ML14035A094
| ML14035A094 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 02/04/2014 |
| From: | Entergy Operations |
| To: | Office of Nuclear Reactor Regulation |
| Wang A | |
| References | |
| Download: ML14035A094 (29) | |
Text
NFPA 805 LAR Supplement Waterford 3 - NRC Public Meeting February 4, 2014 1
Agenda Introduction Changes to Supporting Analyses Resulting Impact to:
Modifications and Implementation Items Recovery Actions LAR Attachment Change Summary Comparison of Risk Areas to Original LAR Impact on RAIs Questions/General Discussion 2
Introduction Updated Internal Events PRA and Fire PRA
- Resolved Request for Additional Information (RAIs)
- Updated Fire PRA to use accepted methods.
- Corrected legacy issues
- Update to the Nuclear Safety Capability Assessment (NSCA) impacted Variance from Deterministic Requirements (VFDRs) and Recovery Actions 3
Changes to Supporting Analysis Internal Events PRA Addressed RAIs
- Resolved Peer Review F&Os
- CCW Makeup Ultimate Heat Sink Modeling (Fan Requirements)
HVAC Requirements by Fire Area/Room LERF
- Containment Isolation Size Threshold (> 2 Inches)
- Containment Atmosphere Release System (CARS) Modeling Update o Routine 5 year Update (Plant Changes/Data Update) 4
Changes to Supporting Analysis Fire PRA Majority of Changes Addressing RAIs
- Updated to use accepted methods
- Control Room Abandonment Analysis (CCDP)
- Fire Modeling Changes
- Refined Transient and Fixed Source Scenarios
- Refined MCA including Sensitive Electronics Fire Scenario Analysis Transient Combustible Analysis
- Heat Release Rates (HRRs) increased
- Secondary Combustibles (RAB 27 impact) 5
Changes to Supporting Analysis Addressed RAIs Related to PRA Methods Transient Combustible Fire Heat Release Rates
- 69 kW to 317 kW Severity Factor for Severe Pump Oil Fires
- 2/98 to 10/90 Large oil pump fire/Small oil pump fire split fraction Adjustment Factors Removed
- Transient Combustible Fire Ignition Frequency
- Hot Work Ignition Frequency
- Electric Cabinet Fire Ignition Frequency 6
Changes to Supporting Analysis RAIs Addressed in Supplement EDG Severity Fire Factor Removed Use of assumed CCDP (Probability of mitigation failure) to calculated value
- Control Room Abandonment
- TGB Structural Failure o Sensitive Electronics - Temperature threshold for damage 7
Changes to Supporting Analysis Nuclear Safety Capability Assessment (NSCA)
Separated NSCA and SSA Calculations VFDR list re-validated
- Removed Cold Shutdown (CSD) VFDRs
- Removed unnecessary VFDRs for Recovery Actions, Heymc and multiple Success Paths VFDRs identified in 3 additional Fire Areas: TGB, EDG A, and CCW HX A Removed credit for Partial Height Walls:
- Relay Room (RAB7)
- Switchgear Room (RAB8) 8
Results due to Analysis Changes Fire Risk Evaluations (FREs) 3 New FREs prepared for TGB, EDG A, and CCW HX A Fire Areas Relay Room (RAB 7) Analyzed as one Fire Area Switchgear Room (RAB 8) Analyzed as one Fire Area Single Recovery Action to Manually Trip RCP Motor Breakers in 4 Fire Areas (RAB 1, RAB 7, RAB 8, TGB)
N2 Accumulator mission time increased to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 9
o 22 MOVs Require Modification to eliminate IN 92-18 Concerns o Fire Area RAB 6 requires ERFBS to support Risk Assumptions (4 Fire Areas in Original LAR) o Radiant Barrier not required in RAB 2 to protect the Essential Chillers o HEAF Barrier not required in Fire Area RAB 8 o Secondary Combustible removal in Fire Area RAB 27 10
Resulting Impacts Original LAR Supplement Risk CDF 3.4 E-5 1.62 E-5 CDF 8.4 E-6 2.31 E-6 LERF 7.3E-7 2.89 E-6 LERF 1.1E-7 1.29 E -7 Number of Mods MOVs 15 22 ERFBS (wrap) 4 1 HEAF Barrier 1 0 Radiant Barrier 1 0 Code Compliance 7 7 Recovery Actions 30 4 Same RA in 4 Areas 11
Attachment Change Summary Attachment A (B-1 Table)
- Section 3.3.8 revised to state WF3 does not have Bulk Storage of Flammable Liquids located in Structures containing SSCs important to nuclear safety
- NEI 00-01 Rev 1 to Rev 2 Gap Analysis updates 12
Attachment Change Summary Attachment C-Table C-1 (B-3 Table)
- Regenerated to reflect 31 new/revised FREs and revised format
- Revised Licensing Actions (Attachments K and T)
Attachment C - Table C-2 (Formerly Table 4-3)
- Regenerated to reflect 31 new/revised FREs and Revised format
- Revised Licensing Actions (Attachments K and T)
Attachment G - (Recovery Actions)
- Recovery Actions changed due to revised FREs Single Action (Manually Trip RCP Motor Breakers in TGB Switchgear) 4 Fire Areas (RAB 1, RAB 7, RAB 8, TGB) 13
Attachment Change Summary Attachment H (FAQs)
- Updated to reflect revised FPRA methods
- Added 06-0016 Ignition source counting guidance for Electrical Cabinets 06-0017 Ignition source counting guidance for High Energy Arcing Faults (HEAF) 06-0018 Ignition source counting guidance for Main Control Board (MCB) 10-0059 (updated to Revision 5) Monitoring Plan
- Removed 08-0042 Fire propagation from electrical cabinets (Did not screen any cabinets due to being sealed construction) 08-0044 Large spill oil fire size (not used) 14
Attachment Change Summary Attachment J (Fire Modeling V&V)
- Regenerated due to changes in Fire Modeling Attachment K (Licensing Actions)
- LAR Supplement transitions 5 Deviations (12, 16, 36, 42 & 43)
- Original LAR transitioned 23 NRC-approved Deviations
- 13 Deviations not required per New GL 86-10 evaluations
- 5 Deviations not required under NFPA 805 Separation requirements 15
Attachment Change Summary Attachment S (Plant Modifications and Implementation Items)
Table S-1 Revised/New S1-1 revised list of MOVs due to IN 92-18 Evaluation Update S1-5 Removed ERFBS (fire wrap) requirements for Fire Areas RAB 2, RAB 5, RAB 17 S1-8 Updated text in Risk Informed Characterization column S1-14 (New) Action to remove combustibles from Fire Area RAB 27 S1-15 (New) Added MOVs to modify to eliminate IN 92-18 failure mechanism on valves that their failure is undesirable, however are not credited in the FREs.
Table S-1 Deletions S1-2 no MOVs needed to modify for NPO.
S1-3 HEAF Barrier in RAB 8(c) not required S1-4 Radiant Barrier in RAB 2 not required S1-6 Recovery Actions that required additional lighting (local operation of HVAC components) not required 16
Attachment Change Summary Attachment S (Plant Modifications and Implementation Items) o Table S-2 Items S2-8 Revised to add procedure EN-DC-161 Control of Combustibles to support DID recommendations S2-21 (New) Revise surveillance procedure to preserve fire scenario-specific mission time assumptions in Fire PRA for selected Nitrogen Accumulators S2-22 (New) Verify the validity of the analysis results post-mod and procedure updates S2-9 Deleted, floor markings are not required 17
Attachment Change Summary Attachment T (NRC Clarifications) 2 previous Clarifications deleted due to completion of new GL 86-10 Evaluations Control Room Barrier EDG removable wall panels Attachment U (Internal Events PRA Quality)
- Regenerated due to revised models and Focused Peer Reviews
- 51 Total F&Os
- All 37 Impacting FPRA Closed
- 14 Open F&Os with no impact on FPRA
- 8 deal with Flooding Analysis
- 6 related to internal PRA documentation 18
Attachment Change Summary Attachment V (Fire PRA Quality)
Updated to include F&Os and corresponding dispositions from new Focused Scope Peer Review of the Fire PRA Removed Section V.2 which provided Alternate Methods Sensitivity Attachment W (Fire PRA Insights)
- Regenerated due to revised Fire PRA and FREs 19
Resulting Fire Area Ranking Supplement LAR rank rank CDF CDF Notes RAB 1 1 6.90E-06 3 3.17E-06 Doubled due to detailed MCR abandonment analysis Similar number - increase due to multi-compartment and sensitive electronic issues, but reduced due to re-mapping RAB 7 2 4.33E-06 2 3.67E-06 corrections Updated number smaller by factor of 10 primarily due to RAB 8 3 2.55E-06 1 1.63E-05 component mapping (limited dual bus failures)
TGB much higher now due to removal of oil fire split fraction TGB 4 1.01E-06 20 3.12E-08 and use of plant specific suppression reliability RAB 15 5 3.84E-07 7 5.63E-07 Higher due to removal of split fraction method for EDG fire RAB 16 6 3.01E-07 14 1.43E-07 Higher due to removal of split fraction method for EDG fire Increase due to update transient methodology (higher HRR RAB 31 7 1.92E-07 18 3.55E-08 with larger ZOI = more targets).
Yard was redefined to include Fire Pump House and YARD 8 1.37E-07 5 7.88E-07 Condensate Polisher Bldg Reduced due to removal of HVAC requirements from PRA RAB 2 36 1.20E-09 4 3.00E-06 model for many areas.
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Resulting Scenario Ranking (Top 9)
% Total % Total LAR Scenario CDF CDF Supplement Scenario CDF CDF 31AB SWGR Fire with HEAF 1.12 E-5 32.8 MCR Transient Fire w/ HVAC 2.43 E-6 15.0 Aux Panel 4 Fire 2.82 E-6 8.3 3B SWGR Fire with HEAF 7.17 E-7 4.4 1B SWGR Fire (7kV) 1.33 E-6 3.9 MCR Transient Fire w/ No HVAC 7.16 E-7 4.4 Relay Room Fixed Source Fire CP-10 Fire 1.03 E-6 3.0 MCA 6.64 E-7 4.1 3B SWGR Fire with Relay Room Transient Fire in RAB HEAF 7.46 E-7 2.2 7A 5.24 E-7 3.2 Relay Room Fixed Source Fire Oil Fire A & B Chillers 6.88 E-7 2.0 MCA 4.42 E-7 2.7 Chilled Water Pump A Oil Relay Room Fixed Source Fire Fire (Moderate) 6.61 E-7 1.9 MCA 4.42 E-7 2.7 Chilled Water Pump B Oil MCR Electrical Cabinet Fire with Fire (Severe) 6.61 E-7 1.9 HVAC and abandonment 4.42 E-7 2.7 MCR Electrical Cabinet Fire with ESFAS 3A Panel Fire 5.65 E-7 1.7 No HVAC and abandonment 3.03 E-7 1.9 21
Resulting Impacts Original LAR Supplement Risk CDF 3.4 E-5 1.62 E-5 CDF 8.4 E-6 2.31 E-6 LERF 7.3E-7 2.89 E-6 LERF 1.1E-7 1.29 E -7 Number of Mods MOVs 15 22 ERFBS (wrap) 4 1 HEAF Barrier 1 0 Radiant Barrier 1 0 Code Compliance 7 7 Recovery Actions 30 4 Same RA in 4 Areas 22
Resulting Impacts RAIs Information contained in many RAI responses is superseded by the Supplement and supporting documentation/analysis Some RAI responses provided description of methodology, results of preliminary analysis or sensitivity studies, with indication of pending future analysis.
In most cases, the descriptions remain valid, however, the numerical values in the LAR Supplement supersede those in the RAI.
In some cases, the reanalysis replaces the RAI response information in total.
Some RAIs are no longer applicable as the methods in question have been replaced with methods that are believed to be acceptable.
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Resulting Impacts RAIs RAI Responses Superseded by LAR Supplement 1 PRA-01 PRA-20 PRA-33 PRA-45 PRA-56 PRA-07 PRA-21 PRA-34 PRA-47 PRA-57 PRA-12 PRA-23 PRA-35 PRA-50 PRA-58(b)
PRA-13 PRA-28 PRA-38 PRA-51 PRA-59 PRA-16 PRA-29 PRA-42 PRA-53 FPE-05 PRA-17 PRA-32 PRA-44 PRA-54(d) SS-14 PRA-18 1 Preliminary Review 24
Resulting Impacts RAIs1 PRA-06 & PRA-40 The methodology discussion in the below RAI responses remain valid, however, the numerical results from the Supplement should be used in lieu of data from the RAI responses due to new or revised analysis.
PRA-11, PRA-43, PRA-52, SS-02, SS-02.01 a(iii), & SS-06 Revisions to Table S-1 supersedes information in the RAIs.
SS-07, SS-08, & SS-13 Attachment G revisions supersedes information in the RAIs.
PRA-05 Nitrogen accumulator availability duration is 24 hrs SS-01 NSCA calculation is EC-F13-001, not revision to ECF00-026 1 Preliminary Review 25
Responses to Draft PRA RAIs RAI # Subject Disposition Basis Refernece Explain how plausible secondary ignition Explain: Actual analysis PRA-W3-05-006T PRA RAI 01.01 sources are defined performed PRA-W3-05-006F FRE description should clarify how ignition This process is only briefly PRA RAI 04.01 frequency and CCDP are considered together covered in the FRE(s) but is in with other aspects of the fire scenario, such very good detail in the DID as propagation, detection, and suppression. report (WF3-FP-13-0004). WF3-FP-13-0004 Did FRE results include UAMs as basis for PRA RAI 10.01 evaluation risk No UAMs, see FM-07 response N/A no UAMs Analysis accounts for Sensitive PRA RAI 16.01 Impact to sensitive electronics in non- electronics, see FM-07 PRA-W3-05-006T adjacent cabinets response PRA-W3-05-006F 15 minutes for the manual non-suppression probability is listed time to damage for Cite references for 15 min PRA RAI 25.01 secondary cable targets of 19 minutes from assumption and sensitive PRA-W3-05-006T NUREG/CR-6850" electronics sensitivity study PRA-W3-05-006F PAU ceiling heights of 7 or 12 ft, or the PRA RAI 29.01 (a) assumed cabinet height of 7 ft, describe how Explain: Analysis used actual PRA-W3-05-005 the generic methodology is applied ceiling heights Rev 1 Reference is made to two groupings for New methodology conforms to PRA RAI 29.01 (b) HRRs, 69 kW and 702 kW. It is unclear 6850, RAI is no longer PRA-W3-05-005 where these groupings arise applicable Rev 1 With regard to the 69 kW HRR grouping Explain: 69 kw not used. See PRA-W3-05-005 PRA RAI 29.01 (c) discussed in (b), Clarify HGL screening FM-07 for HGL discussion Rev 1 PRA RAI 43.01 Clarify which S table items are in PRA model Explain S-1 & S-2 mods. Attachment S 26
Responses to Draft PRA RAIs (cont.)
RAI # Subject Disposition Basis Refernece PRA RAI 44.01 (a) PRA data counting method Explain with requested justification Attachment U PRA RAI 44.01 (b) The action associated with this RAI (operation of SI-120/121) is HEP value based on timing change no longer credited (CSD) PRA-W3-05-003 PRA RAI 44e and stated that the assumed HEP value for EHFMANTNR PRA RAI 44.01 (c) has no impact on the FPRA results since the event does not appear in a EHFMANTNR in cutset with CDF ~1E-13 in IEPRA. Not in Fire single cutset PRA cutset due to truncation PSA-WF3-01-HR PRA RAI 44.01 (d) WCT success criteria Explain: modeled now PRA-WF3-01-SC The explanation of modeling of the PRA RAI 44.01 (e) battery in RAI PRA 44h, but did not provide sufficient information Explain: Add detail PSA-WF3-01-SYS Loss of inventory over time considered Explain: 1/3 acceptable flow diversion may impact inventory over PRA RAI 44.01 (f) with flow diversions in Fire PRA? time. This consequence in FPRA? PRA-W3-05-040 PRA RAI 53.01 Modeling of SOVs in Fire PRA including SOV hot shorts included with actuator failure as appropriate SOV's that are part of AOV's (EFW valves, for example) PSA-W3-03-01 Clarify "the non-compliant case includes PRA RAI 58.01 (a) basic events that no credit can be given PSA-WF3-03-01 to when compliant with NFPA 805" Explain: eliminate use of confusing verbiage RSC 13-19 PRA RAI 58.01 (b), Explain "True" as used in Franx and The term/verbiage "True" is not longer in the supporting No longer (c), (d) FPRA Fault trees documentation applicable Open status in the previous submitted LAR meant that the associated VFDR had a proposed modification associated with it.
The updated LAR B-3 does not use the term open and has No longer VFDRs with "Open" Status more specific status classifications. applicable HEP is set to a value of TRUE then the PRA RAI 60 joint human error probability (JHEP) is set to 0. Explain: model should already be fixed PRA-W3-05-043 How failure to isolate component PRA RAI 61 (a) cooling water (CCW) is modeled in FPRA Explain: how are CCW cross connects handled in model PRA-W3-05-040 How CCW makeup modeled in FPRA. PRA-W3-05-040 was done and the result was to add the CCW makeup system is not included in CCWMU support to the model. Basically any size flow diversion PRA RAI 61 (b) the FPRA according to Table B-3 of the in CCW may require makup since it is closed loop with fixed LAR inventory. The makup function is not explictly modeled. PRA-W3-05-040 27
Conclusions o LAR Supplement
- Addresses RAIs
- Provides results using methods described in NUREG/CR-6850 Overall Risk Results are comparable to original LAR Minimal Changes to list of Modifications and Implementation Items o Waterford 3 will support any additional working level meeting(s) on technical details necessary for RAI closure.
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Questions?