ML18213A391

Public Meeting

ML18213A391
Person / Time
Site:	Point Beach
Issue date:	07/12/2018
From:	Point Beach
To:	Division of Operating Reactor Licensing
Chawla M, 415-8371
References
Download: ML18213A391 (10)

Text

CONSTRUCTION TRUSS License Amendment Request Point Beach Nuclear Plant Units 1 & 2 Public Meeting July 12th 2018

1 AGENDA

• Introductions

• Purpose

• Changes made since Nov 2017 audit

• Reviews performed

• Summary

• Questions

NextEra Personnel

• Steve Catron Corporate Licensing

• Eric Schulz Point Beach Licensing

• Rich LaPlante Point Beach Engineering

• Ted Kulczycky Corporate PRA

• Anil Julka Corporate PRA

PURPOSE

• Provide overview of changes made to seismic and thermal hazard analysis.

• Summarize results of independent review.

Changes Made Since the Audit In Nov 2017

• CAFTA based event trees and fault trees used to assess seismic and thermal hazards.

• Integrated Internal Events Model into seismic and thermal hazard models.

- Open findings addressed in Attachment A of PRA analysis. Most dispositioned as no impact, conservative impact, or addressed with sensitivity analysis.

• Seismic fragilities from IPEEE.

- Some IPEEE fragilities updated. Addressed modifications made to the plant post IPEEE based on IPEEE insights.

• Commitment to modification that will fully protect U2 PORV control cables from missile hazards - spring 2020.

• HEPs based on latest EPRI methodology.

• Quantified LERF based on bounding or conservative qualitative and quantitative assumptions related to containment integrity post construction truss failure.

• Comprehensive sensitivity studies address key uncertainties. Followed guidance in RG 1.174 and NUREG 1855.

INDEPENDENT REVIEW Summary of third party review Review Scope Key Comments Overall methodology and results Innovative approach supported with good Bounding Analysis arguments that justify methodology.

Demonstrably Conservative Analysis Confirmed key issues addressed appropriately.

HRA Editorial comments helped clarify methodology Conformance to RG 1.174; defense in depth, for reviewers.

safety margin, and risk acceptance Validated assumptions were reasonable and well guidelines. supported.

Conformance to RG 1.200 - high level Recommended additional sensitivity analyses to review. address key uncertainties associated with Reasonableness of assumptions and inputs. quantitative and qualitative inputs and assumptions.

Appropriate integration of structural inputs.

Supporting HRA documentation enhanced in Appropriate integration of internal events conjunction with limited quantification revision model and Seismic IPEEE.

No changes required to model structure Uncertainty Conformance to NUREG 1855 guidance Clarifications made on seismic/structural inputs Confirm sensitivity studies address key ALL COMMENTS INCORPORATED OR RESOLVED.

uncertainties.

6

RESULTS Point Beach ALL HAZARDS PRA Results HAZARD CDF (1/Rx Yr) LERF (1/Rx Yr)

Unit 1 Unit 2 Unit 1 Unit 2 TOTAL 7.2E-05 8.2E-05 2.3E-06 2.5E-06 Case CDF LERF Bounding 1.93E-06 7.55E-07 Demonstrably Conservative 2.19E-07 5.26E-08 NRC RG 1.174 FIGURE 4 NRC RG 1.174 FIGURE 5 TOTAL CDF - ALL HAZARDS TOTAL LERF - ALL HAZARDS

CONCLUSION

• Low risk impact

• PRA Identified mods that will protect critical mitigating functions during seismic and thermal events.

• Supporting evaluations based on bounding and conservative assumptions

• Meets RG 1.174 requirements

- PRA quality meets RG 1.200

- Open F&O impacts will be addressed

• Independent reviews from industry experts confirmed validity of methodology and assumptions.

QUESTIONS

• Questions