ML101890803

Summary of Closed Meeting with Duke Energy Carolinas, LLC, to Discuss External Flooding at Oconee

ML101890803
Person / Time
Site:	Oconee
Issue date:	07/26/2010
From:	Jacqueline Thompson Plant Licensing Branch II
To:
Thompson Jon, NRR/DORL/LPL 2-1, 415-1119
Shared Package
ML14055A421	List: ML090570117 ML090680737 ML091620669 ML092020480 ML092940769 ML100280954 ML101750619 ML101890803 ML102990064 ML103410042 ML12268A404 ML14055A410 ML14055A411 ML14055A474 ML14058A015 ML14058A016 ML14058A017 ML14058A018 ML14058A019 ML14058A020 ML14058A021 ML14058A022 ML14058A023 ML14058A024 ML14058A025 ML14058A026 ML14058A027 ML14058A028 ML14058A029 ML14058A030 ML14058A031 ML14058A032 ML14058A033 ML14058A034 ML14058A035 ML14058A036 ML14058A037 ML14058A038 ML14058A039 ML14058A040 ML14058A042 ML14058A043 ML14058A044 ML14058A045 ML14058A046 ML14058A047 ML14058A048 ML14058A049 ML14058A050 ML14058A051 ... further results
References
TAC ME3065, TAC ME3066, TAC ME3067, FOIA/PA-2012-0325, FOIA/PA-2013-0213
Download: ML101890803 (5)

Text

OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 26, 2010 LICENSEE: DUKE ENERGY CAROLINAS, LLC FACILITY: OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 (OCONEE)

SUMMARY

OF CLOSED JUNE 29, 2010, MEETING TO DISCUSS EXTERNAL FLOODING AT OCONEE (TAC NOS. ME3065, ME3066, AND ME3067)

On June 29, 2010, a closed technical meeting was held between the U.S. Nuclear Regulatory Commission (NRC) staff and representatives of Duke Energy Carolinas, LLC (Duke, the licensee), at NRC Headquarters. The purpose of the meeting was to continue a dialogue with the licensee on the resolution of external flooding issues, including a flood caused by the potential failure of the Jocassee Dam, at Oconee. The meeting was closed to the public because the topic of discussion was security-related information.

The licensee presented information related to the licensee's activities since March 5, 2010: the response to the Request for Information (RAI) sent by the NRC staff on January 29, 2010 (Agencywide Documents Access and Management System (ADAMS), Accession No. ML100271591). intake and swale wall installations, and independent review of models. A copy of the licensee's slides is available at ADAMS Accession No. ML101890726. Enclosed is a list of meeting attendees.

Licensee's Activities Since March 5, 2010 After introductions, the meeting began with a discussion of recent licensee activities. This included a discussion of additional HEC-RAS and 2-D model runs, interim action review and update, self-assessment of interim actions, interim action improvements, and the diversion wall and related assessments.

Response to RAis This discussion came next and occupied most of the meeting time. The licensee provided status and a discussion of preliminary results for RAI questions one, four, and seven from the NRC staff's letter of January 29, 2010:

RAI Question 1: Responses to RAI Question 1 were described as interim in that they were dependent on final results in response to Question 4. The Keowee embankment has been further analyzed by adding 6 HEC-RAS runs that vary the failure time. The same methodology was used for Jocasee and Keowee and results were conservative in that faster breaches result in lower water levels. Literature research did not yield clear and concise information related to cascading failures.

OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION

OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION

-2

• RAI Question 4: The licensee was examining the sensitivity of the projected Oconee yard water heights due to potential faster failures of the Keowee. It also examined the potential impacts of faster failures at the Oconee intake canal and the Little River Dam.

• A table with model run #1 DO, Case 2, describing breach parameters and associated results was presented. For the most recent runs, the extended boundaries have been added in the geography in order to increase accuracy.

Some additional storage areas were not modeled into the boundaries due to the negligible difference they have on results.

• Six additional HEC-RAS runs for Case 2 (model run # 100) were performed.

Runs 100b and 1DOc produced a significant discharge and the lowest failure time and the licensee focused their attention on them. 2D models were used in order to assess sensitivity.

• The preliminary run results support the statement that faster failure times reduce the second peak at the tailwater. The licensee states that faster breach times for the Keowee main Dam do not produce higher water levels for the Oconee site for both the "first peak" and the "second peak."

• RAI Question 7: The licensee would like additional detail on what information should be submitted to address this question.

Intake and Swale Walls

• These walls serve to reduce peak water heights, divert water from entering the Oconee site and to assure the integrity of a secured water source. These walls divert water that may enter the site from going towards certain areas. Walls are made of post-rolled galvanized steel and filled with sand.

• With the addition of the walls, model runs were presented that differentiated the levels of water at the site based on the modifications. The licensee expressed that with new modifications, the sustained flood levels would be lower.

Independent Review of the Models

• The licensee expressed that an independent review of the models, specifically focusing on a set of parameters, was performed by Dr. Chris Wilson and that his recommendations were to be included in the final results package to complement the Oconee efforts.

Closing In closing, the licensee summarized the interim actions that have been put in place, the progress made in addressing RAI questions, and their study of long-term solutions. The licensee expressed that they were putting considerable work into addressing these issues. The HEC-RAS model typically takes approximately 7 days, with frequent user inputs, to finish a run.

The licensee clarified that a discussion of the intake and swale walls would not be in the RAI response. The response would address the RAI questions as they were stated in the NRC staff's letter of January 29,2010.

OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION

OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION

-3 Please direct any inquiries to John Stang at 301-415-1345, or John.Stang@nrc.gov.

Sincerely, Jon Thompson, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287

Enclosure:

List of Attendees OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION

OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION ATTENDEES AT THE CLOSED JUNE 29, 2010, MEETING WITH DUKE ENERGY CAROLINAS, LLC (DUKE), TO DISCUSS EXTERNAL FLOODING ISSUES AT OCONEE NUCLEAR STATION, UNITS 1,2, AND 3 NRC DUKE HDR G. Wilson R. Freudenberger C.Ey J. Thompson J. Thomas A. McCoy R. Wescott R. McCoy N. Coleman J. Uribe F. Ferrante J. Mittman C. Rapp*

A. Sabisch*

J. Bartley*

• Participated by phone Enclosure OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION

PKG ML101890811 Meeting Summary ML101890803 Handouts ML101890726 NRR-106 OFFICE DORULPL2-1/PM DORULPL2-1/LA DORULPL2-1/BC DORULPL2-1/PM NAME JThompson MO'Brien GKulesa (RMartin for) JThompson DATE 07/12/10 07/12/10 07/26/10 07/26/10