ML072780152
| ML072780152 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 08/06/2007 |
| From: | Ertman J, Miskiewicz D, Bebbie Rhodes Nuclear Generation Group, Progress Energy Co |
| To: | Office of Nuclear Reactor Regulation |
| Oudinot D | |
| Shared Package | |
| ML072830337 | List:
|
| References | |
| Download: ML072780152 (10) | |
Text
Page 1 Circuit Analysis Methodology Update Jeff Ertman, Corporate Fire Protection Supervisor Bob Rhodes, HNP Safe Shutdown Dave Miskiewicz, Corporate PSA Group
Page 2 Circuit Analysis Overview O PE SSA/AppR/NSCA methodology under NFPA 805 as previously presented Z Generally rely on existing SSA re-validation methods X Methodology true-up using NEI 04-02, App B-2 X This included initial look for multiples (pairs) from systems approach -
HNP, RNP Z Utilize expert panel to identify multiple combinations of concern X More systematic and better documented approach to identify multiples then what was done previously - tested at CR3 X This includes PRA input using available information Z Use Fire PRA quantification results to identify multiples of concern that were not previously considered X Use RG1.205 guidance to disposition X Those multiples meeting RG1.205 criteria will be included in NSCA
Page 3 Circuit Analysis Recap - NEI 00-01 Rev 1 O NEI 04-02 B-2 comparison to deterministic NEI 00-01 Chapter 3 method as endorsed by RIS 2005-30 O RG 1.205 allows use of risk methods O Will modify PE approach to include risk methods to address multiple spurious operations
Page 4 Circuit Analysis Recap - NFPA 805 O Expert panel - identify scenarios beyond current deterministic analysis Z Initiating events (as discussed in FPIP-0122)
Z Diversion paths Z Multiple train/path spurious operations may need to be evaluated further O Utilize PRA internal events information to identify pairs - prior to Fire PRA upgrade:
Z Search assumptions for previously screened components based on low probability Z Risk ranking of spurious event combinations
Page 5 Circuit Analysis Recap - NFPA 805 O Use Fire PRA quantification results to identify multiples of concern that were not previously considered Z Requires completed Fire PRA Z Use similar risk ranking tools as with internal events XFocus search on important functions Z Review cut sets XExtract spurious event combinations O Evaluate MSO candidates for inclusion in SSA
Page 6 Circuit Analysis Recap - Fire PRA Post-Processing O Add new PSA components to Dbase (those not already in Dbase for SSD)
Z Add Database flags for SSD and PSA O PSA circuit analysis - same methodology as SSA O These are not part of SSA unless identified as candidates per methodology
Page 7 Circuit Analysis Cable Selection Details O How results fit into SSA/App R/NSCA process Z CA performed - failure scenarios analyzed on conductor level using component schematics Z One output is to identify cables as spurious/fail, fail, achieve based on conductor level results Z Cables are located in specific Fire Areas, Zones, Compartments Z Information used in NSCA Fire Area Analysis to identify impact of fire on affected components X Note: Data also used in Fire PRA Z Impact on components is assessed and resolution strategies provided
Page 8 Circuit Analysis B-2 Review - Cable to Cable Hot Short O Currently at HNP Z Cable-to-cable shorts are not postulated to occur (SSER 3, Section 9.5.1.4 (page 9-15)).
X The plant design reflected this in development of SSA modifications in late 80s Z This approach was not credited during cable selection phase during re-validation X E.g. scope of cables not decreased due to this assumption Z This approach was used in some resolution strategies during the fire area analysis as part of recent SSA re-validation
Page 9 Circuit Analysis B-2 Review - Cable to Cable Hot Short O Impact Under NFPA 805 NSCA methodology previously discussed:
Z The cable to cable interactions of concern are expected to be included in the step to use Fire PRA results X Use Fire PRA quantification results to identify multiples of concern that were not previously considered Z Some spurious actuations may be identified during post quantification PRA review as having higher significance Z These will need to be dispositioned similar to other CLB items that may have importance per fire PRA results Z The NSCA compliance documentation will need to be updated with any changes in resolution strategies that result from this review
Page 10 Circuit Analysis (CA)
Going Forward O
Proposed NSCA methodology under NFPA 805 going forward - currently under internal PE review:
Z Generally rely on existing SSA re-validation methods X Methodology true-up using NEI 04-02, App B-2 X This included initial look for multiples (pairs) from systems approach - HNP, RNP Z
Utilize expert panel to identify multiple combinations of concern X More systematic and better documented approach to identify multiples then what was done previously - tested at CR3 - use at all PE sites X This includes PRA input using available information Z
Use Fire PRA quantification results to identify multiples of concern that were not previously considered X Use RG1.205 criteria to disposition X Those multiples meeting RG 1.205 criteria will be included in NSCA Z
Use Fire PRA quantification results to identify cable-cable interactions of concern that were not previously considered X Disposition as part of PRA effort X Same approach use for this as planned for other higher importance items that currently meet CLB