ML21098A145

2A - Generic Issue - Overview of GI Process for Aluminum HEAF

ML21098A145
Person / Time
Issue date:	04/06/2021
From:	Js Hyslop NRC/NRR/DRA/APLB
To:
Kenneth Hamburger
Shared Package
ML21098A144	List: ML21098A145 ML21098A146
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Download: ML21098A145 (7)

Text

Overview of GI process for Aluminum HEAF NRR/Division of Risk Assessment RES/Division of Risk Analysis Dr. J.S. Hyslop, NRR/DRA/APLB, presenting

No Immediate Safety Concern

• HEAF already evaluated in plants with a PRA

• A larger ZOI for Al HEAF does not necessarily mean a higher risk

• Plants maintain defense-in-depth to safely shutdown a plant following a fire

• Measures are in place at plants which can prevent a HEAF

• Plants already have contingency plans for loss of large areas from fires and explosions HEAF Pre-Generic Issue Update - April 6th, 2021 2

Met Screening Phase Criteria

• Potentially significant risk increase from Al HEAF (above existing approach for HEAF)

- Test results indicate potential for larger ZOI

- Al HEAF, like fire PRA in general, is highly configuration specific

• Issue applies to two or more plants

• Issue is well defined, discrete, and technical

• Issue is not being addressed using other regulatory programs and processes, existing regulations, policies, or guidance.

HEAF Pre-Generic Issue Update - April 6th, 2021 3

Met Screening Phase Criteria (cont.)

• Issue can be resolved by new or revised regulation, policy, or guidance

• Resolution of the issue may involve review, analysis, or action by the affected licensees

- Can resolve issue by licensees identifying location of Al and performing analysis, and taking appropriate action HEAF Pre-Generic Issue Update - April 6th, 2021 4

Assessment Phase

• Current phase

• Al HEAF is Pre-GI 018 at this phase

• EPRI survey indicates that all plants have Aluminum in some HEAF susceptible equipment

• Evaluate increase in risk due to Al HEAF enhanced model for current configuration of plants with fire PRAs

- Use PRA methodology for Al HEAF under development by NRC/EPRI MOU working group, including new ZOIs

• Evaluate impact on protected train for plants with no fire PRA (i.e. a subset of those plants with a deterministic licensing basis)

HEAF Pre-Generic Issue Update - April 6th, 2021 5

Regulatory Office Implementation(ROI)

Phase

• Should the assessment determine that either a plant with a fire PRA, or a plant with a deterministic licensing basis and no fire PRA, meet the staff criteria for significance, then the issue will transition to the ROI phase.

• Perform a regulatory analysis for plants with a fire PRA

• Courses of action evaluated

• Generic communication as necessary

• Advantages to industry and the NRC for plants to participate in Assessment and ROI phases HEAF Pre-Generic Issue Update - April 6th, 2021 6

GI Process Summary HEAF Pre-Generic Issue Update - April 6th, 2021