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Category:Code Relief or Alternative
MONTHYEARML23278A1292023-12-14014 December 2023 Units 1 & 2; Limerick, Units 1 & 2; Nine Mile Point, Units 1 & 2; and Peach Bottom, Units 2 & 3 -Revision to Approved Alternatives to Use Boiling Water Reactor Vessel and Internals Project Guidelines ML23262B4442023-09-26026 September 2023 Authorization and Safety Evaluation for Alternative Request No. I4R-14 ML22194A9152022-07-15015 July 2022 Proposed Alternative I4-R13 for Repair of Recirculation Flow Control Valves RS-22-032, Relief Request I4R-13 Relief from Code Examinations for 1B33-F060A and 1B33-F060B Repairs2022-03-0202 March 2022 Relief Request I4R-13 Relief from Code Examinations for 1B33-F060A and 1B33-F060B Repairs ML21280A0782021-10-27027 October 2021 Proposed Alternative to Use of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-893 (Epids L-2020-LLR-0147 and L-2020-LLR-0148) ML21230A2062021-09-0303 September 2021 Proposed Alternative to Use ASME OM Code Case OMN-28 ML21216A2202021-08-0505 August 2021 Proposed Alternative to Eliminate Certain Documentation Requirements for Pressure Retaining Bolting ML20269A2002020-09-30030 September 2020 Request to Use a Provision of Later Edition of the ASME Boiler and Pressure Vessel Code, Section XI (EPID L2020-LLR-0117 ML20113F0412020-04-30030 April 2020 Proposed Alternative to the Submittal Schedule for Certain Reports (COVID-19) ML20099D9552020-04-17017 April 2020 Request to Use Provisions in the 2013 Edition of the ASME Boiler and Pressure Vessel Code for Performing Non-Destructive Examinations ML19269C5342019-09-27027 September 2019 Proposed Alternative to Use Encoded Phased Array Ultrasonic Examination Techniques RS-19-066, Relief Request RV-03 Related to Pressure Isolation Valve Testing Frequency2019-06-28028 June 2019 Relief Request RV-03 Related to Pressure Isolation Valve Testing Frequency ML19161A2572019-06-0404 June 2019 BWR Fleet Msv/Srv - Testing Frequency Relief Request NRC Pre-Application Meeting June 4, 2019 ML19121A3172019-05-20020 May 2019 Relief Request 13R-15, Relief from the Requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&Pv) Code, Section X1, Rules for Inservice Inspection (EPID-L-2018-LLR-0123) ML19098A0342019-04-30030 April 2019 Units 1 and 2; Limerick, Units 1 and 2; Peach Bottom, Units 2 and 3, and Quad Cities, Units 1 and 2 - Revision to Approved Alternative to Use BWR Vessel and Internal Proj Guidelins JAFP-19-0023, Relief Request Associated with the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds2019-02-15015 February 2019 Relief Request Associated with the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds RS-18-112, End of Interval Relief Request Associated with the Third Ten-Year Inservice Inspection (ISI) Interval2018-09-19019 September 2018 End of Interval Relief Request Associated with the Third Ten-Year Inservice Inspection (ISI) Interval JAFP-18-0052, Proposed Alternative to Utilize Code Case N-8792018-05-30030 May 2018 Proposed Alternative to Utilize Code Case N-879 JAFP-18-0053, Proposed Alternative to Utilize Code Cases N-878 and N-8802018-05-30030 May 2018 Proposed Alternative to Utilize Code Cases N-878 and N-880 ML18011B1112018-01-23023 January 2018 Relief from the Requirements of the ASME Code and OM Code Relief Requests I4R-04, Proposed Alternatives to Various Inservice Inspection Interval (ISI) Requirements of the American Society of Mechanical Engineers, Section XI, 2007 Edition ML18003A2472018-01-0808 January 2018 Relief from the Requirements of the ASME Code and OM Code Relief Requests I4R-01 (CAC Nos. MF9758 and MF9759; EPID L-2017-LLR-0057) ML17354A8542018-01-0303 January 2018 Approval of Alternative to the ASME Code Regarding Inspection of Hydrogen Recombiner System Piping - Relief Request I4R-08 (CAC Nos. MF9772 and MF9773; EPID L-2017-LLR-0036) RA17-086, County Station, Units I & 2 - 10CFR50.55a Relief Request 14R-012017-11-10010 November 2017 County Station, Units I & 2 - 10CFR50.55a Relief Request 14R-01 ML17261A0782017-10-12012 October 2017 Request for Additional Information Regarding Relief Request I4R-01 (CAC Nos. MF9758 and MF9759; EPID L-2017-LLR-0057) ML17171A3202017-07-0505 July 2017 Relief from the Requirements of the ASME Code Regarding Relief Request I4-R-10, Proposed Alternative to Utilize Code Case N-513-4 ML17170A0132017-06-26026 June 2017 Proposed Alternative to Eliminate Examination of Threads in Reactor Pressure Vessel Flange (CAC Nos. MF8712-MF8729 and MF9548) ML17059C5832017-03-0101 March 2017 Relief from ASME Code for OM Code Re. RR RV-01 Proposed Alternative to Inservice Testing Requirement of ASME Code for OM Code ML17024A2652017-02-22022 February 2017 Letter to Licensee, Approvals of Relief Requests-G-01, RP-01, and RP-04 for the Fourth 10-Year Inservice Testing Intervals (MF8490, MF8491, MF8492, MF8493, MF8498, and MF8499) ML17047A5862017-02-22022 February 2017 Letter to Licensee, Approvals of Relief Requests-RP-02, and RP-03 for the Fourth 10-Year Inservice Testing Intervals (CAC Nos. MF8494 - MF8497) ML16230A2372016-09-0606 September 2016 Fleet Request for Proposed Alternative to Use ASME Code Case N-513-4 (CAC Nos. MF7301-MF7322) ML15226A4122015-10-30030 October 2015 MF5654 & MF5655, Letter to Licensee -Authorization of RR-I3R14 (MF5654 & MF5655-Lasalle RRI3R14(08-14-2015) ML12121A6372012-05-10010 May 2012 Request to Use Code Case N-789 ML0925703212009-09-21021 September 2009 Relief Request CR-26, Inservice Inspection Program Relief Regarding Examination Coverage for the Second 10-Year Inservice Inspection Interval, MD9817 - MD9818 ML0809301222008-05-0707 May 2008 Request for Relief from ASME OM Code for the Third Inservice Testing Interval ML0809803112008-04-30030 April 2008 Relief Request to Use Boiling Water Reactor Vessel & Internals Project Guidelines.. ML0736105872008-01-30030 January 2008 Request for Relief Nos. I3R-03, I3R-04, I3R-08, I3R-09 and I3R-10: Third 10-Year Interval Inservice Inspection Program Plan ML0333001472004-01-28028 January 2004 Relief Request, Shell Weld Inspection, TAC No MB9755 and MB9756 ML0219800132002-07-29029 July 2002 Code Relief, Relief Request RV-13 to Delay Sr/V Setpoint Testing 2023-09-26
[Table view] Category:Letter
MONTHYEARIR 05000373/20230042024-01-24024 January 2024 County Station - Integrated Inspection Report 05000373/2023004 and 05000374/2023004 ML24024A1332024-01-24024 January 2024 Confirmation of Initial License Examination IR 05000373/20230122024-01-18018 January 2024 County Station - Biennial Problem Identification and Resolution Inspection Report 05000373/2023012 and 05000374/2023012 ML23354A2902024-01-0505 January 2024 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0028 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) ML23360A6082023-12-27027 December 2023 County Station Request for Information for NRC Commercial Grade Dedication Inspection: Inspection Report 05000373/2024010 and 05000374/2024010 ML23278A1292023-12-14014 December 2023 Units 1 & 2; Limerick, Units 1 & 2; Nine Mile Point, Units 1 & 2; and Peach Bottom, Units 2 & 3 -Revision to Approved Alternatives to Use Boiling Water Reactor Vessel and Internals Project Guidelines ML23305A1402023-12-13013 December 2023 Units 1 & 2; Nine Mile Point, Unit 2; Peach Bottom, Units 2 & 3; and Quad Cities, Units 1 and 2 - Issuance of Amendments to Adopt Traveler TSTF-580 ML23317A1192023-11-10010 November 2023 Constellation Energy Generation, LLC - 2023 Annual Report - Guarantees of Payment of Deferred Premiums RS-23-120, Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information2023-11-10010 November 2023 Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information IR 05000373/20230032023-11-0909 November 2023 County Station Integrated Inspection Report 05000373/2023003, 05000374/2023003, and 07200070/2023001 ML23286A2602023-11-0808 November 2023 Issuance of Amendment Nos. 260 and 245 to Renewed Facility Operating Licenses Relocation of Pressure and Temperature Limit Curves to the Pressure Temperature Report IR 05000373/20234012023-11-0707 November 2023 County Station Security Baseline Inspection Report 05000373/2023401 and 05000374/2023401 RS-23-103, Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-10-13013 October 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation RS-23-097, Constellation Energy Generation, LLC, Advisement of Leadership Changes and Submittal of Updated Standard Practice Procedures Plans2023-10-12012 October 2023 Constellation Energy Generation, LLC, Advisement of Leadership Changes and Submittal of Updated Standard Practice Procedures Plans IR 05000374/20230102023-10-11011 October 2023 NRC Inspection Report 05000374/2023010 IR 05000373/20233012023-09-15015 September 2023 Errata to NRC Initial License Examination Report 05000373/2023301; 05000374/2023301 RS-23-080, Constellation Energy Generation, LLC, Application to Revise Technical Specifications to Adopt TSTF-264-A, Revision 0, 3.3.9 and 3.3.10 - Delete Flux Monitors Specific Overlap Requirement SRs2023-08-30030 August 2023 Constellation Energy Generation, LLC, Application to Revise Technical Specifications to Adopt TSTF-264-A, Revision 0, 3.3.9 and 3.3.10 - Delete Flux Monitors Specific Overlap Requirement SRs RS-23-087, Revision to Approved Alternatives Associated with the Use of the BWRVIP Guidelines in Lieu of Specific ASME Code Requirements on Reactor2023-08-0404 August 2023 Revision to Approved Alternatives Associated with the Use of the BWRVIP Guidelines in Lieu of Specific ASME Code Requirements on Reactor ML23212A9012023-08-0303 August 2023 Regulatory Audit Report to Support the Review of the Amendments to Relocation of the Pressure Temperature Limit Curves to the Pressure and Temperature Limits Report IR 05000373/20230022023-08-0101 August 2023 County Station - Integrated Inspection Report 05000373/2023002 and 05000374/2023002 ML23208A3182023-07-27027 July 2023 Notification of an NRC Biennial Licensed Operator Requalification Program Inspection and RFI RS-23-084, Response to Request for Additional Information Regarding the Application to Revise Design Basis to Allow Use of Plastic Section Properties in Lower Downcomer Braces Analysis2023-07-24024 July 2023 Response to Request for Additional Information Regarding the Application to Revise Design Basis to Allow Use of Plastic Section Properties in Lower Downcomer Braces Analysis ML23192A5272023-07-12012 July 2023 NRC Initial License Examination Report 05000373/2023301; 05000374/2023301 ML23186A2062023-07-0606 July 2023 Information Request for a NRC Post-Approval Site Inspection for License Renewal 05000374/2023010 ML23181A1502023-06-30030 June 2023 Combined Response to Request for Additional Information and Supplemental Information in Support of LAR to Relocate Pressure and Temperature Limit Curves to the Pressure and Temperature Limits Report ML23178A2422023-06-28028 June 2023 Reassignment of the U.S. Nuclear Regulatory Commission Branch Chief in the Division of Operating Reactor Licensing for Plant Licensing Branch III IR 05000373/20230112023-06-26026 June 2023 County Station - Quadrennial Fire Protection Team Inspection Report 05000373/2023011 and 05000374/2023011 RS-23-077, Response to NRC Regulatory Issue Summary 2023-01, Preparation and Scheduling of Operator Licensing Examinations2023-06-16016 June 2023 Response to NRC Regulatory Issue Summary 2023-01, Preparation and Scheduling of Operator Licensing Examinations ML23167A0352023-06-16016 June 2023 Registration of Use of Cask to Store Spent Fuel ML23171A9562023-06-12012 June 2023 Post Exam Ltr RS-23-042, Application to Revise Technical Specifications to Adopt TSTF-580, Provide Exception from Entering Mode 4 with No Operable RHR Shutdown Cooling2023-05-25025 May 2023 Application to Revise Technical Specifications to Adopt TSTF-580, Provide Exception from Entering Mode 4 with No Operable RHR Shutdown Cooling IR 05000373/20230012023-05-10010 May 2023 County Station - Integrated Inspection Report 05000373/2023001 and 05000374/2023001 ML23123A2202023-05-0303 May 2023 Relief Request I4R-14 for Alternative Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection ML23118A3472023-05-0101 May 2023 County, 1 & 2; Nine Mile Point, 2; and Quad Cities, 1 & 2 - Correction of Amendment No. 193 Adoption of TSTF-306, Revision 2, Add Action to LCO 3.3.6.1 to Give Option to Isolate the Penetration EPID L-2022-LLA-0143 ML23121A1612023-05-0101 May 2023 Information Meeting (Open House) with a Question-and-Answer Session to Discuss NRC 2022 End-of-Cycle Plant Performance Assessment of LaSalle County Station, Units 1 and 2 ML23114A2522023-04-28028 April 2023 Request to Use a Provision of a Later Edition of the ASME Boiler & Pressure Vessel Code, Section XI ML23081A0382023-04-25025 April 2023 County, 1 & 2; Nine Mile Point, 2; and Quad Cities, 1 & 2 - Issuance of Amendments to Adopt TSTF-306, Rev. 2, Add Action to LCO 3.3.6.1 to Give Option to Isolate the Penetration ML23110A3202023-04-21021 April 2023 Information Request to Support the NRC Annual Baseline Emergency Action Level and Emergency Plan Changes Inspection ML23107A1822023-04-18018 April 2023 Operator Licensing Examination Approval Lasalle County Station, May 2023 RS-23-049, Constellation Energy Generation, LLC, Report on Status of Decommissioning Funding for Reactors and Independent Spent Fuel Storage Installations2023-03-23023 March 2023 Constellation Energy Generation, LLC, Report on Status of Decommissioning Funding for Reactors and Independent Spent Fuel Storage Installations ML23073A2182023-03-22022 March 2023 Issuance of Amendment No. 258 to Renewed Facility Operating Licenses Exigent Amendment to Revise Design Basis Related to Seismic Requirements RS-23-048, Exigent Amendment Request to Revise Design Basis Related to Seismic Requirements2023-03-0707 March 2023 Exigent Amendment Request to Revise Design Basis Related to Seismic Requirements ML23061A1632023-03-0303 March 2023 Reassignment of the U.S. Nuclear Regulatory Commission Branch Chief in the Division of Operating Reactor Licensing for Plant Licensing Branch 3 IR 05000373/20220062023-03-0101 March 2023 Annual Assessment Letter for LaSalle County Station, Units 1 and 2 (Report 05000373/2022006 and 05000374/2022006) RS-23-045, Constellation Energy Generation, LLC Submittal of Fitness for Duty Performance Data Reports for 2022 Per 10 CFR 26.717(c) & 10 CFR 26.2032023-02-28028 February 2023 Constellation Energy Generation, LLC Submittal of Fitness for Duty Performance Data Reports for 2022 Per 10 CFR 26.717(c) & 10 CFR 26.203 RS-23-037, Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station2023-02-22022 February 2023 Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station ML23024A1372023-02-0303 February 2023 Request for Withholding Information from Public Disclosure for LaSalle County Station, Unit Nos. 1 and 2 ML23031A1972023-01-31031 January 2023 Notification of NRC Fire Protection Team Inspection Request for Information, Inspection Report Nos. 05000373/2023011 and 05000374/2023011 IR 05000373/20220042023-01-31031 January 2023 County Station - Integrated Inspection Report 05000373/2022004 and 05000374/2022004 RS-23-003, Constellation Energy Generation, LLC, Summary of Changes to Quality Assurance Topical Report, NO-AA-10, and Decommissioning Quality Assurance Program, NO-DC-102023-01-31031 January 2023 Constellation Energy Generation, LLC, Summary of Changes to Quality Assurance Topical Report, NO-AA-10, and Decommissioning Quality Assurance Program, NO-DC-10 2024-01-05
[Table view] |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 12, 2017 Mr. Bryan C. Hanson Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer (CNO)
Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
LASALLE COUNTY STATION, UNITS 1 AND 2, REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST 14R-01, REQUESTS APPROVAL OF ALTERNATIVE RISK-INFORMED INSERVICE INSPECTION INTERVAL PROGRAM AND EXAMINATION CRITERIA FOR EXAMINATION CATEGORY 8-F, 8-J, C-F-1, AND C-F-2 PRESSURE RETAINING PIPING WELDS IN ACCORDANCE WITH ASME CODE CASE N-578-1, "RISK-INFORMED REQUIREMENTS FOR CLASS 1, 2, OR 3 PIPING, METHOD B, SECTION XI, DIVISION 1." (CAC NOS. MF9758 AND MF9759; EPID L-2017-LLR-0057)
Dear Mr. Hanson:
By letter dated May 30, 2017, as supplemented by letter dated July 20, 2017 (Agencywide Documents Access management System (ADAMS) Accession Nos. ML17150A449 and ML17201Q396, respectively), Exelon Generation Company, LLC (the licensee) submitted relief request 14R-01, Requests Approval Of Alternative Risk-Informed lsi Program And Examination Criteria For Examination Category 8-F, 8-J, C-F-1, and C-F-2 Pressure Retaining Piping Welds In Accordance With ASME Code Case N-578-1, "Risk-Informed Requirements For Class 1, 2, or 3 Piping, Method B, Section Xi, Division 1," for the LaSalle County Station, Units 1 and 2.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure to this letter. During the telephone discussion between the NRC staff and the licensee on October 11, 2017, for clarification of these requests for additional information (RAls), it was agreed that the licensee will provide the responses to these RAls no later than close of business on November 13, 2017.
The NRC staff considers that timely responses to these RAls help ensure sufficient time is available for NRC staff review and contribute toward the NRC's goal of efficient and effective use of staff resources.
B. Hanson If you have any questions, please call me at 301-415-3308.
Sincerely,
~~
Bhalchandra Vaidya, Project Manager Plant Licensing Branch Ill Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-373 and 50-37 4
Enclosure:
Request for Additional Information cc w/encl: Distribution via ListServ
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST 14R-01, REQUESTS APPROVAL OF ALTERNATIVE RISK-INFORMED INSERVICE INSPECTION INTERVAL PROGRAM AND EXAMINATION CRITERIA FOR EXAMINATION CATEGORY 8-F, 8-J, C-F-1, AND C-F-2 PRESSURE RETAINING PIPING WELDS IN ACCORDANCE WITH ASME CODE CASE N-578-1, "RISK-INFORMED REQUIREMENTS FOR CLASS 1, 2, OR 3 PIPING, METHOD B, SECTION XI, DIVISION 1."
LA SALLE COUNTY STATION, UNITS 1 AND 2 (CAC NOS. MF9758 AND MF9759)
By letter dated May 30, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17150A449), as supplemented by letter dated July 20, 2017 (ADAMS ML17201Q396), Exelon Generation Company, LLC (the licensee), submitted its fourth 10-year inservice inspection (ISi) interval program relief requests for LaSalle County Station, Units 1 and 2. In accordance with Title 10 of the Code of Federal Regulations (1 O CFR),
Section 50.55a(z)(1 ), the licensee is requesting relief on the basis that the proposed alternative utilizing Electric Power Research Institute (EPRI) Topical Report 112657, "Revised Risk-Informed In-service Inspection Evaluation Procedure," Revision B-A (ADAMS No.
ML013470102), along with two enhancements from the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) Case N-578-1, "Risk-Informed Requirements for Class 1, 2, or 3 Piping, Method B,Section XI," will provide an acceptable level of quality and safety. To complete this review, the U.S. Nuclear Regulatory Commission (NRC) staff requests responses to the following questions:
Probabilistic Risk Assessment (PRA) Request for Additional Information (RAI) 1- Logic Model Enhancement identified as PRA Maintenance In the letter dated July 20, 2017, (ADAMS No. ML172010396), the licensee identified four changes to the PRA model as shown below. The licensee classified each change as PRA maintenance rather than a PRA upgrade with respect to the definitions provided in American Society of Mechanical Engineers /American Nuclear Society RA-Sa-2009, "Addenda to ASME RA-S-2008 Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications" (the PRA Standard). In order for the NRC staff to confirm that the changes qualified as maintenance as opposed to upgrades, provide the following:
I. 2011 PRA Model Change, "Deleted loss of bus 241 Y and 242Y as initiating events and added loss of bus 241X, 242X and 251 as initiating events."
According to Section 1-A.3.5 of the PRA Standard, replacement of point estimates with system fault trees for support system initiators constitutes an upgrade, although Enclosure
this may be permitted as maintenance rather than upgrade if the contribution is not risk significant:
Discuss whether the added initiating events were incorporated as point estimates or fault trees. If any were fault trees:
- a. Discuss whether the initiator frequencies rose or fell bafter the incorporation of the fault trees and, if they did rise, describe whether they were risk-significant and provide an explanation of this fluctuation.
- b. Discuss whether any potential interactions with other systems were included in the PRA model (e.g., interactions to ensure that any common cause failures have been addressed) and provide details of these interactions.
II. 2011 PRA Model Change, "Created a new event tree for isolated Turbine Building and Auxiliary Building floods."
Provide the justification for citing the impact of this new event as "small."
Ill. 2011 PRA Model Change, "Converted the Human Reliability Analysis (HRA) Calculations to the EPRI HRA Calculator," software platform. The HRA Calculator was also used to facilitate the human error probability (HEP) dependence analysis.
- a. In adopting the HRA Calculator, describe whether the exact same methods, steps, and sequence that were used in the pre-existing manual HRA calculations, were exactly mirrored when adopting the HRA Calculator (e.g., Human Cognitive Reliability (HCR)/Operator Reliability Experiments (ORE) Method for the diagnostic phase and Technique For Human Error Rate Prediction (THERP) for the execution phase).
- b. Describe whether the independent review of the HRA was performed by an analyst experienced in HRA Calculations who is not a licensee employee or a contractor involved in the incorporation of the HRA Calculator, and provide a description of the analyst's professional profile.
IV. 2011 PRA Model Change, "The fault trees related to recovery of AC [alternating current]
power in the intermediate timeframe were enhanced by modifying the gate names and descriptors to clarify that the intermediate timeframe is 2 to 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />. Also, the conditional probability that the battery fails was changed and was or'ed [OR Gated] with the operator action to load shed."
- a. Explain why clarification was needed regarding the "intermediate timeframe is 2 to 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />." Describe whether the intermediate timeframe in the PRA model was changed to "2 to 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />" from some other values, and provide justification, as necessary, to support a change in timeframe.
- b. Describe whether this change is comparable to example l-A.3.13 (Revised Modeling of Station Blackout) in the PRA Standard and if so, explain why this change is considered maintenance as opposed to an upgrade.
PRA RAI 2- Evaluation of the Change in Risk In Attachment 1 to the letter dated May 30, 2017 (ADAMS Accession No. ML17150A449), the licensee provided tables on pages 4 through 6 for delta (L'.l) core damage frequency (CDF) and i:l large early release frequency (LEAF).
- i. Table - page 4, "Change in Risk from LaSalle County Station Pre-RI [risk informed]-ISI,Section XI Program to Fourth Interval RI-ISi Program," explain why both i:l CDF and i:l LEAF are roughly equivalent for each unit since LEAF is typically at least an order of magnitude lower than CDF.
ii. Table - page 5, "LaSalle County Station Unit 1 Delta-CDF and Delta-LEAF by System,"
explain why the values appear to have roughly equal i:l CDFs and i:l LERFs for the feedwater, main steam, reactor core isolation cooling and reactor water cleanup systems.
iii. Table - page 5, "LaSalle County Station Unit 1 Break Exclusion Region (BER) Weld Delta-CDF and Delta-LEAF by System," explain why the i:l CDF and i:l LEAF values for the emergency core cooling system (ECCS) are negative (implying a decrease)?
iv. Table - page 6, "LaSalle County Station Unit 2 Delta-CDF and Delta-LEAF by System,"
explain why the value for i:l LEAF for the ECCS system is negative.
- v. Table - page 6, "LaSalle County Station Unit 2 Delta-CDF and Delta-LEAF by System,"
for both the ECCS and high pressure core spray systems (HPCS), explain why there is an increase (or decrease) for i:l CDF and the opposite trend for i:l LEAF.
vi. With respect to the ECCS:
- a. Explain why the i:l CDF is positive as shown in the table on page 6, "LaSalle County Station Unit 2 Delta-CDF and Delta-LEAF by System," while the i:l CDF is negative as shown in the table on page 6, "LaSalle County Station Unit 2 BER Weld Delta-CDF and Delta-LEAF by System."
- b. Explain why the i:l LEAF is greater in magnitude as shown in the table on page 6 "LaSalle County Station Unit 2 BER Weld Delta-GDF and Delta-LEAF by System" than the i:l LEAF shown in the table on page 6 "LaSalle County Station Unit 2 Delta-CDF and Delta-LEAF by System."
vii. With respect to the HPCS, explain why the i:l CDF is negative in the table on page 6, "LaSalle County Station Unit 2 Delta-CDF and Delta-LEAF by System," while the i:l CDF for the BER welds is positive as shown in the table on page 6, "LaSalle County Station Unit 2 BER Weld Delta-CDF and Delta-LEAF by System."
PRA RAI 3- Supporting Requirements (SRs) Not Met In the letter dated July 20, 2017 (ADAMS Accession No. ML172010396), both SR DA-C6 and DA-C10 state similar conclusions including:
"The plant data sources and developed demand estimates, however, are judged to be reasonable to support the PRA. Pursuing plant demand data per the explicit direction in the SR is not expected to result in significant impacts upon the PRA results. Therefore, DA-C6 is being self-assess as "Not Met" is not judged to impact this application."
Provide the justification for SRs that are not expected to result in significant impacts to the PRA.
Explain whether the data sources align with the four listed as acceptable in SR DA-C6.
PRA RAI 4- Safety Significance of Piping Segments Based on the information provided, the NRC staff could not determine whether the licensee reviewed the safety significance of the piping segments subject to inspection to ascertain whether there should be any changes in inspection locations for this fourth interval. Discuss whether there were any changes and, if so, explain the basis for those changes.
B. Hanson
SUBJECT:
LASALLE COUNTY STATION, UNITS 1 AND 2, REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST 14R-01, REQUESTS APPROVAL OF ALTERNATIVE RISK-INFORMED ISi PROGRAM AND EXAMINATION CRITERIA FOR EXAMINATION CATEGORY 8-F, 8-J, C-F-1, AND C-F-2 PRESSURE RETAINING PIPING WELDS IN ACCORDANCE WITH ASME CODE CASE N-578-1, "RISK-INFORMED REQUIREMENTS FOR CLASS 1, 2, OR 3 PIPING, METHOD B, SECTION XI, DIVISION 1."
(CAC NOS. MF9758 AND MF9759; EPID L-2017-LLR-0057) DATED OCTOBER 12, 2017 DISTRIBUTION:
PUBLIC RidsNrrPMLaSalle Resource RidsRgn3MailCenter Resource RidsAcrs_MailCTR Resource RidsNrrLASRohrer Resource RidsNrrDorlLp13 Resource RidsNrrDraApla Resource RidsNrrDeEpnb Resource ARezai, NRR/EPNB LFields, NRR/DRA/APLA RGallucci, NRR/DRA/APLA ADAMS Access1on No.: ML17261A078 (*)N o su bst an t"1a I c hanges f rom th eema1*1 OFFICE DORULPL3/PM DORL/LPL3/LA APLA/BC(*) DORULPL3/BC DORULPL3/PM NAME BVaidya SRohrer SRosenberg DWrona BVaidya DATE 9/25/2017 9/25/2017 9/21/2017 10/12/2017 10/12/2017 OFFICIAL RECORD COPY