ML20289A658

Enclosure 3 - NRC Presentation on NRCs Crediting FLEX Effort

ML20289A658
Person / Time
Issue date:	10/08/2020
From:	Matthew Humberstone Office of Nuclear Regulatory Research
To:
Kichline M
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ML20289A715	List: ML20289A570 ML20289A645 ML20289A650 ML20289A658 ML20289A671 ML20289A678 ML20289A694 ML20289A710
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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

• Leveraging the IDHEAS HRA methodology

• Prioritized Industry Support

• IDHEAS-ECA tool developed

• FLEX Scenarios developed (Fall 2019)

• Workshop (Dec 2019)

• 6 HRA experts (3 NRC, 3 Industry)

• FLEX expert support (2 site visits)

• Future Tasks

• Document Workshop results

• Release draft data report 5

Task 1

• Finalize IDHEAS - General Methodology

• Audit Industry FLEX Data Task 2

• Assess range of FLEX cases

• Incorporated Data into SPAR Models Task 3

• Issue tool and guidance RIL 2020-02

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 0

10