Letter Sequence Request |
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CAC:MF2400, Control Room Habitability (Approved, Closed) CAC:MF2402, Control Room Habitability (Approved, Closed) |
Administration
- Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting
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MONTHYEARML15274A5992015-10-0101 October 2015 10-01-15 Public Phone Call Project stage: Request ML16011A0612016-02-0202 February 2016 Summary of 10/1/15 Meeting with STP Nuclear Operating Company to Discuss Revised Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 at South Texas Project, Units 1 and 2 (CAC MF Project stage: Meeting ML16028A1522016-02-18018 February 2016 1/14/2016 Summary of Public Meeting with STP Nuclear Operating Company Regarding Modifications to the Licensee'S Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 Project stage: Meeting ML16088A2432016-04-0101 April 2016 2/18/2016, Summary of Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2400-MF2409) Project stage: Meeting ML16092A0442016-04-11011 April 2016 Summary of 3/3/2016 Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2400-MF2409) Project stage: Meeting ML16082A5072016-04-11011 April 2016 Request for Additional Information, Phased Response Requested, Exemption and License Amendment Request for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 (CAC Nos. MF2400-MF2409) Project stage: RAI ML16095A0102016-04-13013 April 2016 Summary of November 17-19, 2015 Thermal-Hydraulic Review at Texas A&M University; Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 (CAC MF2400-MF2409) Project stage: Other ML16092A0852016-04-13013 April 2016 3/17/2016 Summary of Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2401-MF2409) Project stage: Meeting ML16096A0652016-04-13013 April 2016 Summary of February 4 and 16, 2016, Regulatory Audit at Westinghouse in Rockville, MD, Boric Acid Precipitation, Exemption and License Amendment Request, Risk-Informed Approach to Resolve Generic Safety Issue 191 Project stage: Other ML16111A0272016-04-18018 April 2016 STP Nuclear Operating Company Slideshow for Public Meeting on April 21, 2016 for GSI-191 Resolution (CAC No. MF2400-01) Project stage: Meeting ML16103A3442016-04-26026 April 2016 Summary of February 24-26, 2016 Audit, Debris Transport Review at Alion Science and Technology Corporation, Albuquerque, Nm; Pilot Submittal and Exemption Request, Risk-Informed Approach to Resolve GSI 191 Project stage: Other ML16032A4032016-04-26026 April 2016 FRN, Draft Environmental Assessment and Finding of No Significant Impact, Revise Licensing Basis as Documented in the UFSAR and Request for Exemptions, Risk-Informed Approach to Address GSI-191 (CAC MF2400-MF2409) Project stage: Draft Other ML16032A3872016-04-26026 April 2016 Draft Environmental Assessment and Finding of No Significant Impact, Revise Licensing Basis as Documented in the UFSAR and Request for Exemptions, Risk-Informed Approach to Address GSI-191 (CAC MF2400-MF2409) Project stage: Draft Other ML16127A4002016-05-11011 May 2016 Audit Summary, Thermal-Hydraulic Review on February 23-25, 2016 at Texas A&M University; Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue 191 (CAC MF2400-MF2409) Project stage: Other ML16125A2902016-05-26026 May 2016 Request for Additional Information, Risk Review, Exemption and License Amendment Request for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 (CAC Nos. MF2400-MF2409) Project stage: RAI ML16141B0812016-05-31031 May 2016 Audit Summary, Risk Audit on April 12-13, 2016, at Alumni Center at the University of Texas, Austin, Tx; Pilot Generic Safety Issue 191 Submittal and Exemption Request, and Draft Request for Additional Information Project stage: Draft RAI ML16175A1082016-06-24024 June 2016 Summary of 4/21/2016 Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 Project stage: Meeting ML16190A0082016-07-13013 July 2016 Summary of 6/22/2016 Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2400-MF2409) Project stage: Meeting ML16194A2342016-07-21021 July 2016 Request for Withholding Information from Public Disclosure - 5/6/16 Affidavit Executed by D. Munoz and M. Rozboril, Alion Science and Technology, Response to Follow-up RAIs 18, 38, and 44 Project stage: RAI ML16242A0102016-08-23023 August 2016 NRR E-mail Capture - (External_Sender) FW: South Texas Project GSI-191 Draft Risk Responses to Questions for Public Meeting on August 29, 2016 Project stage: Request ML16242A0092016-08-25025 August 2016 NRR E-mail Capture - (External_Sender) South Texas Project GSI-191 Draft thermal-hydraulic Responses to Questions for Public Meeting on August 29, 2016 Project stage: Request ML16238A5272016-09-0101 September 2016 Summary of 7/28/16, Public Meeting with STP Nuclear Operating Company to Discuss the License Amendment and Exemption Requests to Use a Risk-Informed Approach to the Resolution of GSI-191 (CAC Nos. MF2400 - MF2409) Project stage: Meeting ML16258A3672016-09-0606 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution SNPB-3-2, Bullet 4 16 -inch Bounding Break Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A1002016-09-12012 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI APLA-3-2 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A1042016-09-12012 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI SNPB-3-13 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A0962016-09-13013 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI SSIB-3-4 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A0982016-09-13013 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI 33 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A2072016-09-14014 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI 37 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A2082016-09-14014 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI 34 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16246A0222016-10-0505 October 2016 Summary of Public Meeting with STP Nuclear Operating Company Regarding Open Items Related to Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2400 - MF2409) Project stage: Meeting ML16279A3312016-10-27027 October 2016 Summary of Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2400-MF2409) Project stage: Meeting ML16302A4532016-12-12012 December 2016 Closeout of Request for Additional Information Questions That Are No Longer Applicable, Resolution of Generic Safety Issue (GSI) 191 (CAC Nos. MF2400-MF2409) Project stage: RAI ML16351A1502016-12-16016 December 2016 Correction Letter Closeout of Request for Information Questions That Are No Longer Applicable Associated with the Resolution of Generic Safety Issue 191 (CAC Nos. MF2400 - MF2409) Project stage: RAI ML16278A5982017-05-0202 May 2017 Letter, Environmental Assessment and Finding of No Significant Impact, Revise Licensing Basis as Documented in the UFSAR and Request for Exemptions, Risk-Informed Approach to Address GSI-191 (CAC MF2400 to MF2409) Project stage: Other ML16278A5992017-05-0202 May 2017 Environmental Assessment and Finding of No Significant Impact, Revise Licensing Basis as Documented in the UFSAR and Request for Exemptions, Risk-Informed Approach to Address GSI-191 (CAC MF2400 to MF2409) Project stage: Other ML17137A3252017-05-17017 May 2017 Safety Evaluation of LAR by South Texas Project Nuclear Operating Company to Adopt a Risk-Informed Resolution of Generic Safety Issue-191 Project stage: Approval ML17151A8432017-06-16016 June 2017 OEDO-17-00326 - EDO Response to ACRS Chairman, Safety Evaluation of License Amendment Request by STP Nuclear Operating Company to Adopt a Risk-Informed Resolution of Generic Safety Issue-191 Project stage: Approval NRC-2016-0092, South Texas Project, Units 1 and 2 - FRN: Exemption from the Requirements of 10 CFR 50.46 and 10 CFR Part 50, Appendix a, General Design Criteria 35, 38, 41 (CAC Nos. MF2402-MF2409)2017-07-11011 July 2017 South Texas Project, Units 1 and 2 - FRN: Exemption from the Requirements of 10 CFR 50.46 and 10 CFR Part 50, Appendix a, General Design Criteria 35, 38, 41 (CAC Nos. MF2402-MF2409) Project stage: Approval ML17037C8712017-07-11011 July 2017 Letter, Exemption from the Requirements of 10 CFR Part 50, Section 50.46 (CAC Nos. MF2402-MF2409) Project stage: Approval ML17037C8762017-07-11011 July 2017 FRN: Exemption from the Requirements of 10 CFR 50.46 and 10 CFR Part 50, Appendix a, General Design Criteria 35, 38, 41 (CAC Nos. MF2402-MF2409) Project stage: Approval ML17055A5002017-07-11011 July 2017 Enclosure 4 to Amendment Nos. 212 and 198, Resolution of Licensee Comments on Safety Evaluation - Risk-Informed Approach to Resolve Generic Safety Issue 191 Project stage: Approval ML17019A0032017-07-11011 July 2017 Attachment 2 to Safety Evaluation - In-Vessel Thermal-Hydraulic Analysis, Issuance of Amendment Nos. 212 and 198 - Risk-Informed Approach to Resolve Generic Safety Issue 191 Project stage: Approval ML17038A2232017-07-11011 July 2017 Issuance of Amendment Nos. 212 and 198 - Risk-Informed Approach to Resolve Generic Safety Issue 191 Project stage: Approval ML17019A0022017-07-11011 July 2017 Safety Evaluation, Enclosure 3 to Amendment Nos. 212 and 198 - Risk-Informed Approach to Resolve Generic Safety Issue 191 Project stage: Approval 2016-05-31
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Category:E-Mail
MONTHYEARML23334A0062023-11-29029 November 2023 NRR E-mail Capture - South Texas Project - Request for Additional Information - Proposed Alternative to ASME BPV Code Requirements ML23319A4442023-11-15015 November 2023 NRR E-mail Capture - South Texas Project - Draft Request for Additional Information - Proposed Alternative to ASME BPV Code Requirements ML23278A1532023-10-0505 October 2023 NRR E-mail Capture - South Texas Project Request for Additional Information - Request for Indirect Transfer of Licenses and Conforming Amendments (L-2023-LLM-0004) ML23264A0972023-09-21021 September 2023 NRR E-mail Capture - South Texas Project - Request for Additional Information - License Amendment Request to Revise the Alternate Source Term Dose Calculation (L-2023-LLA-0047) ML23255A2862023-09-12012 September 2023 NRR E-mail Capture - South Texas Project Draft Request for Additional Information License Amendment Request to Revise the Alternate Source Term Dose Calculation (L-2023-LLA-0047) ML23191A0102023-07-0707 July 2023 NRR E-mail Capture - South Texas Project - Acceptance of Request for Indirect Transfer of Licenses and Conforming Amendments (L-2023-LLM-0004) ML23145A1872023-05-24024 May 2023 July 2023 Emergency Preparedness Program Inspection - Request for Information ML23124A3272023-05-0404 May 2023 NRR E-mail Capture - South Texas Project - Acceptance of License Amendment Request to Revise the Alternate Source Term Dose Calculation (L-2023-LLA-0047) ML23115A0702023-04-24024 April 2023 NRR E-mail Capture - South Texas Project Units 1 and 2 - Audit Plan - Proposed Alternative to ASME Code, Section XI Requirements for Containment Building Inspections ML23096A1592023-04-0606 April 2023 NRR E-mail Capture - South Texas Project - Acceptance of Requested Licensing Action - Proposed Alternative to the Requirements of the ASME Code ML23065A0912023-03-0303 March 2023 NRR E-mail Capture - South Texas Project - Draft Supplemental Information Request - Proposed Alternative to the Requirements of the ASME Code ML23003A8082022-11-28028 November 2022 NRR E-mail Capture - Texas Commission on Environmental Quality (TCEQ) Review/Comment Regarding the Draft Environmental Assessment for the South Texas Project Alternate Disposal Request (L-2021-LLL-0022)) ML22249A0692022-09-0606 September 2022 NRR E-mail Capture - South Texas Project - Acceptance of License Amendment Request Regarding Adoption of TSTF-554, Revise Reactor Coolant Leakage Requirements (L-2002-LLA-0113) ML22206A0142022-07-20020 July 2022 NRR E-mail Capture - South Texas Project - Request for Additional Information - 10 CFR 20.2002 Alternate Disposal Request ML22194A0502022-07-0707 July 2022 NRR E-mail Capture - South Texas Project - Updated Draft Request for Additional Information - 10 CFR 20.2002 Alternate Disposal Request ML22194A0492022-06-0808 June 2022 NRR E-mail Capture - South Texas Project - Draft Request for Additional Information - 10 CFR 20.2002 Alternate Disposal Request ML22123A3272022-05-0303 May 2022 STP EP Exercise Inspection July 2022 RFI ML22115A2632022-04-19019 April 2022 Email Response to David Lochbaum Regarding Interim Configuration of Holtec HI-STORE FW Spent Fuel Multipurpose Canister at South Texas Project Energy Generating Station ML22105A5642022-04-0505 April 2022 Request for Information for Problem Identification and Resolution at STP Nuclear Operating Company ML21344A0072021-12-0909 December 2021 NRR E-mail Capture - South Texas Project - Acceptance of Requested Licensing Action - Alternative Disposal Request ML21305B8022021-11-0101 November 2021 NRR E-mail Capture - South Texas Project - Acceptance of Requested Licensing Action - Inservice Inspection Impracticality ML21257A2262021-09-14014 September 2021 NRR E-mail Capture - South Texas Project - Acceptance of License Amendment Request Regarding Adoption of TSTF-577, Revised Frequencies for Steam Generator Tube Inspections (L-2021-LLA-0151) ML21160A1522021-06-0909 June 2021 Request for Information NRC Inspection 2021-003 Public Radiation Safety ML21133A2372021-05-0505 May 2021 Request for Additional Information: STP EP Exercise Inspection - July 2021 ML21117A3242021-04-22022 April 2021 NRR E-mail Capture - (External_Sender) STP Questions About Eplan Amendment SE ML21103A0072021-04-12012 April 2021 NRR E-mail Capture - South Texas Project - Acceptance of License Amendment Request to Add a Note to TS 3.6.3 and to Remove the TS Index (L-2021-LLA-0041) ML21058A0002021-02-26026 February 2021 NRR E-mail Capture - South Texas Units 1 and 2 - License Amendment Request to Revise Moderator Temperature Coefficient SRs - Audit Plan and Setup of Online Document Access (L-2021-LLA-0004) ML21049A2652021-02-16016 February 2021 NRR E-mail Capture - South Texas Project - Acceptance of License Amendment Request to Revise the Moderator Temperature Coefficient Surveillance Requirements (L-2021-LLA-0004) ML21039A8902021-02-0808 February 2021 NRR E-mail Capture - South Texas Project - Request for Additional Information - 1RE22 Inspection Summary Report for Steam Generator Tubing ML21029A3312021-01-29029 January 2021 NRR E-mail Capture - South Texas Project - Draft Request for Additional Information - 1RE22 Inspection Summary Report for Steam Generator Tubing ML20244A0222020-08-28028 August 2020 NRR E-mail Capture - South Texas Project - Acceptance of License Amendment Request to Adopt TSTF-374, Revision to TS 5.5.13 and Associated TS Bases for Diesel Fuel Oil. (L-2020-LLA-0172) ML20135H1982020-05-14014 May 2020 NRR E-mail Capture - South Texas Unit 1 - License Amendment Request to Revise Safety Injection System Accumulator Pressure - Audit Plan and Setup of Online Reference Portal ML20125A3312020-05-0404 May 2020 NRR E-mail Capture - South Texas Project - Acceptance of License Amendment Request to Revise the Emergency Plan (L-2020-LLA-0057) ML20111A0052020-04-17017 April 2020 NRR E-mail Capture - South Texas Project - Request for Additional Information - Proposed Alternative to ASME OM Code 2012 Edition - Relief Request PRR-01 ML20050E1192020-02-19019 February 2020 NRR E-mail Capture - South Texas Project - Acceptance of Requested Licensing Actions - Proposed Alternatives to ASME OM Code Requirements (EPID: L 2020-LLR-0007 to L-2020-LLR-0010) ML19344A0092019-12-0909 December 2019 NRR E-mail Capture - South Texas Project - Acceptance of Requested Licensing Action - Proposed Alternative to ASME Code Requirements for the Repair of Essential Cooling Water System Class 3 Buried Piping ML19309F1412019-11-0404 November 2019 Supplemental Information Request - Proposed Alternative to ASME Code Requirements for the Repair of Essential Cooling Water System Class 3 Buried Piping (EPID L 2019-LLR-0096) (Draft) ML19291A0332019-10-17017 October 2019 NRR E-mail Capture - Acceptance Review Results: STP License Amendment Request Regarding Request to Delete E Bar Definition ML19165A1032019-06-14014 June 2019 NRR E-mail Capture - Draft RAI for STP TS 3.8.1.1 Sbdg SR Change ML19162A1162019-05-22022 May 2019 NRR E-mail Capture - Acceptance Review Results: STP License Amendment Request Regarding TSTF-529 ML19095A6562019-04-0404 April 2019 NRR E-mail Capture - (External_Sender) Handout for 4/10/19 Meeting to Discuss a Proposed Request for South Texas Project, Units 1 and 2, Regarding Repair of Piping Using Carbon Fiber Repair Methods ML19081A1512019-03-21021 March 2019 NRR E-mail Capture - Draft Round 2 RAI - Sbdg Voltage and Frequency LAR (L-2018-LLA-0078) ML19078A3792019-03-19019 March 2019 NRR E-mail Capture - Acceptance Review Results: STP RR-ENG-3-23 (L-2018-LLR-0021) ML18292A7272018-10-19019 October 2018 NRR E-mail Capture - Acceptance Review Results: TSTF-522 (L-2018-LLA-0271) ML18283B9522018-10-10010 October 2018 NRR E-mail Capture - Final RAI - South Texas Standby DG TS Change (L-2018-LLA-0078) ML18263A1432018-09-12012 September 2018 NRR E-mail Capture - Final RAI for South Texas Project RR-ENG-E-16 (L-2018-LLR-0097) ML18190A5002018-07-0909 July 2018 NRR E-mail Capture - Acceptance Review Results - South Texas Unit 1 Relief Request - Relief Request RR-ENG-3-16 (L-2018-LLR-0097) ML18121A0322018-04-30030 April 2018 NRR E-mail Capture - Acceptance Review Results - South Texas Project Technical Specification Change for Standby Diesel Generator Surveillance Requirements Acceptance Criteria (L-2018-LLA-0078) ML18060A3062018-03-0101 March 2018 NRR E-mail Capture - Acceptance Review Results for South Texas Project Relief Request to Extend the Timeframe for Volumetric Exams of B-A and B-D Reactor Vessel Welds (L-2018-LLR-0010) ML18016A1542018-01-16016 January 2018 NRR E-mail Capture - Acceptance Review Results - South Texas Project Relief Request to Use Ultrasonic Examination Techniques in Lieu of Radiography (L-2017-LLR-0154) 2023-09-21
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Text
NRR-PMDAPEm Resource From: Harrison Albon <awharrison@STPEGS.COM>
Sent: Tuesday, September 13, 2016 4:09 PM To: Regner, Lisa; Klos, John Cc: Richards, Drew; Schulz, William
Subject:
[External_Sender] STPNOC Draft Response to SSIB Follow-up to RAI 33 Attachments: 16 Sept DRAFT adder to followup RAI 33 9-13 1400.pdf Lisa, John, Here is STPs draft response to SSIB Follow-up to RAI 33 for discussion with Steve Smith in the public call scheduled for tomorrow.
It refers to Follow up to RAI 34, which we also expect to provide prior to the call.
Wayne Harrison STP Licensing (979) 292-6413 1
Hearing Identifier: NRR_PMDA Email Number: 3055 Mail Envelope Properties (94960344217740aaa247b2d4e59aecb5)
Subject:
[External_Sender] STPNOC Draft Response to SSIB Follow-up to RAI 33 Sent Date: 9/13/2016 4:08:39 PM Received Date: 9/13/2016 4:08:44 PM From: Harrison Albon Created By: awharrison@STPEGS.COM Recipients:
"Richards, Drew" <amrichards@STPEGS.COM>
Tracking Status: None "Schulz, William" <weschulz@STPEGS.COM>
Tracking Status: None "Regner, Lisa" <Lisa.Regner@nrc.gov>
Tracking Status: None "Klos, John" <John.Klos@nrc.gov>
Tracking Status: None Post Office: CMBXEXCH03.CORP.STPEGS.NET Files Size Date & Time MESSAGE 289 9/13/2016 4:08:44 PM 16 Sept DRAFT adder to followup RAI 33 9-13 1400.pdf 208756 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:
Recipients Received:
DRAFT RESPONSE TO SSIB RAI 33 (9/13/16)
Follow-up RAI 33 - In the December 23, 2009 RAIs, the NRC staff asked the licensee to provide the margin to flashing and the assumptions for the calculation. The licensee provided a calculation for the margin to flashing for large break loss of coolant accidents (LOCAs) at the start of recirculation as (in pounds per square inch [psi]):
Containment pressure + submergence - total strainer head loss - vapor pressure
= 43.1 + 0.3 - 1.5 - 39
= 2.9 psi The licensee stated that post LOCA containment over pressure credit is needed to eliminate the potential for flashing. The licensee stated that the minimum strainer submergence was conservatively determined to be 0.5 inch for small break LOCA (SBLOCA), sump temperature and containment pressure would be lower for a SBLOCA than a large break LOCA (LBLOCA), strainer flow rate would also be lower, and debris transported to strainers would be much less such that there would be open strainer areas.
Therefore, flashing is not expected to be an issue for SBLOCAs. The NRC guidance 1 is that sump temperature should be calculated conservatively high and containment pressure conservatively low to ensure no flashing will occur. It is acceptable to perform a time based calculation taking viscosity, chemical timing, and strainer submergence into account. Most design basis calculations maximize containment pressure, which is non conservative from a flashing perspective. Please explain in detail how sump temperature and containment pressure were calculated.
1 "Revised Content Guide for Generic Letter 2004-02 Supplemental Responses, November 2007" (ADAMS Accession No. ML073110278), and Regulatory Guide 1.82, "Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident."
Response
The response to the December 23, 2009 RAI included a sump temperature and containment pressure that were calculated as part of the LOCA containment pressure and temperature response analysis. This was performed using the CONTEMPT computer code. The most recent LOCA containment pressure/temperature analysis was performed using the computer code GOTHIC.
This resulted in a higher maximum sump temperature which was evaluated not to significantly impact the NPSH evaluation. An alternate analysis to change the design basis to maximize the sump temperature using COBRA/TRAC is an option but has not been fully evaluated to implement.
Addition to Response (Sept 2016)
Also see discussion in response to Follow-Up RAI 34 that addresses flashing and states that sump pool boiling does not occur. The maximum sump temperature determined for the initial submittals used the CONTEMPT code which was a
DRAFT RESPONSE TO SSIB RAI 33 (9/13/16) conservative determination. The change to GOTHIC (with more conservatism) resulted in a higher maximum sump temperature. The maximum sump temperature resulted from a case that was different from the case that yielded the maximum peak containment pressure. Other conservatisms include use of mass and energy (M&E) release rates based on a 29 LBLOCA which is greater in size than the largest break of 16 that passes the insulation fiber debris generation limit.
Another conservatism used in the analysis was that the initial Refueling Water Storage Tank (RWST) temperature used was 130 degrees. As discussed in the response to Follow-Up RAI #34, a best estimate case shows that the peak sump temperature is much lower than the value of 273.6°F determined using GOTHIC.
Based on a sensitivity study for a large dry containment similar to STP, the use of COBRA/TRAC for M&E release rates would lower the maximum sump temperature by ~20 degrees. This is because the code provides a two-fluid, three-field representation of two-phase flow. It features extremely flexible noding for both the hydrodynamic mesh and the heat transfer solution. The previous vessel component of the code was somewhat restrictive in the geometries that could be modeled and also could not treat the entrainment of liquid drops from the continuous liquid phase directly. COBRA/TRAC has a more realistic model for stored energy in the primary and secondary systems. This treatment results in a longer time for stored energy to be released and also in a longer time to start recirculation.
Another consideration is that there is adequate margin to flashing due to the pump design. The Westinghouse CS and SI pump design provides for the NPSH requirement to be met by the inherent design of the pump. The pumps are vertical motor-driven pumps, each sitting in an individual barrel. The design calls for a distance of 15 ft. in this barrel between the suction nozzle centerline and the pump first-stage impeller. The 15-ft liquid-head in the pump barrel is thus expected to inherently satisfy the 15-ft NPSH requirement.