ML033440343
| ML033440343 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 10/29/2003 |
| From: | Head S South Texas |
| To: | Jaffe D NRC/NRR/DLPM/LPD4 |
| Jaffe D, NRR/DLPM, 415-1439 | |
| References | |
| Download: ML033440343 (7) | |
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I C:\\WINDOWS\\TEMP\\GW)00001.TMP Pagie 1 1 I C:\\WINDOWS\\TEMP\\GWIOOOO1.TMP Paae 11-..
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Fwd: RI-IST Files to be Forwarded to the NRC 10/29/03 10:24AM "Scott Head" <smhead@stpegs.com>
smhead @ stpegs.com Recipients nrc.gov owf4_po.0WFNDO DHJ (David Jaffe)
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Size 14 Date & Time 10/29/03 10:24AM 76336 None Standard No None No Standard
DaI P
d Jaffe - Fwd: RI-IST Files to be Forwarded to the NRC Page-1 From:
'Scott Head" <smhead @ stpegs.com>
To:
<Dhj~nrc.gov>
Date:
10/29/03 10:26AM
Subject:
Fwd: RI-IST Files to be Forwarded to the NRC As promised.
I David Jaffe - RI-IST Files to be Forwarded to the NRC Page 1 I From:
To:
Date:
Subject:
'Glen Schinzel <geschinzel@stpegs.com>
'Scott Head" <smhead~stpegs.com>
10/29/03 8:33AM RI-IST Files to be Forwarded to the NRC Scott, here are the files to be forwarded to the NRC to support an RI-IST phone call on Thursday.
Glen CC:
'Bradley Scott <bjscott~stpegs.com>, "Carl Grantom" <crgrantom~stpegs.com>,
"Daniel Stillwell" <dwstillwell @stpegs.com>, "Mark McBurnett <mamcburnett @stpegs.com>, "Michael Berg" <mjberg@stpegs.com>, 'Philip Walker' <plwalker@stpegs.com>
STP's Approach for a Future RI-IST Resubmittal
- Resubmittal of RI-IST will comply with SONGS template F-V threshold adjusted Treatment of RAW common cause adjusted RG-1.175 satisfied
- RI-IST process will only be applied to those components remaining within the scope of IST following application of the Exemption allowances
- RI-IST will not affect the GQA categorization results nor the scope of components subjected to IST controls
- RI-IST treatments will comply with the SONGS approach RI-IST 'High' SSCs continue to receive full treatment RI-IST 'Low/High' SSCs can have intervals between tests extended as long as compensatory measures are put in place RI-IST 'Low' SSCs can have intervals extended up to a 6 year periodicity
- Determine if terminology of 'High, Low/High, Low' can be changed to something like 'IST Treatment Category 1, 2, 3'
- RI-IST proposed testing strategies will be generated by a RI-IST Working Group, and approved by the Comprehensive Risk Management Expert Panel (same Panel that reviews and approves the GQA categorization results)
- While some RP-1ST treatment categories may initially appear inconsistent with GQA categorization results, the RI-IST treatment categories focus on defining required inservice testing only
- RI-IST component examples will be used to demonstrate how an RI-IST treatment category compares to the GQA categorization
Low Head Safety Injection Pump 1A Discharge MOV - 2N121XSIO018A GOA Rank: Medium Basis: Supports the following system functions High risk: Injection and Cold leg recirc modes Medium risk: Hot leg recirc mode Low risk: Pressure boundary and Containment Isolation GQA ranked Medium based on:
Initial PRA rank of Medium (recently lowered to Low)
Redundant Trains Valve is normally open and stays open (i.e., passive) to support the High-risk functions.
Transfer closed is not a credible failure.
Valve is closed to isolate RHR from the LHSI pump when RHR is used for long-term accident recovery. Failure to close mitigated by the inside containment check valve.
RI-IST Treatment: Low Basis: Valve is normally open which satisfies its safety function The 'remain open' function is considered passive IST testable function is to 'close on demand' RI-IST Treatment of Low based on:
F-V value of 4.3E-4 and a RAW value of 1.2 Valve is normally in it's required safety position - no change of state required Redundancy exists with three 100% safety trains to satisfy the injection modes
- Diversity exists with 3 High Head pumps to support recirculation and injection Valve is routinely monitored by other means to check valve position and flow
==
Conclusion:==
The GQA categorization process initially determines the risk of system functions, and then determines the risk of individual components that support these functions. The RI-IST process focuses directly on IST-scoped components and determines their specific importance. The GQA approach introduces additional conservatisms into the categorization process since all components in a given system are assessed. In addition, the GQA Working Group deterministically ranked this component as Medium risk based on its support of High-ranked functions.
Low Head Safety Injection Pump 1A - 2N121NPA102A GOA Rank: High Basis: Supports the following system functions
- High risk: Injection and Cold leg recirc modes
- Medium risk: Hot leg recirc mode Low risk: Pressure boundary and positive RCS volume control GQA ranked High based on:
Initial PRA rank of High (recently lowered to Medium*)
Supports High risk functions No credit taken for redundancy RI-IST Treatment: Low Basis: Active function to 'start and run' to support injection and recirculation functions RI-IST Treatment of Low based on:
F-V value of 7.78E-4 and a RAW value of 1.2 Redundancy exists with three 100% safety trains to satisfy the injection modes Diversity exists with 3 High Head pumps to support recirculation and injection
==
Conclusion:==
The GQA categorization process initially determines the risk of system functions, and then determines the risk of individual components that support these functions. The RI-IST process focuses directly on IST-scoped components and determines their specific importance. The GQA approach introduces additional conservatisms into the categorization process since all components in a given system are assessed. Also, the GQA process conservatively addresses RAW common cause, whereas the RI-IST process addresses common cause using the SONGS template. In addition, the GQA Working Group deterministically ranked this component as High risk based on its support of High-ranked functions with no credit taken for redundancy.
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