ML20289A658

Enclosure 3 - NRC Presentation on Nrc'S Crediting FLEX Effort

ML20289A658
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Issue date:	10/08/2020
From:	Matthew Humberstone Office of Nuclear Regulatory Research
To:
Kichline M
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Download: ML20289A658 (10)

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NRCs Crediting FLEX effort Matthew Humberstone, PhD Division of Risk Analysis, Office of Nuclear Regulatory Research 1

Objective

• Brief History

• Challenges

• Completed Tasks

• Example Areas

• Questions 2

Project History

• Fukushima Daiichi Accident (March 2011)

• NRC Mitigating Strategies (MS) Order (2012)

• 10 CFR 50.155, Mitigation of beyond-design-basis events (2019)

• NRCs Risk-Informed Steering Committee (RISC)

• Directed effort to evaluate and provide appropriate credit

• FLEX can be utilized beyond the orders to enhance safety

• The NRC wants to encourage safety enhancements

• Need to provide proper regulatory footprint

• (outages, defense-in-depth, LARs)

• 2 Approaches taken

• Industry developed NEI 16-06

• NRC evaluated areas of applications 3

FLEX OpE Data

• FLEX data needed to develop equipment failure probabilities

• Risk assessments that credit FLEX

• PWROG has taken the lead

• Collecting data from the industry and developing a report

• Report to the NRC in Feb 2020

• NRC audit

• March 24th - May 4th

• Audit team (NRR, RES, RI, INL)

• Audit Summary (ML20155K827)

• Commissions PRA policy statement:

PRA evaluations in support of regulatory decisions should be as realistic as practicable and appropriate supporting data should be publicly available for review.

4

HRA challenge for FLEX

• Current HRA methods not adequate

• Complex FLEX actions

• NRCs ongoing effort

• Finalize IDHEAS - General Methodology

• Audit Industry FLEX Data

• Leveraging the IDHEAS HRA methodology Task 1

• Prioritized Industry Support

• IDHEAS-ECA tool developed

• Assess range of FLEX cases

• Incorporated Data into SPAR Models

• FLEX Scenarios developed (Fall 2019) Task 2

• Workshop (Dec 2019)

• 6 HRA experts (3 NRC, 3 Industry)

• Issue tool and guidance RIL 2020-02

• FLEX expert support (2 site visits) Task 3

• Future Tasks

• Document Workshop results

• Release draft data report 5

Completed Tasks Review NEI 16-06 (Tier 1, Tier 2, and Tier 3)

• NRR Office Director memo to NEI (ML16167A034) (August, 2016)

• Internal memo to NRR/DRA Office Director (ML17031A269) (June 2017)

NUMARC 93-01 Revision (Maintenance Rule Scoping criteria)

• Endorsement in RG 1.160 Update to the RASP Handbook

• Guidance on modeling FLEX in recovery events IMC-0609 App O - Moved to App A

• SDP for FLEX findings Rules of Engagement Guidance

• Tiered Approach to crediting FLEX in risk assessments 6

Completed Tasks Continued SPAR model updates

• All SPAR models have FLEX capability Working Groups

• Crediting FLEX in Deterministic reviews (NRR, NRO, NSIR)

• Updating the ROP for FLEX (DRO led)

Communications (Internal and External)

• Several RISC Meeting Briefings

• OEDO and RA Briefing

• Multiple public meetings

• Several RIC Sessions

• NEI Risk Forums

• Conferences

• MIT Executive Course on risk management Monitoring and Engaging crediting FLEX activities 7

Crediting FLEX examples

• License Amendment Requests (LARs)

• Deterministic Applications

• Risk-Informed Applications

• AOT extensions

• EDGs

• Pumps

• NFPA 805

• Significance Determination Process (SDP)

• Crediting FLEX is common

• FLEX has had impacts in some SDPs

• Notice of Enforcement Discretion (NOED) 8

Conclusions

• The NRC is providing credit for FLEX

• Lots of work has been accomplished

• NEI 16-06, NUMARC 93-01, IMC-0609 App O, SDPs, NOEDs, LARs, ROP updates, etc.

• Resolving Remaining Challenges

• FLEX OpE data

• HRA for FLEX

• Developing a more predictable and consistent approach to crediting FLEX 9

Questions???

1 10 0