nrc seismic margin methodology with enhancements
TRANSCRIPT
![Page 1: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/1.jpg)
NRC Seismic Margin Methodology with
Enhancements
March 1, 2012
Jim Xu and Nilesh Chokshi
Office of New Reactors
1
![Page 2: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/2.jpg)
Outline of Presentation
• History of SMA• SMA Concepts
2
• NRC SMA Methodology• Additional Enhancements• Broader Technical Issues
![Page 3: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/3.jpg)
History of SMA• Seismic Safety Margin Research Program in
early eighties• NRC formed an expert panel to address the
question of seismic margin• NRC expert panel addressed easier task
review the plant against a specific earthquake level (i.e., SME) and determine whether plant has a high confidence of low probability of failure for SMEif less than SME, then calculate the plant “high-confidence low probability of failure (HCLPF)” capacity
• Fragility Analysis (FA) and Conservative Deterministic Failure Margin (CDFM) methodologies
3
![Page 4: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/4.jpg)
History of SMA (cont.)
• NRC expert panel (NRC Methodology)–NUREG/CR-4334
• Maine Yankee plant trial review using NRC method– NUREG/CR- 4826method NUREG/CR 4826
• EPRI Methodology - EPRI NP-6041• Catawba trial review using EPRI method – EPRI
NP-6359 • EPRI NP-6041, Revision 1• IPEEE guidance document, NUREG 1407• IPEEE Insights – NUREG - 1742• ASME/ANS Standard (Including Augmented
SMA)
4
![Page 5: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/5.jpg)
Seismic Margin Concepts
5
SYSTEM MODELINGSYSTEM MODELINGAbbreviated system models for dominant initiators
IDENTIFICATION OF SSCs
System andWalk downs
SCREENING OF SSCs
Eq. exp., PRAs, Tests
CAPACITY OF COMPONENTS
DeterministicFragility method
EARTHQUAKE (GROUND) MOTION
One fixed level (RLE)> Design Basis
RESULTSPlant capacity statement
Seismic Margin Overview
![Page 6: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/6.jpg)
NRC SMA
6
SMA
From NUREG/CR-4826
![Page 7: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/7.jpg)
Example of Evaluated Functions for PWRs
7From NUREG/CR-4826
![Page 8: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/8.jpg)
Example of Evaluated Functions for BWRs
8From NUREG/CR-4826
![Page 9: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/9.jpg)
Loop Initiated Transient
9
![Page 10: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/10.jpg)
Small LOCA
10
![Page 11: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/11.jpg)
Example of Plant Level HCLPFs
11
![Page 12: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/12.jpg)
Enhancements
• Full Scope from NUREG-1407– Walkdowns using EPRI-6041
Relay Chatter evaluations
12
– Relay Chatter evaluations
– Address soil induced failures
– 72 hours mission time
• Non-seismic failures and human performance expected fully integrated in logic models
![Page 13: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/13.jpg)
Enhancements (cont.)
• HCLPF Calculations– Fragility method
– Conservative Deterministic Failure Margin
13
g(CDFM)
• Applicable requirements on Part 5 and Part 10 of ASME/ANS Standard
![Page 14: NRC Seismic Margin Methodology with Enhancements](https://reader036.vdocuments.us/reader036/viewer/2022062312/62a8038ff303b3248f362db8/html5/thumbnails/14.jpg)
Broader Technical Issues
• High frequency evaluations
• System functions to accommodate extended mission time
14
• Need for development of additional guidance