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
Waterford 3 - NRC Public Meeting February 4, 2014 1
Introduction Changes to Supporting Analyses Resulting Impact to:
x Risk (CDF, LERF) x Modifications and Implementation Items x Recovery Actions LAR Attachment Change Summary Comparison of Risk Areas to Original LAR Impact on RAIs Questions/General Discussion 2
Agenda
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
Introduction
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 Internal Events 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
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 Addressed RAIs Related to PRA Methods
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 RAIs Addressed in Supplement
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 Changes to Supporting Analysis Nuclear Safety Capability Assessment (NSCA)
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
Results due to Analysis Changes Fire Risk Evaluations (FREs)
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
11 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
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 x Single Action (Manually Trip RCP Motor Breakers in TGB Switchgear) x 4 Fire Areas (RAB 1, RAB 7, RAB 8, TGB) 13 Attachment Change Summary
Attachment H (FAQs)
- Updated to reflect revised FPRA methods
- Added x 06-0016 Ignition source counting guidance for Electrical Cabinets x 06-0017 Ignition source counting guidance for High Energy Arcing Faults (HEAF) x 06-0018 Ignition source counting guidance for Main Control Board (MCB) x 10-0059 (updated to Revision 5) Monitoring Plan
- Removed x 08-0042 Fire propagation from electrical cabinets (Did not screen any cabinets due to being sealed construction) x 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 x S1-1 revised list of MOVs due to IN 92-18 Evaluation Update x S1-5 Removed ERFBS (fire wrap) requirements for Fire Areas RAB 2, RAB 5, RAB 17 x S1-8 Updated text in Risk Informed Characterization column x S1-14 (New) Action to remove combustibles from Fire Area RAB 27 x 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 x S1-2 no MOVs needed to modify for NPO.
x S1-3 HEAF Barrier in RAB 8(c) not required x S1-4 Radiant Barrier in RAB 2 not required x 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 x S2-8 Revised to add procedure EN-DC-161 Control of Combustibles to support DID recommendations x S2-21 (New) Revise surveillance procedure to preserve fire scenario-specific mission time assumptions in Fire PRA for selected Nitrogen Accumulators x S2-22 (New) Verify the validity of the analysis results post-mod and procedure updates x S2-9 Deleted, floor markings are not required 17 Attachment Change Summary
Attachment T (NRC Clarifications) x 2 previous Clarifications deleted due to completion of new GL 86-10 Evaluations x Control Room Barrier x 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) x Updated to include F&Os and corresponding dispositions from new Focused Scope Peer Review of the Fire PRA x Removed Section V.2 which provided Alternate Methods Sensitivity Attachment W (Fire PRA Insights)
- Regenerated due to revised Fire PRA and FREs 19 Attachment Change Summary
20 Resulting Fire Area Ranking Supplement rank CDF LAR rank CDF Notes RAB 1 1
6.90E-06 3
3.17E-06 Doubled due to detailed MCR abandonment analysis RAB 7 2
4.33E-06 2
3.67E-06 Similar number - increase due to multi-compartment and sensitive electronic issues, but reduced due to re-mapping corrections RAB 8 3
2.55E-06 1
1.63E-05 Updated number smaller by factor of 10 primarily due to component mapping (limited dual bus failures)
TGB 4
1.01E-06 20 3.12E-08 TGB much higher now due to removal of oil fire split fraction 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 RAB 31 7
1.92E-07 18 3.55E-08 Increase due to update transient methodology (higher HRR with larger ZOI = more targets).
YARD 8
1.37E-07 5
7.88E-07 Yard was redefined to include Fire Pump House and Condensate Polisher Bldg RAB 2 36 1.20E-09 4
3.00E-06 Reduced due to removal of HVAC requirements from PRA model for many areas.
21 Resulting Scenario Ranking (Top 9)
% Total CDF Supplement Scenario CDF
% Total 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 CP-10 Fire 1.03 E-6 3.0 Relay Room Fixed Source Fire MCA 6.64 E-7 4.1 3B SWGR Fire with HEAF 7.46 E-7 2.2 Relay Room Transient Fire in RAB 7A 5.24 E-7 3.2 Oil Fire A & B Chillers 6.88 E-7 2.0 Relay Room Fixed Source Fire MCA 4.42 E-7 2.7 Chilled Water Pump A Oil Fire (Moderate) 6.61 E-7 1.9 Relay Room Fixed Source Fire MCA 4.42 E-7 2.7 Chilled Water Pump B Oil Fire (Severe) 6.61 E-7 1.9 MCR Electrical Cabinet Fire with HVAC and abandonment 4.42 E-7 2.7 ESFAS 3A Panel Fire 5.65 E-7 1.7 MCR Electrical Cabinet Fire with No HVAC and abandonment 3.03 E-7 1.9
22 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
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.
x In most cases, the descriptions remain valid, however, the numerical values in the LAR Supplement supersede those in the RAI.
x 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.
23 Resulting Impacts RAIs
RAI Responses Superseded by LAR Supplement 1 24 Resulting Impacts RAIs 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
PRA-06 & PRA-40 x 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 x Revisions to Table S-1 supersedes information in the RAIs.
SS-07, SS-08, & SS-13 x Attachment G revisions supersedes information in the RAIs.
PRA-05 x Nitrogen accumulator availability duration is 24 hrs SS-01 x NSCA calculation is EC-F13-001, not revision to ECF00-026 25 Resulting Impacts RAIs1 1 Preliminary Review
26 26 Responses to Draft PRA RAIs RAI #
Subject Disposition Basis Refernece PRA RAI 01.01 Explain how plausible secondary ignition sources are defined Explain: Actual analysis performed PRA-W3-05-006T PRA-W3-05-006F PRA RAI 04.01 FRE description should clarify how ignition frequency and CCDP are considered together with other aspects of the fire scenario, such as propagation, detection, and suppression.
This process is only briefly covered in the FRE(s) but is in very good detail in the DID report (WF3-FP-13-0004).
WF3-FP-13-0004 PRA RAI 10.01 Did FRE results include UAMs as basis for evaluation risk No UAMs, see FM-07 response N/A no UAMs PRA RAI 16.01 Impact to sensitive electronics in non-adjacent cabinets Analysis accounts for Sensitive electronics, see FM-07 response PRA-W3-05-006T PRA-W3-05-006F PRA RAI 25.01 15 minutes for the manual non-suppression probability is listed time to damage for secondary cable targets of 19 minutes from NUREG/CR-6850" Cite references for 15 min assumption and sensitive electronics sensitivity study PRA-W3-05-006T PRA-W3-05-006F PRA RAI 29.01 (a)
PAU ceiling heights of 7 or 12 ft, or the assumed cabinet height of 7 ft, describe how the generic methodology is applied Explain: Analysis used actual ceiling heights PRA-W3-05-005 Rev 1 PRA RAI 29.01 (b)
Reference is made to two groupings for HRRs, 69 kW and 702 kW. It is unclear where these groupings arise New methodology conforms to 6850, RAI is no longer applicable PRA-W3-05-005 Rev 1 PRA RAI 29.01 (c)
With regard to the 69 kW HRR grouping discussed in (b), Clarify HGL screening Explain: 69 kw not used. See FM-07 for HGL discussion PRA-W3-05-005 Rev 1 PRA RAI 43.01 Clarify which S table items are in PRA model Explain S-1 & S-2 mods.
Attachment S
27 27 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)
HEP value based on timing change The action associated with this RAI (operation of SI-120/121) is no longer credited (CSD)
PRA-W3-05-003 PRA RAI 44.01 (c)
PRA RAI 44e and stated that the assumed HEP value for EHFMANTNR has no impact on the FPRA results since the event does not appear in a single cutset EHFMANTNR in cutset with CDF ~1E-13 in IEPRA. Not in Fire PRA cutset due to truncation PSA-WF3-01-HR PRA RAI 44.01 (d)
WCT success criteria Explain: modeled now PRA-WF3-01-SC PRA RAI 44.01 (e)
The explanation of modeling of the battery in RAI PRA 44h, but did not provide sufficient information Explain: Add detail PSA-WF3-01-SYS PRA RAI 44.01 (f)
Loss of inventory over time considered with flow diversions in Fire PRA?
Explain: 1/3 acceptable flow diversion may impact inventory over time. This consequence in FPRA?
PRA-W3-05-040 PRA RAI 53.01 Modeling of SOVs in Fire PRA including SOV's that are part of AOV's SOV hot shorts included with actuator failure as appropriate (EFW valves, for example)
PSA-W3-03-01 PRA RAI 58.01 (a)
Clarify "the non-compliant case includes basic events that no credit can be given to when compliant with NFPA 805" Explain: eliminate use of confusing verbiage PSA-WF3-03-01 RSC 13-19 PRA RAI 58.01 (b),
(c), (d)
Explain "True" as used in Franx and FPRA Fault trees The term/verbiage "True" is not longer in the supporting documentation No longer applicable PRA RAI 58.01 (e)
VFDRs with "Open" Status 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 more specific status classifications.
No longer applicable PRA RAI 60 HEP is set to a value of TRUE then the joint human error probability (JHEP) is set to 0.
Explain: model should already be fixed PRA-W3-05-043 PRA RAI 61 (a)
How failure to isolate component cooling water (CCW) is modeled in FPRA Explain: how are CCW cross connects handled in model PRA-W3-05-040 PRA RAI 61 (b)
How CCW makeup modeled in FPRA.
CCW makeup system is not included in the FPRA according to Table B-3 of the LAR PRA-W3-05-040 was done and the result was to add the CCWMU support to the model. Basically any size flow diversion in CCW may require makup since it is closed loop with fixed inventory. The makup function is not explictly modeled.
PRA-W3-05-040
o LAR Supplement
- Addresses RAIs
- Provides results using methods described in NUREG/CR-6850 x Overall Risk Results are comparable to original LAR x 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.
28 Conclusions
Questions?