor, U.S. Nuclear Regulatory Commission, November 18, 2015.

CONFERENCE CALL PARTICIPANTS November 18, 2015 Name Organization Hosung Ahn U. S Nuclear Regulatory Commission (NRC)

Don Bentley Entergy Operations, Inc. (Entergy)

Dan Brown Areva Andy Campbell NRC Chris Cook NRC Victor Hall NRC Fred Hopkins Entergy Tori Liggans-Robinson Entergy Michael Marshall NRC Aida Rivera-Varona NRC Enclosure 1

ML15324A086 *via email OFFICE NRR/JLD/JHMB/PM NRR/JLD/JHMB/PM NRR/JLD/LA NAME MMarshall VHall SLent DATE 11/23/2015 11/23/2015 11/23/2015 OFFICE NRO/DSEA/RHM/BC NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM NAME CCook* MShams MMarshall DATE 11/23/2015 11/24/2015 11/24/2015