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| | issue date = 11/02/2011 | | | issue date = 11/02/2011 |
| | title = RAI Prairie PINGP, Units 1 and 2 | | | title = RAI Prairie PINGP, Units 1 and 2 |
| | author name = Wengert T J | | | author name = Wengert T |
| | author affiliation = NRC/NRR/DORL/LPLIII-1 | | | author affiliation = NRC/NRR/DORL/LPLIII-1 |
| | addressee name = Myers G | | | addressee name = Myers G |
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| | docket = 05000282, 05000306 | | | docket = 05000282, 05000306 |
| | license number = DPR-042, DPR-060 | | | license number = DPR-042, DPR-060 |
| | contact person = Wengert T J | | | contact person = Wengert T |
| | case reference number = TAC ME2609, TAC ME2610 | | | case reference number = TAC ME2609, TAC ME2610 |
| | package number = ML113110102 | | | package number = ML113110102 |
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| | page count = 3 | | | page count = 3 |
| | project = TAC:ME2609, TAC:ME2610 | | | project = TAC:ME2609, TAC:ME2610 |
| | stage = Other | | | stage = RAI |
| }} | | }} |
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| =Text= | | =Text= |
| {{#Wiki_filter: REQUEST FOR ADDITIONAL INFORMATION PRAIRIE ISLAND NUCLEAR GENERATING STATION, UNITS 1 AND 2 DOCKET NOS. 50-282 AND 50-306 By letter dated October 27, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML093160583), supplemented by letters dated April 29, 2010, May 25, 2010, June 23, 2010, August 12, 2010, December 17, 2010, June 22, 2011, July 11, 2011, and August 9, 2011, (ADAMS Accession Nos. ML101200083, ML101460064, ML101760017, ML102300295, ML103510322, ML111740145, ML111930157, and ML112220098, respectively), Northern States Power Company, a Minnesota corporation (the licensee) requested Technical Specifications changes related to adoption of an Alternative Source Term (AST) Methodology for the Prairie Island Nuclear Generating Plant (PINGP), Units 1 and 2. Recently, the U.S. Nuclear Regulatory Commission (NRC) staff conducted several conference calls with the licensee to discuss the technical details of the licensee's main steam line break atmospheric dispersion model, which was submitted with its AST application. To complete its review, the staff requests the following additional information. Background Following a conference call with the NRC staff on September 22, 2011, the licensee provided the following information concerning the design criteria for the Common Area of the Auxiliary Building (CAAB): Updated Safety Analysis Report (USAR), Table 12.2-1, Page 1 indicates that the Common Area of the Auxiliary Building is a Design Class III* structure (i.e., above the concrete part of the structure). The CAAB is referred to as "Auxiliary Building (Except Class I or I*)" in the Table. This is a Design Class III* structure. USAR Table 12.2-4 indicates that Class III* structures are designed for Dead + Live + Wind or Snow normal operating loads and Dead + Live + Uniform Building Code Zone I (earthquake) Loads. USAR Section 12.2.1.3.1 defines snow loading as 50 lbs per sq-ft and the design wind speed as 100 mph. USAR Section 12.2.1.4.1d describes the load combinations for Class III* structures. These structures are designed for the greater of the above load combinations, where the Uniform Building Code Zone I earthquake loads are 0.05g. Although the CAAB is a corrugated steel building, it is structurally sound with fairly rigorous design criteria. Request for Additional Information | | {{#Wiki_filter:REQUEST FOR ADDITIONAL INFORMATION PRAIRIE ISLAND NUCLEAR GENERATING STATION, UNITS 1 AND 2 DOCKET NOS. 50-282 AND 50-306 By letter dated October 27, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML093160583), supplemented by letters dated April 29, 2010, May 25, 2010, June 23, 2010, August 12, 2010, December 17, 2010, June 22, 2011, July 11, 2011, and August 9, 2011, (ADAMS Accession Nos. ML101200083, ML101460064, ML101760017, ML102300295, ML103510322, ML111740145, ML111930157, and ML112220098, respectively), Northern States Power Company, a Minnesota corporation (the licensee) requested Technical Specifications changes related to adoption of an Alternative Source Term (AST) Methodology for the Prairie Island Nuclear Generating Plant (PINGP), Units 1 and 2. |
| | Recently, the U.S. Nuclear Regulatory Commission (NRC) staff conducted several conference calls with the licensee to discuss the technical details of the licensees main steam line break atmospheric dispersion model, which was submitted with its AST application. To complete its review, the staff requests the following additional information. |
| | |
| | ===Background=== |
| | Following a conference call with the NRC staff on September 22, 2011, the licensee provided the following information concerning the design criteria for the Common Area of the Auxiliary Building (CAAB): |
| | Updated Safety Analysis Report (USAR), Table 12.2-1, Page 1 indicates that the Common Area of the Auxiliary Building is a Design Class III* structure (i.e., above the concrete part of the structure). The CAAB is referred to as Auxiliary Building (Except Class I or I*) in the Table. This is a Design Class III* structure. USAR Table 12.2-4 indicates that Class III* structures are designed for Dead + Live + Wind or Snow normal operating loads and Dead + Live + Uniform Building Code Zone I (earthquake) Loads. |
| | USAR Section 12.2.1.3.1 defines snow loading as 50 lbs per sq-ft and the design wind speed as 100 mph. USAR Section 12.2.1.4.1d describes the load combinations for Class III* structures. These structures are designed for the greater of the above load combinations, where the Uniform Building Code Zone I earthquake loads are 0.05g. |
| | Although the CAAB is a corrugated steel building, it is structurally sound with fairly rigorous design criteria. |
| | Request for Additional Information |
| : 1. With regard to a postulated release into the CAAB associated with the faulted steam generator in a main steam line break accident, please summarize the release scenario from the point of release at the failure location to the location of release to the environment from the CAAB. At the location of release to the environment, the effluent is assumed to be uniformly and homogenously distributed along a line in width of approximately 52.2 meters (m) prior to proceeding to the 121 CR (control room) intake or 59.7 m prior to proceeding toward the 122 CR intake. These dimensions are the product of the initial diffusion coefficients on page 35 of the October 27, 2009, PINGP alternative source term license amendment request (ADAMS Accession No. ML093160583) multiplied by a factor of 6. | | : 1. With regard to a postulated release into the CAAB associated with the faulted steam generator in a main steam line break accident, please summarize the release scenario from the point of release at the failure location to the location of release to the environment from the CAAB. At the location of release to the environment, the effluent is assumed to be uniformly and homogenously distributed along a line in width of approximately 52.2 meters (m) prior to proceeding to the 121 CR (control room) intake or 59.7 m prior to proceeding toward the 122 CR intake. These dimensions are the product of the initial diffusion coefficients on page 35 of the October 27, 2009, PINGP alternative source term license amendment request (ADAMS Accession No. ML093160583) multiplied by a factor of 6. |
| The response should include a discussion of the CAAB leak tightness and other factors causing the effluent to be uniformly and homogenously mixed within the CAAB. In addition, the licensee should include any applicable scenarios when pressurization or other factors could cause a reduction in the CAAB normal leakage integrity which would result in effluent releases from the CAAB being of a lesser dimension than the values cited above. This includes a range of potential conditions, from enhanced localized leakage without loss of structural integrity to conditions that may result in breaches in the CAAB (e.g., blowout panel activation). | | |
| : 2. The NRC staff's understanding is that the common area of the auxiliary building (CAAB) is from elevation 755' to 809' and between columns 7 to 11 and J to Q (from USAR Figure 1.1-8 and Figure 1.1-16). The CAAB has metal siding between elevations 775' and 809'. There are no ventilation systems directly supplying fresh air to or providing exhaust from this area. Under normal operation the CAAB pressure is maintained negative relative to atmosphere through indirect connection to one of the two unit's auxiliary building exhaust systems. Below elevation 775', the CAAB walls are concrete construction or have adjacent unit specific auxiliary building spaces. Please verify if the NRC staff's understanding is correct or provide information needed to correct the staff's understanding. 3. Figure 3 of the LAR, along with Attachment 1 of L-PI-09-056 (ADAMS Accession No. ML091210703), show the control room outdoor air intake at column coordinates 5-G. Attachment 2 of L-PI-09-056 shows an elevator close to the same coordinates (5.2-G.8). a. Does this elevator have a rooftop equipment room equipped with ventilation? If yes: b. Please discuss the potential for a flow path from a main-steam line break into the elevator shaft through any shaft ventilation openings in the auxiliary building and/or around the doors, out through the elevator equipment room ventilation and to the Unit 1 control room outdoor air intake. 4. Please discuss releases from the Auxiliary Building Exhaust stacks (USAR Fig. 10.3-6). The auxiliary building exhaust stacks are identified on USAR Figure 10.3-6 at approximate coordinates A-9 and A-10. These exhaust stacks are not identified as a potential release point in Table 3.1-2, "Release Points and Receptor Locations", of the LAR. These exhaust stacks are not discussed in LAR section 3.1.3. Discussion of the auxiliary building exhaust stacks was not identified in any other section of the LAR, however, such discussion may have been missed by the reviewer. The discussion should indicate why the auxiliary building exhaust stacks are not considered a release point. If the justification is the exhaust fans are tripped on a safety related signal at the onset of an accident (e.g., emergency diesel load sequencing), verify the fans are shut down on an accident with no loss of offsite power. If potential releases are enveloped by a more conservative release-receptor combination, please indicate so. 5. The auxiliary building ventilation make-up air intakes are evaluated as a release point for a RWST release. Please discuss the potential for a release through the auxiliary building ventilation make-up air intakes from a main-steam line break through the ventilation system (back through the fan isolation damper and through the make-up air fan). If the continued operation of the ventilation system during the main-steam line break is credited for preventing such a release, please discuss how the reliability of system operation is justified. | | The response should include a discussion of the CAAB leak tightness and other factors causing the effluent to be uniformly and homogenously mixed within the CAAB. In addition, the licensee should include any applicable scenarios when pressurization or other factors could cause a reduction in the CAAB normal leakage integrity which would result in effluent releases from the CAAB being of a lesser dimension than the values cited above. This includes a range of potential conditions, from enhanced localized leakage without loss of structural integrity to conditions that may result in breaches in the CAAB (e.g., blowout panel activation). |
| 6. Attachment 1 of L-PI-09-056 (ADAMS Accession No. ML091210703) shows a vent pipe above the roof on the north side of the auxiliary building high bay area (drawing coordinates J.3, 6.7 and J.3, 11.3). Please identify what is vented from this pipe and if this vent can be a release point during any accident. | | : 2. The NRC staffs understanding is that the common area of the auxiliary building (CAAB) is from elevation 755 to 809 and between columns 7 to 11 and J to Q (from USAR Figure 1.1-8 and Figure 1.1-16). The CAAB has metal siding between elevations 775 and 809. There are no ventilation systems directly supplying fresh air to or providing exhaust from this area. |
| }} | | Under normal operation the CAAB pressure is maintained negative relative to atmosphere through indirect connection to one of the two units auxiliary building exhaust systems. |
| | Below elevation 775, the CAAB walls are concrete construction or have adjacent unit specific auxiliary building spaces. Please verify if the NRC staffs understanding is correct or provide information needed to correct the staffs understanding. |
| | : 3. Figure 3 of the LAR, along with Attachment 1 of L-PI-09-056 (ADAMS Accession No. ML091210703), show the control room outdoor air intake at column coordinates 5-G. |
| | Attachment 2 of L-PI-09-056 shows an elevator close to the same coordinates (5.2-G.8). |
| | : a. Does this elevator have a rooftop equipment room equipped with ventilation? If yes: |
| | : b. Please discuss the potential for a flow path from a main-steam line break into the elevator shaft through any shaft ventilation openings in the auxiliary building and/or around the doors, out through the elevator equipment room ventilation and to the Unit 1 control room outdoor air intake. |
| | : 4. Please discuss releases from the Auxiliary Building Exhaust stacks (USAR Fig. 10.3-6). The auxiliary building exhaust stacks are identified on USAR Figure 10.3-6 at approximate coordinates A-9 and A-10. These exhaust stacks are not identified as a potential release point in Table 3.1-2, Release Points and Receptor Locations, of the LAR. These exhaust stacks are not discussed in LAR section 3.1.3. Discussion of the auxiliary building exhaust stacks was not identified in any other section of the LAR, however, such discussion may have been missed by the reviewer. The discussion should indicate why the auxiliary building exhaust stacks are not considered a release point. If the justification is the exhaust fans are tripped on a safety related signal at the onset of an accident (e.g., emergency diesel load sequencing), verify the fans are shut down on an accident with no loss of offsite power. If potential releases are enveloped by a more conservative release-receptor combination, please indicate so. |
| | : 5. The auxiliary building ventilation make-up air intakes are evaluated as a release point for a RWST release. Please discuss the potential for a release through the auxiliary building ventilation make-up air intakes from a main-steam line break through the ventilation system (back through the fan isolation damper and through the make-up air fan). If the continued operation of the ventilation system during the main-steam line break is credited for preventing such a release, please discuss how the reliability of system operation is justified. |
| | : 6. Attachment 1 of L-PI-09-056 (ADAMS Accession No. ML091210703) shows a vent pipe above the roof on the north side of the auxiliary building high bay area (drawing coordinates J.3, 6.7 and J.3, 11.3). Please identify what is vented from this pipe and if this vent can be a release point during any accident.}} |
Letter Sequence RAI |
|---|
TAC:ME2609, Control Room Habitability, Deletion of E BAR Definition and Revision to RCS Specific Activity Tech Spec (Approved, Closed) TAC:ME2610, Control Room Habitability, Deletion of E BAR Definition and Revision to RCS Specific Activity Tech Spec (Approved, Closed) |
Results
Other: L-PI-10-076, Calculation No. GEN-PI-083, Revision 1, Locked Rotor Accident (LRA) Analysis Using AST, Attachment 5, L-PI-11-060, Response to Requests for Additional Lnformation (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology, L-PI-11-079, Response to Requests for Additional Lnformation (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology, L-PI-13-111, Notification of Alternative Source Term (AST) Implementation and Unit 2 Steam Generator Replacement, ML102300296, ML102300297, ML102300298, ML111822669
|
MONTHYEARL-PI-09-114, License Amendment Request to Adopt the Alternative Source Term Methodology2009-10-27027 October 2009
License Amendment Request to Adopt the Alternative Source Term Methodology
Project stage: Request
ML0935704512009-12-23023 December 2009
Acceptance Review of LAR to Adopt Alternative Source Term Methodology (TAC Nos. ME2609 & ME2610)
Project stage: Acceptance Review
L-PI-10-041, Response to Requests for Additional Information License Amendment Request to Adopt the Alternative Source Term Methodology2010-04-29029 April 2010
Response to Requests for Additional Information License Amendment Request to Adopt the Alternative Source Term Methodology
Project stage: Response to RAI
L-PI-10-046, Response to Requests for Additional Lnformation License Amendment Request to Adopt the Alternative Source Term Methodology2010-05-25025 May 2010
Response to Requests for Additional Lnformation License Amendment Request to Adopt the Alternative Source Term Methodology
Project stage: Request
L-PI-10-054, Response to Requests for Additional Information License Amendment Request to Adopt the Alternative Source Term Methodology2010-06-23023 June 2010
Response to Requests for Additional Information License Amendment Request to Adopt the Alternative Source Term Methodology
Project stage: Response to RAI
L-PI-10-076, Calculation No. GEN-PI-083, Revision 1, Locked Rotor Accident (LRA) Analysis Using AST, Attachment 52010-07-23023 July 2010
Calculation No. GEN-PI-083, Revision 1, Locked Rotor Accident (LRA) Analysis Using AST, Attachment 5
Project stage: Other
ML1023002982010-07-23023 July 2010
Calculation No. GEN-PI-082, Revision 1, Control Rod Ejection Accident - AST, Attachment 4
Project stage: Other
ML1023002972010-07-23023 July 2010
Calculation No. GEN-PI-081, Revision 1, Eab, LPZ, and CR Doses Due to Steam Generator Tube Rupture Accident - AST, Attachment 3
Project stage: Other
ML1023002962010-07-23023 July 2010
Calculation No. GEN-PI-078, Revision 1, Main Steam Line Break (MSLB) Accident Analysis Using AST, Attachment 2
Project stage: Other
ML1022200872010-08-10010 August 2010
Forthcoming Meeting with Northern States Power Company - Minnesota (Nspm), to Discuss the Prairie Island Nuclear Generating Plant Steam Generator Margin-to-Overfill Analysis as It Relates to Pingp'S License Amendment Request to Adopt...
Project stage: Meeting
ML1023002952010-08-12012 August 2010
Response to Requests for Additional Information License Amendment Request to Adopt the Alternative Source Term Methodology
Project stage: Response to RAI
ML1023805712010-08-25025 August 2010
Meeting Presentation Alternative Source Term Steam Generator Tube Rupture Margin to Overfill Evaluation - Prairie Island Nuclear Generating Plant
Project stage: Request
ML1025903972010-09-23023 September 2010
Prairie Island, Summary of Meeting with Northern States Power Company to Discuss the Alternative Source Term License Amendment Request
Project stage: Meeting
ML1032205572010-11-15015 November 2010
Draft RAI Concerning AST SGTR Mto Analysis
Project stage: Draft RAI
ML1032205552010-11-15015 November 2010
Draft RAI Concerning AST SGTR Mto Analysis
Project stage: Draft RAI
L-PI-10-112, Prairie Lsland Nuclear Generating Plant Units 1 and 2, Response to Request for Additional Information License Amendment Request to Adopt the Alternative Source Term Methodology (TAC Nos. ME2609 and ME26102)2010-12-17017 December 2010
Prairie Lsland Nuclear Generating Plant Units 1 and 2, Response to Request for Additional Information License Amendment Request to Adopt the Alternative Source Term Methodology (TAC Nos. ME2609 and ME26102)
Project stage: Response to RAI
ML1110400212011-04-0404 April 2011
NRR E-mail Capture - Prairie Island - Revised Alternative Source Term LAR Draft RAI 4-4-2011
Project stage: Draft RAI
ML1035404332011-05-12012 May 2011
Requests for Additional Information (RAI) Associated with Adoption of the Alternative Source Term
Project stage: RAI
L-PI-11-060, Response to Requests for Additional Lnformation (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology2011-06-22022 June 2011
Response to Requests for Additional Lnformation (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology
Project stage: Other
ML1118226692011-06-29029 June 2011
PINGP - AST Methodology - ME2609 and ME2610
Project stage: Other
L-PI-11-068, Response to Requests for Additional Information (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology2011-07-11011 July 2011
Response to Requests for Additional Information (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology
Project stage: Response to RAI
ML1120819672011-07-20020 July 2011
E-mail Prairie Island - Request for Clarification of June 22, 2011 Request for Additional Information (RAI) Response
Project stage: RAI
L-PI-11-079, Response to Requests for Additional Lnformation (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology2011-08-0909 August 2011
Response to Requests for Additional Lnformation (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology
Project stage: Other
ML1125503562011-09-0101 September 2011
Ngp - Draft RAI Concerning SGTR Instrumentation for Alternative Source Term LAR
Project stage: Draft RAI
ML1125503572011-09-0101 September 2011
PINGP Draft RAI - AST Instrumentation
Project stage: Draft RAI
ML1131100842011-11-0202 November 2011
Alternative Source Term Draft Request for Additional Information
Project stage: Draft RAI
ML1131100942011-11-0202 November 2011
RAI Prairie PINGP, Units 1 and 2
Project stage: RAI
L-PI-11-099, Response to Requests for Additional Information Regarding Regulatory Guide 1.97 Instrumentation Associated with Adoption of the Alternative Source Term (AST) Methodology2011-12-0808 December 2011
Response to Requests for Additional Information Regarding Regulatory Guide 1.97 Instrumentation Associated with Adoption of the Alternative Source Term (AST) Methodology
Project stage: Response to RAI
L-PI-12-010, Response to Requests for Additional Information Associated with Adoption of the Alternative Source Term Methodology2012-02-13013 February 2012
Response to Requests for Additional Information Associated with Adoption of the Alternative Source Term Methodology
Project stage: Response to RAI
L-PI-12-013, Response to Requests for Additional Information Associated with Adoption of the Alternative Source Term (AST) Methodology2012-02-24024 February 2012
Response to Requests for Additional Information Associated with Adoption of the Alternative Source Term (AST) Methodology
Project stage: Response to RAI
L-PI-12-082, Response to Requests for Additional Information (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology2012-09-13013 September 2012
Response to Requests for Additional Information (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology
Project stage: Response to RAI
ML1125212892013-01-22022 January 2013
Issuance of Amendments Adoption of Alternative Source Term Methodology
Project stage: Approval
L-PI-13-111, Notification of Alternative Source Term (AST) Implementation and Unit 2 Steam Generator Replacement2014-01-13013 January 2014
Notification of Alternative Source Term (AST) Implementation and Unit 2 Steam Generator Replacement
Project stage: Other
2011-12-08
[Table View] |
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Category:Request for Additional Information (RAI)
MONTHYEARML24197A2012024-07-15015 July 2024
Notification of NRC Baseline Inspection and Request for Information; Inspection Report 05000282/2024004
ML24149A3712024-05-29029 May 2024
(Ping) - Information Request for the Cyber-Security Baseline Inspection, Notification to Perform Inspection
ML24141A0452024-05-20020 May 2024
Information Request to Support the NRC Annual Baseline Emergency Action Level and Emergency Plan Changes Inspection
ML24116A2532024-04-25025 April 2024
Final Request for Additional Information for LAR to Revise SR 3.8.1.2 Note 3 (EPID: L- 2023-LLA-0135)
ML24045A0862024-02-12012 February 2024
Final RAI for Alternative RR-09
ML23335A1152023-12-0101 December 2023
NRR E-mail Capture - Prairie Island Units 1 and 2 - Request for Additional Information LAR to Revise TS 3.7.8 Required Actions
ML23248A3462023-09-0505 September 2023
NRR E-mail Capture - Request for Additional Information for Monticello Nuclear Generating Plant and Prairie Island Nuclear Generating Plant - Decommissioning Funding Status Reports
ML23214A2032023-08-0202 August 2023
Request for Information for an NRC Quadrennial Comprehensive Engineering Team Inspection: Inspection Report 05000282/2024010; 05000306/2024010
ML23199A0922023-07-18018 July 2023
Notification of NRC Baseline Inspection and Request for Information; Inspection Report 05000306/2023004
ML23096A3082023-04-0707 April 2023
Notification of Inspection an NRC Biennial Licensed Operator Requalification Program Inspection and Request for Information
ML23055B0562023-02-27027 February 2023
Request for Information for NRC Commercial Grade Dedication Inspection Inspection Report 05000282/2023010 and 05000306/2023010
ML23053A1432023-02-22022 February 2023
Information Request to Support Upcoming Problem Identification and Resolution (Pi&R) Inspection at Prairie Island Nuclear Generating Plant
ML22166A4112022-06-15015 June 2022
NRR E-mail Capture - Request for Additional Information Prairie Island Nuclear Generating Plant, Unit 2, Alternative RR-08, PIV Leakage
ML22160A6022022-06-0909 June 2022
NRR E-mail Capture - Draft Request for Additional Information Prairie Island Nuclear Generating Plant, Units 1 and 2, 24-Month Operating Cycle Amendment
ML22145A4152022-05-25025 May 2022
Information Request for the Cyber-Security Baseline Inspection, Notification to Perform Inspection 05000282/2022402 05000306/2022402
ML22131A2652022-05-11011 May 2022
NRR E-mail Capture - Request for Additional Information Xcel Energy Amendment Request to Create a Common Eplan and EOF for Monticello and Prairie Island
ML22130A5792022-05-11011 May 2022
Information Request to Support the NRC Annual Baseline Emergency Action Level and Emergency Plan Changes Inspection
ML21321A0452021-11-10010 November 2021
Request for Additional Information: Prairie Island 24-Month Cycle Amendment Request
ML21305A0102021-10-29029 October 2021
NRR E-mail Capture - Request for Additional Information Prairie Island Cooling Water Amendment
ML21252A0122021-08-30030 August 2021
NRR E-mail Capture - Request for Additional Information Amendment Request to Adopt TSTF-471 and 517-T for Prairie Island
ML21147A5232021-06-0303 June 2021
Prarie Island Nuclear Generating Plant, Units 1 and 2 - Information Request to Support the NRC Annual Baseline Emergency Action Level and Emergency Plan Changes Inspection
ML21131A0752021-05-10010 May 2021
Notification of NRC Baseline Inspection and Request for Information; Inspection Report 05000282/2021004; 05000306/2021004
ML21099A0972021-04-0909 April 2021
Information Request to Support Upcoming Temporary Instruction 2515/194 Inspection; Inspection Report 05000282/2021012 and 05000306/2021012
ML21062A0532021-03-0202 March 2021
Information Request to Support Upcomng Problem Identification and Resolution (Pi&R) Inspection at the Prairie Island Nuclear Generating Plant
ML21033A6112021-02-0101 February 2021
Request for Information for an NRC Triennial Baseline Design Bases Assurance Inspection (Team); Inspection Report 05000282/2021010 and 05000306/2021010
ML20343A1292020-12-0808 December 2020
NRR E-mail Capture - Request for Additional Information
ML20192A1442020-07-0707 July 2020
NRR E-mail Capture - Request for Additional Information Prairie Island License Amendment Request to Adopt TSTF-505
ML20189A1782020-07-0606 July 2020
Notification of NRC Baseline Inspection and Request for Information; Inspection Report 05000282/2020004; 05000306/2020004
ML20133K0692020-05-14014 May 2020
Information Request to Support the NRC Annual Baseline Emergency Action Level and Emergency Plan Changes Inspection
ML20077K6242020-04-13013 April 2020
License Amendment Request - Request for Additional Information
ML20052F4102020-02-21021 February 2020
Notification of Nrc Design Bases Assurance Inspection (Programs) (05000282/202010; 05000306/202010) and Initial Request for Information
ML20035F1552020-02-0404 February 2020
NRR E-mail Capture - Request for Additional Information Monticello and Prairie Island Alternative Requests to Adopt Code Cases N-786-3 and N-789-3 (Epids: L-2019-LLR-0078 and L-2019-LLR-0079)
ML19233A0032019-08-14014 August 2019
NRR E-mail Capture - Request for Additional Information Prairie Island Relief Requests 1-RR-10 and 2-RR-10
ML19057A1652019-02-26026 February 2019
NRR E-mail Capture - Request for Additional Information Prairie Island 50.69 Amendment Request
ML18313A0832018-11-0707 November 2018
NRR E-mail Capture - Request for Additional Information Prairie Island NFPA-805 License Condition Modification Amendment Request
ML18264A1912018-09-19019 September 2018
NRC Information Request (9/19/2018); Part B Items (Onsite) IP 71111.08 - E-Mailed 09/19/18 (DRS-M.Holmberg)
ML18235A2982018-08-23023 August 2018
NRR E-mail Capture - Request for Additional Information Prairie Island TSTF-425 License Amendment Request
ML18169A4202018-06-25025 June 2018
Supplemental Information Needed for Acceptance of Requested Licensing Action Amendment to Modify Renewed Facility Operating License Paragraph 2.C(4)(c)
ML18025C0152018-01-24024 January 2018
Request for Information for an NRC Triennial Baseline Design Bases Assurance Inspection (Team): Inspection Report 05000282/2018011; 05000306/2018011 (DRS-A.Dunlop)
ML17277B3332017-10-0404 October 2017
NRR E-mail Capture - Request for Additional Information Prairie Island Special Heavy Lifting Devices LAR
ML17249A9232017-09-0606 September 2017
Notification of NRC Baseline Inspection and Request for Information; Inspection Report 05000282/2017004; 05000306/2017004 (Exf)
ML17235A9982017-08-23023 August 2017
NRR E-mail Capture - Request for Additional Information Prairie Island EAL Scheme Change
ML17221A3892017-08-0909 August 2017
NRR E-mail Capture - Request for Additional Information for Prairie Island Nuclear Generating Plant License Amendment Request Dated February 23, 2017 Emergency Response Organization
ML17219A0762017-08-0707 August 2017
NRR E-mail Capture - Request for Additional Information for Prairie Island Nuclear Generating Plant License Amendment Request Dated February 23, 2017 Emergency Response Organization
ML17038A5132017-02-0707 February 2017
NRR E-mail Capture - Prairie Island NFPA 805 LAR, PRA RAI 21.01
ML17018A4272017-01-18018 January 2017
NRR E-mail Capture - Request for Additional Information: Prairie Island License Amendment Request to Revise Technical Specification 3.8.7 to Remove Non-Conservative Required Action
ML16326A3532016-11-18018 November 2016
NRR E-mail Capture - Draft Request for Information Related to Prairie Island NFPA-805 License Amendment
ML16265A1652016-09-20020 September 2016
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[Table view] |
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REQUEST FOR ADDITIONAL INFORMATION PRAIRIE ISLAND NUCLEAR GENERATING STATION, UNITS 1 AND 2 DOCKET NOS. 50-282 AND 50-306 By letter dated October 27, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML093160583), supplemented by letters dated April 29, 2010, May 25, 2010, June 23, 2010, August 12, 2010, December 17, 2010, June 22, 2011, July 11, 2011, and August 9, 2011, (ADAMS Accession Nos. ML101200083, ML101460064, ML101760017, ML102300295, ML103510322, ML111740145, ML111930157, and ML112220098, respectively), Northern States Power Company, a Minnesota corporation (the licensee) requested Technical Specifications changes related to adoption of an Alternative Source Term (AST) Methodology for the Prairie Island Nuclear Generating Plant (PINGP), Units 1 and 2.
Recently, the U.S. Nuclear Regulatory Commission (NRC) staff conducted several conference calls with the licensee to discuss the technical details of the licensees main steam line break atmospheric dispersion model, which was submitted with its AST application. To complete its review, the staff requests the following additional information.
Background
Following a conference call with the NRC staff on September 22, 2011, the licensee provided the following information concerning the design criteria for the Common Area of the Auxiliary Building (CAAB):
Updated Safety Analysis Report (USAR), Table 12.2-1, Page 1 indicates that the Common Area of the Auxiliary Building is a Design Class III* structure (i.e., above the concrete part of the structure). The CAAB is referred to as Auxiliary Building (Except Class I or I*) in the Table. This is a Design Class III* structure. USAR Table 12.2-4 indicates that Class III* structures are designed for Dead + Live + Wind or Snow normal operating loads and Dead + Live + Uniform Building Code Zone I (earthquake) Loads.
USAR Section 12.2.1.3.1 defines snow loading as 50 lbs per sq-ft and the design wind speed as 100 mph. USAR Section 12.2.1.4.1d describes the load combinations for Class III* structures. These structures are designed for the greater of the above load combinations, where the Uniform Building Code Zone I earthquake loads are 0.05g.
Although the CAAB is a corrugated steel building, it is structurally sound with fairly rigorous design criteria.
Request for Additional Information
- 1. With regard to a postulated release into the CAAB associated with the faulted steam generator in a main steam line break accident, please summarize the release scenario from the point of release at the failure location to the location of release to the environment from the CAAB. At the location of release to the environment, the effluent is assumed to be uniformly and homogenously distributed along a line in width of approximately 52.2 meters (m) prior to proceeding to the 121 CR (control room) intake or 59.7 m prior to proceeding toward the 122 CR intake. These dimensions are the product of the initial diffusion coefficients on page 35 of the October 27, 2009, PINGP alternative source term license amendment request (ADAMS Accession No. ML093160583) multiplied by a factor of 6.
The response should include a discussion of the CAAB leak tightness and other factors causing the effluent to be uniformly and homogenously mixed within the CAAB. In addition, the licensee should include any applicable scenarios when pressurization or other factors could cause a reduction in the CAAB normal leakage integrity which would result in effluent releases from the CAAB being of a lesser dimension than the values cited above. This includes a range of potential conditions, from enhanced localized leakage without loss of structural integrity to conditions that may result in breaches in the CAAB (e.g., blowout panel activation).
- 2. The NRC staffs understanding is that the common area of the auxiliary building (CAAB) is from elevation 755 to 809 and between columns 7 to 11 and J to Q (from USAR Figure 1.1-8 and Figure 1.1-16). The CAAB has metal siding between elevations 775 and 809. There are no ventilation systems directly supplying fresh air to or providing exhaust from this area.
Under normal operation the CAAB pressure is maintained negative relative to atmosphere through indirect connection to one of the two units auxiliary building exhaust systems.
Below elevation 775, the CAAB walls are concrete construction or have adjacent unit specific auxiliary building spaces. Please verify if the NRC staffs understanding is correct or provide information needed to correct the staffs understanding.
- 3. Figure 3 of the LAR, along with Attachment 1 of L-PI-09-056 (ADAMS Accession No. ML091210703), show the control room outdoor air intake at column coordinates 5-G.
Attachment 2 of L-PI-09-056 shows an elevator close to the same coordinates (5.2-G.8).
- a. Does this elevator have a rooftop equipment room equipped with ventilation? If yes:
- b. Please discuss the potential for a flow path from a main-steam line break into the elevator shaft through any shaft ventilation openings in the auxiliary building and/or around the doors, out through the elevator equipment room ventilation and to the Unit 1 control room outdoor air intake.
- 4. Please discuss releases from the Auxiliary Building Exhaust stacks (USAR Fig. 10.3-6). The auxiliary building exhaust stacks are identified on USAR Figure 10.3-6 at approximate coordinates A-9 and A-10. These exhaust stacks are not identified as a potential release point in Table 3.1-2, Release Points and Receptor Locations, of the LAR. These exhaust stacks are not discussed in LAR section 3.1.3. Discussion of the auxiliary building exhaust stacks was not identified in any other section of the LAR, however, such discussion may have been missed by the reviewer. The discussion should indicate why the auxiliary building exhaust stacks are not considered a release point. If the justification is the exhaust fans are tripped on a safety related signal at the onset of an accident (e.g., emergency diesel load sequencing), verify the fans are shut down on an accident with no loss of offsite power. If potential releases are enveloped by a more conservative release-receptor combination, please indicate so.
- 5. The auxiliary building ventilation make-up air intakes are evaluated as a release point for a RWST release. Please discuss the potential for a release through the auxiliary building ventilation make-up air intakes from a main-steam line break through the ventilation system (back through the fan isolation damper and through the make-up air fan). If the continued operation of the ventilation system during the main-steam line break is credited for preventing such a release, please discuss how the reliability of system operation is justified.
- 6. Attachment 1 of L-PI-09-056 (ADAMS Accession No. ML091210703) shows a vent pipe above the roof on the north side of the auxiliary building high bay area (drawing coordinates J.3, 6.7 and J.3, 11.3). Please identify what is vented from this pipe and if this vent can be a release point during any accident.
