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Category:Letter
MONTHYEARML24221A1892024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Nansemond Indian Nation ML24221A1932024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Upper Mattaponi Tribe ML24221A1862024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Eastern Band of Cherokee Indians ML24221A1842024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Delaware Nation, Oklahoma ML24221A1902024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Pamunkey Indian Tribe ML24163A3002024-08-0808 August 2024 Request for Relief Request N1-I5-NDE-007 Inservice Inspection Alternative ML24206A0052024-08-0808 August 2024 SLR Final EIS Letter to Achp ML24221A1872024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Eastern Shawnee Tribe of Oklahoma ML24221A1942024-08-0808 August 2024 Tribal Section 106 Letters-North Anna-United Keetoowah Band of Cherokee Indians in Oklahoma ML24206A0062024-08-0808 August 2024 Notice of Availability of the Final Environmental Impact Statement for the North Anna Nuclear Power Station Unit Numbers 1 and 2 Subsequent License Renewal (Docket Numbers: 50-338 and 50-339) ML24221A1812024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Catawba Indian Nation ML24221A1852024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Delaware Tribe of Indians ML24208A0142024-08-0808 August 2024 Tribal Section 106 Letters-North Anna-Absentee-Shawnee Tribe of Indians of Oklahoma ML24221A1922024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Tuscarora Nation of New York ML24221A1882024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Monacan Indian Nation ML24221A1832024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Chickahominy Indian Tribe-Eastern Division ML24221A1822024-08-0808 August 2024 Tribal Section 106 Letters - North Anna - Chickahominy Indian Tribe ML24221A1912024-08-0808 August 2024 Tribal Section 106 Letters-North Anna - Rappahannock Tribe, Inc IR 05000338/20240022024-08-0202 August 2024 Integrated Inspection Report 05000338/2024002 and 05000339/2024002 ML24206A0432024-07-26026 July 2024 Feis - Letter to the Applicant ML24206A0902024-07-24024 July 2024 Owners Activity Report ML24178A2422024-06-25025 June 2024 2023 Annual Report of Emergency Core Cooling System (ECCS) Model, Changes Pursuant to the Requirements of 10 CFR 50.46 ML24177A2792024-06-20020 June 2024 Preparation and Scheduling of Operator Licensing Examinations ML24143A1622024-06-12012 June 2024 – Correction to Issuance of Amendment Nos. 297 and 280 and Surry Units 1 and 2, Correction to Issuance of Amendment Nos. 317 and 317, to Change Emergency Plan Staff Augmentation Times ML24170B0532024-06-10010 June 2024 DOM-NAF-2-P/NP-A, Revision 0.5, Reactor Core Thermal-Hydraulics Using the VIPRE-D Computer Code IR 05000338/20240102024-05-24024 May 2024 NRC Fire Protection Team Inspection (FPTI) Report 05000338/2024010 and 05000339/2024010 IR 05000338/20240012024-05-10010 May 2024 Integrated Inspection Report 05000338/2024001 and 05000339/2024001 IR 05000338/20244032024-04-30030 April 2024 – Security Baseline Inspection Report 05000338-2024403 and 05000339-2024403 ML24110A1502024-04-18018 April 2024 Independent Spent Fuel Storage Installation (ISFSI) - Annual Radioactive Effluent Release Report ML24110A1392024-04-18018 April 2024 Annual Environmental Operating Report ML24110A1462024-04-18018 April 2024 Independent Spent Fuel Storage Installation (Sfsi) - Annual Radiological Environmental Operating Report ML24087A0572024-04-16016 April 2024 Correction to Issuance of Amendment Nos. 296 and 279 ML24088A2692024-03-27027 March 2024 Core Operating Limits Report Cycle 31 Pattern Sos Revision 0 ML24086A4292024-03-25025 March 2024 Response to Request for Additional Information Associated with Alternative Request N1-I5-NDE-007 Request to Deter Additional Required Reactor Coolant Pump Casing Inspection ML24082A2742024-03-22022 March 2024 Request for Approval of Alternative Request N1-I5-NDE-007 to Deter Additional Required Reactor Coolant Pump Casing Inspection ML24086A4682024-03-21021 March 2024 Summary of Facility Changes, Tests and Experiments ML24032A1112024-02-0101 February 2024 Owner'S Activity Report for North Anna, Unit 2, Refueling Outage N2R29 - First Period of the Fifth ISI Interval ML24032A4662024-01-16016 January 2024 Response to Comments on Draft Vpdes Permit No. VA0052451 ML24017A0802024-01-11011 January 2024 Notification of Licensed Operator Initial Examination 05000338/2024301 and 05000339/2024301 ML23332A7272024-01-0909 January 2024 Notice of Availability of the Draft Site-Specific Environmental Impact Statement for the North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8422024-01-0909 January 2024 Letter to Paul Barton, Thpo, Eastern Shawnee Tribe of Oklahoma, Notice of Availability of Draft Site-Specific Environmental Impact Statement for North Anna Power Station Units 1 and 2, Subsequent License Renewal ML24003A8412024-01-0909 January 2024 Notice of Availability of the Draft Site-Specific Environmental Impact Statement for the North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8432024-01-0909 January 2024 Letter to Robert Gray, Chief, Pamunkey Indian Tribe, Notice of Availability of the Draft Site-Specific EIS for North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8492024-01-0909 January 2024 Letter to W. Frank Adams, Chief, Upper Mattaponi Tribe Re Re Notice of Availability of the Draft Site-Specific Environmental Impact Statement for North Anna Power Station Subsequent License Renewal ML24003A8402024-01-0909 January 2024 Letter to Katelyn Lucas, Thpo, Delaware Nation, Oklahoma, Notice of Availability of Draft Site-Specific Environmental Impact Statement for North Anna Power Station Units 1 and 2, Subsequent License Renewal ML24003A8392024-01-0909 January 2024 Letter to Gerald Stewart, Chief, Chickahominy Indian Tribe, Eastern Division Re Re Notice of Availability of the Draft Site-Specific Environmental Impact Statement for North Anna Power Station Subsequent License Renewal ML24003A8472024-01-0909 January 2024 Letter to Tom Jonathan, Chief, Tuscarora Nation, Notice of Availability of the Draft Site-Specific EIS for North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8462024-01-0909 January 2024 Notice of Availability of the Draft Site-Specific Environmental Impact Statement for the North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8482024-01-0909 January 2024 Notice of Availability of the Draft Site-Specific Environmental Impact Statement for the North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8442024-01-0909 January 2024 Letter to Russell Townsend, Thpo, Eastern Band of Cherokee Indians 2024-08-08
[Table view] Category:Request for Additional Information (RAI)
MONTHYEARML24087A0112024-03-23023 March 2024 NRR E-mail Capture - Draft RAIs for Reactor Coolant Pump (RCP) Relief Request (L-2024-LLR-0022) ML23318A1172023-11-13013 November 2023 NRR E-mail Capture - Formal Issuance of RAIs for North Anna Technical Support Center (TSC) License Amendment Request (LAR) (L-2023-LLA-0006) ML23257A2092023-09-14014 September 2023 NRR E-mail Capture - Formal Issuance of 2nd Round RAIs for Surry Units 1&2 and North Anna Units 1&2 Emergency Plans LAR ML23243A9862023-08-31031 August 2023 NRR E-mail Capture - Draft RAIs for EP Staff Augmentation Times LAR (L-2022-LLA-0166) ML23219A1602023-08-0707 August 2023 003 Radiation Safety Baseline Inspection Information Request ML23171B0522023-06-20020 June 2023 NRR E-mail Capture - RAI for Review of Appendix F to DOM-NAF-2-P (Redacted) ML23081A5282023-04-26026 April 2023 Request for Additional Information - North Anna Subsequent License Renewal Application Environmental Review ML23075A0232023-03-15015 March 2023 NRR E-mail Capture - RAI - License Amend Req (LAR) to Revise Tech Spec (Ts) 3.6.8 Limiting Condition for Operation to Remove Refueling Water Chemical Addition Tank and Replace the Containment Sump Buffer North Anna, 1 and 2 (L-2022-LLA-0162 ML23060A0932023-03-0101 March 2023 NRR E-mail Capture - Formal Issuance of RAIs for Surry/North Anna Emergency Plans LAR ML23059A2282023-02-28028 February 2023 NRR E-mail Capture - Draft RAIs for Containment Buffer Change to Natb (L-2022-LLA-0162) ML22251A1292022-09-0909 September 2022 Request for Additional Information Related to Response to Generic Letter 2004-04 ML22242A0452022-08-23023 August 2022 NRR E-mail Capture - Dominion GL 04-02 Response Draft RAIs (L-2017-LRC-0000) ML22083A2102022-03-24024 March 2022 NRR E-mail Capture - Draft RAI - Relief Request N2-14-LMT-003 Fourth Ten Year Inservice Inspection Interval ML21327A3652021-11-23023 November 2021 NRR E-mail Capture - Draft RAI for TSTF-577 LAR ML21322A0962021-11-18018 November 2021 Final Request for Additional Information Set 5 - North Anna SLRA Safety Review (EPID No. L-2020-SLR-0000) - Email ML21322A0992021-11-18018 November 2021 Final Request for Additional Information Set 5 - North Anna SLRA Safety Review (EPID No. L-2020-SLR-0000) - Enclosure ML21256A0672021-09-13013 September 2021 Final Request for Confirmation of Information Set 2 - North Anna SLRA Safety Review (EPID No. L-2020-SLR-0000) - Email ML21256A0692021-09-13013 September 2021 Final Request for Confirmation of Information Set 2 - North Anna SLRA Safety Review (EPID No. L-2020-SLR-0000) - Request for Confirmation of Information ML21238A0942021-08-25025 August 2021 Draft Request for Additional Information Set Z - North Anna SLRA Safety Review (EPID No. L-2020-SLR-0000) - Email ML21238A0982021-08-25025 August 2021 Draft Request for Additional Information Set Z - North Anna SLRA Safety Review (EPID No. L-2020-SLR-0000) - Enclosure ML21225A5022021-08-13013 August 2021 Request for Additional Information for North Anna Power Station, Units 1 and 2, Surry Power Station, Units 1 and 2, and Millstone Power Station, Units 2 and 3, Appendix E of Fleet Report Com-Naf-2 (EPID:L02021-LLT-0000) Public Version ML21195A2442021-07-13013 July 2021 NRR E-mail Capture - Draft RAI Appendix E to Topical Report DOM-NAF-2 Qualification of the Framatome BWU-I CHF Correlation in the Dominion Energy VIPRE-D Computer Code ML21188A1632021-07-0707 July 2021 Final Request for Additional Information Set 4 - North Anna SLRA Safety Review (EPID No. L-2020-SLR-0000) - Email ML21188A1652021-07-0707 July 2021 Final Request for Additional Information Set 4 - North Anna SLRA Safety Review (EPID No. L-2020-SLR-0000) - Enclosure ML21174A1952021-06-23023 June 2021 Safety RAIs - Set Y - Draft - Enclosure ML21166A3512021-06-15015 June 2021 Safety RAIs - Set 4 - Draft ML21123A2972021-05-0303 May 2021 Final Request for Additional Information Set 3 - North Anna SLRA Safety Review (EPID No. L-2020-SLR-0000) - E-mail ML21123A2982021-05-0303 May 2021 Final Request for Additional Information Set 3 - North Anna SLRA Safety Review (EPID No. L-2020-SLR-0000) - Enclosure ML21091A0032021-04-0101 April 2021 Final Request for Additional Information Set 2 - North Anna SLRA Safety Review (EPID No. L-2020-SLR-0000) - Enclosure 1 - RAIs ML21091A0042021-04-0101 April 2021 SLRA Safety Review - Withdrawn Requests for Information (EPID No. L-2020-SLR-0000) - Enclosure 2 ML21076A4622021-03-17017 March 2021 NRR E-mail Capture - Draft RAI for Versatile Internals and Component Program for Reactors Vipre Code Review (L-2021-LLT-0000) ML21075A0032021-03-12012 March 2021 Emergency Preparedness Exercise Inspection Request for Information for - Brunswick, Catawba, North Anna, Oconee, Vogtle 1 & 2 ML21063A5602021-03-0404 March 2021 Final Request for Additional Information Set 1 - North Anna SLRA Safety Review (EPID L-2020-SLR-0000) - Enclosure ML21049A0212021-02-17017 February 2021 Notification of an NRC Fire Protection Team Inspection (FPTI) (NRC Inspection Report 05000338/2021012 and 05000339/2021012) and Request for Information (RFI) ML21028A3902021-01-29029 January 2021 Request for Additional Information - North Anna Subsequent License Renewal Application Environmental Review (EPID Number: L-2020-SLE-0000) (Docket: 50-338 and 50-339) ML21028A4352021-01-28028 January 2021 Notification of Target Set Inspection and Request for Information (NRC Inspection Report No. 05000338/2021404 and 05000339/2021404) ML21012A3412021-01-22022 January 2021 Requests for Confirmation of Information for the Environmental Review of the North Anna Power Station, Units 1 and 2, Subsequent License Renewal Application (EPID Number: L-2020-SLE-0000) (Docket: 50-338 and 50-339) ML21019A4512021-01-19019 January 2021 Notification of Inspection and Request for Information ML20316A0422020-11-10010 November 2020 NRR E-mail Capture - FW: Draft RAI for North Anna Unit 2 Steam Generator Tube Inspection Report (ML19179A075) ML20223A3412020-08-10010 August 2020 003 Radiation Safety Baseline Inspection Information Request ML20218A4282020-08-0505 August 2020 Notification of Inspection and Request for Information ML20125A0762020-05-0101 May 2020 NRR E-mail Capture - Draft RAI Related to Revised Reactor Vessel Material Surveillance Capsule Withdrawal Schedule Dominion Energy Virginia North Anna Power Station Units 1 and 2 (L-2020-LLL-0038) ML20113A5792020-04-21021 April 2020 NRR E-mail Capture - Draft RAI North Anna Fifth 10-year Interval Relief Request (L-2020-LLR-0023) ML19354B6142019-12-20020 December 2019 NRR E-mail Capture - Draft RAI for North Anna Relief Request P-9 ML19317F1042019-11-0707 November 2019 NRR E-mail Capture - Draft RAIs for SB LOCA LAR (Non Prop) ML19191A2512019-07-10010 July 2019 NRR E-mail Capture - Request for Additional Information Open Phase Condition LAR ML19169A0962019-06-17017 June 2019 NRR E-mail Capture - Request for Additional Information Emergency Action Level Scheme Change for Millstone Power Station - Units 1, 2, and 3, North Anna Power Station - Units 1 and 2, and Surry Power Station - Units 1 and 2 ML19162A0052019-06-10010 June 2019 NRR E-mail Capture - Draft RAIs for Dominion EAL Scheme Change ML19108A1902019-04-18018 April 2019 Emergency Preparedness Program Inspection Request for Information ML19060A2432019-03-0101 March 2019 Related to License Amendment Request to Address Open Phase Conditions 2024-03-23
[Table view] |
Text
August 8, 2005 Mr. David A. Christian Sr. Vice President and Chief Nuclear Officer Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Blvd.
Glen Allen, Virginia 23060-6711
SUBJECT:
NORTH ANNA POWER STATION, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST TO INCREASE COMPLETION TIMES FOR ECCS-LHSI, AFW, QUENCH SPRAY AND CHEMICAL ADDITION SYSTEMS
Dear Mr. Christian:
By letter dated December 17, 2004, Virginia Electric and Power Company (VEPCO) submitted a proposed license amendment request to change the Technical Specifications by increasing the completion times for the Emergency Core Cooling System-Low Head Safety Injection subsystem, Auxiliary Feedwater, Quench Spray and Chemical Addition Systems from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days for North Anna Power Station, Units 1 and 2. Based on its review of the December 17, 2004, submittal, the NRC staff has determined that additional information is required to complete its review.
The NRC staffs questions are provided in the Enclosure. VEPCO is requested to provide a response to the request for additional information within 60 days of the date of this letter.
Sincerely,
/RA/
John Honcharik, Project Manager, Section 1 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-338 and 50-339
Enclosure:
As stated cc w/encl: See next page
ML052160294 NRR-088 OFFICE PDII-1/PM PDII-2/LA PDII-1/SC NAME JHoncharik CHawes EMarinos DATE 8/4/05 8/4/05 8/8/05 REQUEST FOR ADDITIONAL INFORMATION PROPOSED LICENSE AMENDMENT REQUEST TO INCREASE THE COMPLETION TIMES FOR THE ECCS-LHSI, AFW, QUENCH SPRAY AND CHEMICAL ADDITIONS SYSTEMS FOR NORTH ANNA, UNITS 1 AND 2 VIRGINIA ELECTRIC AND POWER COMPANY DOCKET NOS. 50-338 AND 50-339 By letter dated December 17, 2004, Virginia Electric and Power Company (VEPCO) submitted a proposed license amendment request to change the Technical Specifications (TS) by increasing the completion times (CTs) for the Emergency Core Cooling System-Low Head Safety Injection (ECCS-LHSI) subsystem, Auxiliary Feedwater (AFW), Quench Spray (QS) and Chemical Addition Systems (CAS) from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days for North Anna Power Station, Units 1 and 2. Attachment 1 to the letter dated December 17, 2004, provides a discussion on the proposed changes to the TS. The Nuclear Regulatory Commission (NRC) staff has the following requests for additional information.
- 1. Please resolve several apparent inconsistencies concerning the use of compensatory measures to manage risk during maintenance:
- a. On July 23, 2004, VEPCO was granted [ADAMS Accession No. ML042050457] an emergency one-time TS change to extend the CT of the A ECCS-LHSI to 7 days.
The NRC staff granted this change, in part, because VEPCO had proposed six compensatory measures. In contrast, VEPCO is proposing to permanently change the ECCS-LHSI pump CT to 7 days without offering any specific compensatory measures.
- b. Attachment 1, Table 7 of the submittal dated December 17, 2004, identifies some plant configurations that should be avoided during specific maintenance activities.
Yet, no specific compensatory measures are offered to manage the risk during these configurations. Regulatory Guide (RG) 1.177, An Approach for Plant-Specific, Risk Informed Decision Making-Technical Specifications, Section 2.3.6 provides the guidance for the use of compensatory measures. Please list and discuss each of the compensatory measures you plan to take for ECCS-LHSI TS change to reduce risk.
- c. Attachment 1, Section 5.1.2 of the submittal dated December 17, 2004, states that risk achievement worth importance measures are used to identify Tier 2 configurations. In contrast, Section 5.1.3 states that the NUMARC 93-01 risk limits are used to identify high-risk plant configurations. What specific risk metrics are used to identify high-risk plant configurations?
Enclosure
- d. How does plant management decide how many compensatory measures to impose to mitigate a given high-risk plant configuration? If several types of compensatory measures are possible, how does plant management decide which one (or ones) to impose?
- 2. Pages 7 and 8 of Attachment 1 of the submittal dated December 17, 2004, evaluate the risk impacts of the proposed change to the ECCS-LHSI CT. The analyses differentiated between scheduled (preventative) activities and repair (unscheduled) activities. On page 8, it is stated that Therefore, a higher failure probability is used for the operable train, which accounts for the possibility of common cause failure. Please explain this statement in detail, identifying which events in the probabilistic risk assessment (PRA) model have been modified and discussing how the higher failure probability was calculated. Was this approach also used during the risk evaluation of the proposed CT extensions for the QS and AFW systems? If so, provide the same information as requested above for the ECCS-LHSI system.
- 3. Section 5.1.3 of Attachment 1 of the submittal dated December 17, 2004, indicates that the safety monitor tool is used to monitor, analyze, and manage the systems addressed by the proposed TS change as part of the plants Maintenance Rule program, 10 CFR 50.65(a)(4). Page 13 indicates that the safety monitor model explicitly accounts for grid loading and stability. Please explain how the safety monitor achieves this capability.
Are the loss of offsite power frequency and offsite power recovery probabilities being changed as grid conditions change? What is the technical basis for changing the affected numerical values used in the PRA model? How often is the safety monitor updated to reflect current grid conditions?
- 4. Attachment 1, Section 5.1.4 of the submittal dated December 17, 2004, states that the risk assessment of external events has not been updated since completion of the individual plant examination of external events (IPEEE). However, significant modifications (as identified in Attachment 1, Enclosure 2) have been made to the PRA since completion of the individual plant examination. Therefore, the conclusions of the IPEEE may no longer constitute an adequate technical basis for deciding whether or not a proposed plant maintenance configuration has acceptable risk. Assess the impact on the IPEEE conclusions concerning fire risk from each of the PRA modifications identified in Attachment 1, Enclosure 2.
- 5. Identify the risk-significant fire scenarios during scheduled (preventative) maintenance and repair (unscheduled) activities on the ECCS-LHSI system, the QS system, and the AFW system.
- 6. The fire-induced vulnerability evaluation (FIVE) methodology identifies risk-significant fire scenarios by performing a series of successive screening steps to the baseline internal events PRA. Justify the use of qualitative assessments, based on extrapolating the results of the FIVE methodology, to identify the risk-significant fire scenarios of a proposed plant maintenance configuration (i.e., when specific equipment is planned to be out of service).
- 7. When was the industry peer review of the PRA conducted? Do the facts and observations presented in Attachment 1, Enclosure 1 reflect all of the findings of this
review having a significance level of A or B, or only the set of unresolved findings judged to be applicable to the proposed TS change? Please state what progress has been made in resolving the complete set of peer review facts and observations (including those having a significance level of A, B, C, or D), and describe the plan to reach complete resolution of them.
- 8. Concerning Attachment 1, Enclosure 1, please amplify the Impact on Application discussion about Peer Review Fact and Observation SY-14, which implies that the PRA model does not address the risk due to internal flooding scenarios. In contrast, Attachment 1, Enclosure 2, Item 3 indicates that internal floods were added to the living PRA. Do the PRA and safety monitor models address internal floods?
- 9. Describe the process used to evaluate the risk of emergent conditions. Specifically, describe the following:
- a. Who performs and reviews the risk evaluation?
- b. How long does it take to perform and review the risk evaluation?
- c. Describe how the impact of external events (e.g., fires) is addressed when evaluating the risk of emergent conditions.
- 10. Describe any reviews, benchmarking, or other approaches used to ensure the technical adequacy of the safety monitor.
- 11. Attachment 1, Section 5.2 of this license amendment provides the list of Defense-in-Depth Assessment elements. This section does not discuss how you meet these requirements for defense-in-depth for the ECCS-LHSI, QS and AFW system TS changes.
RG 1.177, Section 2.2.1 discusses the defense-in-depth guidance for risk-informed TS change. Please provide detailed discussion regarding each element of defense-in-depth, how you meet these requirements for ECCS-LHSI with the increase in completion times from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days.
- 12. Attachment 1, Section 5.1 stated the following:
The Chemical Addition System is not modeled in the North Anna PRA model due to its limited ability to impact the magnitude of a radioactive release from the Containment in severe accidents and the limited corrosion damage which might occur to equipment over the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from a non-alkaline pH. In severe accidents, the iodine release is so large that the Chemical Addition System is assumed incapable of scavenging a significant portion of the iodine. Also, as long as the Containment integrity is maintained in a severe accident, studies have shown that the radioactive release from the Containment cannot cause a large early release as defined in Regulatory Guide 1.174.
If the Containment fails in a severe accident, [then] there is insufficient NaOH available in the Chemical Addition System to impact the consequences of the large iodine release.
The licenses is requested to respond to the following questions related to the text above:
- a. The role of the CAS is to maintain sump water pH at or above 7 by the addition of NaOH. When this is performed, most of the radioactive iodine will stay dissolved in the sump water and is prevented from leaking to the outside. Why is the CAS system incapable of maintaining dissolved (scavenged) iodine in the sump water?
- b. What quantifies a relatively small radioactive iodine release?
- c. Since NaOH is normally added to the sump water by the chemistry addition system to keep most of the iodine dissolved, the amount of iodine released to the outside should be, therefore, only a function of the condition of the containment.
Obviously the amount of iodine released to the outside will be higher for a failed containment. Therefore, why is the amount of NaOH insufficient to impact the consequences of the large iodine release?
- 13. The licensee should provide justification for the proposed completion time for the CAS, including how the proposed CT takes into account the ability of the spray system to remove iodine at a reduced capability and the low probability of the worst case Design Basis Accident occurring during this period.
- 14. Attachment 1, Table 7 lists Tier 2 considerations for when one AFW pump is out-of-service (inoperable). Insert 4 is a TS Bases addition listing these considerations/constraints. The licensee is requested to provide a discussion/justification of these constraints.
North Anna Power Station, Units 1 & 2 cc:
Mr. C. Lee Lintecum Mr. Jack M. Davis County Administrator Site Vice President Louisa County North Anna Power Station Post Office Box 160 Virginia Electric and Power Company Louisa, Virginia 23093 Post Office Box 402 Mineral, Virginia 23117-0402 Ms. Lillian M. Cuoco, Esq.
Senior Counsel Dr. Robert B. Stroube, MD, MPH Dominion Resources Services, Inc. State Health Commissioner Building 475, 5 th floor Office of the Commissioner Rope Ferry Road Virginia Department of Health Waterford, Connecticut 06385 Post Office Box 2448 Richmond, Virginia 23218 Dr. W. T. Lough Virginia State Corporation Commission Office of the Attorney General Division of Energy Regulation Commonwealth of Virginia Post Office Box 1197 900 East Main Street Richmond, Virginia 23218 Richmond, Virginia 23219 Old Dominion Electric Cooperative Senior Resident Inspector 4201 Dominion Blvd. North Anna Power Station Glen Allen, Virginia 23060 U. S. Nuclear Regulatory Commission 1024 Haley Drive Mr. Chris L. Funderburk, Director Mineral, Virginia 23117 Nuclear Licensing & Operations Support Dominion Resources Services, Inc.
Innsbrook Technical Center 5000 Dominion Blvd.
Glen Allen, Virginia 23060-6711