ML20080M159

PFHA-2020-3C-1-Kanney-NRC-LIP_Flooding_PFHA_Pilot-Rev

ML20080M159
Person / Time
Issue date:	02/19/2020
From:	M'Lita Carr, Joseph Kanney, Prasad R, Yuan Y Office of Nuclear Regulatory Research, Pacific Northwest National Laboratory
To:	Office of Nuclear Regulatory Research
T. Aird
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Download: ML20080M159 (7)

Text

1 Local Intense Precipitation (LIP)

PFHA Pilot Study Joseph Kanney*1, Meredith Carr1, Rajiv Prasad2,Yong Yuan2 1U.S. Nuclear Regulatory Commission 2Pacific Northwest National Laboratory 5th Annual PFHA Research Workshop NRC HQ, Rockville, MD February 19 - 21, 2020

Outline

• Motivation

• Objectives

• Tasks

• Status 2

Motivation

• Local Intense Precipitation (LIP) flooding scenario must be analyzed for every NPP regardless of setting

• LIP flooding comprises unique aspects compared to other scenarios

- Possibly very short warning time

• Forecasting limitations

• Short time to peak flow

- High percentage of impervious surfaces

- Complex flows

• Sheet flow

• Flow around and between buildings

• Other structures (e.g., vehicle barrier systems)

• Drainage from roofs

• Subsurface drainage systems 3

Pilot Study Objectives

• Include key mechanisms and features that make LIP flooding unique and challenging

• Quantify aleatory variability and epistemic uncertainties and examine sensitivities

- Structured analysis favoring realism over stylized conservatism

• Assess strength and weaknesses of available modeling tools

• Provide practical input for risk-informed decision-making (e.g. water levels, timing)

• Inform development of PFHA guidance for LIP scenario 4

Tasks

• Task 1 - Review characteristics of LIP flooding on industrial sites and available software to support LIP flood modeling

- General purpose hydrologic and hydraulic models

- Specialized stormwater models

- Eulerian and Lagrangian (particle tracking) models

• Task 2 - Analyze LIP flooding aleatory variability and epistemic uncertainties

- e.g., rainfall amount, temporal distribution

- e.g., model structure, parameters, resolution

• Task 3 - Perform LIP PFHA for (hypothetical) NPP site

- Synthetic site with features found to be significant in previous studies

• Task 4 - Knowledge Transfer

- Presentations and seminars

- Technical letter reports, final technical report 5

Status

• Task 1 in progress

- Technical Letter Report submitted

• Under review by NRC staff

- Expected completion 04/2020

• Task 2 in progress

- Expected completion 07/2020

• Task 3 - expected completion 01/2021

• Task 4 - expected completion 03/2021 6

7 Contact Information NRC PM: Joseph Kanney Email: joseph.kanney@nrc.gov Phone: +1 301-415-1920 PNNL PI: Rajiv Prasad Email: Rajiv.Prasad@pnnl.gov Phone: +1 509-375-2096