A Collaboration of the Electric Power Research Institute (EPRI) & U.S. NRC Office of Nuclear Regulatory Research (RES)

PSA 2017 Pittsburgh, PA

September 24-28, 2017

Timeline Development for Main Control Abandonment HRA Due to Fire Conditions

Kaydee Gunter, Jeffrey Julius, Erin Collins, Paul Amico JENSEN HUGHES, Rockville, MD, USA Mary Presley, Ashley Lindeman

Electric Power Research Institute, Charlotte, NC, USA Susan E. Cooper, Tammie Rivera

US Nuclear Regulatory Commission, Rockville, MD, USA Stacey Hendrickson

Sandia National Laboratories, Albuquerque, NM, USA John Wreathall

John Wreathall & Co, Inc., Dublin, OH, USA

PSA 2017 - Pittsburgh, PA September 24-28, 2017

Overview • Introduction • Main Control Room Abandonment (MCRA) Timeline Overview • Three Time Phases of MCRA Scenarios • Examples of MCRA timelines

• Individual Actions • Dual Unit Abandonment

• Timeline Conclusions • Future work related to EPRI 3002009215/NUREG-1921, Supplement 1

- EPRI/NRC-RES Fire Human Reliability Analysis Guidelines: Qualitative Analysis for Main Control Room Abandonment Scenarios

2 A Collaboration of the Electric Power Research Institute (EPRI)

& U.S. NRC Office of Nuclear Regulatory Research (RES)

PSA 2017 - Pittsburgh, PA September 24-28, 2017

Introduction • Human Reliability Analysis (HRA) guidance for fire probabilistic risk

assessments (PRAs) is provided in NUREG-1921/EPRI 1023001, EPRI/NRC-RES Fire Human Reliability Analysis Guidelines (July 2012)

• In 2015, EPRI & NRC’s Office of Nuclear Regulatory Research (RES) started a project to develop guidance for HRA in MCRA scenarios, working jointly under a Memorandum of Understanding (MOU) • Both loss of habitability (LOH) & loss of control (LOC) scenarios are addressed • Two stages: Qualitative guidance and Quantitative guidance

• Qualitative guidance is documented as Supplement 1 to NUREG-1921/EPRI 3002009215 • Development of quantitative guidance is currently being developed & will be documented as

a joint EPRI/NRC technical report

• EPRI 3002009215/NUREG-1921, Supplement 1 - EPRI/NRC-RES Fire Human Reliability Analysis Guidelines: Qualitative Analysis for Main Control Room Abandonment Scenarios • Published in August 2017 and available at epri.com • NRC publication in progress

A Collaboration of the Electric Power Research Institute (EPRI)

& U.S. NRC Office of Nuclear Regulatory Research (RES)

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PSA 2017 - Pittsburgh, PA September 24-28, 2017

MCRA Timing and Timelines • NUREG-1921 provided guidance for timelines of individual Human Failure Events

(HFEs), and the guidance in NUREG-1921 can be applied to MCR Abandonment HFEs.

• In addition, MCR Abandonment HRA needs to account for: • Timing aspects related to the decision to abandon • Time associated with fire impacts • Multiple operators in different locations, performing simultaneous actions • Communications among operators stationed at different locations.

• The key to MCRA timing is to integrate the several different timing sources into a single understanding of timing concerns with respect to the same time origin. • Fire protection typically starts their timing validation when the operators leave the MCR • Fire modeling results are documented with respect to the start of the fire • Procedure progression and operator response times are typically documented with respect to

time of reactor trip or the time of the cue.

A Collaboration of the Electric Power Research Institute (EPRI) & U.S. NRC Office of Nuclear Regulatory Research (RES)

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PSA 2017 - Pittsburgh, PA September 24-28, 2017

Three Time Phases of MCRA Scenarios

5 A Collaboration of the Electric Power Research Institute (EPRI)

& U.S. NRC Office of Nuclear Regulatory Research (RES)

Phase I

Phase II

Phase III

PSA 2017 - Pittsburgh, PA September 24-28, 2017

Phase I - Before the Decision to Abandon

• Phase I starts concurrent with the fire starting • Fire PRA/HRA assumes that reactor trip occurs at the same time as

the fire starts • Most MCR Fire PRA scenarios have some time between when the fire

starts and when operator leave the MCR • During Phase I

• Operators remain in the MCR • Enter the EOPs and/or fire procedures to address the reactor trip and fire

conditions, as appropriate. • Command and control remains in the MCR, and the plant procedural usage is

similar in structure to internal events scenarios.

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& U.S. NRC Office of Nuclear Regulatory Research (RES)

PSA 2017 - Pittsburgh, PA September 24-28, 2017

Phase II – Decision to Abandon • Phase II starts once the MCRA criteria are met • Phase II ends when the decision to abandon has been made • Loss of Habitability (LOH) scenarios

• the timing associated with the decision to abandon is very short • the decision should be obvious given the environmental conditions in the MCR

• Loss of Control (LOC) scenarios • the time associated with Phase II will be dependent on procedure, cues, guidance,

training, plant conditions • the HRA analyst will need to define, time available, time required and time

margin, for the decision to abandon; given the time required for Phase III

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& U.S. NRC Office of Nuclear Regulatory Research (RES)

PSA 2017 - Pittsburgh, PA September 24-28, 2017

Phase III – After the Decision to Has Been Made

• Phase III starts once the decision to abandon has been made

• Timeline helps understand the dependencies between operators, including coordination and communication

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& U.S. NRC Office of Nuclear Regulatory Research (RES)

• After leaving the MCR, there is the potential to have multiple operators stationed at different location and performing simultaneous actions

PSA 2017 - Pittsburgh, PA September 24-28, 2017

Example of Individual Timelines For Phase III Actions

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& U.S. NRC Office of Nuclear Regulatory Research (RES)

PSA 2017 - Pittsburgh, PA September 24-28, 2017

A Collaboration of the Electric Power Research Institute (EPRI) & U.S. NRC Office of Nuclear Regulatory Research (RES)

Example of Dual Unit Timeline

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PSA 2017 - Pittsburgh, PA September 24-28, 2017

Conclusions • Timelines assist the analyst to understand the complex response following

fire ignition and fire growth, thermal-hydraulic response, and operator progression through procedures

• An integrated timeline helps with the qualitative analysis by providing a means to check feasibility and providing insights on performance shaping factors

• Dividing the timeline into time phases is a modeling tool to decompose the timeline into time periods governed by different cognitive aids such as procedures, plant information available and availability of additional, supporting staff

• Developing an integrated timeline helps understand the dependencies between the collective set of operators, including coordination and communication associated with command and control

11 A Collaboration of the Electric Power Research Institute (EPRI)

& U.S. NRC Office of Nuclear Regulatory Research (RES)

PSA 2017 - Pittsburgh, PA September 24-28, 2017

EPRI 3002009215/NUREG-1921, Supplement 1 Project status & future work • Supplement 2 – Quantification Guidance

• In progress • Planning 1st draft by Fall/Winter 2017 • Planning peer review, testing, etc. for 2018 • Final report 2018

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& U.S. NRC Office of Nuclear Regulatory Research (RES)

A Collaboration of the Electric Power Research Institute (EPRI) & U.S. NRC Office of Nuclear Regulatory Research (RES)

John Wreathall & Co., Inc.

PSA 2017 - Pittsburgh, PA September 24-28, 2017 13