ML20134Q284
| ML20134Q284 | |
| Person / Time | |
|---|---|
| Issue date: | 11/26/1996 |
| From: | Craig C NRC (Affiliation Not Assigned) |
| To: | Matthews D NRC (Affiliation Not Assigned) |
| References | |
| PROJECT-694 NUDOCS 9612020216 | |
| Download: ML20134Q284 (28) | |
Text
?$'
- Mco p
- IZj UNITED STATES
'j NUCLEAR REGULATORY COMMISSION g
o WASHINGTON, D.C. 20555-0001 November 26, 1996 l
MEMORANDUM T0:
David B. Matthews, Chief Generic Issues and Environmental Projects Branch Division of Reactor Program Management Office of Nuclear Reactor Regulation FROM:
Claudia M. Craig, Senior Project Manage MR Generic Issues and Environmental Projects Branch Division of Reactor Program Management
.0ffice of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF MEETING WITH THE WESTINGH0USE OWNERS GROUP (WOG) TO DISCUSS PRA METHODS TO EXTEND CERTAIN SURVEILLANCE TEST INTERVALS AND ALLOWED OUTAGE ITEMS The subject meeting was held at the Nuclear Regulatory Commission (NRC) office in Rockville, Maryland on October 15, 1996, between representatives of Westinghouse, the WOG, and the NRC staff.
The purpose of the meeting was to discuss WOG risk-informed program initiatives regarding accumulator. allowed outage time (A0T) relaxations and reactor trip breaker (RTB) A0T and surveillance test interval (STI) relaxations. Attachment 1 is the list of meeting participants. Attachment 2 is a copy of.the non-proprietary presentation material that was discussed at the meeting and provided in a letter dated October 21, 1996.
For the accumulator A0T relaxation initiative, Westinghouse is planning to develop a technical approach for justifying extensions of A0Ts, and would like the first extension to be applied to accumulators.
The overall technical approach is similar to the Combustion Engineering Owners Group (CE0G) approach, which is currently under. review by the staff.
Westinghouse plans to develop a general methodology for~ assessing A0T. increases and each utility 4
would then apply the methodology using their plant specific PRA models.
Westinghouse discussed their process for assessing the impact of changes to A0Ts on plant safety.
Discussions were held on the NRC experience with the CE0G submittal.
It was suggested by the staff that the WOG obtain a copy of 4
i the staff's request for additional information (RAI) that was sent to the CE0G and the CE0G response to that request.
The staff felt'that this would provide the WOG some insights into the staff review and then the WOG could address those issues in their submittal.
1 The WOG also discussed their plans for providing a technical justification for
~
extending the RTB STI, extending the master relay and logic cabinet STI, and I
extending the RTB A0T consistent with the logic cabinet A0T.
This methodology would apply to both relay and solid state protection system plants.
The n'
C) O I
020023 Or/ pao's lo4k 9612020216 961126 PDR PROJ 694 PDR
\\
D. Matthews November 26, 1996 1
methodology uses portions of WCAP-14333, "Probabilistic Risk Analysis of the RPS and ESFAS Test Times and Completion Times," which is currently under NRC staff review. Westinghouse discussed the overall approach and the technical approach for extending the STIs and A0T.
Also discussed at the meeting was staff question number 18 on WCAP-14333, which was outlined in an RAI dated June 28, 1996. The question had two parts and requested a discussion of the type of analysis performed to identify risk significant configurations for which changes are proposed and the procedures that are to be followed to avoid or restrict risk significant occurrences.
The staff also requested a discussion of programs for configuration management, consistent with the maintenance rule, to assess risk impacts prior to entry into the A0Ts that are being proposed for extension.
The WOG was concerned that the question was asking the WOG to generically commit to a configuration risk management program, which the WOG felt it could not do on a generic basis. The issue was discussed and the staff suggested the WOG review the CE0G response to the staff's RAI in that the same question was asked of the CE0G.
Project No. 694 Attachments: As stated cc w/atts:
See next page
November 26, 1996 D. Matthews
, methodology uses portions of WCAP-14333, "Probabilistic Risk Analysis of the RPS and ESFAS Test Times and Completion Times," which is. currently. under NRC '
staff review. Westinghouse discussed the overall approach'and the technical approach for extending the STIs and A0T.
Also discussed at the meeting was staff question number 18 on WCAP-14333, which was outlined in an RAI dated June 28, 1996.
The question had.two parts and requested a discussion of the type of analysis performed to identify risk significant configurations for which changes are proposed and the procedures that are to be followed to avoid or restrict risk significant occurrences.
.The staff also requested a discussion of programs for configuration management, consistent with the maintenance rule, to assess risk impacts prior to entry into the A0Ts that are being proposed for extension. The WOG was concerned-that the question was asking the WOG to generically commit to a configuration risk management program, which the WOG felt-it could not do on a
~
generic basis. The issue was discussed and the staff suggested the WOG review
~
the CEOG response to the staff's RAI in that the same question was asked of-the~CEOG.
1 Project No. 694 Attachments: As stated cc w/atts: See next page DISTRIBUTION-See attached page DOCUMENT NAME:, 10_15. min To pesolve a sepy of thle desunient,lasmosee la the ben: "C" = Copy without ettechenent/ enclosure
- E" = Copy with attachment / enclosure v - w.
py s.e e,. e Con.unen e j
OFFICE PGEB N i(\\
SC:PGEB (l U8C:TSB*
BS:PICB*
i NAME CCra@isw' RArchitzel CGrimes JWetmiel I
D TE gll 96 1 0 96 11 13 96
,1h 0FFICE BC:SRXBff BC:SP B.
BC:PGEB /VN
^
NAME wTCollirfs ab RJoneViC)/ \\
DMatthewd DATE " 11/4/95 ll/2i / S 6 \\
11/)//96 FICIAL RECORD COPY
1 cc:
Mr. Nicholas Liparulo
)
Westinghouse Electric Corporation P.O. Box 355 i
Pittsburgh, PA 15230-0355 Mr. Hank A. Sepp Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, PA 15230-0355 Mr. Andrew Drake, Project Manager Westinghouse Owners Group Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, PA 15230-0355 Mr. Mark Beaumont i
Westinghouse Electric Corporation One Montrose metro 11921 Rockville Pike, Suite 450-Rockville, MD 20852
)
i
i WOG / NRC-MEETING OCTOBER 15, 1996 AT ROCKVILLE, MD MEETING PARTICIPANTS N8ME ORGANIZATION Claudia Craig NRC/NRR/PGEB j
Hukam Garg NRC/NRR/DRCH Ian Jung NRC/NRR/DSSA Eric Weiss NRC/NRR/SRXB i
Nanette Gilles NRC/NRR/TSB Millard Wohl NRC/NRR/SPSB Sarita Brewer NRC/NRR/SRXB Chu-yu Liang NRC/NRR/SRXB Ray Schneider ABB/CE i
Jim Andrachek Westinghouse Jack Stringfellow Southern Nuclear /WOG Adrian Heymer NEI l
Gary Merka TU Electric (CPSES)
Bob Howard Westinghouse 4
P.J. Fulfor LIS 4
Bennett M. Brady NRC/AE0D/SPD Jerry Andre Westinghouse John Flack NRC/NRR/SPSB i
E i
ATTACHMENT 1
y.
wo j
)
+
i Wegin@mse Energy Systems '
85 355 Electric Corporation Pittsburgh Pennsylvania 15230-0355 e
1 i
1 i-SMPD-RAS-96-140
)
i October 21,1996 i
1 1
t I
i i
Claudia Craig U.S. Nuclear Regulatory Commission Mail Stop O-10H5 Washington, DC 20555 1
4
Dear Claudia:
i l
Attached is a copy of the presentation material used in the meeting between the NRC and the Westinghouse Owners Group Licensing Subcommittee held on October 15. This i
material was determined to be Westinghouse Non-Proprietary Class 3.
Please contact me if any additionalinformation is necessary.
1 Best regards, G.R. Andre' Risk Assessment Services Westinghouse Electric Corporation Attachment cc: B. Monty w/o attachment 0047CG:JRA/102196 l
ATTACHMENT 2
.=
Westinghouse Non-Propristary Class 3 NRC/WOG Meeting RISK-BASED PROGRAM INITIATIVES WOG Licensing Subcommittee October 15,1996 i
WESTIGNHOUSE ELECTRIC CORPORATION Energy Systems Business Unit l
P.O. Box 355 Pittsburgh, PA 15230 o 1996 Westinghouse Electric Corporation All Rights Reserved t
i
___--__.m_._..
~-
Westinghouse Non-Proprietary Class 3 AGENDA 1:00 Introduction Jack Stringfellow, SNC i
Licensing Subcommittee Chair i
1:15 Accumulator Allowed Outage Time Relaxations
- Program Objective and Technical Approach Jerry Andre', Westinghouse
- Status of CEOG AOT Improvement Program NRC
- Discussion and NRC Comments All i
2:45 Tech Spec RTS and ESF Logic and Reactor Trip Breaker AOT and STI Relaxations j
Program Objective and Technical Approach Bob Howard, Westinghouse Jerry Andre', Westinghouse
[
- Discussion and NRC Comments All l
3:45 Discuss NRC RAI #18 on WCAP-14333 4:30 Meeting Summary Jack Stringfellow, SNC l
i-i 6
Westinghousa Non-Propristary Class 3 MEETING OBJECTIVES e Discuss technical approach and regulatory requirements with the NRC for the following risk-based programs:
i
- Accumulator Allowed Outage Time Relaxations l
D
- Tech Spec RTS and ESF Logic and Reactor Trip Breaker AOT and STI Relaxations i
e Discuss NRC RAI #18 on WCAP-14333 ("Probabilistic Risk Analysis of the RPS and l
ESFAS Test Times and Completion Times")
i i
k I
[
t
-[
Westinghouse Non-Proprietary Class 3 WOG PR'OGRAM INTERACTIONS I
6A,-,A
("COMPAR
" ""^"
q,ReV 7 AcceMeLAA I
AOT RELAXATION I
I I ROGRA r
KAe-4e>
UNDER REVIEW
)
u I I N - LIN FUTURE A
[
l MAINTENANCE l
IMPROVEMENT l
(INSTRUMENTATION PROGRAM PROGRAMS l
STI RELAXATION I
i OGRA N
Westinghousa Non-Propristary Class 6 Accumulator Allowed Outage Time Relaxations Program Objective:
e Develop the technical approach for justifying extensions to AOTs (not accumulator specific)
- Apply this approach to the accumulators (increase AOT to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />)
Current Accumulator Tech Spec Requirements (NUREG-1431)
- 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> completion time for boron concentration e 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> completion time for all other reasons
Westinghouss Non-Propriatary Class 3 Accumulator Allowed Outage Time Relaxations (Cont'd) i Overall Technical Approach e Similar to CEOG approach to AOT changes-e Develop a general methodology to be applied for assessing other AOT increases e Develop accumulator specific methodology from the general methodology l
e Each utility applies this methodology using their plant specific PRA model(s) f e The technical approach and each plant's results are provided to the NRC in one document (WCAP) l t
i l
l m..
.m m
m
Westinghouss Non-Propristary Class 3 FIGURE 1' PROCESS FOR ASSESSING THE IMPACT OF CHANGES TO TECHNICAL, SPECIFICATION AOTS ON PLANT SAFETY STEP 1: IDENTIFY THE TECH SPEC AOT IMPROVEMENTS o
I I q r ASSESSMENT OF ASSESSMENT OF DETERMINISTIC IMPACT l
RISK IMPACT t
i 1 F I f STEP 2A: ASSESS STEP 28: ASSESS
{
THE IMPACT ON r
THE IMPACT ON PLANT SAFETY PLANT SAFETY I
I r
i l
l STEP 3: IDENTIFY THE t
IMPACT ON PLANT PSA MODEL I
i I
l o
STEP 4: MODIFY THE PSA MODEL AND AOT
[
RELATED PARAMETERS l
1 r STEP 5: IDENTIFY THE l
RISK MEASURES i
l o
u
- =
h
.- t
~.,
. Westinghouss Non-Propristary Class _3 FIGURE 1 (CONT.)
. PROCESS FOR ASSESSING THE IMPACT OF CH NGES TO TECHNICAL. SPECIFICATION AOTS ON PLANT SAFETY n
STEP 6: QUANTIFY THE PSA MODEL o
STEP 7: PRELIMINARY REVISE CHANGES AND RESULTS COLLECTION CONSIDER COMPEN-AND DISCUSSION SATORY ACTIONS a,
Ii
[
l f
RESULT No ACCEPTABLE?
j i
YES o
I P
STEP 8: FINAL RESULTS COLLECTION AND REVIEW i
l
~
i l
i f
I t
l STEP 9: IDENTIFY CHANGE REQUESTS i
f
[
I f
' l STEP 10: DOCUMENTATION l
i
[
l
,,-.e e
,--ea--v,,
nn-n
--n,-~
ann.---,-,e,
,.----.-,--a--,v-,--nr..-,e,-a-,,e,or.,--,
n,--
~..-e.-
r, a
<-w er
- -~
Westinghousa Non-Propriatary Class 3 Accumulator Allowed Outage Time Relaxations (Cont'd) i r
issues to be Resolved Step 3: Identify the Impact on the Plant PSA Model Accumulator success criteria varies between plant PSA models.
- FSAR success criteria to no accumulators required l
- Only modeled for large LOCA event mitigation l
l Accumulator failure modes
- Typically modeled failure modes are check valves fail to open and tank rupture
- Use current accumulator model in PRAs with addition of T and M unavailability
[
h
~
k
,. ", c Westinghouse Non-Propristary Class 3 Accumulator Allowed Outaae Time Relaxations (Cont'd) o i
Issues to be Resolved (Cont'd)
Step 4: Modify the PSA Model and AOT Related Parameters j
How is the impact of the extended AOTs factored into the PSA model?
Use realistic test and maintenance times (do not assume the' full AOT will be used)
- Test activities, corrective and preventive maintenance activities
- See following Tables for recommended approach i
Step 5: Identify the Risk Measures
- Risk measures to be provided i
- Yearly average CDF
- Yearly average LERF l
- Conditional core damage frequencies i
i
Westinghnuse Non-Proprietary CI:ss 3
.I Table 2 Worksheet for Determining the impact of increased AOTs on Mean Test Downtimes i
Test Activity Current (C)
Test With Current AOT impact of With Extended AOT (3) or New (N)
Frequency AOT Activity Change on i
Downtime
' Test Test Downtime Test Downtime per Test Activity
[
per Test Activity
- Activity thr)
Unavail (1)
(2)
Activity thr)
Unavail (1) l f
i t
i t
A Total i
I b
i Notes:
i
- 1. Test Activity Unavailability = Test Frequency x Downtime per Test Activity
{
- 2. This should be given as a factor increase, such as 2X. Justification for this factor will need to documented.
- 3. Downtime per Test Activity (with extended AOT) = lmpact of AOT Change on Test Downtime x Downtime per Test Activity (with i
current AOT)
I
)
~
_ - _ ~. _ _ _
Wastinghousa Non-Proprist:ry Cliss 3 Table 3 Worksheet for Determining the impact of increased AOTs on Mean Maintenance Downtimes Maintenance Activity Current (C)
Maint.
With Current AOT impact of With Extended AOT (3)
(Scheduled (S) or or New (N)
Frequency AOT Repair (RI)
Activity Change on Downtime Maint.
Maint.
Downtime Maint.
Downtime per Maint.
Activity I
per Maint.
Activity Activity (hr)
Unavail (1)
(2)
Activity (hr)
Unavail (1) i t
Total Notes:
- 1. Maint. Activity Unavailability = Maint. Frequency x Downtime per Maint. Activity
- 2. This should be given as a factor increase, such as 2X. Justification for this factor will need to documented.
- 3. Downtime per Maint. Activity (with extended AOT) = impact of AOT Change on Maint. Downtime x Downtime per Maint. Activity j
(with current AOT) 4
Westinghousa Non-Propristary Class 3 Accumulator Allowed Outage Time Relaxations (Cont'd)
Issues to be Resolved (Cont'd)
Step 6: Quantify the PSA Model
- What, if any, sensitivity cases are expected (CEOG experience)?
NRC review of PSA models necessary?
Step 7: Preliminary Results Collection and Discussion
- Follow the EPRI PSA Applications Guide for acceptable risk changes Step 10: Documentation
- Quantification results
- Worksheets for determining impact of AOT increase on T and M times
- Success criteria
- Events requiring the system for mitigation
- Typical system fault tree models
Westinghousa Non-Proprititary Class 3 Tech Soec RTS and ESF Logic and RTB AOT and STI Relaxations t
Program Objective e Provide the technical justification for:
Extending the reactor trip breakers STI from 2 to 6 months Extending the master relay and logic cabinet STI from 2 to 18/24 months Extend the RTB AOT consistent with the logic cabinet AOT (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) l
- Applicable to relay and solid state protection system plants i
i I
[
I I
I i
h
[
. Wastinghouss Non-Propriatary Class 3 Tech Spec RTS and ESF Logic and RTB AOT and STI Relaications (Cont'd)
Background
i i
e WCAP-10271 with Supplements 1-and 2 analyzed STI and AOT changes to the analog channels, logic cabinets, master and slave relays, and trip breakers
^
- NRC approved changes to analog channel STis and AOTs and logic cabinet, master relay, and slave relay AOTs e Changes to logic cabinet, master relay, and slave relay STis not requested j
e Changes to reactor trip breaker STis and AOTs withdrawn e WCAP-14333 requested changes to AOTs for analog channels, logic cabinets, l
master and slave relays e WCAP-14333 analysis currently under review e Detailed reactor trip and engineered safety features actuation signal fault trees
[
developed t
e Conservative assumptions used regarding relation between component failure
[
probability and test interval e Generic component failure rate data used j
I
Westinghouss Non-Propriatary Class 3
~
Tech Soec RTS and ESF Logic and RTB AOT and STI Relaxations (Cont'd)
Overall Program Approach e
Meet with the NRC to discuss conceptual approach and expectations e Use of PSA to assess impact of STI and AOT changes on plant safety e Application of instrumentation unavailability models and plant PSA model used in WCAP-14333 e Remove conservative assumptions Replace generic data with industry specific data Improved assessment of impact of STI extensions on component failure probability e impact of reduced testing on spurious reactor trips and sis 1
s
.m -.
. =
m m
m
~... -.... -. - ~. -. -..
-. -.. ~... _ -. -
Westinghouss Non-Propri:itary Class 3 Tech Soec RTS and ESF Logic and RTB AOT and STI Relaxations (Cont'd)
Technical Approach e Phase 1: Meet with the NRC to discuss conceptual approach and expectations f
e Phase 2: Analysis L
Data collection / utility survey /WOG-TRAP database review i.
Reactor trip breaker performance ii.
Master relay performance iii. Logic cabinet card level performance
- Calculation of new failure rates (assume linear relation between P, and STI)
RT and-ESF actuation signal unavailability assessment (WCAP-10271 and WCAP-14333 models) l t
- Risk analysis (WCAP-14333 model)
}
- WCAP 6
i Westinghouss Non-Propristary Class 3 Tech Spec RTS and ESF Loaic and RTB AOT and STI Relaxations (Cont'd)
Technical Approach (Cont'd) h e Phase 3 (if necessary)
FMECAs to improve P,/STI linear assumption
- RT and ESF actuation signal unavailability assessment (WCAP-10271 and WCAP-14333 models)
Risk analysis (WCAP-14333 model)
- WCAP L
i I
f
[
i
L 1
Wastinghouss Non-Propristary CI:ss 3 i
1 Figure 1 Component Failure Probability as a Function of Test interval i
i r
i CURVE 1 t
t H
5 m
t 4
(D O
l tr Q.
t CURVE 2 l
l 3
t J
1 fs -
P t
i i
i i
)
P i
0 0
I TEST INTERVAL
~
Key:
Curve 1 - Assumes there is a linear relationship between the test interval and the
' failure probability, immediately following the test, the component is perfect.
Curve 2 Divides the failure probability into time-independent and time dependent components.
P,, represents the time-independent (or shock) component of the t
f ailure probability.
?
e
..s.
.a
', c Westinghouse Non-Propriatary Class 3 Tech Spec RTS and ESF Logic and RTB AOT and STI Relaxations (Cont'd) i h
issues to be Resolved e Program STis and AOTs are acceptable to change?
t e Use of RT and ESF actuation signal fault trees from WCAP-10271 and WCAP-14333 l
e Use of risk model from WCAP-14333 e Reference the results back to Pre-TOP and TOP (WCAP-10271) AOT and STI conditions l
o Risk measures to be reported
- AOT changes (yearly average CDF, yearly average LERF, conditional CDF)
- STI changes (yearly average CDF, yearly average LERF) e Acceptable changes in the risk measures - follow the EPRI PSA Applications Guide
- What, if any, sensitivity cases are expected?
j I
= m
...g Westinghousa Non-Propriatary Class 3 t
Discuss NRC RAI #18 on WCAP-14333 ("Probabilistic Risk Analysis of the RPS and ESFAS Test Times and Comoletion Times")
I i
RAI#18.
a.
(Second area) Given the proposed T/M plant configuration, what are the other risk-significant systems or equipment? Please discuss the analysis performed to identify risk-significant configurations for which changes are proposed and the procedures followed, or will be followed, to avoid / restrict such occurrences.
i r
b.
(Third area) Explain how you are going to address the issue of configuration and i
control, consistent with the Maintenance Rule, i.e., evaluate the impact of maintenance activities on plant configurations. Please discuss the programs for configuration management in Westinghouse plants to address assessment of risk l
impacts prior to entry into the RPS and ESFAS bypass time or AOT, being j
proposed for extension.
j i
i I
t i
?
DISTRIBUTION w/ attachments:
Sumary of October 15, 1996, with Westinghouse dated November 26, 1996 Cent ~ral File PUBLIC PGEB i
RArchitzel CCraig E-Mail FMiraglia/AThadani RZimmerman TMartin GHolahan BSheron JRoe BBoger SVarga GVissing EWeiss IJung HGarg i
NGilles MWohl SBrewer CLiang JFlack BBrady CGrimes JWermiel RJones