ML20266G441

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Insights Obtained from Review of Robinson Seismic Probabilistic Risk Assessment
ML20266G441
Person / Time
Site: Robinson Duke Energy icon.png
Issue date: 09/24/2020
From: Valentin M
NRC/NRR/DRA/APLC
To: Randy Musser
NRC/RGN-II/DRP/RPB3
Valentin, M.
References
Download: ML20266G441 (3)


Text

September 24, 2020 MEMORANDUM TO: Randy Musser, Chief Reactor Projects Branch 3 Division of Reactor Projects Region II FROM: Milton Valentin, Project Manager /RA/

PRA Licensing Branch C Division of Risk Assessment Office of Nuclear Reactor Regulation

SUBJECT:

INSIGHTS OBTAINED FROM REVIEW OF THE H.B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 SEISMIC PROBABILISTIC RISK ASSESSMENT By letter dated September 22, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20156A093), the U.S. Nuclear Regulatory Commission (NRC) staff documented its conclusions regarding the review of the H.B. Robinson Steam Electric Plant, Unit No. 2 (Robinson) seismic probabilistic risk assessment (SPRA). The Robinson SPRA was submitted in response to the NRCs request for information dated March 12, 2012 (ADAMS Accession No. ML12053A340), issued under Title 10 of the Code of Federal Regulations Section 50.54(f) (hereafter referred to as the 50.54(f) letter), as part of the agencys response to the events at Fukushima Dai-ichi. As part of the SPRA submittal, by letter dated June 19, 2020 (ADAMS Accession No. ML20171A761), Duke Energy Progress, LLC (Duke, the licensee) provided regulatory commitments to perform certain plant modifications at Robinson. These commitments were an important consideration in the staffs conclusions that no further actions regarding Recommendation 2.1, Seismic, of the 50.54(f) letter were required.

Specifically, the licensees commitments relate to the following plant modifications:

Reconfiguration of the existing pre-staged discharge hose from the Diverse and Flexible Coping Strategies (FLEX) auxiliary feedwater (AFW) pumps to include a branch which routes to the existing FLEX AFW connection (AFW-165) located inside the Motor-Driven AFW Pump Room. The completion time for this modification is July 30, 2021.

Installation of isolation valves, hose connections and pipe for the existing deepwell pumps A, B and C, to protect the above ground portion of the piping from the seismic event. The completion time for this modification is May 29, 2021.

CONTACT: Milton Valentin, NRR (301) 415-2864

R. Musser Routing of hose and/or pipe from each of the existing deepwell pumps A, B and C, to the suction header for the existing FLEX AFW pumps. This modification supplements proposed permanent modification discussed in the second item above. The completion time for this modification is June 30, 2021.

Install a new deepwell pump E to provide suction directly to the existing FLEX AFW pumps. The completion time for this modification is December 31, 2021.

Based on the importance of the planned modifications to the staffs conclusions regarding the Robinson 50.54(f) submittal, as well as the risk insights the SPRA provided, the senior management review panel (SMRP),1 convened to reach a screening decision for the Robinson SPRA, and determined that further regulatory action associated with NTTF Recommendation 2.1 Seismic is not warranted for Robinson. As part of its decisionmaking, the SMRP noted that the Robinson resident inspectors could consider inspecting these modifications as part of routine baseline inspection activities within the reactor oversight process (e.g., equipment alignment and plant modification samples).

Should you have any questions in this matter please do not hesitate to call me.

Docket No.: 50-261

1. The SMRP is comprised of division management from the Divisions of Operating Reactor Licensing (DORL),

Engineering and Exhernal Hazards (DEX) and Risk Assessment (DRA) in the Office of Nuclear Reactor Regulation (NRR). Its function regarding SPRA submittals is described in the regulatory decisionmaking process for evaluating the 50.54(f) letter responses outlined by memo dated March 2, 2020 (ADAMS Accession No. ML20043D958).

ML20266G441 *via e-mail OFFICE NRR/DRA/APLC/PM* NRR/DANUL/UARL/LA* NRR/DORL/LPMB/BC(A)* NRR/DRA/APLC/PM*

NAME MValentin SLent KMorgan-Butler MValentin DATE 09/22/2020 09/22/2020 09/23/2020 09/24/2020