Letter Sequence Approval |
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MONTHYEARML20089A0072020-03-31031 March 2020
Verbal Authorization by the Office of Nuclear Reactor Regulation for Relief Request I4R-23
Project stage: Approval
ML20092M0032020-03-31031 March 2020
Email Re Limerick Generating Station, Unit 1 (LGS) - Suppression Pool Relief Request Verbal Authorization Related to COVID-19 Issues
Project stage: Approval
ML20089A0012020-04-20020 April 2020
Issuance of Relief Request I4R-23 Associated with Pandemic-Related Issues - Examination of Containment Surfaces Requiring Augmented Examination (Category E-C) (EPID L-2020-LLR-0044 (COVID-19))
Project stage: Approval
2020-03-31
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Category:Code Relief or Alternative
MONTHYEARML23354A0032024-01-19019 January 2024
Authorization and Safety Evaluation for Alternative Request Associated with Successive Inspections for Generic Letter 88-01 / BWRVIP-75-A Augmented Examinations
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
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
ML20322A0092020-12-10010 December 2020
Issuance of Alternative Requests 41-VRR-8 and 41-VRR-7 Regarding Certain Inservice Testing Program Requirements for Safety Relief Valves
ML20280A7572020-11-0505 November 2020
Revised Safety Evaluation of Relief Requests GVRR-8, 11 PRR-1, 90 PRR-1, and 47 VRR-2 Regarding the Fourth 10-Year Interval of the Inservice Testing Program (EPID L-2018-LLR-0384 Through EPID L-2018-LLR-0387)
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
ML20252A1352020-09-0404 September 2020
Relief Request I4R-24 Associated with Residual Heat Removal Heat Exchanger Category C-A and C-B Examinations
ML20188A2642020-07-0606 July 2020
Clinton Power Station, R.E. Ginna Station, Limerick Station, Nine Mile Point Station & Peach Bottom Station - Proposed Alternative to Utilize Code Case OMN-26 - Response to Request for Additional Information
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
ML20093M8202020-04-0303 April 2020
Exemption from Select Requirements of 10 CFR Part 26 (EPID L-2020-LLR-0014 (COVID-19))
ML20090A6522020-03-31031 March 2020
Verbal Authorization of Relief Request GVRR-9
ML20089A0072020-03-31031 March 2020
Verbal Authorization by the Office of Nuclear Reactor Regulation for Relief Request I4R-23
ML20089A0082020-03-29029 March 2020
Relief Request GVRR-9 Associated with Pandemic Related Issues - Inservice Testing Interval Extension for Motor Operated Valves
ML20088B0222020-03-28028 March 2020
Relief Request I4R-23 Associated with Pandemic Related Issues - Examination of Containment Surfaces Requiring Augmented Examination (Category E-C)
RS-20-020, Relief Request for Alternative Frequency to Supplemental Indication Requirements of 10 CFR 50.55a(b)(3)(xi)2020-02-28028 February 2020
Relief Request for Alternative Frequency to Supplemental Indication Requirements of 10 CFR 50.55a(b)(3)(xi)
ML19228A1952019-10-28028 October 2019
Safety Evaluation of Relief Requests GVRR-8, 11-PRR-1 and 47-VRR-2 Fourth 10-Year Interval of the Inservice Inspection Program EPID L-2018-LLR-0384, EPID L-2018-LLR-0385, EPID L-2018-LLR-0386, and
ML19269C5342019-09-27027 September 2019
Proposed Alternative to Use Encoded Phased Array Ultrasonic Examination Techniques
ML19161A2572019-06-0404 June 2019
BWR Fleet Msv/Srv - Testing Frequency Relief Request NRC Pre-Application Meeting June 4, 2019
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
ML19099A2632019-04-22022 April 2019
Issuance of Relief Request 14R-08, Revision 1, Regarding Pressure Testing of Containment Atmospheric Control Penetration Piping
ML19099A3072019-04-16016 April 2019
Issuance of Relief Request 14R-18 Associated with Inaccessible Supports for the Fourth 10-Year Inservice Inspection Interval Pipping
ML19009A0022019-03-0505 March 2019
Issuance of Relief Request IR4-17, Revision 1, Reactor Pressure Vessel Nozzle Repair in Lieu of Specific ASME Code Requirements
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
ML18274A0152018-10-0101 October 2018
Relief Request 14R-OB, Revision 1, Associated with Pressure Testing of Containment Atmospheric Control Penetration Piping
ML18165A0022018-06-11011 June 2018
Relief Request 14R-18 Associated with Inaccessible Emergency Service Water and Residual Heat Removal Service Water Pump Supports
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
JAFP-18-0052, Proposed Alternative to Utilize Code Case N-8792018-05-30030 May 2018
Proposed Alternative to Utilize Code Case N-879
ML18129A3312018-05-0404 May 2018
Proposed Relief Request Associated with Reactor Pressure Vessel Nozzle Repairs
ML17208A0902017-08-14014 August 2017
Relief Request I4R-17 Associated with the Alternate Repair of a 2-Inch Instrument Line Nozzle at Penetration N-16D on the Reactor Pressure Vessel
ML17170A0132017-06-26026 June 2017
Proposed Alternative to Eliminate Examination of Threads in Reactor Pressure Vessel Flange (CAC Nos. MF8712-MF8729 and MF9548)
ML17137A3072017-05-17017 May 2017
Verbal Authorization by the Office of Nuclear Reactor Regulation for Relief Request I4R-17
ML17004A0632017-02-0707 February 2017
Proposed Alternative Request GVRR-8 Inservice Testing Program Third 10-Year Interval
ML16344A3242016-12-29029 December 2016
Safety Evaluation of Relief Request I4R-01 for the Fourth 10-Year Interval of the Inservice Inspection Program for Limerick Generating Station, Units 1 and 2
ML16301A4012016-11-21021 November 2016
Safety Evaluation of Relief Requests I4R-02 and I4R-10 for the Fourth 10-Year Interval of the Inservice Inspection Program for Limerick Generating Station, Units 1 and 2
ML16230A2372016-09-0606 September 2016
Fleet Request for Proposed Alternative to Use ASME Code Case N-513-4 (CAC Nos. MF7301-MF7322)
ML12121A6372012-05-10010 May 2012
Request to Use Code Case N-789
ML0930803822009-11-17017 November 2009
Evaluation of Relief Requests Associated with the Third Inservice Testing Interval (TAC ME0742 - ME0751)
ML0809803112008-04-30030 April 2008
Relief Request to Use Boiling Water Reactor Vessel & Internals Project Guidelines..
ML0312601152003-06-23023 June 2003
Relief Request Review, American Society of Mechanical Engineers Boiler and Pressure Vessel Code-Relief for Qualification Requirements for Dissimilar Metal Piping Welds
ML0311300292003-05-0505 May 2003
Relief from Requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI, Concerning Check Valve Inservice Testing Program, MB4804 & MB4805
ML0306204912003-03-0303 March 2003
Relief, American Society of Mechanical Engineers Boiler and Pressure Vessel Code - Relief for Risk-Informed Inservice Inspection of Piping, MB4633 and MB4634
ML0208701612002-05-0202 May 2002
Evaluation of Relief Requests RR-05, RR-07, RR-12, Tables RR-12-5 and RR-12-9 and RR-13, Tables RR-13-8 (TAC Nos. MB1018 and MB1019)
ML0210607752002-05-0202 May 2002
Evaluation of Relief Request RR-12, Table RR-12-6, Rotation of Snubbers and Relief Valves (TAC Nos. MB1018 and MB1019)
ML0208604792002-03-15015 March 2002
Request for Relief, Alternative to ASME Boiler & Pressure Vessel Code Section XI Requirements for Class 1 & 2 Piping
ML0201501402002-02-14014 February 2002
Evaluation of Relief Request RR-12, Table RR-12-7, Underwater Welding (Tac Nos. MB1018 and MB1019)
ML0202502652002-02-14014 February 2002
Evaluation of Relief Request RR-04 - ASME Class 1, 2, 3 Snubbers Visual Examination and Functional Testing (TAC Nos. MB1018 and MB1019)
2024-01-19
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Text
VERBAL AUTHORIZATION BY THE OFFICE NUCLEAR REGULATION 10 CFR 50.55a REQUEST TO POSTPONE AUGMENTED EXAMINATION OF CONTAINMENT SURFACES DUE TO PANDEMIC-RELATED HARDSHIP LIMERICK GENERATING STATION, UNIT 1 EXELON GENERATION COMPANY, LLC DOCKET NO. 50-352 March 31, 2020 Technical Evaluation read by Scott Krepel, Acting Chief of the Piping and Head Penetrations Branch, Division of New and Renewed Licenses, Office of Nuclear Reactor Regulation By letter dated March 28, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20088B022), Exelon Generation Company, LLC. (the licensee),
proposed an alternative to the requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Table IWE-2500-1, Item Number E4.11, and subparagraph IWE-2420(b), for Limerick Generating Station, Unit 1 (LGS).
Pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(z)(2), the licensee submitted Alternative Request, I4R-23, requesting NRC approval of a proposed alternative to postpone required ASME Code,Section XI inspections of submerged areas of the suppression pool liner and suppression pool vent system. The licensee has concluded that complying with the specified ASME Code requirement to conduct successive inspections would result in hardship without a compensating increase in the level of quality or safety, noting that it would not be possible to conduct the inspections while implementing the recommendation for social distancing due to the COVID-19 outbreak. The licensee requested approval of the proposed alternative for the first period of the third containment inservice inspection (ISI) interval and noted that the inspections will be completed no later than the next refueling outage (Li1R19 - Spring 2022).
On March 13, 2020, the United States government declared a national emergency associated with the COVID-19 outbreak. In response to the outbreak, the Centers for Disease Control (CDC) is recommending social distancing, which is defined as remaining out of congregate settings, avoiding mass gatherings, and maintaining distance (approximately 6 feet or 2 meters) from others when possible. The licensee noted that the inspections of containment surfaces require work in close spaces and cannot be completed while implementing the recommendation for social distancing. Due to the COVID-19 pandemic, and to comply with CDC guidance, the licensee requested relief associated with performing successive and augmented inspections of the suppression pool liner and downcomers during the Spring 2020 refueling outage, which are required by ASME Section XI IWE-2420(b) and Examination Category E-C, Item Number E4.11.
These inspections are required for locations that did not meet acceptance criteria during the previous inspection (Spring 2016, LiR16) and were accepted for continued service by engineering evaluation. The licensee proposed to perform the required inspections during the next refueling outage in Spring 2022 (Li1R19).
During the Spring 2016 refueling outage, an underwater inspection of 100 percent of the accessible areas of the suppression pool liner and downcomers was performed. The results of that inspection were as follows:
- all areas of localized corrosion greater than 45 mils were recoated;
- the maximum depth of localized corrosion on the liner that was not recoated was 44.7 mils;
- the maximum depth of general area corrosion on the liner was 44 mils for the liner; and
- the maximum depth of localized corrosion identified on any downcomer was 35 mils.
In addition to the results from 2016, results from inspections during outages in 1996, 2004, 2012, and 2016 have been used to develop a general corrosion rate. This data has shown a corrosion rate of approximately 1 to 2 mils per year with a maximum rate between of 3.6 mils per year between 2012 and 2016.
The licensee also developed site-specific acceptance criteria for the suppression pool and downcomers which ensure the structural integrity of the components is maintained. Based on the analysis, the maximum allowable metal loss was determined to be 125 mils for general area of the liner plate, 187.5 mils for localized areas, and 62.5 mils for the downcomers. Using the most recent data from the 2016 inspection, and the corrosion rate of 3.6 mils, the licensee estimated the most restrictive location would be the downcomers, and the metal loss at the beginning of the 2022 refueling outage on the downcomers would be 56.6 mils. This value is below the associated acceptance criteria of 62.5 mils.
Based on the information provided above, the NRC staff finds that the licensee has adequately projected the metal loss in the suppression pool liner and downcomers, and the remaining metal thickness at the 2022 refueling outage is adequate to ensure the structural integrity and leaktightness of the suppression pool and to ensure the downcomers can perform their intended function. Therefore, it is acceptable for the licensee to defer the required ASME Section XI, IWE-2420(b) inspections of the submerged portions of the suppression pool and dowcomers until no later than the Spring 2022 refueling outage.
The NRC staff finds that the proposed alternative will provide reasonable assurance that the structural integrity of the suppression pool liner and downcomers will be maintained until the next scheduled refueling outage in Spring 2022, when the required ASME Code inspections will be performed.
Authorization read by James Danna, Chief of the Plant Licensing Branch I, Office of Nuclear Reactor Regulation As Chief of the Plant Licensing Branch I, Office of Nuclear Reactor Regulation, I agree with the conclusions of the Piping and Head Penetration Branch.
The NRC staff concludes that the proposed alternative will provide reasonable assurance that the structural integrity and leaktightness will be maintained until the next scheduled refueling outage in Spring 2022, when the required ASME Code inspections will be performed. The NRC staff finds that complying with the requirements of the ASME Code,Section XI, would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(z)(2).
Therefore, effective March 31st, 2020, the NRC authorizes to defer the required ASME Section XI, IWE-2420(b) inspections of the submerged portions of the suppression pool and dowcomers until no later than the Spring 2022 refueling outage.
All other requirements in ASME Code,Section XI for which relief was not specifically requested and approved in this relief request remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.
This verbal authorization does not preclude the NRC staff from asking additional clarification questions regarding the proposed alternative while subsequently preparing the written safety evaluation.
