ML21217A262

13 - NRC - Materials Exchange Public Meeting - HELB

ML21217A262
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Issue date:	08/11/2021
From:	NRC/NRR/DNRL
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Materials Programs Technical Information Exchange Public Meeting Update on High-Energy Line Break Activities Nuclear Regulatory Commission August 11, 2021 Virtual Meeting

Overview and Timeline June 2019: January 2021:

2015: Public Meeting New UNR that focuses User Need Request ML19214A095 on recommended option May 2019: Fall 2019 - Winter 2020: March 2021:

TLR - BTP 3-4 NRC staff developed Public Meeting Background and recommended option for ML21089A005 History alternative criteria ML19144A089

Revising BTP 3-4: Underlying Philosophy

• Significantly revamp existing BTP o Eliminate stress reduction criteria, relax CUF criterion o Consider other degradation mechanisms o Tailor fatigue evaluations, as needed, to applicable systems/components

• Support operating reactor, new reactor, and advanced reactor applications o Provide identical framework and approach o Require unique evaluations or analysis depending on reactor type

• Approach should be risk-informed o Consider both susceptibility to degradation and failure consequences o Utilize a graded approach consistent with the risk

• Broaden scope beyond classical, LWR welded-piping systems o Include other types of connections (e.g., bolted) o Include other appropriate passive components/systems

• The approach will be similarly applicable for high and moderate-energy level breaks

Guidance Approach: Similar Philosophy to SRP 3.6.3 - Leak-Before-Break (LBB)

Screening Analyses SRP 3.6.3 - LBB Determination Address consequences of Increasing Risk failure and susceptibility to Screening applicable degradation mechanisms Break Preclusion Demonstration Perform analyses to demonstrate that the Analyses probability of piping failure is extremely low Increasing Rigor

Current Status and Path Forward

• NRC staff is developing the framework and associated technical basis

• Future deliverables:

o TLR on the technical basis for the alternative framework (mid 2022) o TLR that documents the alternative framework and associated technical basis (late 2022) o NUREG documenting the technical basis for the alternative framework (2023)