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) | |
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Page 1 Circuit Analysis Methodology UpdateJeff Ertman, Corporate Fire Protection SupervisorBob Rhodes, HNP Safe ShutdownDave Miskiewicz, Corporate PSA Group Page 2 Circuit Analysis OverviewPE SSA/AppR/NSCA methodology under NFPA 805 as previously presentedGenerally rely on existing SSA re-validation methodsMethodology true-up using NEI 04-02, App B-2 This included initial look for multiples (pairs) from systems approach -
HNP, RNPUtilize expert panel to identify multiple combinations of concernMore systematic and better documented approach to identify multiples then what was done previously -tested at CR3This includes PRA input using available information Use Fire PRA quantification results to identify multiples of concern that were not previously considered Use R G1.205 guidance to disposition Those multiples meeting RG1.205 criteria will be included in NSCA Page 3 Circuit Analysis Recap -NEI 00-01 Rev 1 NEI 04-02 B-2 comparison to deterministic NEI 00-01 Chapter 3 method as endorsed by
RIS 2005-30 RG 1.205 allows use of risk methods Will modify PE approach to include risk
methods to address mu ltiple spurious operations Page 4 Circuit Analysis Recap -NFPA 805Expert panel -identif y scenarios beyond current deterministic analysis Initiating events (as discussed in FPIP-0122) Diversion paths Multiple train/path spurious operations may need to be evaluated furtherUtilize PRA internal events information to identify pairs -prior to Fire PRA upgrade: Search assumptions for previously screened components based on low probability Risk ranking of spurious event combinations Page 5 Circuit Analysis Recap -NFPA 805 Use Fire PRA quantification results to identify multiples of concern that were not previously considered Requires completed Fire PRA Use similar risk ranking tools as with internal eventsFocus search on important functionsReview cut sets Extract spurious event combinationsEvaluate MSO candidates for inclusion in SSA Page 6 Circuit Analysis Recap -Fire PRA Post-ProcessingAdd new PSA components to Dbase (those not already in Dbase for SSD)Add Database "flags" for SSD and PSAPSA circuit analysis -same methodology as SSAThese are not part of SSA unless identified as
'candidates' per methodology Page 7 Circuit Analysis Cable Selection DetailsHow results fit into SSA/App R/NSCA processCA performed -failure scenarios analyzed on conductor level using component schematics One output is to identify cables as spurious/fail, fail, achieve based on conductor level resultsCables are located in specific Fire Areas, Zones, Compartments Information used in NSCA Fire Area Analysis to identify impact of fire on affected componentsNote: Data also used in Fire PRAImpact on components is assessed and resolution
strategies provided Page 8 Circuit AnalysisB-2 Review -Cable to Cable Hot Short Currently at HNP Cable-to-cable shorts ar e not postulated to occur (SSER 3, Section 9.5.1.4 (page 9-15)).The plant design reflected this in development of SSA modifications in late 80's This approach was not credited during cable selection phase during re-validationE.g. scope of cables not decreased due to this assumptionThis 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 Impact Under NFPA 805 NSCA methodology previously discussed: The cable to cable interactions of concern are expected to be included in the step to use Fire PRA results'Use Fire PRA quantification results to identify multiples of concern that were not previously considered'Some spurious actuations may be identified during post quantification PRA review as having higher significance These will need to be dispositioned similar to other CLB items that may have importanc e per fire PRA results 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 ForwardProposed NSCA methodology under NFPA 805 going forward -currently under internal PE review:Generally rely on existing SSA re-validation methodsMethodology true-up using NEI 04-02, App B-2 This included initial look for multiples (pairs) from systems approach -HNP, RNPUtilize expert panel to identify multiple combinations of concernMore systematic and better documented approach to identify multiples then what was done previously -tested at CR3 -use at all PE sitesThis includes PRA input using available information Use Fire PRA quantification results to identify multiples of concern that were not previously consideredUse RG1.205 criteria to disposition Those multiples meeting RG 1.205 criteria will be included in NSCA Use Fire PRA quantification results to identify cable-cable interactions of concern that were not previously consideredDisposition as part of PRA effortSame approach use for this as planned for other higher importance items that currently meet CLB