ML17310B232
| ML17310B232 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie, Point Beach, Seabrook, Turkey Point  |
| Issue date: | 11/07/2017 |
| From: | Florida Power & Light Co, Nextera Energy |
| To: | |
| PooleJ, NRR/DORL/LPL1 | |
| Shared Package | |
| ML17310B213 | List: |
| References | |
| EPID L-2017-LRC-0000 | |
| Download: ML17310B232 (19) | |
Text
1 GSI-191 Issue Resolution Pre-submittal Meeting September 20, 2017
2 ATTENDEES Larry Nicholson - Director Licensing & Regulatory Affairs Dan Forter - Senior Director of Projects Jarrett Mack - NextEra Licensing Paul Leonard - ENERCON Tom McCarthy - ENERCON Introductions / Opening Remarks
3 The foundation for everything we do are the Values and Core Principles of our Nuclear Excellence Model
4 Introductions / Opening Remarks Purpose and Desired Outcome General Approach for Fleet St. Lucie Unit 1 and Unit 2 Resolution Approach Turkey Point Unit 3 Resolution Approach Turkey Point Unit 4 Resolution Approach Point Beach Unit 1 and Unit 2 Resolution Approach Seabrook Resolution Approach NEI 04-07 Section 6 - Alternate Evaluation Methodology Conclusion Next Steps Agenda
5 Purpose Present the resolution approaches being taken for each PWR plant in the fleet Gain feedback from the NRC staff as to additional information for the submittals that would facilitate their review Desired Outcome NextEra/FPL and NRC have mutual understanding of the general content to be contained in the submittals to support closure Alignment on path forward and timing on plant submittals Purpose and Desired Outcome
6 All Plants In NextEra/FPL Fleet Utilizing Option 2a from SECY-12-0093 In-vessel debris loading utilizing methodology from WCAP-17788 (under NRC review)
Content of Submittals Aligned With NRC Guidance Revised Content Guide (November 2007)
NRC Staff Review Guidance for Head Loss, Coating, and Chemical Effects (March 2008)
Stand-Alone Submittals Submittals do not refer to previous submittals Previous RAIs will not be specifically addressed (by calling them out) but will have sufficient information in the submittal to support their closure, if still applicable Submittals provide reasonable assurance that the necessary attributes have been satisfied to demonstrate the capability of each plant to mitigate the very low probability event from impacting the health and safety of onsite personnel and the public.
General Approach for Fleet
7 Overall Approach Is Fully Deterministic All aspects of the Revised Content Guide and Staff Review Guidance were addressed with fully deterministic approaches and methodologies previously accepted by the NRC, except for in-vessel fiber loading (WCAP-17788 - under NRC review)
PSL1 now has 7,244 ft2 strainer (GE), PSL2 has 5,607 ft2 strainer (PCI)
Debris generation considered DEGBs at all ISI Class 1 welds inside first isolation valve from 0.5 to 42 diameter Strainers fully submerged during recirculation Unit specific head loss and penetration (bypass) testing was performed, with a portion of one head loss tested observed by NRC staff at the test lab Debris quantities above calculated transport quantities used for testing to provide operational margin Strainer head loss and NPSH determination demonstrate that operating margin is available Coatings generation and transport aligned with NRC expectations Ex-vessel downstream effects demonstrated no blockage or wear concerns Chemical effects conservatively determined chemical precipitates based on aluminum quantities used for initial licensing and hydrogen generation analysis.
Completed walkdowns determined significantly lower aluminum quantities Fuel rod debris loading (LOCADM) acceptance criteria is met for all break sizes In-vessel debris loading analysis per WCAP-17788 demonstrated quantities below the current limits for AREVA fuel (U2 transitioning)
St. Lucie Unit 1 and Unit 2 Resolution Approach
8 Overall Approach Is Fully Deterministic All aspects of the Revised Content Guide and Staff Review Guidance were addressed with fully deterministic approaches and methodologies previously accepted by the NRC, except for in-vessel fiber loading (WCAP-17788 - under NRC review)
PTN3 now has 4,699 ft2 strainer (GE)
Debris generation considered DEGBs at all ISI Class 1 welds inside first isolation valve from 0.5 to 31 diameter Strainers fully submerged during recirculation Using PSL1 head loss testing to bound PTN3 head loss Using Diablo Canyon penetration (bypass) testing to bound PTN3 penetration Strainer head loss and NPSH determination demonstrate that operating margin is available Coatings generation and transport aligned with NRC expectations Ex-vessel downstream effects demonstrated no blockage or wear concerns Chemical effects conservatively determined chemical precipitates based on aluminum quantities post-EPU Fuel rod debris loading (LOCADM) acceptance criteria is met for all break sizes In-vessel debris loading analysis per WCAP-17788 demonstrated quantities below the current limits for Westinghouse fuel Turkey Point Unit 3 Resolution Approach
9 Overall Approach Utilizes Fully Deterministic and Section 6 Approach All aspects of the Revised Content Guide and Staff Review Guidance were addressed with fully deterministic approaches and methodologies previously accepted by the NRC, except for strainer head loss and in-vessel fiber loading (WCAP-17788 - under NRC review)
Strainer head loss resolution utilizes NEI 04-07 Section 6 Alternate Evaluation Methodology for breaks larger than 23 PTN4 now has 3,600 ft2 strainer (PCI)
Debris generation considered DEGBs and partial breaks at all ISI Class 1 welds inside first isolation valve from 0.5 to 31 diameter. Partial breaks (hemispherical ZOI) taken at 45o intervals around circumference of pipe Strainers fully submerged during recirculation Unit specific head loss and penetration (bypass) testing was performed Deterministic head loss criteria met for all breaks up to 23 Point Beach head loss testing used to bound all PTN4 breaks >23 up to 31 Deterministic penetration criteria met for all breaks up to 31 Strainer head loss and NPSH determination demonstrate that operating margin is available for both Region I and Region II breaks Region II breaks use pre-event air partial pressure for determination of NPSH available. Containment accident pressure was not utilized.
Turkey Point Unit 4 Resolution Approach
10 Coatings generation and transport aligned with NRC expectations Ex-vessel downstream effects demonstrated no blockage or wear concerns Chemical effects conservatively determined chemical precipitates based on aluminum quantities post-EPU Fuel rod debris loading (LOCADM) acceptance criteria is met for all break sizes In-vessel debris loading analysis per WCAP-17788 demonstrated quantities below the current limits for Westinghouse fuel The Turkey Point Unit 3 and Unit 4 Resolution Contained In Combined Submittal Turkey Point Unit 4 Resolution Approach (continued)
11 Overall Approach Utilizes Fully Deterministic and Section 6 Approach All aspects of the Revised Content Guide and Staff Review Guidance were addressed with fully deterministic approaches and methodologies previously accepted by the NRC, except for strainer head loss and in-vessel fiber loading (WCAP-17788 - under NRC review)
Strainer head loss resolution utilizes NEI 04-07 Section 6 Alternate Evaluation Methodology for breaks larger than 17 PBN1 and PBN2 now have 1904.6 ft2 strainers (PCI) for each of the separate and independent trains Debris generation considered DEGBs and partial breaks at all ISI Class 1 welds inside first isolation valve from 0.5 to 31 diameter. Partial breaks (hemispherical ZOI) taken at 45o intervals around circumference of pipe Strainers fully submerged during recirculation Bounding (PBN1 and PBN2) head loss testing was performed assuming a single strainer train in service Deterministic head loss criteria met for all breaks up to 17 To bound all breaks >17 up to 31, assumption made that both strainer trains in service Bounding (PBN1 and PBN2) penetration (bypass) testing was performed assuming both strainer trains in service Deterministic penetration criteria met for all breaks up to 31 Point Beach Unit 1 and Unit 2 Resolution Approach
12 Strainer head loss and NPSH determination demonstrate that operating margin is available for both Region I and Region II breaks Region II breaks use cooldown of sump water and conservatively determined chemical precipitation temperatures for determination of NPSH available. Containment accident pressure was not utilized.
Coatings generation and transport aligned with NRC expectations Ex-vessel downstream effects demonstrated no blockage or wear concerns Chemical effects conservatively determined chemical precipitates based on aluminum quantities Fuel rod debris loading (LOCADM) acceptance criteria is met for all break sizes In-vessel debris loading analysis per WCAP-17788 demonstrated quantities below the current limits for Westinghouse fuel in upper plenum injection plant Submittal will include commitments to complete pending modifications that formed the basis for the completed deterministic analyses Point Beach Unit 1 and Unit 2 Resolution Approach (continued)
13 Overall Approach Utilizes Fully Deterministic and Section 6 Approach All aspects of the Revised Content Guide and Staff Review Guidance were addressed with fully deterministic approaches and methodologies previously accepted by the NRC, except for debris transport, strainer head loss, and in-vessel debris loading SBK now has 2,412 ft2 strainers (GE) for each of the separate and independent trains Debris generation considered DEGBs and partial breaks at all ISI Class 1 welds inside first isolation valve from 0.5 to 31 diameter. Partial breaks (hemispherical ZOI) taken at 45o intervals around circumference of pipe Strainers fully submerged during recirculation Debris transport for Region 2 breaks (>17) credited some fines holdup at the debris interceptors based on the testing previously performed In line with the Alternate Evaluation Methodology of NEI 04-07 Section 6 Strainer head loss and in-vessel fiber loading resolution utilizes NEI 04-07 Section 6 Alternate Evaluation Methodology for breaks larger than 17 Head loss testing was performed assuming a single strainer train in service Testing performed was GE/CDI sector testing (2 strainer disks)
Debris quantities at time of test do not bound current values however submittal provides justification for acceptance of the difference Seabrook Resolution Approach
14 PSL1 penetration (bypass) testing used to bound SBK penetration Deterministic penetration criteria met for all breaks up to 17 To bound all breaks >17 up to 31, assumption made that both strainer trains in service Strainer head loss and NPSH determination demonstrate that operating margin is available for both Region I and Region II breaks Region II breaks use pre-event air partial pressure for determination of NPSH available. Containment accident pressure was not utilized.
Coatings generation and transport aligned with NRC expectations Ex-vessel downstream effects demonstrated no blockage or wear concerns Chemical effects conservatively determined chemical precipitates based on aluminum quantities Fuel rod debris loading (LOCADM) acceptance criteria is met for all break sizes In-vessel debris loading analysis per WCAP-17788 (under NRC review) demonstrated quantities below the current limits for Westinghouse fuel Submittal will include commitment to modify the refueling cavity drain system to ensure the water that could collect there would be available for the containment sump pool Seabrook Resolution Approach (continued)
15 Break Size For plants where this approach is utilized, the smallest break that meets all traditional deterministic criteria is larger than the Debris Generation Break Size (DGBS) called out in Section 6 (Region I) 17 for PBN and SBK, 23 for PTN4 Though not being specifically credited, the risk associated with these break sizes is Very Small per RG 1.174 Mitigation Approaches for Region II Break Sizes For PTN4, credit is being taken for pre-event air partial pressure to ensure acceptable NPSH margin is maintained For PBN, credit is being taken for having two trains in service during the most limiting sump recirculation conditions to ensure acceptable NPSH margin is maintained RHR pumps are only pumps that take direct suction from strainers Provides for debris to be divided between the two independent strainers For SBK, credit is being taken for having two complete trains of ECCS and CBS in service to ensure acceptable NPSH margin is maintained and flow split is considered for in-vessel debris loading Credit for strainer backwash may be taken for those plants where it can be accomplished (PBN and PTN4)
Credit for pump or train swap to place non-debris laden strainer in service may be taken (PBN and SBK)
NEI 04-07 Section 6 - Alternate Evaluation Methodology
16 Mitigation Approaches for Region II Break Sizes (continued)
Credit for other water sources or cross-ties from unaffected Unit may be taken (PTN and SBK)
Credit for non-safety related equipment may be taken Containment coolers (SBK)
FLEX equipment (SBK)
Procedure changes and training will occur after NRC agreement with specific approach NEI 04-07 Section 6 - Alternate Evaluation Methodology
17 Significant effort has been taken by all plants to provide reasonable assurance that in the unlikely event that a LOCA did occur, the plant would be able to protect the health and safety of on-site personnel and the public As stated in SRM-SECY-12-0093, the plants have demonstrated adequate defense-in-depth as a result of:
Installed vastly enlarged advanced strainers Compensatory measures already taken Low probability of challenging pipe breaks The approaches outlined demonstrate mitigative capability and adequate defense-in-depth without the need for further and extensive efforts except for those few committed items Significant conservatisms exist in the treatment of potential LOCA scenarios and the debris generated from them The assumption that RCS piping will instantaneously fail and fully separate is in contrast to the mechanistic evaluations that were performed which allowed plants to credit Leak-Before-Break (GDC-4)
The quantity and size of debris generated from a LOCA has been very conservatively established Conclusions
18 Significant conservatisms exist in the treatment of potential LOCA scenarios and the debris generated from them (continued)
The transport of debris to the sump strainers has been very conservatively estimated without reasonable credit being taken for debris holdup in containment and agglomeration of debris enabling much of the debris to settle in lower turbulence regions of the containment sump pool The formation of chemical precipitates has been very conservatively established without credit for the specific types of precipitate that would be expected to form, and the timing and quantity of precipitate formation that would be expected based on sump pool concentrations The approach taken for determination of the quantity of fine fiber debris that would pass through the strainer and transport to the reactor vessel is very conservative since testing is only performed with fiber Fiber and particulates will agglomerate in the sump pool limiting the quantity of fines that will pass through the strainer Conclusions
19 Following this meeting, NextEra/FPL will incorporate any necessary learnings in the submittals If necessary, plant specific discussions will be held to ensure the appropriate content is provided to the NRC The submittals will be sent to the NRC for their review The current timeline anticipates this will occur within approximately the next month It is anticipated that following the NRC review, closeout letters can be issued to each plant It is also understood that the closeout letters will address all aspects except for the specific debris loading determined for in-vessel effects as provided by WCAP-17788 which is currently under NRC review Next Steps