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| | number = ML14086A385 | | | number = ML14086A385 |
| | issue date = 03/17/2014 | | | issue date = 03/17/2014 |
| | title = South Texas Project, Units 1 & 2 - Response to NRC Accident Dose Branch Request for Additional Information Regarding STP Risk-Informed GSI-191 Application | | | title = Project, Units 1 & 2 - Response to NRC Accident Dose Branch Request for Additional Information Regarding STP Risk-Informed GSI-191 Application |
| | author name = Powell G T | | | author name = Powell G T |
| | author affiliation = South Texas Project Nuclear Operating Co | | | author affiliation = South Texas Project Nuclear Operating Co |
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| | document type = Letter | | | document type = Letter |
| | page count = 8 | | | page count = 8 |
| | project = TAC:MF2401, TAC:MF2400 | | | project = TAC:MF2400, TAC:MF2401 |
| | stage = RAI | | | stage = Request |
| }} | | }} |
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| {{#Wiki_filter:Nuclear Operating Company.S'uli Tevas Ah ,fr'd r/lertri (7Cenemfi;So 7., PO. bS 2,59 W?&Wjh'ýn Tckxi 774,1JMarch 17, 2014NOC-AE-1400308210 CFR 50.1210 CFR 50.90U. S. Nuclear Regulatory CommissionAttention: Document Control DeskWashington, DC 20555-0001South Texas ProjectUnits 1 & 2Docket Nos. STN 50-498, STN 50-499Response to NRC Accident Dose Branch Request for Additional InformationRegarding STP Risk-Informed GSI-191 Application(TAC NOs MF2400 and MF2401)References:1. Letter, G. T. Powell, STPNOC, to NRC Document Control Desk, "Supplement 1 toRevised STP Pilot Submittal and Requests for Exemptions and License Amendment forRisk-Informed Approach to Resolving Generic Safety Issue (GSI)-191," November 13,2013, NOC-AE-13003043, ML13323A1832. Email, Andrea George, NRC, to Albon Harrison, STPNOC, "RAI's Regarding SouthTexas Project's Submittal for Risk-Informed Resolution of GS-191", January 14, 2014,ML14015A045This submittal responds to requests for additional information in Reference 2 with regard to theSTP Nuclear Operating Company (STPNOC) risk-informed application for the .resolution of GSI-191 (Reference 1).There are no regulatory commitments in this letter.T 66ST133816627. | | {{#Wiki_filter:Nuclear Operating Company.S'uli Tevas Ah ,fr'd r/lertri (7Cenemfi;So 7., PO. bS 2,59 W?&Wjh'ýn Tckxi 774,1J March 17, 2014 NOC-AE-14003082 10 CFR 50.12 10 CFR 50.90 U. S. Nuclear Regulatory Commission Attention: |
| NOC-AE-1 4003082Page 2 of 3If there are any questions, please contact Mr. Michael Murray at 361-972-8164.I declare under penalty of perjury that the foregoing is true and correct.Executed on: u t-1 zo-G. T. PowellSite Vice PresidentawhAttachments:1. Response to Accident Dose Branch Request for Additional Information2. Risk-Informed GSI-191 AADB RAI 3 Response3. Alternate Source Term Dose Analysis: An Estimate of Risk Attributed to GSI-191STP-RIGSI191-RAI.1 NOC-AE-1 4003082Page 3 of 3cc:(paper copy)(electronic copy)Regional Administrator, Region IVU. S. Nuclear Regulatory Commission1600 East Lamar BoulevardArlington, TX 76011-4511Balwant K. SingalSenior Project ManagerU.S. Nuclear Regulatory CommissionOne White Flint North (MS 8 B1)11555 Rockville PikeRockville, MD 20852NRC Resident InspectorU. S. Nuclear Regulatory CommissionP.O. Box 289, Mail Code: MN116Wadsworth, TX 77483Jim CollinsCity of AustinElectric Utility Department721 Barton Springs RoadAustin, TX 78704Steven P. Frantz, EsquireA. H. Gutterman, EsquireMorgan, Lewis & Bockius LLPBalwant K. SingalMichael MarkleyJohn StangU. S. Nuclear Regulatory CommissionJohn RaganChris O'HaraJim von SuskilNRG South Texas LPKevin PolioRichard PefiaL. D. BlaylockCity Public ServicePeter NemethCrain Caton & James, P.C.C. MeleCity of AustinRichard A. RatliffRobert FreeTexas Department of State Health Services NOC-AE-1 4003082Attachment 1Response to Accident Dose BranchRequest for Additional Information NOC-AE-1 4003082Attachment 1Page 1 of 4Risk Informed GSI-191 Accident Dose Branch (AADB) RAI ITo ensure a complete and accurate review of the dose consequence analyses, please provideadditional information in tabular form describing, for each design basis accident affected by theproposed Risk Informed GSI-191 submittal, all the basic parameters used in the doseconsequence analyses. For each parameter, please indicate the current licensing basis (CLB)value, the revised GSI-191 value where applicable, as well as the basis for any changes to theCLB. An example of the input/assumptions needed is provided in Table 4.3-11 "Dose AnalysisInputs for LOCA" provided in STP's alternate source term submittal [Agencywide DocumentsAccess Management System (ADAMS) Accession No. ML070890474]. The staff requests thatthe information provided include all of the basic parameters whether or not the individualparameter is being changed for the GSI-1 91 amendment. The staff also requests that theinformation be provided in separate tables for each affected accident (i.e., loss-of-coolantaccident (LOCA), the fuel handing accident (FHA), the main steam line break accident (MSLB),the steam generator tube rupture accident (SGTR), the control rod ejection accident (CREA),and the locked rotor accident (LRA)).STP Response:Other than to add a study calculation for the response to RAI 3 below, STPNOC did notrevise the licensing basis dose analyses, including the Alternate Source Term analyses,for the risk-informed GSI-1 91 licensing application. The analyses and results currentlydescribed in the STP UFSAR for the events identified above remain valid.Risk Informed GSI-191 AADB RAI 2STP identified the following condition related to the alternative source term (AST) licenseamendments currently in effect at STP Units 1 and 2. Westinghouse Electric Company NuclearSafety Advisory Letter (NSAL)-06-15, dated December 13, 2006, advised operators ofWestinghouse plants that the single-failure scenario for the SGTR analysis that licensees usedin their accident analysis may not be limiting. As stated in the STP AST NRC Safety Evaluationdated March 6, 2008 (ADAMS Accession No. ML080160013), "The licensee has evaluated theapplicability of NSAL-06-15 against the accident analysis assumptions and has determined thatthe current single-failure assumption for the STP SGTR analysis is not limiting. Therefore, thelicensee is operating under compensatory measures to meet regulatory dose guidelines. Thelicensee plans to resolve this condition at the earliest opportunity so that the assumptions,including the limiting single failure, for the SGTR accident analysis described herein areconsistent with the plant response to this event. To support the limiting single-failureassumptions in the SGTR analysis, STP will maintain an administrative limit for reactor coolantsystem (RCS) dose equivalent iodine 131 (DEI) so that the radiological dose reference valuesfor the SGTR analysis remain bounding, and the licensee will continue to comply with GDC 19."Has this condition been resolved? If so, how? Also, provide justification that GDC 19continues to be met. | | Document Control Desk Washington, DC 20555-0001 South Texas Project Units 1 & 2 Docket Nos. STN 50-498, STN 50-499 Response to NRC Accident Dose Branch Request for Additional Information Regarding STP Risk-Informed GSI-191 Application (TAC NOs MF2400 and MF2401) |
| NOC-AE-1 4003082Attachment 1Page 2 of 4STPNOC Response:The condition described in the RAI above was resolved by a design change to make thesteam valves to the moisture separator reheater fail closed. The design change hasbeen implemented in both STP units. This corrective action restored the original designand licensing basis and eliminated the need for the administrative limit on DEI that hadbeen implemented as a compensatory action. Condition Record 07-2887 details theresolution in accordance with the STPNOC Corrective Action Program.Restoration of the original design basis as described above maintains the originalcompliance with GDC 19 without need for compensatory action.STPNOC also addresses the relation between the risk-informed GSI-191 analyses andthe AST analyses with respect to compliance with GDC 19 in Section 2.2 of Enclosure 2-1 of Reference 1 to the cover letter.Risk Informed GSI-191 AADB RAI 3The LOCA analysis assumes that iodine will be removed from the containment atmosphere bycontainment spray and natural diffusion to the containment walls. As a result of these removalmechanisms a large fraction of the released activity will be deposited in the containment sump.The sump water will retain soluble gases and soluble fission products such as iodines andcesium, but not noble gases. The guidance from RG 1.183 specifies that the iodine deposited inthe sump water can be assumed to remain in solution as long as the containment sump pH ismaintained at or above 7.The AST application indicates:"After the first day, the containment sump pH will begin to decrease, reaching 6.8 by the end ofthe 30-day duration of the radiological consequence analysis for the DBA LOCA, and the impactof that decrease has been reflected in the Control Room and offsite doses."It is noted that the AST application further indicates:"The design inputs for calculating the containment sump pool pH were conservativelyestablished by the licensee to maximize the acidic contribution to sump pH and minimize thebasic contribution."The GSI-1 91 application indicates the possibility that debris generated during a LOCA couldclog the containment sump strainers in pressurized-water reactors (PWRs) and result in loss ofnet positive suction head (NPSH) for the ECCS and CSS pumps, impeding the flow of waterfrom the sump.Discuss the exemption justification as they relate to the effects on sump water pH, radiologicalconsequences, and loss of the containment spray system. | | |
| NOC-AE-1 4003082Attachment 1Page 3 of 4STPNOC Response:Enclosure 2-4 "Request for Exemption from General Design Criterion 41" of the licenseamendment, STPNOC addressed exemption from 10 CFR Part 50 Appendix A, GeneralDesign Criteria (GDC) 41, Criterion 41 -Containment atmosphere cleanup. STPNOC didnot revise the licensing basis dose analyses, including the Alternate Source Term (AST)analyses, for the risk-informed GSI-191 licensing application except to add a studycalculation for the response to this RAI. The analyses and results currently described inthe STP UFSAR for the events identified above remain valid.The licensing application is structured to show that the sumps are sufficiently reliable asa support function for CSS as currently licensed. STP has applied RG 1.174 to assessthe effects of debris using a risk-informed approach and shown acceptable results. Inorder to provide a risk-informed perspective on the sump design, the risk associated withGSI-191 is evaluated to include the failure mechanisms associated with sump blockageaffecting Containment Spray System (CSS) recirculation mode.In the risk-informed application, the sump pH history was investigated over 30 days bothanalytically and experimentally [1] (attached). The investigation shows the STP sump pHwill remain substantially above 7.0 for thirty days.Any loss of loss of net positive suction head (NPSH) for the Emergency Core CoolingSystem (ECCS) and Containment Spray System (CSS) pumps, impeding the flow ofwater from the sump has been analyzed using a risk-informed approach [2] (attached.)The risk-informed analysis assesses the impact of a GSI-191 related sump failure on theCSS and associated AST acceptance criteria. For breaks that result in sump blockageand which initially have two or more CSS trains available (consistent with single failure ofone CSS train, per the deterministic AST analysis), the analysis determines theexpected time that the CSS trains would operate before failing due to blockage. Thetime is then evaluated using the STP AST engineering calculation to determine thecontrol room and Technical Support Center dose. Finally the risk-informed analysisevaluates the fraction of the cases that would result in exceeding the AST acceptancecriteria.As shown in [2], Figure 1, sump clogging doesn't start until about 2.5 hours. As shown inthe reference analysis [2], the risk for exceeding dose limits identified in RG 1.183 isacceptably low. Most events (-81%) result in dose within the AST limit, and the largestdose for the relatively small fraction of events (-19%) that do exceed the acceptancecriteria is less than 2 rem over the 5 rem limit and the probability is very low(-3.7E-09/yr). The table below is a summary of the AST analysis for dose after loss(CSS Cutoff) of two or more CSS pumps. As can be seen, the dose limits (10 CFR50.67 limits) at the Exclusion Area Boundary (EAB) and Low Population Zone (LPZ) willnot be challenged for early losses of CSS (see the tabulated values at 2.185 hours). | | ==References:== |
| NOC-AE-1 4003082Attachment 1Page 4 of 4Dose at CSS Cutoff Time(sum of results from Tables D3, D4, & D5 LB dose analysis)EAB LPZ CR TSC(REM)* (REM) (REM) (REM)10CFR50.67 Limit 25 25 5 5Design Basis 5.68 2.89 3.74 4.40CSS Cutoff @ 2.185 5.70 4.69 6.70 6.33hoursCSS Cutoff @ 4 hours 5.68 3.50 4.76 5.04CSS Cutoff @ 4.25 5.68 3.41 4.62 4.95hoursCSS Cutoff @ 6.5 hours 5.68 3.03 3.98 4.54CSS Cutoff @ 7.6 hours 5.68 2.96 3.87 4.47CSS Cutoff @ 16 hours 5.68 2.89 3.74 4.40l*#- dose is a worst 2-nour integratedvalues.value. All otner aoses are 30u day integratedAlso as described in Enclosure 4-1 to Reference 1 of the cover letter, realizing thesource term necessary to produce the doses as calculated in the dose assessment isunlikely based on the Regulatory Guide 1.174 evaluation that shows defense in depthand substantial safety margin.References (attached)[1] Risk-Informed GSI-191 AADB RAI 3 Response (Attachment 2 listed in cover letter)[2] Alternate Source Term Dose Analysis: An Estimate of Risk Attributed to GSI-1 91STP-RIGSI191-RAI.1 (Attachment 3 listed in cover letter) | | : 1. Letter, G. T. Powell, STPNOC, to NRC Document Control Desk, "Supplement 1 to Revised STP Pilot Submittal and Requests for Exemptions and License Amendment for Risk-Informed Approach to Resolving Generic Safety Issue (GSI)-191," November 13, 2013, NOC-AE-13003043, ML13323A183 |
| }} | | : 2. Email, Andrea George, NRC, to Albon Harrison, STPNOC, "RAI's Regarding South Texas Project's Submittal for Risk-Informed Resolution of GS-191", January 14, 2014, ML14015A045 This submittal responds to requests for additional information in Reference 2 with regard to the STP Nuclear Operating Company (STPNOC) risk-informed application for the .resolution of GSI-191 (Reference 1).There are no regulatory commitments in this letter.T 66 ST133816627. |
| | NOC-AE-1 4003082 Page 2 of 3 If there are any questions, please contact Mr. Michael Murray at 361-972-8164. |
| | I declare under penalty of perjury that the foregoing is true and correct.Executed on: u t-1 zo-G. T. Powell Site Vice President awh Attachments: |
| | : 1. Response to Accident Dose Branch Request for Additional Information |
| | : 2. Risk-Informed GSI-191 AADB RAI 3 Response 3. Alternate Source Term Dose Analysis: |
| | An Estimate of Risk Attributed to GSI-191 STP-RIGSI191-RAI.1 NOC-AE-1 4003082 Page 3 of 3 cc: (paper copy)(electronic copy)Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 1600 East Lamar Boulevard Arlington, TX 76011-4511 Balwant K. Singal Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North (MS 8 B1)11555 Rockville Pike Rockville, MD 20852 NRC Resident Inspector U. S. Nuclear Regulatory Commission P.O. Box 289, Mail Code: MN116 Wadsworth, TX 77483 Jim Collins City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704 Steven P. Frantz, Esquire A. H. Gutterman, Esquire Morgan, Lewis & Bockius LLP Balwant K. Singal Michael Markley John Stang U. S. Nuclear Regulatory Commission John Ragan Chris O'Hara Jim von Suskil NRG South Texas LP Kevin Polio Richard Pefia L. D. Blaylock City Public Service Peter Nemeth Crain Caton & James, P.C.C. Mele City of Austin Richard A. Ratliff Robert Free Texas Department of State Health Services NOC-AE-1 4003082 Attachment 1 Response to Accident Dose Branch Request for Additional Information NOC-AE-1 4003082 Attachment 1 Page 1 of 4 Risk Informed GSI-191 Accident Dose Branch (AADB) RAI I To ensure a complete and accurate review of the dose consequence analyses, please provide additional information in tabular form describing, for each design basis accident affected by the proposed Risk Informed GSI-191 submittal, all the basic parameters used in the dose consequence analyses. |
| | For each parameter, please indicate the current licensing basis (CLB)value, the revised GSI-191 value where applicable, as well as the basis for any changes to the CLB. An example of the input/assumptions needed is provided in Table 4.3-11 "Dose Analysis Inputs for LOCA" provided in STP's alternate source term submittal |
| | [Agencywide Documents Access Management System (ADAMS) Accession No. ML070890474]. |
| | The staff requests that the information provided include all of the basic parameters whether or not the individual parameter is being changed for the GSI-1 91 amendment. |
| | The staff also requests that the information be provided in separate tables for each affected accident (i.e., loss-of-coolant accident (LOCA), the fuel handing accident (FHA), the main steam line break accident (MSLB), the steam generator tube rupture accident (SGTR), the control rod ejection accident (CREA), and the locked rotor accident (LRA)).STP Response: Other than to add a study calculation for the response to RAI 3 below, STPNOC did not revise the licensing basis dose analyses, including the Alternate Source Term analyses, for the risk-informed GSI-1 91 licensing application. |
| | The analyses and results currently described in the STP UFSAR for the events identified above remain valid.Risk Informed GSI-191 AADB RAI 2 STP identified the following condition related to the alternative source term (AST) license amendments currently in effect at STP Units 1 and 2. Westinghouse Electric Company Nuclear Safety Advisory Letter (NSAL)-06-15, dated December 13, 2006, advised operators of Westinghouse plants that the single-failure scenario for the SGTR analysis that licensees used in their accident analysis may not be limiting. |
| | As stated in the STP AST NRC Safety Evaluation dated March 6, 2008 (ADAMS Accession No. ML080160013), "The licensee has evaluated the applicability of NSAL-06-15 against the accident analysis assumptions and has determined that the current single-failure assumption for the STP SGTR analysis is not limiting. |
| | Therefore, the licensee is operating under compensatory measures to meet regulatory dose guidelines. |
| | The licensee plans to resolve this condition at the earliest opportunity so that the assumptions, including the limiting single failure, for the SGTR accident analysis described herein are consistent with the plant response to this event. To support the limiting single-failure assumptions in the SGTR analysis, STP will maintain an administrative limit for reactor coolant system (RCS) dose equivalent iodine 131 (DEI) so that the radiological dose reference values for the SGTR analysis remain bounding, and the licensee will continue to comply with GDC 19." Has this condition been resolved? |
| | If so, how? Also, provide justification that GDC 19 continues to be met. |
| | NOC-AE-1 4003082 Attachment 1 Page 2 of 4 STPNOC Response: The condition described in the RAI above was resolved by a design change to make the steam valves to the moisture separator reheater fail closed. The design change has been implemented in both STP units. This corrective action restored the original design and licensing basis and eliminated the need for the administrative limit on DEI that had been implemented as a compensatory action. Condition Record 07-2887 details the resolution in accordance with the STPNOC Corrective Action Program.Restoration of the original design basis as described above maintains the original compliance with GDC 19 without need for compensatory action.STPNOC also addresses the relation between the risk-informed GSI-191 analyses and the AST analyses with respect to compliance with GDC 19 in Section 2.2 of Enclosure 2-1 of Reference 1 to the cover letter.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 containment sump.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 maintained at or above 7.The AST application indicates: "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 radiological consequence 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 application further indicates: "The design inputs for calculating the containment sump pool pH were conservatively established by the licensee to maximize the acidic contribution to sump pH and minimize the basic contribution." The GSI-1 91 application indicates the possibility that debris generated during a LOCA could clog the containment sump strainers in pressurized-water reactors (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, radiological consequences, and loss of the containment spray system. |
| | NOC-AE-1 4003082 Attachment 1 Page 3 of 4 STPNOC Response: Enclosure 2-4 "Request for Exemption from General Design Criterion 41" of the license amendment, STPNOC addressed exemption from 10 CFR Part 50 Appendix A, General Design Criteria (GDC) 41, Criterion 41 -Containment atmosphere cleanup. STPNOC did not revise the licensing basis dose analyses, including the Alternate Source Term (AST)analyses, for the risk-informed GSI-191 licensing application except to add a study calculation for the response to this RAI. The analyses and results currently described in the STP UFSAR for the events identified above remain valid.The licensing application is structured to show that the sumps are sufficiently reliable as a support function for CSS as currently licensed. |
| | STP has applied RG 1.174 to assess the effects of debris using a risk-informed approach and shown acceptable results. In order to provide a risk-informed perspective on the sump design, the risk associated with GSI-191 is evaluated to include the failure mechanisms associated with sump blockage affecting Containment Spray System (CSS) recirculation mode.In the risk-informed application, the sump pH history was investigated over 30 days both analytically and experimentally |
| | [1] (attached). |
| | The investigation shows the STP sump pH will remain substantially above 7.0 for thirty days.Any loss of loss of net positive suction head (NPSH) for the Emergency Core Cooling System (ECCS) and Containment Spray System (CSS) pumps, impeding the flow of water from the sump has been analyzed using a risk-informed approach [2] (attached.) |
| | The risk-informed analysis assesses the impact of a GSI-191 related sump failure on the CSS and associated AST acceptance criteria. |
| | For breaks that result in sump blockage and which initially have two or more CSS trains available (consistent with single failure of one CSS train, per the deterministic AST analysis), the analysis determines the expected time that the CSS trains would operate before failing due to blockage. |
| | The time is then evaluated using the STP AST engineering calculation to determine the control room and Technical Support Center dose. Finally the risk-informed analysis evaluates the fraction of the cases that would result in exceeding the AST acceptance criteria.As shown in [2], Figure 1, sump clogging doesn't start until about 2.5 hours. As shown in the reference analysis [2], the risk for exceeding dose limits identified in RG 1.183 is acceptably low. Most events (-81%) result in dose within the AST limit, and the largest dose for the relatively small fraction of events (-19%) that do exceed the acceptance criteria is less than 2 rem over the 5 rem limit and the probability is very low (-3.7E-09/yr). |
| | The table below is a summary of the AST analysis for dose after loss (CSS Cutoff) of two or more CSS pumps. As can be seen, the dose limits (10 CFR 50.67 limits) at the Exclusion Area Boundary (EAB) and Low Population Zone (LPZ) will not be challenged for early losses of CSS (see the tabulated values at 2.185 hours). |
| | NOC-AE-1 4003082 Attachment 1 Page 4 of 4 Dose at CSS Cutoff Time (sum of results from Tables D3, D4, & D5 LB dose analysis)EAB LPZ CR TSC (REM)* (REM) (REM) (REM)10CFR50.67 Limit 25 25 5 5 Design Basis 5.68 2.89 3.74 4.40 CSS Cutoff @ 2.185 5.70 4.69 6.70 6.33 hours CSS Cutoff @ 4 hours 5.68 3.50 4.76 5.04 CSS Cutoff @ 4.25 5.68 3.41 4.62 4.95 hours CSS Cutoff @ 6.5 hours 5.68 3.03 3.98 4.54 CSS Cutoff @ 7.6 hours 5.68 2.96 3.87 4.47 CSS Cutoff @ 16 hours 5.68 2.89 3.74 4.40l*#- dose is a worst 2-nour integrated values.value. All otner aoses are 30u day integrated Also as described in Enclosure 4-1 to Reference 1 of the cover letter, realizing the source term necessary to produce the doses as calculated in the dose assessment is unlikely based on the Regulatory Guide 1.174 evaluation that shows defense in depth and substantial safety margin.References (attached) |
| | [1] Risk-Informed GSI-191 AADB RAI 3 Response (Attachment 2 listed in cover letter)[2] Alternate Source Term Dose Analysis: |
| | An Estimate of Risk Attributed to GSI-1 91 STP-RIGSI191-RAI.1 (Attachment 3 listed in cover letter)}} |
Letter Sequence Request |
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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:Letter
MONTHYEARIR 05000498/20240022024-08-0909 August 2024 Integrated Inspection Report 05000498/2024002 and 05000499/2024002 IR 05000498/20240102024-08-0808 August 2024 Biennial Problem Identification and Resolution Inspection Report 05000498/2024010 and 05000499/2024010 NOC-AE-240040, Application for Order Consenting to Direct Transfer of Licenses2024-07-31031 July 2024 Application for Order Consenting to Direct Transfer of Licenses ML24218A1462024-07-26026 July 2024 2. EPA Comments on South Texas Project Exemption Ea/Fonsi ML24207A1782024-07-25025 July 2024 Licensed Operator Positive Fitness-For-Duty Test IR 05000498/20244042024-06-0303 June 2024 Cyber Security Inspection Report 05000498/2024404 (Cover Letter) ML24141A0482024-05-17017 May 2024 EN 56958_1 Ametek Solidstate Controls, Inc ML24136A2842024-05-15015 May 2024 Independent Spent Fuel Storage Installation Supplement to Request for Exemption from Various Part 72 Regulations Resulting from Fuel Basket Design Control Compliance ML24136A2872024-05-15015 May 2024 Submittal of 2024 Nrc/Fema Evaluated Exercise Scenario Manual NOC-AE-240040, Operator Licensinq Examination Schedule Revision 32024-05-15015 May 2024 Operator Licensinq Examination Schedule Revision 3 ML24128A1572024-05-0707 May 2024 Independent Spent Fuel Storage Installation Request for Exemption from Various Part 72 Regulations Resulting from Fuel Basket Design Control Compliance IR 05000498/20240012024-05-0606 May 2024 Integrated Inspection Report 05000498/2024001 & 05000499/2024001 ML24116A3032024-04-25025 April 2024 Operations Quality Assurance Plan Condition Adverse to Quality Definition Change Resulting in a Reduction in Commitment ML24116A2282024-04-25025 April 2024 Annual Environmental Operating Report ML24117A1602024-04-24024 April 2024 2023 Radioactive Effluent Release Report ML24102A2452024-04-23023 April 2024 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0046 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) ML24113A3122024-04-22022 April 2024 Cycle 24 Core Operating Limits Report NOC-AE-240040, Relief Request Number RR-ENG-4-07 – Request for an Alternative to ASME Code Case N-729-6 for Reactor Vessel Head Penetration 752024-04-0606 April 2024 Relief Request Number RR-ENG-4-07 – Request for an Alternative to ASME Code Case N-729-6 for Reactor Vessel Head Penetration 75 NOC-AE-240040, Financial Assurance for Decommissioning - 2024 Update2024-03-28028 March 2024 Financial Assurance for Decommissioning - 2024 Update ML24081A3972024-03-21021 March 2024 Response to Request for Additional Information for Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML24080A2902024-03-19019 March 2024 Nuclear Liability Certificates of Insurance ML24079A1312024-03-0505 March 2024 Nuclear Insurance Protection ML24060A1742024-02-28028 February 2024 Submittal of Annual Fitness for Duty Performance Report for 2023 IR 05000498/20230062024-02-28028 February 2024 Annual Assessment Letter for South Texas Project Electric Generating Station, Units 1 and 2 (Report 05000498/2023006 and 05000499/2023006) IR 05000498/20240132024-02-27027 February 2024 Design Basis Assurance Inspection (Programs) Commercial Grade Dedication IR 05000498/2024013 and 05000499/2024013 ML24050A0082024-02-19019 February 2024 Evidence of Financial Protection ML24045A0922024-02-16016 February 2024 Response to STP FOF Move Letter (2024) NOC-AE-240040, Unit L & 2, Supplement to Modify the Implementation Date for License Amendment Request to Revise Alternate Source Term Dose Calculation2024-02-0808 February 2024 Unit L & 2, Supplement to Modify the Implementation Date for License Amendment Request to Revise Alternate Source Term Dose Calculation ML24039A1112024-02-0808 February 2024 Operator Licensing Examination Schedule Revision 2 ML24038A3342024-02-0707 February 2024 Change to South Texas Project Electric Generating Station (Stepgs) Emergency Plan ML24033A3002024-02-0707 February 2024 Summary of Regulatory Audit Regarding a Proposed Alternative to ASME Code, Section XI Requirements for Containment Building Inspections ML24029A2752024-01-29029 January 2024 Request to Reschedule Evaluated Force-on-Force Drill IR 05000498/20230042024-01-29029 January 2024 Integrated Inspection Report 05000498/2023004 and 05000499/2023004 ML24024A1162024-01-24024 January 2024 STP Unit 2 Request for Information IR 05000498/20230032023-12-28028 December 2023 Acknowledgment of Reply to a Notice of Violation (NRC Inspection Report 05000498/2023003 and 05000499/2023003) ML23360A1692023-12-26026 December 2023 FEMA, Submittal of Radiological Emergency Preparedness Final Report for the South Texas Project Medical Services Drill Evaluated on August 31, 2023 NOC-AE-230040, Supplement to Proposed Alternate Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection (Relief Request RR-ENG-4-06)2023-12-14014 December 2023 Supplement to Proposed Alternate Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection (Relief Request RR-ENG-4-06) NOC-AE-230039, Docket Nos. Stn 50-498, Stn 50-499 - Reply to a Notice of Violation, NRC Inspection Report 05000498/2023003 and 05000499/20230032023-12-12012 December 2023 Docket Nos. Stn 50-498, Stn 50-499 - Reply to a Notice of Violation, NRC Inspection Report 05000498/2023003 and 05000499/2023003 ML23339A1902023-12-0505 December 2023 Update Foreign Ownership, Control, or Influence (FOCI) ML23326A2592023-12-0505 December 2023 Review of the Fall 2022 Steam Generator Tube Inspection Report IR 05000498/20234012023-12-0404 December 2023 Security Baseline Inspection Report 05000498/2023401 and 05000499/2023401 ML23324A0102023-11-16016 November 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML23310A2282023-11-13013 November 2023 Integrated Inspection Report 05000498/2023003 and 05000499/2023003, and Notice of Violation ML23311A2082023-11-0909 November 2023 Reassignment of U.S. Nuclear Regulatory Commission Branch Chief in the Division of Operating Reactor Licensing for Plant Licensing Branch IV ML23298A0002023-11-0101 November 2023 the Associated Independent Spent Fuel Storage Installation - Issuance of Amendment Nos. 226 and 211 Related to Order Approving Indirect Transfer of Licenses and Conforming License Amendments ML23279A0342023-10-30030 October 2023 Associated Independent Spent Fuel Storage Installation - Order Approving Indirect Transfer of Licenses and Draft Conforming License Amendments (EPID L-2023-LLM-0004) (Letter) ML23303A0782023-10-30030 October 2023 Submittal of Supplemental Information in Response to Order Consenting to License Transfers and Approval of Draft Conforming License Amendments IR 05000498/20234032023-10-26026 October 2023 Material Control and Accounting Program Inspection Report 05000498/2023403 and 05000499/2023403 (Cover Letter) ML23317A1262023-10-12012 October 2023 South. Texas Project Physical Security Plan, Training and Qualification Plan, Safeguards Contingency Plan, and Independent Spent Fuel Storage Installation Security Program Revision 26 ML23279A1382023-10-0505 October 2023 Responses to Requests for Additional Information Related to Application for Order Approving Indirect Transfer of Control of Licenses 2024-08-09
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Nuclear Operating Company.S'uli Tevas Ah ,fr'd r/lertri (7Cenemfi;So 7., PO. bS 2,59 W?&Wjh'ýn Tckxi 774,1J March 17, 2014 NOC-AE-14003082 10 CFR 50.12 10 CFR 50.90 U. S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, DC 20555-0001 South Texas Project Units 1 & 2 Docket Nos. STN 50-498, STN 50-499 Response to NRC Accident Dose Branch Request for Additional Information Regarding STP Risk-Informed GSI-191 Application (TAC NOs MF2400 and MF2401)
References:
- 1. Letter, G. T. Powell, STPNOC, to NRC Document Control Desk, "Supplement 1 to Revised STP Pilot Submittal and Requests for Exemptions and License Amendment for Risk-Informed Approach to Resolving Generic Safety Issue (GSI)-191," November 13, 2013, NOC-AE-13003043, ML13323A183
- 2. Email, Andrea George, NRC, to Albon Harrison, STPNOC, "RAI's Regarding South Texas Project's Submittal for Risk-Informed Resolution of GS-191", January 14, 2014, ML14015A045 This submittal responds to requests for additional information in Reference 2 with regard to the STP Nuclear Operating Company (STPNOC) risk-informed application for the .resolution of GSI-191 (Reference 1).There are no regulatory commitments in this letter.T 66 ST133816627.
NOC-AE-1 4003082 Page 2 of 3 If there are any questions, please contact Mr. Michael Murray at 361-972-8164.
I declare under penalty of perjury that the foregoing is true and correct.Executed on: u t-1 zo-G. T. Powell Site Vice President awh Attachments:
- 1. Response to Accident Dose Branch Request for Additional Information
- 2. Risk-Informed GSI-191 AADB RAI 3 Response 3. Alternate Source Term Dose Analysis:
An Estimate of Risk Attributed to GSI-191 STP-RIGSI191-RAI.1 NOC-AE-1 4003082 Page 3 of 3 cc: (paper copy)(electronic copy)Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 1600 East Lamar Boulevard Arlington, TX 76011-4511 Balwant K. Singal Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North (MS 8 B1)11555 Rockville Pike Rockville, MD 20852 NRC Resident Inspector U. S. Nuclear Regulatory Commission P.O. Box 289, Mail Code: MN116 Wadsworth, TX 77483 Jim Collins City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704 Steven P. Frantz, Esquire A. H. Gutterman, Esquire Morgan, Lewis & Bockius LLP Balwant K. Singal Michael Markley John Stang U. S. Nuclear Regulatory Commission John Ragan Chris O'Hara Jim von Suskil NRG South Texas LP Kevin Polio Richard Pefia L. D. Blaylock City Public Service Peter Nemeth Crain Caton & James, P.C.C. Mele City of Austin Richard A. Ratliff Robert Free Texas Department of State Health Services NOC-AE-1 4003082 Attachment 1 Response to Accident Dose Branch Request for Additional Information NOC-AE-1 4003082 Attachment 1 Page 1 of 4 Risk Informed GSI-191 Accident Dose Branch (AADB) RAI I To ensure a complete and accurate review of the dose consequence analyses, please provide additional information in tabular form describing, for each design basis accident affected by the proposed Risk Informed GSI-191 submittal, all the basic parameters used in the dose consequence analyses.
For each parameter, please indicate the current licensing basis (CLB)value, the revised GSI-191 value where applicable, as well as the basis for any changes to the CLB. An example of the input/assumptions needed is provided in Table 4.3-11 "Dose Analysis Inputs for LOCA" provided in STP's alternate source term submittal
[Agencywide Documents Access Management System (ADAMS) Accession No. ML070890474].
The staff requests that the information provided include all of the basic parameters whether or not the individual parameter is being changed for the GSI-1 91 amendment.
The staff also requests that the information be provided in separate tables for each affected accident (i.e., loss-of-coolant accident (LOCA), the fuel handing accident (FHA), the main steam line break accident (MSLB), the steam generator tube rupture accident (SGTR), the control rod ejection accident (CREA), and the locked rotor accident (LRA)).STP Response: Other than to add a study calculation for the response to RAI 3 below, STPNOC did not revise the licensing basis dose analyses, including the Alternate Source Term analyses, for the risk-informed GSI-1 91 licensing application.
The analyses and results currently described in the STP UFSAR for the events identified above remain valid.Risk Informed GSI-191 AADB RAI 2 STP identified the following condition related to the alternative source term (AST) license amendments currently in effect at STP Units 1 and 2. Westinghouse Electric Company Nuclear Safety Advisory Letter (NSAL)-06-15, dated December 13, 2006, advised operators of Westinghouse plants that the single-failure scenario for the SGTR analysis that licensees used in their accident analysis may not be limiting.
As stated in the STP AST NRC Safety Evaluation dated March 6, 2008 (ADAMS Accession No. ML080160013), "The licensee has evaluated the applicability of NSAL-06-15 against the accident analysis assumptions and has determined that the current single-failure assumption for the STP SGTR analysis is not limiting.
Therefore, the licensee is operating under compensatory measures to meet regulatory dose guidelines.
The licensee plans to resolve this condition at the earliest opportunity so that the assumptions, including the limiting single failure, for the SGTR accident analysis described herein are consistent with the plant response to this event. To support the limiting single-failure assumptions in the SGTR analysis, STP will maintain an administrative limit for reactor coolant system (RCS) dose equivalent iodine 131 (DEI) so that the radiological dose reference values for the SGTR analysis remain bounding, and the licensee will continue to comply with GDC 19." Has this condition been resolved?
If so, how? Also, provide justification that GDC 19 continues to be met.
NOC-AE-1 4003082 Attachment 1 Page 2 of 4 STPNOC Response: The condition described in the RAI above was resolved by a design change to make the steam valves to the moisture separator reheater fail closed. The design change has been implemented in both STP units. This corrective action restored the original design and licensing basis and eliminated the need for the administrative limit on DEI that had been implemented as a compensatory action. Condition Record 07-2887 details the resolution in accordance with the STPNOC Corrective Action Program.Restoration of the original design basis as described above maintains the original compliance with GDC 19 without need for compensatory action.STPNOC also addresses the relation between the risk-informed GSI-191 analyses and the AST analyses with respect to compliance with GDC 19 in Section 2.2 of Enclosure 2-1 of Reference 1 to the cover letter.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 containment sump.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 maintained at or above 7.The AST application indicates: "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 radiological consequence 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 application further indicates: "The design inputs for calculating the containment sump pool pH were conservatively established by the licensee to maximize the acidic contribution to sump pH and minimize the basic contribution." The GSI-1 91 application indicates the possibility that debris generated during a LOCA could clog the containment sump strainers in pressurized-water reactors (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, radiological consequences, and loss of the containment spray system.
NOC-AE-1 4003082 Attachment 1 Page 3 of 4 STPNOC Response: Enclosure 2-4 "Request for Exemption from General Design Criterion 41" of the license amendment, STPNOC addressed exemption from 10 CFR Part 50 Appendix A, General Design Criteria (GDC) 41, Criterion 41 -Containment atmosphere cleanup. STPNOC did not revise the licensing basis dose analyses, including the Alternate Source Term (AST)analyses, for the risk-informed GSI-191 licensing application except to add a study calculation for the response to this RAI. The analyses and results currently described in the STP UFSAR for the events identified above remain valid.The licensing application is structured to show that the sumps are sufficiently reliable as a support function for CSS as currently licensed.
STP has applied RG 1.174 to assess the effects of debris using a risk-informed approach and shown acceptable results. In order to provide a risk-informed perspective on the sump design, the risk associated with GSI-191 is evaluated to include the failure mechanisms associated with sump blockage affecting Containment Spray System (CSS) recirculation mode.In the risk-informed application, the sump pH history was investigated over 30 days both analytically and experimentally
[1] (attached).
The investigation shows the STP sump pH will remain substantially above 7.0 for thirty days.Any loss of loss of net positive suction head (NPSH) for the Emergency Core Cooling System (ECCS) and Containment Spray System (CSS) pumps, impeding the flow of water from the sump has been analyzed using a risk-informed approach [2] (attached.)
The risk-informed analysis assesses the impact of a GSI-191 related sump failure on the CSS and associated AST acceptance criteria.
For breaks that result in sump blockage and which initially have two or more CSS trains available (consistent with single failure of one CSS train, per the deterministic AST analysis), the analysis determines the expected time that the CSS trains would operate before failing due to blockage.
The time is then evaluated using the STP AST engineering calculation to determine the control room and Technical Support Center dose. Finally the risk-informed analysis evaluates the fraction of the cases that would result in exceeding the AST acceptance criteria.As shown in [2], Figure 1, sump clogging doesn't start until about 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. As shown in the reference analysis [2], the risk for exceeding dose limits identified in RG 1.183 is acceptably low. Most events (-81%) result in dose within the AST limit, and the largest dose for the relatively small fraction of events (-19%) that do exceed the acceptance criteria is less than 2 rem over the 5 rem limit and the probability is very low (-3.7E-09/yr).
The table below is a summary of the AST analysis for dose after loss (CSS Cutoff) of two or more CSS pumps. As can be seen, the dose limits (10 CFR 50.67 limits) at the Exclusion Area Boundary (EAB) and Low Population Zone (LPZ) will not be challenged for early losses of CSS (see the tabulated values at 2.185 hours0.00214 days <br />0.0514 hours <br />3.058862e-4 weeks <br />7.03925e-5 months <br />).
NOC-AE-1 4003082 Attachment 1 Page 4 of 4 Dose at CSS Cutoff Time (sum of results from Tables D3, D4, & D5 LB dose analysis)EAB LPZ CR TSC (REM)* (REM) (REM) (REM)10CFR50.67 Limit 25 25 5 5 Design Basis 5.68 2.89 3.74 4.40 CSS Cutoff @ 2.185 5.70 4.69 6.70 6.33 hours3.819444e-4 days <br />0.00917 hours <br />5.456349e-5 weeks <br />1.25565e-5 months <br /> CSS Cutoff @ 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 5.68 3.50 4.76 5.04 CSS Cutoff @ 4.25 5.68 3.41 4.62 4.95 hours0.0011 days <br />0.0264 hours <br />1.570767e-4 weeks <br />3.61475e-5 months <br /> CSS Cutoff @ 6.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 5.68 3.03 3.98 4.54 CSS Cutoff @ 7.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> 5.68 2.96 3.87 4.47 CSS Cutoff @ 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> 5.68 2.89 3.74 4.40l*#- dose is a worst 2-nour integrated values.value. All otner aoses are 30u day integrated Also as described in Enclosure 4-1 to Reference 1 of the cover letter, realizing the source term necessary to produce the doses as calculated in the dose assessment is unlikely based on the Regulatory Guide 1.174 evaluation that shows defense in depth and substantial safety margin.References (attached)
[1] Risk-Informed GSI-191 AADB RAI 3 Response (Attachment 2 listed in cover letter)[2] Alternate Source Term Dose Analysis:
An Estimate of Risk Attributed to GSI-1 91 STP-RIGSI191-RAI.1 (Attachment 3 listed in cover letter)