|
---|
Category:Letter type:
MONTHYEAR2CAN012401, U.S. Additional Protocol2024-01-17017 January 2024 U.S. Additional Protocol 2CAN012403, Supplemental Information - Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 42024-01-11011 January 2024 Supplemental Information - Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4 0CAN012401, Registration of Cask Use2024-01-10010 January 2024 Registration of Cask Use 1CAN122301, Responses to Request for Additional Information for Request for Alternative for Implementation of Extended Reactor Vessel Inservice Inspection Interval (ANO1-ISl-037)2023-12-14014 December 2023 Responses to Request for Additional Information for Request for Alternative for Implementation of Extended Reactor Vessel Inservice Inspection Interval (ANO1-ISl-037) 2CAN112302, Submittal of Amendment 31 to Safety Analysis Report2023-11-16016 November 2023 Submittal of Amendment 31 to Safety Analysis Report 0CAN102303, Registration of Cask Use2023-10-24024 October 2023 Registration of Cask Use 0CAN102302, (ANO) Emergency Plan Revision 49 and Emergency Plan On-Shift Staffing Analysis Revision 32023-10-11011 October 2023 (ANO) Emergency Plan Revision 49 and Emergency Plan On-Shift Staffing Analysis Revision 3 0CAN102301, Evacuation Time Estimate (ETE) Study2023-10-0404 October 2023 Evacuation Time Estimate (ETE) Study 1CAN092301, Supplemental Information - Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 42023-09-21021 September 2023 Supplemental Information - Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4 0CAN092302, Supplement to Request for Alternative Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection (ANO-CISI-002)2023-09-14014 September 2023 Supplement to Request for Alternative Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection (ANO-CISI-002) 2CAN092301, Reply to a Notice of Violation2023-09-0808 September 2023 Reply to a Notice of Violation 0CAN092301, Emergency Plan Implementing Procedure Revision2023-09-0505 September 2023 Emergency Plan Implementing Procedure Revision 0CAN082301, Units 1 and 2 - Changes to the Quality Assurance Program Approval Form for Radioactive Material Package No. 03412023-08-17017 August 2023 Units 1 and 2 - Changes to the Quality Assurance Program Approval Form for Radioactive Material Package No. 0341 2CAN082301, Inservice Inspection Summary Report for the Arkansas Nuclear One, Unit 2, Twenty-Ninth Refueling Outage (2R29)2023-08-10010 August 2023 Inservice Inspection Summary Report for the Arkansas Nuclear One, Unit 2, Twenty-Ninth Refueling Outage (2R29) 0CAN072301, Registration of Cask Use2023-07-18018 July 2023 Registration of Cask Use 1CAN062304, Supplement Related to License Amendment Request to Remove Technical Specification Condition Allowing Two Reactor Coolant Pump Operation2023-06-29029 June 2023 Supplement Related to License Amendment Request to Remove Technical Specification Condition Allowing Two Reactor Coolant Pump Operation 0CAN062301, Status of Actions to Return to Compliance2023-06-26026 June 2023 Status of Actions to Return to Compliance 0CAN062302, Submittal of Revision 22 of the ANO Fire Hazards Analysis2023-06-20020 June 2023 Submittal of Revision 22 of the ANO Fire Hazards Analysis 1CAN062301, Request for Alternative for Implementation of Extended Reactor Vessel Inservice Inspection Interval (ANO1-ISI-037)2023-06-0808 June 2023 Request for Alternative for Implementation of Extended Reactor Vessel Inservice Inspection Interval (ANO1-ISI-037) 0CAN052303, Annual 10 CFR 50.46 Report for Calendar Year 20222023-05-24024 May 2023 Annual 10 CFR 50.46 Report for Calendar Year 2022 0CAN052302, Emergency Plan Rev. 482023-05-11011 May 2023 Emergency Plan Rev. 48 0CAN052301, Units 1 and 2 - Annual Radiological Environmental Operating Report for 20222023-05-0909 May 2023 Units 1 and 2 - Annual Radiological Environmental Operating Report for 2022 2CAN052301, Cycle 30 Core Operating Limits Report (COLR)2023-05-0303 May 2023 Cycle 30 Core Operating Limits Report (COLR) 0CAN042302, Annual Occupational Radiation Exposure Report for 20222023-04-27027 April 2023 Annual Occupational Radiation Exposure Report for 2022 0CAN042301, Radioactive Effluent Release Report for 20222023-04-14014 April 2023 Radioactive Effluent Release Report for 2022 2CAN042301, License Amendment Request to Revise Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 42023-04-0505 April 2023 License Amendment Request to Revise Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4 1CAN032301, License Amendment Request to Modify the Arkansas Nuclear One, Unit 1, Technical Specification 3.3.1, Reactor Protection System Instrumentation, Turbine Trip Function on Low Control Oil Pressure2023-03-30030 March 2023 License Amendment Request to Modify the Arkansas Nuclear One, Unit 1, Technical Specification 3.3.1, Reactor Protection System Instrumentation, Turbine Trip Function on Low Control Oil Pressure 2CAN032303, Responses to Request for Additional Information Concerning the Request for Alternative Regarding the Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 462023-03-29029 March 2023 Responses to Request for Additional Information Concerning the Request for Alternative Regarding the Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 46 2CAN032304, Supplement to the Request for Alternative Regarding the Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 462023-03-29029 March 2023 Supplement to the Request for Alternative Regarding the Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 46 2CAN032305, 03 Post Examination Analysis2023-03-23023 March 2023 03 Post Examination Analysis 1CAN032302, Inspection Summary Report for the Thirtieth Refueling Outage (1R30)2023-03-20020 March 2023 Inspection Summary Report for the Thirtieth Refueling Outage (1R30) 1CAN012301, Responses to Request for Additional Information for Request for Relief ANO1-ISI-0352023-01-30030 January 2023 Responses to Request for Additional Information for Request for Relief ANO1-ISI-035 2CAN012303, U.S. Additional Protocol2023-01-23023 January 2023 U.S. Additional Protocol 2CAN012302, Relief Request ANO2-RR-23-001, Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 462023-01-20020 January 2023 Relief Request ANO2-RR-23-001, Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 46 1CAN122201, License Amendment Request to Revise Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 42022-12-22022 December 2022 License Amendment Request to Revise Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4 0CAN122202, Registration of Cask Use2022-12-21021 December 2022 Registration of Cask Use 0CAN122201, Reply to a Notice of Violation; EA-22-0992022-12-0808 December 2022 Reply to a Notice of Violation; EA-22-099 0CAN112201, Request for Alternative Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection (ANO-CISI-002)2022-11-10010 November 2022 Request for Alternative Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection (ANO-CISI-002) 1CAN102202, Application to Remove Technical Specification Condition Allowing Two Reactor Coolant Pump Operation2022-10-31031 October 2022 Application to Remove Technical Specification Condition Allowing Two Reactor Coolant Pump Operation 1CAN102203, Cycle 31 Core Operating Limits Report2022-10-24024 October 2022 Cycle 31 Core Operating Limits Report 1CAN102201, Supplement to Proposed Technical Specifications 3.4.12 and 3.4.13 Revised Dose Calculations2022-10-13013 October 2022 Supplement to Proposed Technical Specifications 3.4.12 and 3.4.13 Revised Dose Calculations 0CAN092201, Supplement to License Amendment Request for Approval of Changes to the Emergency Plan Staffing Requirements2022-09-29029 September 2022 Supplement to License Amendment Request for Approval of Changes to the Emergency Plan Staffing Requirements 1CAN092201, Supplement to Request for Relief from American Society of Mechanical Engineers Section XI Volumetric Examination Requirements - Fifth 10-Year Interval, First Period2022-09-0808 September 2022 Supplement to Request for Relief from American Society of Mechanical Engineers Section XI Volumetric Examination Requirements - Fifth 10-Year Interval, First Period 0CAN082201, License Amendment Request for Approval of Changes to the Emergency Plan Staffing Requirements2022-08-30030 August 2022 License Amendment Request for Approval of Changes to the Emergency Plan Staffing Requirements 1CAN082201, Request for Relief from American Society of Mechanical Engineers Section XI Volumetric Examination Requirements - Fifth 10-Year Interval, First Period2022-08-24024 August 2022 Request for Relief from American Society of Mechanical Engineers Section XI Volumetric Examination Requirements - Fifth 10-Year Interval, First Period 2CAN072201, Response to Request for Additional Information Requests for Relief from American Society of Mechanical Engineers Section XI Volumetric Examination Requirements - Fourth 10-Year Interval, Second and Third Periods2022-07-20020 July 2022 Response to Request for Additional Information Requests for Relief from American Society of Mechanical Engineers Section XI Volumetric Examination Requirements - Fourth 10-Year Interval, Second and Third Periods 0CAN072201, Registration of Cask Use2022-07-14014 July 2022 Registration of Cask Use 0CAN062202, Registration of Cask Use2022-06-0909 June 2022 Registration of Cask Use 1CAN062201, Response to the Request for Additional Information Proposed Technical Specifications 3.4.12 and 3.4.13 Revised Dose Calculations2022-06-0202 June 2022 Response to the Request for Additional Information Proposed Technical Specifications 3.4.12 and 3.4.13 Revised Dose Calculations 1CAN052201, Request for Relief Related to American Society of Mechanical Engineers (ASME) Code Case N-729-6 Augmented Examination Requirements ANO1-ISI-0352022-05-31031 May 2022 Request for Relief Related to American Society of Mechanical Engineers (ASME) Code Case N-729-6 Augmented Examination Requirements ANO1-ISI-035 2024-01-17
[Table view] Category:Request for Additional Information (RAI)
MONTHYEARML23130A2972023-05-17017 May 2023 Notification of Inspection (NRC Inspection Report 05000313/2023003) and Request for Information ML23104A1052023-03-10010 March 2023 NRR E-mail Capture - ANO-2 Final RAI Alternative Request for Life-of-Repair of RVCH Pen. 46 ML23019A0672023-01-19019 January 2023 Inservice Inspection Request for Information ML22349A0112022-12-14014 December 2022 NRR E-mail Capture - Final RAI Relief Request ANO1-ISI-035 ML22213A1662022-08-0101 August 2022 Information Request, Security IR 2022401 ML22208A0542022-07-26026 July 2022 Request for Information ML22174A1362022-06-23023 June 2022 NRR E-mail Capture - ANO-2 Final RAI Relief Requests ANO2-ISI-023 Through -028 (EPIDs L-2022-LLR-0022 Through -0027) ML22159A3242022-06-0909 June 2022 Notification of NRC Triennial Heat Exchanger/Sink Performance Inspection (05000313/2022003 and 05000368/2022003) and Request for Information ML22151A3262022-05-31031 May 2022 August 2022 Emergency Preparedness Exercise Inspection - Request for Information ML22122A2952022-05-0404 May 2022 Notification of Inspection NRC Inspection Report 05000368/2022003 and Request for Information ML22124A2452022-05-0404 May 2022 NRR E-mail Capture - ANO-1 and ANO-2 - Final RAI 2 License Amendment Requests to Implement Provisions of 10 CFR 50.69 (L-2021-LLA-0105/-0106) ML22108A1642022-04-18018 April 2022 NRR E-mail Capture - ANO-1: Final RAI License Amendment Request Concerning TS Changes Due to Revised Dose Calculations (L-2021-LLA-0181) ML22034A5482022-02-0303 February 2022 NRR E-mail Capture - Final RAI License Amendment Requests to Implement Provisions of 10 CFR 50.69 (L-2021-LLA-0105/-0106) ML22020A0822022-01-19019 January 2022 NRR E-mail Capture - ANO-1 and 2 - Final RAI 2 License Amendment Requests to Allow the ECP to Remain Operable on a One-Time Basis for Up to 65 Days to Perform Piping Upgrade (L-2021-LLA-0015) ML21312A0382021-11-0505 November 2021 NRR E-mail Capture - ANO-2 RAI Relief Request ANO2-RR-21-002 ML21286A7132021-10-15015 October 2021 ANO2022010 Tfp RFI Stg, Arkansas Nuclear One, Units 1 and 2 - Notification of an NRC Fire Protection Baseline Inspection (NRC Inspection Report 05000313/2022010 and 05000368/2022010) and Request for Information ML21273A0672021-09-29029 September 2021 NRR E-mail Capture - ANO-2 Final RAI 2 License Amendment Request to Adopt a Safety Function Determination Program ML21236A3222021-09-19019 September 2021 Request for Information ML21252A0052021-08-20020 August 2021 NRR E-mail Capture - ANO-1 and 2 Final RAI License Amendment Request to Allow the ECP to Remain Operable on a One-Time Basis for Up to 65 Days to Perform Piping Upgrade (L-2021-LLA-0015) ML21217A3302021-08-0505 August 2021 (ANO) Problem Identification and Resolution (PIR) Request for Information Combined ML21204A0842021-07-28028 July 2021 ANO Phase 4 2021013 RFI Gap ML21197A0372021-07-16016 July 2021 NRR E-mail Capture - ANO-1 and 2 - Final RAI Final Response to GL 2004-02 0CAN042105, Supplement to Response to Request for Additional Information Reduction of Commitment to the Entergy Operation'S Quality Assurance Program Manual Description2021-04-30030 April 2021 Supplement to Response to Request for Additional Information Reduction of Commitment to the Entergy Operation'S Quality Assurance Program Manual Description ML21116A1092021-04-26026 April 2021 NRR E-mail Capture - ANO-1 and ANO-2: Final Supplemental RAI Proposed Alternative to ASME Section XI Requirements for Repair/Replacement of ECP Supply Piping ML21105A0122021-04-0909 April 2021 NRR E-mail Capture - ANO-2 Final RAI License Amendment Request to Adopt a Safety Function Determination Program ML21071A2172021-03-10010 March 2021 NRR E-mail Capture - ANO-1 and ANO-2 - Final RAI Proposed Change to Quality Assurance Program Manual ML21026A2682021-01-26026 January 2021 Request for Information ML21022A0842021-01-22022 January 2021 Request for Additional Information - Proposed Alternative to ASME Section XI Requirements for Repair/Replacement of Emergency Cooling Pond Supply Piping - Arkansas Nuclear One,Units 1 and 2 -Entergy Operations, Inc. NON-PROPRIETARY Redacted ML21019A5142021-01-14014 January 2021 March 2021 Emergency Preparedness Exercise Inspection - Request for Information ML20324A6412020-11-19019 November 2020 NRR E-mail Capture - ANO-1 - Final RAI Relief Request ANO1-ISI-034 ML20316A0102020-11-0202 November 2020 NRR E-mail Capture - ANO-1 and ANO-2 - Final RAI Concerning Relief Request EN-20-RR-01 ML20262H0752020-09-17017 September 2020 NRR E-mail Capture - ANO-2 Final RAI 2 License Amendment Request Concerning Proposed Technical Specification Additions, Deletions, and Relocations ML20260H4762020-09-0909 September 2020 NRR E-mail Capture - ANO-1 Final RAI License Amendment Request to Revise Lov Relay Allowable Values ML20154K7622020-06-0101 June 2020 NRR E-mail Capture - ANO-2 Final RAI License Amendment Request Concerning Proposed Technical Specification Additions, Deletions, and Relocations ML20119A0982020-04-28028 April 2020 Notification of Inspection (NRC Inspection Report 05000368/2020003 and Request for Information ML20106E8522020-04-13013 April 2020 Information Request, NRC Inspection Report 05000313/2020410 and 05000368/2020410 ML20065H7992020-03-0606 March 2020 Supplemental Information Needed for Acceptance of Requested Licensing Action License Amendment Request to Revise Loss of Voltage Relay Allowable Values ML20055E9092020-02-24024 February 2020 NRR E-mail Capture - ANO-2 Final RAI License Amendment Request to Revise Control Element Assembly Drop Time ML20036D3092020-02-0505 February 2020 NRR E-mail Capture - ANO-2 - Final RAI Alternative Request VRR-ANO2-2019-1 ML20013C7472020-01-10010 January 2020 NRR E-mail Capture - ANO-1 and 2 -- Final RAI #2 LAR to Incorporate Tornado Missile Risk Evaluator (TMRE) Into Licensing Basis ML19316A0242019-11-0707 November 2019 NRR E-mail Capture - ANO-1 - - Final RAI Concerning Relief Request ANO1-ISI-033 (L-2019-LLR-0100) ML19280A0402019-10-0707 October 2019 NRR E-mail Capture - ANO-1 and 2 - Final RAI #1 License Amendment Request to Incorporate Tornado Missile Risk Evaluator (TMRE) Into Licensing Basis ML19339F5902019-09-23023 September 2019 Request for Information: Arkansas Nuclear One, IR 05000313/2019-004 Occupational Radiation Safety Inspection ML19281E0032019-08-0505 August 2019 ANO 2019 PIR Request for Information ML19203A0122019-07-16016 July 2019 Request for Information - Inservice Inspection Activities (NRC Inspection Report 05000313/2019004) ML19106A4322019-04-16016 April 2019 NRR E-mail Capture - ANO-2 Final RAI Re LAR to Add TS Actions to Address Inoperability of the Containment Building Sump ML19058A8332019-02-27027 February 2019 NRR E-mail Capture - ANO-1 - Final RAI Relief Request ANO1-ISI-032 ML18324A8052018-11-19019 November 2018 Notification of an NRC Triennial Fire Protection Baseline Inspection Report 05000313/2019010 and 05000368/2019010) and Request for Information ML18263A3022018-09-19019 September 2018 NRR E-mail Capture - ANO-1 - Final RAI License Amendment Request to Adopt TSTF-425, Revision 3 ML18263A1482018-09-11011 September 2018 NRR E-mail Capture - ANO-2 - Final RAI #2 LAR to Update the RCS Pressure-Temperature Limits 2023-05-17
[Table view] |
Text
2CAN061002
June 24, 2010
U.S. Nuclear Regulatory Commission
Attn: Document Control Desk Washington, DC 20555
SUBJECT:
Request for Additional Information Technical Specification Changes and Analyses Relating to
Use of Alternative Source Term
Arkansas Nuclear One, Unit 2
Docket No. 50-368 License No.
NPF-6
REFERENCES:
- 1. Entergy letter to the NRC, dated March 31, 2010, "License Amendment Request Technical Specification Changes and Analyses Relating to Use of Alternative Source Term" (2CAN031001)
- 2. Email from Kaly Kalyanam (NRC) to Robert W. Clark (Entergy), dated May 25, 2010, "Request for Additional Information on the AST LAR -
ME3678"
- 3. Entergy letter to the NRC, dated October 5, 2007, "License Amendment Request Technical Specification Change Request Associated with Replacement of Containment Sump Buffer" (2CAN100703)
- 4. Entergy letter to the NRC, dated February 19, 2008, "License Amendment Request Replacement of Containment Sump Buffer Request for Additional Information" (2CAN020802)
- 5. NRC letter to Entergy dated March 31, 2008, "Arkansas Nuclear One, Unit No. 2 - Issuance of Amendment RE: Technical Specifications
3.6.2.2, 'Containment Sump Buffering Agent Trisodium Phosphate (TSP)'
(TAC No. MD6933)" (2CNA030809)
Dear Sir or Madam:
With Reference 1, Entergy Operations, Inc. (Entergy) submitted a request to change the Technical Specifications (TSs) for Arkansas Nuclear One, Unit 2 (ANO-2). In particular the amendment would modify the TS requirements related to the use of an alternate source term associated with accident offsite and control room dose consequences. Entergy Operations, Inc. 1448 S.R. 333 Russellville, AR 72802 Tel 479-858-3110 Kevin T. Walsh Vice President, Operations Arkansas Nuclear One
2CAN061002 Page 2 of 3
During the review of the material provided in Reference 1, the NRC determined that additional information was required to complete the Staff's evaluation of the Reference 1 request. In Reference 2, the NRC requested Entergy to respond to the requests for additional information (RAIs). Attached to this submittal are the RAIs included in Reference 2 and Entergy's response.
It should be noted that Entergy has changed the buffering agent for ANO-2 as presented in Reference 3. One important factor associated with the buffering agent change to sodium tetraborate (NaTB) was the post accident pH in the sump. An RAI that is very similar to the one in Reference 2 was responded to in Reference 4. The following was stated in the safety evaluation report presented in Reference 5:
Based on information provided by licens ee's letter dated February 19, 2008, the NRC staff performed an evaluation to confirm the licensee's pH calculations. The NRC staff reviewed the licensee's methodology, assumptions, and performed hand calculations to verify the resulting pH value after 30 day
- s. The NRC staff concluded that the licensee's methodology and calculations are conservative. The NRC staff's independent verification demonstrated the containment sump pH would remain greater than or equal to 7 for at least 30 days post-LOCA with the quantities of NaTB described above.
This letter contains no new commitments.
If you have any questions or require additional information, please contact David Bice at 479-858-5338.
I declare under penalty of perjury that the foregoing is true and correct. Executed on June 24, 2010
Sincerely, Original signed by K. T. Walsh
KTW/rwc
Attachment:
Response to Request for Additional Information Related to the Use of Alternative Source Term (AST)
2CAN061002 Page 3 of 3
cc: Mr. Elmo E. Collins Regional Administrator U. S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125
NRC Senior Resident Inspector Arkansas Nuclear One P. O. Box 310 London, AR 72847
U. S. Nuclear Regulatory Commission Attn: Mr. Kaly Kalyanam MS O-8 B1 One White Flint North 11555 Rockville Pike
Rockville, MD 20852
Mr. Bernard R. Bevill
Arkansas Department of Health Radiation Control Section 4815 West Markham Street Slot #30 Little Rock, AR 72205
Attachment to 2CAN061002 Response to Request for Additional Information Related to the Use of Alternative Source Term (AST)
Attachment to 2CAN061002
Page 1 of 5 Response to Request for Additional Information Related to the Use of Alternative Source Term (AST)
- 1. Describe the methodology used to verify that the minimum possible post-LOCA sump pH remains greater than 7.0. Specifically, please describe how the following parameters were accounted for in the calculation. a. What is the maximum, beginning of cycle, boron concentration in the reactor coolant and borated water storage tank? The maximum allowable Reactor Coolant System boron concentration during a fuel cycle is 2000 parts per million (ppm). The maximum allowable boron concentration in the refueling water tank (RWT) (this is the same as a borated water storage tank) is 3000 ppm per Arkansas Nuclear One, Unit 2 (ANO-2) Technical Specification (TS) 3.5.4 (Reference 1). In addition, it should be noted that the minimum post-Loss of Coolant Accident (LOCA) sump pH calculation includes consideration of the maximum boron concentrations contained in the safety injection tanks (3000 ppm) and the boric acid makeup tank (6125 ppm).
- b. What is the minimum volume of water assumed in the calculation of post-LOCA sump pH? The calculation of post-LOCA sump pH assumed a minimum volume of water of 135,174,893 in 3, or ~78,226.21 ft
- 3.
- c. What is the minimum quantity of buffering agent contained in the baskets? 15,000 pounds mass (lb m) is the minimum quantity of buffering agent contained in the ANO-2 baskets. This is based on the ANO-2 TS 3.6.2.2 minimum requirement of 308 ft 3 and a minimum sodium tetraborate (NaTB) density of 48.7 lb m/ft 3.
- d. What is the buffering agent used at ANO-2 (trisodium phosphate or sodium tetraborate)? ANO-2 uses sodium tetraborate.
- e. What assumptions are made for the dissolution time of the buffering agent? The ANO-2 post-LOCA pH calculation assume s the submerged portions of the NaTB in the baskets, which increases with time until the baskets are completely submerged, dissolve into the sump solution at a constant rate of 1.014 lb m/ft 2-min. This dissolution rate was calculated by multiplying the trisodium phosphate (TSP) dissolution rate of 0.7 lb m/ft 2-min provided in WCAP-11611 (Reference 2) by the dissolution time ratio of TSP-to-NaTB at 200
ûF (i.e. 42 seconds / 29 seconds) given in WCAP-16596-NP Attachment to 2CAN061002
Page 2 of 5 (Reference 3). No credit was taken for dynamic flow. In addition, only the surface area of the four sides of the NaTB baskets is assumed to be exposed to the sump solution.
- f. Describe the analysis used to determine strong acid concentrations in the sump for a period of 30 days post-LOCA. Include a description of the calculations for hydrochloric acid, generated by radiolytic decomposition of Hypalon cable insulation, and nitric acid, produced by irradiation of water and air in the containment
. The analysis of the strong acid concentrations in the sump utilizes a conservative calculation of the total mass of cable jacket and filler materials in the ANO-2 containment to calculate the amount of hydrochloric (HCl) acid produced from exposure to both beta and gamma radiation. This approach is conservative since some cable is located in conduit and shielded from beta radiation. In addition, the filler materials do not contain chlorine. The analysis uses the total integrated 30-day post-LOCA beta and gamma doses in the containment atmosphere to calculate the total moles of HCl acid produced from the cable.
To calculate the total moles of nitric acid produced by irradiation of water and air in the containment post-LOCA, the analysis uses the total integrated 30-day gamma dose in the containment sump.
Irradiation of the cable is assumed to produce 4.6E-4 moles of HCl acid per
lb m-megarad of exposure and irradiation of the sump water produces 7.3E-6 moles of nitric acid per liter-megarad of exposure, consistent with NUREG/CR-5950 (Reference 4).
Using the above approach, a total of 3,473.6 moles of HCl acid and 147.1 moles of nitric acid are calculated to form in the ANO-2 containment sump during the 30-day post-LOCA period.
Given that the rate of acid generation in the sump is unknown, the analysis of the strong acid concentrations assumes that the total amount of acid generated during the 30-day accident is present in the sump instantaneously at the beginning of the accident. This assumption is extremely conservative, if a time-dependent sump pH profile is desired. However, the intent of the calculation was to show that the sump pH reaches, within a reasonable amount of time, then remains at or above 7.0 in the presence of the strong acids and for this purpose, the method was adequate. For comparison, the response to question 3 below also includes the time-dependent sump pH profile for this case.
Attachment to 2CAN061002
Page 3 of 5
- 2. How do the calculations for the proposed AST sump pH analysis differ from the previous calculation of sump pH? No sump pH calculations were performed specifically for the AST analyses. Rather, the AST analyses utilize the results provided in the existing calculation of sump pH. However, the time at which the sump pH is assumed in the AST analyses to reach 7.0 varies slightly from the results contained in the existing sump pH calculation.
The existing sump pH calculation assumes a total Emergency Core Cooling System flow rate during injection of 16,450 gpm and a maximum RWT volume of 503,300 gallons to calculate a time to recirculation of 30.6 minutes. The AST analyses assume a total injection flow rate of 14,250 gpm and the minimum RWT volume of 384,000 gallons to calculate a time to recirculation of 26.95 minutes, consistent with the current, TID-based dose analysis-of-record (AOR). Also, consistent with the current AOR, the AST analyses "round down" the assumed time to recirculation to 26 minutes. This approach is conservative for dose analyses, because Engineered Safety Feature leakage during recirculation consequently starts sooner.
The AST analyses then use the time between start of recirculation and the time for the sump pH to reach 7.0 from the existing sump pH calculation to determine the time in the dose analyses that the sump pH is assumed to be below 7.0. From the sump pH profile provided in response to question 3 below, the time to reach a pH of 7.0 is determined by interpolating between the 30.60 and 45.83 minute time steps. The interpolation yields a pH of 7.0 at 41.38 minutes, or 10.78 minutes following the start of recirculation. The AST dose analyses conservatively round this value up to 11 minutes.
Given the pH value of 6.874 at the onset of recirculation is very near 7.0 and the 11 minute duration that the sump pH is below 7.0 is relatively short, the potential for re-evolution of elemental iodine is not high. However, the potential impact of re-evolved elemental iodine transferring to the containment atmosphere and escaping via the containment leakage pathway was still considered and treated in the following manner. During the 11 minute time frame when pH is less than 7.0, the elemental iodine spray removal coefficient was set to 0, thereby preventing the removal of containment elemental iodines by containment spray. The contribution to the overall doses of the elemental iodines not removed due to the assumed lack of containment spray flow during this time frame more than offsets the contribution to the overall doses of any re-evolved elemental iodine.
- 3. Provide the time dependant sump pH profile for the full duration of the LOCA analysis.
The time-dependant sump pH profile, in tabular form, for the full duration of the LOCA analysis follows:
Attachment to 2CAN061002
Page 4 of 5 Time (min) Minimum Sump pHTime (min) Minimum Sump pH 0.23 5.160 60.00 7.116 0.58 5.372 65.00 7.116 1.25 5.692 70.00 7.116 2.50 5.994 75.00 7.116 3.00 6.024 100.00 7.115 5.00 6.283 125.00 7.114 6.67 6.380 145.83 7.113 10.00 6.574 171.67 7.112 13.33 6.681 191.67 7.112 15.00 6.698 216.67 7.111 20.83 6.829 241.67 7.110 25.00 6.839 766.67 7.104 30.60 6.874 7166.67 7.104 45.83 7.052 14333.33 7.104 50.00 7.098 29166.67 7.104 55.00 7.117 43200.00 7.104 The above table was utilized for the AST analyses and does not include the effects of strong acid generation, which is insignificant during the initial 45 minutes of the accident due to limited radiation exposure during that time and subsequent delays in cable degradation and acid transport to the sump. The time-dependant sump pH profile, accounting for the effect of 30 days of strong acid generation being instantaneously present in the sump at the start of the LOCA, is provided below and shows that after the sump pH reaches 7.0, it remains at or above 7.0 for the duration of the accident. The profile further shows that even in this additional scenario, the sump pH would be approximately 6.974 (or essentially 7.0) at 11 minutes after the start of recirculation.
Time (min) Minimum Sump pH Time (min) Minimum Sump pH 0.23 5.160 60.00 7.012 0.58 5.372 65.00 7.012 1.25 5.692 70.00 7.012 2.50 5.994 75.00 7.012 3.00 6.024 100.00 7.011 5.00 6.283 125.00 7.010 6.67 6.380 145.83 7.009 10.00 6.574 171.67 7.009 13.33 6.681 191.67 7.008 15.00 6.698 216.67 7.007 20.83 6.829 241.67 7.006 25.00 6.839 766.67 7.000 30.60 6.874 7166.67 7.000 45.83 7.013 14333.33 7.000 50.00 7.013 29166.67 7.000 55.00 7.013 43200.00 7.000
Attachment to 2CAN061002
Page 5 of 5
References
- 1. ANO-2 Technical Specifications
- 2. WCAP-11611, "Methodology for Elimination of the Containment Spray Additive," March 1988.
- 3. WCAP-16596-NP, Rev. 0, "Evaluation of Alternative Emergency Core Cooling System Buffering Agents," July 2006.
- 4. NUREG/CR-5950, ORNL/TM-12242, "Iodine Evolution and pH Control," Oak Ridge National Laboratory.