Letter Sequence Other |
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Initiation
- Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request
- Acceptance
- Supplement, Supplement, Supplement, Supplement, Supplement, Supplement, Supplement
Administration
- Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance
- Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting
Results
Other: ML13323A186, ML13323A189, ML13323A190, ML13323A191, ML13323B187, ML13323B191, ML13323B194, ML13323B196, ML13323B198, ML13323B199, ML13323B200, ML13323B201, ML13323B202, ML13323B204, ML13323B207, ML13323B208, ML13323B209, ML14015A045, ML14052A053, ML14072A076, ML14086A386, ML14149A089, ML14149A434, ML14149A435, ML14178A481, ML14321A438, ML14321A677, ML14344A545, ML14344A546, ML14349A790, ML15119A326, ML15175A024, ML15183A007, ML15183A009, ML15246A128, ML15246A129, ML15265A601, ML16230A232, NOC-AE-13003039, Corrections to Information Provided in Revised STP Pilot Submittal and Requests for Exemptions and License Amendment for a Risk-Informed Approach to Resolving Generic Safety Issue (GSI), NOC-AE-13003040, Attachment 1: CHLE-005, Rev. 1, Determination of the Initial Pool Chemistry for the Chle Test., NOC-AE-13003065, Response to STP-GSI-191-EMCB-RAI-1, NOC-AE-14003082, Alternate Source Term Dose Analysis: an Estimate of Risk Attributed to GSI-191, Attachment 3, NOC-AE-14003101, Enclosure 1 to Enclosure 6 Concerning Second Set of Responses to April 2014, Requests for Additional Information Regarding STP Risk-Informed GSI-191 Application, NOC-AE-14003103, University of Texas White Paper, Means of Aggregation and NUREG-1829: Geometric and Arithmetic Means, Rev. 3, Enclosure 2 to Attachment 1, NOC-AE-14003104, Revised Affidavit for Withholding for Casa Grande Analyses for Risk-Informed GSI-191 Licensing Application, NOC-AE-14003105, Third Set of Responses to April, 2014, Requests for Additional Information Regarding STP Risk-Informed GSI-191 Licensing Application, NOC-AE-14003106, Second Submittal of Casa Grande Source Code for Stp'S Risk-Informed GSI- 191 Licensing Application, NOC-AE-14003111, Submittal of Casa Grande Source Code for Stp'S Risk-Informed GSI-191 Licensing Application, NOC-AE-14003190, Attachment 2 to NOC-AE-14003190 - ALION-REP-STP-8998-14, Strainer Test Plan in Support of STP Pilot Risk-Informed GSI-191 Pilot Licensing Application, NOC-AE-15003220, Description of Revised Risk-Informed Methodology and Responses to Round 2 Requests for Additional Information Regarding STP Risk-Informed GSI-191 Licensing Application... further results
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MONTHYEARML13323B1962012-06-12012 June 2012 Attachment 4: CHLE-008, Rev. 3, Debris Bed Preparation and Formation Test Results. Project stage: Other ML13323B1942012-08-11011 August 2012 Attachment 3: CHLE-007, Rev. 3, Debris Bed Requirements and Preparation Procedures. Project stage: Other NOC-AE-13003040, Attachment 1: CHLE-005, Rev. 1, Determination of the Initial Pool Chemistry for the Chle Test.2012-08-13013 August 2012 Attachment 1: CHLE-005, Rev. 1, Determination of the Initial Pool Chemistry for the Chle Test. Project stage: Other ML13323B1912012-08-14014 August 2012 Attachment 2: CHLE-006, Rev. 1, STP Material Calculations. Project stage: Other ML13323B1982012-08-19019 August 2012 Attachment 5: CHLE-010, Rev. 2, Chle Tank Test Results for Blended and NEI Fiber Beds with Aluminum Addition. Project stage: Other ML13323B1992013-01-0909 January 2013 Attachment 6: CHLE-012, Rev. 3, T1 Mbloca Test Report, Cover Through Figure 52 Project stage: Other ML13323B2002013-01-0909 January 2013 Attachment 6: CHLE-012, Rev. 3, T1 Mbloca Test Report, Figure 53 Through End Project stage: Other ML13323B2022013-01-15015 January 2013 Attachment 8: CHLE-015, Rev. 3, Summary of Chemical Effects Testing in 2012 for STP GSI-191 License Submittal. Project stage: Other ML13323B2042013-01-22022 January 2013 Attachment 9: CHLE-016, Rev. 2, Calculated Material Release to Estimate Chemical Effects. Project stage: Other ML13323B2012013-01-22022 January 2013 Attachment 7: CHLE-014, Rev. 2, T2 LBLOCA Test Report. Project stage: Other NOC-AE-13002954, Pilot Submittal and Request for Exemption for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-1912013-01-31031 January 2013 Pilot Submittal and Request for Exemption for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 Project stage: Request ML13214A0312013-08-13013 August 2013 Acceptance Review, Exemption Requests and License Amendment Request to Revise UFSAR for Resolution of Generic Safety Issue 191, Assessment of Debris Accumulation on PWR Sump Performance (TAC MF0613-MF0614; MF2400-09) Project stage: Acceptance Review ML13323B2072013-09-16016 September 2013 Attachment 10: CHLE-018, Rev. 2, Results of Bench Tests to Assess Corrosion of Aluminum in STP Containment Conditions. Project stage: Other ML13323B2082013-09-23023 September 2013 Attachment 11: CHLE-019, Rev. 2, Test Results for Chemical Effect Tests Stimulating Corrosion and Precipitation (T3 & T4) Project stage: Other NOC-AE-13003039, Corrections to Information Provided in Revised STP Pilot Submittal and Requests for Exemptions and License Amendment for a Risk-Informed Approach to Resolving Generic Safety Issue (GSI)2013-10-0303 October 2013 Corrections to Information Provided in Revised STP Pilot Submittal and Requests for Exemptions and License Amendment for a Risk-Informed Approach to Resolving Generic Safety Issue (GSI) Project stage: Other ML13323B2092013-10-0404 October 2013 Attachment 12: CHLE-020, Rev. 2, Test Results for a 10-day Chemical Effects Test Simulating LBLOCA Conditions (T5). Project stage: Other ML13323A1892013-10-22022 October 2013 Enclosure 4-2 - Risk-Informed Closure of GSI-191, Volume 2 Probabilistic Risk Analysis Project stage: Other ML13323B1872013-10-31031 October 2013 Project, Units 1 & 2, Submittal of GSI-191 Chemical Effects Test Reports (TAC Nos. MF2400 and MF2401) Project stage: Other ML13323A1912013-11-0606 November 2013 Enclosure 4-3 Risk-Informed Closure of GSI-191, Volume 3, Engineering (Casa Grande) Analysis, Page 212 of 1-122 Project stage: Other ML13323A1902013-11-0606 November 2013 Enclosure 4-3 Risk-Informed Closure of GSI-191, Volume 3, Engineering (Casa Grande) Analysis, Cover - Page 211 of 248 Project stage: Other ML13323A1862013-11-12012 November 2013 Enclosure 4-1 - Risk-Informed Closure of GSI-191, Volume 1 Project stage: Other NOC-AE-13003043, Enclosure 5 - Response to NRC Supplemental Information Items2013-11-13013 November 2013 Enclosure 5 - Response to NRC Supplemental Information Items Project stage: Supplement ML13323A1832013-11-13013 November 2013 Project Units 1 and 2 - Supplement 1 to Revised STP Pilot Submittal and Requests for Exemptions and License Amendment for a Risk-Informed Approach to Resolving Generic Safety Issue (GSI)-191 Project stage: Supplement NOC-AE-13003054, Supplement 1 to Revised STP Pilot Submittal for a Risk-Informed Approach to Resolving Generic Safety Issue (GSI)-191 to Supersede and Replace the Revised Pilot Submittal2013-11-21021 November 2013 Supplement 1 to Revised STP Pilot Submittal for a Risk-Informed Approach to Resolving Generic Safety Issue (GSI)-191 to Supersede and Replace the Revised Pilot Submittal Project stage: Supplement ML13330B2222013-12-0505 December 2013 Notice of 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 (TAC MF2400-MF24 Project stage: Meeting NOC-AE-13003065, Response to STP-GSI-191-EMCB-RAI-12013-12-23023 December 2013 Response to STP-GSI-191-EMCB-RAI-1 Project stage: Other NOC-AE-13003070, Response to NRC Request for Reference Document for STP Risk-Informed GSI-191 Application2013-12-23023 December 2013 Response to NRC Request for Reference Document for STP Risk-Informed GSI-191 Application Project stage: Request ML13357A2662013-12-24024 December 2013 1/8/14 - Notice of Meeting with STP Nuclear Operating Co. 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 Project stage: Meeting NOC-AE-13003057, Response to Request for Additional Information Re Use of RELAP5 in Analyses for Risk-Informed GSI-191 Licensing Application2014-01-0909 January 2014 Response to Request for Additional Information Re Use of RELAP5 in Analyses for Risk-Informed GSI-191 Licensing Application Project stage: Response to RAI ML14009A3072014-01-0909 January 2014 NRR E-mail Capture - Request for Additional Information - TACs MF2400 Through MF2409 Project stage: RAI ML13358A0622014-01-14014 January 2014 Summary of 12/16/13 Meeting with STP Nuclear Operating Co. 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 Project stage: Meeting ML14015A0452014-01-14014 January 2014 NRR E-mail Capture - Rai'S Regarding South Texas Project'S Submittal for Risk-Informed Resolution of GS-191 Project stage: Other NOC-AE-14003081, STP-Specific Casa Grande Inputs CASA01 JT4, CASA09 JT4, CASA22 JT4, CASA26 JT4, & CASA43 JT42014-02-13013 February 2014 STP-Specific Casa Grande Inputs CASA01 JT4, CASA09 JT4, CASA22 JT4, CASA26 JT4, & CASA43 JT4 Project stage: Request ML14052A0532014-02-13013 February 2014 Project Units 1 & 2, Submittal of Casa Grande Code & Analyses for Risk-Informed GSI-191 Licensing Application Project stage: Other ML14149A4352014-02-14014 February 2014 Project, Units 1 and 2 - ALION-REP-STP-8998-02, Rev. 0, STP Casa Grande Analysis and LAR Enclosure 4-3 RAI Response, Enclosure 1 to Attachment 1 Project stage: Other ML14072A0842014-02-18018 February 2014 CHLE-012, T1 Mbloca Test Report, Revision 4 Project stage: Request ML14072A0792014-02-22022 February 2014 CHLE-020, Test Results for 10-Day Chemical Effects Test Simulating LBLOCA Condition (T5), Revision 3 Project stage: Request ML14072A0852014-02-22022 February 2014 CHLE-014, T2 LBLOCA Test Report, Revision 3 Project stage: Request ML14072A0822014-02-23023 February 2014 CHLE-008, Debris Bed Preparation & Formation Test Results, Revision 4 Project stage: Request ML14072A0832014-02-24024 February 2014 CHLE-010, Chle Tank Test Results for Blended and NEI Fiber Beds with Aluminum Addition, Revision 3 Project stage: Request ML14072A0762014-02-27027 February 2014 Project, Units 1 and 2, Submittal of GSI-191 Chemical Effects Test Reports (TAC Nos. MF2400 and MF2401) Project stage: Other ML14072A2112014-03-0606 March 2014 NRR E-mail Capture - STP Sensitivity Report and Presentation for Proposed Meeting Project stage: Request NOC-AE-14003082, Alternate Source Term Dose Analysis: an Estimate of Risk Attributed to GSI-191, Attachment 32014-03-11011 March 2014 Alternate Source Term Dose Analysis: an Estimate of Risk Attributed to GSI-191, Attachment 3 Project stage: Other ML14086A3862014-03-17017 March 2014 STP Risk-Informed GSI-191 Aadb RAI 3 Response, Attachment 2 Project stage: Other ML14086A3852014-03-17017 March 2014 Project, Units 1 & 2 - Response to NRC Accident Dose Branch Request for Additional Information Regarding STP Risk-Informed GSI-191 Application Project stage: Request NOC-AE-14003111, Submittal of Casa Grande Source Code for Stp'S Risk-Informed GSI-191 Licensing Application2014-03-18018 March 2014 Submittal of Casa Grande Source Code for Stp'S Risk-Informed GSI-191 Licensing Application Project stage: Other NOC-AE-14003114, Seismic Hazard and Screening Report (CEUS Sites), Response NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai..2014-03-31031 March 2014 Seismic Hazard and Screening Report (CEUS Sites), Response NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai.. Project stage: Request ML14091A4522014-04-0808 April 2014 Request for Withholding Information from Public Disclosure - 12/9/13 G. Powell, STPNOC Affidavit Enclosing RELAP5 Digital Media Related to GSI-191 License Amendment and Exemption Requests Project stage: Withholding Request Acceptance ML14087A0752014-04-15015 April 2014 Request for Additional Information, Request for Exemptions and Revised Pilot License Amendment Request for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 Project stage: RAI NOC-AE-14003103, University of Texas White Paper, Means of Aggregation and NUREG-1829: Geometric and Arithmetic Means, Rev. 3, Enclosure 2 to Attachment 12014-04-18018 April 2014 University of Texas White Paper, Means of Aggregation and NUREG-1829: Geometric and Arithmetic Means, Rev. 3, Enclosure 2 to Attachment 1 Project stage: Other 2013-12-05
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Category:- No Document Type Applies
MONTHYEARML22034A3952022-02-16016 February 2022 Enclosure 3 - IP 96001 CY2021 - IR 8 Baseline Inspection Completion ML22034A3972022-02-16016 February 2022 Enclosure 2 - IP 92707 CY2021 - IR 8 Baseline Inspection Completion ML22034A3992022-02-16016 February 2022 Enclosure 1 - IP 71130.03 Cy 2021 - IR 8 Baseline Inspection Completion ML20135H1702020-05-14014 May 2020 Public Notice of Application for Amendment to Renewed Facility Operating License ML17005A1022017-01-18018 January 2017 Attendance List for January 4, 2016, Meeting to Discussion STP - Response to Request for Additional Information the Revised Aluminum Bronze Selective Leaching Aging Management Program for All Potentially Susceptible Welds Throughout the Fac ML16347A3252016-12-0606 December 2016 ASP Analysis-Reject-South Texas Manual Reactor Trip and Valid Auxiliary Feedwater System Actuation-LER 498-2015-001 ML16175A0212016-07-25025 July 2016 June 21, 2016, Attendance List ML16033A0112016-02-0808 February 2016 Attendance List for the January 19, 2016, Public Meeting with STP to Discuss the Plant-Specific Aging Management Program, Selective Leaching of Aluminum Bronze, Associated with STP's License Renewal Application ML15246A1292015-08-20020 August 2015 Attachment 2 - Requests for Exemptions for STP Piloted Risk-Informed Approach to Closure for GS1-191 Through 3-3 Technical Specifications Bases Page Markups (Information Only) ML15182A2282015-06-30030 June 2015 Supplemental Information for 7/2/15 Public Phone Call ML14086A3862014-03-17017 March 2014 STP Risk-Informed GSI-191 Aadb RAI 3 Response, Attachment 2 NOC-AE-13003043, Enclosure 5 - Response to NRC Supplemental Information Items2013-11-13013 November 2013 Enclosure 5 - Response to NRC Supplemental Information Items ML13140A2692013-05-20020 May 2013 NRC Slides for 5/23/13 Meeting Regarding Risk - Informed GSI-191 Pilot Application Initial Review Insights ML12145A4662012-05-18018 May 2012 Loca-Hybrid-Final ML12056A0522012-03-12012 March 2012 Enclosure 6 - List of Power Reactor Licensees and Holders of Construction Permits in Active or Deferred Status ML1206100632012-02-29029 February 2012 Intro for March 8, 2012 Public Meeting to Discuss GSI-191 ML1130606062011-11-0202 November 2011 Questions Associated with Loss-of-Coolant Accident (LOCA) Frequency Analysis ML1127702512011-10-0303 October 2011 STP Responses to Questions Associated with LOCA Frequency Analysis ML1127100332011-09-28028 September 2011 ROP Tabletop Examples and Results ML1126306762011-09-20020 September 2011 NRC Staff Questions, Loss-of-Coolant Accident Frequency Analysis, Resolution Approach for Risk-Informed GSI-191, Assessment of Debris Accumulation on Pressurized-Water Reactor (PWR) Sump Performance. ML11256A0572011-08-31031 August 2011 Documents to Support Review of the South Texas Project License Renewal Application, List of Transmitted Documents Including Copy of Each Document, Enclosure to NOC-AE-11002720 ML1108800492011-03-31031 March 2011 03/02/2011 List of Participants STP, Units 1 and 2, License Renewal Environmental Scoping Meetings ML0926801902009-09-24024 September 2009 Comments, Draft Request for Exemption from Certain Requirements of Revised 10 CFR 26.205(c) and (D) During Severe Weather Conditions ML0925706922009-09-0202 September 2009 Draft Request from Certain Requirements of the Fitness for Duty Rule for Managing Fatigue ML0835102572008-11-24024 November 2008 FEMA Region VI, Radiological Emergency Preparedness (Rep), South Texas Project (REP) Combined License Review, List of 55 RAIs ML0808000362008-03-13013 March 2008 List of Attendees, 03/13/2008 Summary of Meeting with Eight Operating Nuclear Power Plant Licensees to Discuss Emerging Metallurgical Issues Certain Welds in Reactor Coolant System for Pressurized-Water Reactors ML0732400242007-10-25025 October 2007 Examples of Max Thermal Power License Conditions ML0726303192007-09-14014 September 2007 P. Paquin Ltr Amendment to Certificate of Compliance No. 6574 for the Model No. 3-82B Package (TAC L24116)/ Register User List ML0721104332007-07-25025 July 2007 Questions from 1 Through 8 ML0634705992006-12-14014 December 2006 Plant Service List ML0603306172006-01-24024 January 2006 Safety Culture Survey with Slides ML0503400252005-02-0707 February 2005 0POP01-ZO-0006, Rev. 13, Extended Allowed Outage Time ML0503400222005-02-0707 February 2005 OPGP03-ZA-0091 ML0426100722004-09-13013 September 2004 Plant Engineering Branch Closed Items Interim Safety Basis ML0407705892004-04-13013 April 2004 Draft Information Request Response to RAI - Attachment 7 ML0404104922004-02-20020 February 2004 Order EA-03-009 Service List ML0404106572004-02-18018 February 2004 Meeting Summary of January 21, 2004 with STPNOC- Enclosure 4 - Stpnoc'S Response to NRC Staff'S Comments ML0407705932003-12-23023 December 2003 Draft Information Request PRA Analysis Assessment PRA-03-024, Rev. 0 - Attachment 6 ML0329401042003-10-0707 October 2003 Riv Backfit Status ML0329400982003-03-27027 March 2003 Riv Backfit Status 2022-02-16
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NOC-AE-1 4003082 Attachment 2 Risk-Informed GSI-191 AADB RAI 3 Response
Risk-Informed GSI-191 AADB RAI 3 Response Authors Janet Leavitt, PhD Alion Science and Technology Thomas S. Corbitt, PhD Alion Science and Technology Reviewers Bruce Letellier, PhD Alion Science and Technology Seyed Reihani, PhD University of Illinois Urbana-Champaign Kerry Howe, PhD University of New Mexico Ernie Kee South Texas Project Nuclear Operating Company
ALION SCIENCE AND TC.CHNOLOGY TECHNICAL DOCUMENT COVER PAGE Document No: ALION-REP-STP-8998-03 I Revision: 0 Page I of 7 Document
Title:
STP Risk-Informed GSI- 191 AADB RAI 3 Response Project No: STP-8898 Project Name: STP Risk-Informed GSI- 191 Support Client: STP Nuclear Operating Company Document Purpose/Summary: Request for additional information 3 (RAI 3) inquired about the potential for pH changes arising from sump acidification through radiolysis of water and plastic sheathing on cabling. This document provides an explanation for variation of calculated pH and experimentally measured pH as well as expected ECCS performance effects. This document is not considered safety-related.
This report includes 8 total pages.
Design Verification Method:
X Design Review Alternative Calculation
___ Qualification Testing Professional Engineer (if required) Approval: Date S Digitalysigned byThomasS.Cobit N:
.......... S. Corb........... S ........ d Teyhnoloy, J4 .. o 1lTSO, Prepared By: Thomas S. Corbitt emall=tcorblt@alionscience.com.,
Dte.: 2014.02.2016:34:5407.00o c=US Printed/Typed Name Signature Date Reviewed By: Janet Leavitt LeavittC3 Printed/Typed Name Signature Date Approved B Megan A.Stachowiak Approved By: Megan Stachowiak 2014.02.21 08:41:47 -06'00' Printed/Typed Name Signature Date Form 3.3.1 Revision 2 Effective Date: 2/28/07
A L 10ON SCIENCE ANDSTECIUIOLOCY REVISION HISTORY LOG Page 2of 7 Document Number: ALION-REP-STP-8998-03 Revision: 0 Document
Title:
STP Risk-Informed GSI- 191 AADB RAI 3 Response REVISION DATE Description 0 02/20/2014 Initial release i
Form 6.1.3 Revision 2 Effective Date: 3/25/13
CSTP Risk-Informed GSI- 191 AADB RAI 3 Response A LIO N Document No: ALION-REP-STP-8998-03 Rev: 0 Page: 3 of 7 Table of Contents Tab le o f C o n te n ts ............................................................................................................................................................................................ 3 Tab le o f Ta b le s ................................................................................................................................................................................................. 3 Ta b le o f Figu re s ................................................................................................................................................................................................ 3 I Risk Informed GSI-191 AADB RAI 3 ................................................................................................................................................. 4 2 R e sp o n se ................................................................................................................................................................................................... 4
- 2. I Sump Water pH; Calculated vs Measured ............................................................................................................................. 4 2.2 Implications of Experimental Results ........................................................................................................................................ 6 2 .3 Su m m ary .......................................................................................................................................................................................... 6 2 .4 Refe re n ce s ....................................................................................................................................................................................... 7 Table of Tables Table I. Solution characteristics for LB and experimental (CHLE) systems ........................................................... 5 Table of Figures Figure I. 30 day pH trend of LB and experimental (CHLE) systems ............................................................. 5 Figure 2. Acid addition schedule for LB and experimental (CHLE) systems ........................................................... 6
STP Risk-Informed GSI-191 AADB RAI 3 Response AL IO N
,CIO-CE AND TEC-QLOQGý Document No: ALION-REP-STP-8998-03 Rev: 0 Page: 4 of 7 I Risk Informed GSI-191 AADB RAI 3 The LOCA analysis assumes that iodine will be removed from the containment atmosphere by containment spray and natural diffusion to the containment walls. As a result of these removal mechanisms a large fraction of the released activity will be deposited in the containmentsump. The sump water will retain soluble gases and soluble fission products such as iodines and cesium, but not noble gases. The guidance from RG 1.183 specifies that the iodine deposited in the sump water can be assumed to remain in solution as long as the containment sump pH is maintainedat or above 7.
The AST applicationindicates:
"After the first day, the containment sump pH will begin to decrease, reaching 6.8 by the end of the 30-day duration of the radiologicalconsequence analysis for the DBA LOCA, and the impact of that decrease has been reflected in the Control Room and offsite doses."
It is noted that the AST applicationfurther indicates:
"The design inputs for calculatingthe containment sump pool pH were conservatively establishedby the licensee to maximize the acidic contribution to sump pH and minimize the basic contribution."
The GSI-191 applicationindicates the possibility that debris generated during a LOCA could clog the containment sump strainersin pressurized-waterreactors (PWRs) and result in loss of net positive suction head (NPSH) for the ECCS and CSS pumps, impeding the flow of water from the sump.
Discuss the exemption justification as they relate to the effects on sump water pH, radiologicalconsequences, and loss of the containment spray system.
2 Response 2.1 Sump Water pH; Calculated vs. Measured In the following, the pH values resulting from the STP Licensing Basis (LB) alternative source term (AST) calculation [1,2] and the Chemical Head Loss Experiment (CHLE) 30 day tests [3,4] are compared and the differences analyzed. Table 1 summarizes the solution chemistry considered in both the LB calculation and CHLE test [3,4]: concentrations of boric acid; trisodium phosphate (TSP); and radiolysis generated acid. Boric acid and TSP concentrations used to establish initial LB (calculated) sump pH were determined by deterministic analysis. The boric acid and TSP concentrations used for the CHLE experiments were determined from risk-informed analysis of historical plant data [5] and would not be considered conservative in the same sense as the LB AST calculations. Also, unlike the LB calculation, the 30 day CHLE experiments
[3,4] reflect pH trends with the inclusion of corrosion material and fibrous debris. In summary, the observed CHLE pH trend has no effect on potential sump blockage assumed in the LB calculation.
C)STP Risk-Informed GSI- 191 AADB RAI 3 Response A L I ON Document No: ALION-REP-STP-8998-03 Rev: 0 Page: 5 of 7 Table 1: Solution characteristics for both LB [1] and experimental (CHLE [6,7]) systems Chemical Star pH Model CHLE Tests Boron (mM) 283.05 250.50 TSP 1 (mrM) 5.63 8.87 Lithium hydroxide (mM) 0 0.06 30 Day HCI (mM) 0.81 0.81 30 Day HNO3(mM) 0.23 0.23 1
Initial pH 7.0 7.1-7.2 30 day pH 6.8 7.2-7.4 After complete dissolution of TSP After complete TSP dissolution, the two inputs resulted in a difference of approximately 0.1 pH units as summarized in Table 1. The higher initial pH in the CHLE tests reflects the different boric acid and TSP concentrations used to define the systems. There is also a small quantity of lithium hydroxide, 0.06 mM Li, added to the CHLE system. The addition of iodine was not considered in either system. During the 30-day analysis, sump pH in both systems changed. As shown in Figure 1, the LB system predicted a decrease in pH of approximately 0.2 pH units resulting from acid addition over 30 days; however the experimental system produced a slight increase in pH of, on average, 0.18 units over 30 days using the same acid addition schedule used in the LB system (Figure 2).
10
9nCHLE T1 [3]
8 A CHLE T2 [4]
CLIA E
CL 7 6
5 4 5 10 15 20 25 30 0 5 10 15 20 25 30 Time (days)
Figure 1: 30 day pH trend of LB [1] and experimental (CHLE [6,7]) systems.
STP Risk-Informed GSI-191 AADB RAI 3 Response ALI O N Document No: ALION-REP-STP-8998-03 Rev: 0 Page: 6 of 7 QGVR SCIENCE^NO TECHrNO v ag :6o 1.2 1.0 []
E
," 0.8 0
0.6
- StarpH C0.4 ECHLE El M 0.2 0.0 ' I 0 5 10 15 20 25 30 Time (day)
Figure 2: Acid addition schedule for LB [1] and experimental (CHLE [6,7]) systems.
2.2 Implications of Experimental Results The initial pH difference between the LB system and the CHLE test systems [3,4] is expected, primarily due to the difference between the deterministically-assumed boric acid and TSP concentrations and risk-informed (realistic) concentrations. The difference between the LB calculated pH history and the CHLE observed pH history is likely reflective of uncertainty from the LB calculation. The LB calculation is a modeled solution and uncertainties from model development arise from missing reactions, activity corrections and temperature corrected equilibrium data. By neglecting buffering, activity and temperature corrections, the LB system exhibits a greater pH reduction. The additional buffering capacity in the CHLE test system not accounted for in the LB model is a function of the following; 1) greater contribution from TSP, with 8.87 mM TSP versus the 5.63 mM used in the LB system; 2) the presence of fiberglass solids that can contribute to alkalinity by adsorbing H* [8]; 3) addition of a small quantity of lithium hydroxide; and 4) corrosion reactions, specifically aluminum and zinc corrosion.
2.3 Summary The fact that pH in the CHLE system remains above 7.1 despite acid addition for a period greater than 30 days reflects the true buffering capacity of the system. Alkalinity in the CHLE system is augmented by increased initial concentration of TSP and lithium hydroxide, as well as solids such as fiberglass, and by metal corrosion.
The LB system calculations fail to account for these factors. The minor acidic contributions from radiolysis of water and cabling assumed in the LB acid addition schedule would be mitigated by the higher pH as demonstrated in the CHLE experiments. The pH stability observed in the CHLE system indicates that acid additions resulting from radiation exposure will not affect sump blockage and thus are not expected to affect ECCS performance. Furthermore, these experimental results likely represent a lower realistic bound, since the LB case assumes core damage and the effect of strongly basic cesium oxide produced from fuel damage on the basicity of the sump solution [9] is ignored.
2.4 References I. STPNOC UFSAR, Sec. 15.6, Response to RAI 3 in NOC-AE-07002215 and NRC Safety Evaluation.
- 2. STP, "Post-LOCA containment Sump pH and Maximum Iodine DF for AST Chapter 15 Analysis", NC-651 I, 2006.
- 3. Leavitt, J.J., Howe, K.J. T I MBLOCA Test Report, University of New Mexico, Albuquerque, NM November 2012, CHLE-0 12.
- 4. Leavitt, J.J., Howe, K.J. T2 LBLOCA Test Report, University of New Mexico, Albuquerque, NM January 2013, CHLE-014.
- 5. Leavitt, J.J., Howe, K.J. Determination of the initial pool chemistry for the CHLE test, University of New Mexico, Albuquerque, NM August 2012, CHLE-006.
- 6. Leavitt, J.J., Howe, K.J. Test I: Medium Break LOCA Tank Test Parameter Summary, University of New Mexico, Albuquerque, NM August 2012, CHLE-0 I.
- 7. Leavitt, J.J., Howe, K.J. Test 2: Large Break LOCA Tank Test Parameter Summary, University of New Mexico, Albuquerque, NM January 2013, CHLE-0 13.
- 8. Mitchell, L., Leavitt, J.J., Vogtle GSI- 19 1Water Chemistry Evaluation for Bypass Support, ALION-REP-SNC-8586-12I January 2014,
- 9. Beahm, E.C., Lorenz, R.A. Weber, C.F. Iodine Evolution and pH control, Oak Ridge National Laboratory, Oak Ridge, TN, December 1992, NUREG/CR-5950, ORNI/TM-12242R3.