12-21-2017 | On 10/23/2017, during a walkdown of containment at the start of the Unit 3 refueling outage, a leak was identified in a socket weld for a 1-inch diameter instrument line. The line is connected to discharge piping for the 'B' recirculation pump and is part of the reactor coolant system pressure boundary. Because the leak was misting, the leakage rate could not be quantified. However, the reactor coolant system unidentified leakage prior to plant shutdown was 0.18 gpm. RCS pressure boundary leakage while in Mode 1 is a violation of Technical Specification 3.4.4 and is a reportable condition.
The cause of the event was a lack of fusion defect in the weld when it was done in the late 1980's. Normal vibration of the line since it was installed resulted in the crack initiating at the weld defect and propagating to the surface. The section of pipe and associated fitting were replaced, along with welds in similar sections of piping. There were no actual safety consequences as a result of this event. |
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Category:Letter
MONTHYEARML24022A2262024-01-22022 January 2024 (PBAPS) Unit 3 - Submittal of the Inservice Inspection (ISI) Owner'S Activity Report (OAR) for the 24th Refueling Outage for Unit 3 ML23346A2412024-01-17017 January 2024 Staff Assessment of Updated Seismic Hazards Following the NRC Process for the Ongoing Assessment of Natural Hazards Information (EPID L-2019-PMP-0061) - Letter IR 05000277/20234022024-01-11011 January 2024 Security Baseline Inspection Report 05000277/2023402 and 05000278/2023402 and Independent Spent Fuel Storage Installation Security Inspection 07200029/2023401 ML23354A1922024-01-0505 January 2024 Exemption from Select Requirements of 10 CFR Part 73 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting) ML23355A0622023-12-18018 December 2023 Independent Spent Fuel Storage Installation (Isfsi), Security Plan, Training and Qualification Plan, and Safeguards Contingency Plan 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 ML23334A2502023-11-30030 November 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML23270C0072023-11-29029 November 2023 Notice of Proposed Amendment to Decommissioning Trust Agreement ML23317A1192023-11-10010 November 2023 Constellation Energy Generation, LLC - 2023 Annual Report - Guarantees of Payment of Deferred Premiums ML23305A3472023-11-0101 November 2023 Revision of One Form That Implements the Radiological Emergency Response Plan (RERP) IR 05000277/20230032023-10-30030 October 2023 Integrated Inspection Report 05000277/2023003 and 05000278/2023003 and Exercise of Enforcement Discretion ML23286A0012023-10-13013 October 2023 Reply to a Notice of Violation (NOV) - NOV 05000277, 05000278/2023010-01 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 ML23271A1342023-10-11011 October 2023 Dtf Analysis Letter IR 05000277/20244012023-10-0505 October 2023 Information Request for the Cybersecurity Baseline Inspection, Notification to Perform Inspection 05000277/2024401 and 05000278/2024401 ML23265A1502023-09-22022 September 2023 License Amendment Request Revise a License Condition and Certain Technical Specifications to Remove Restrictions in Support of Decommissioning Activities ML23264A8682023-09-21021 September 2023 Independent Spent Fuel Storage Installation Registration of Dry Storage Canister WC-EOS-37PTH-008-B4L, WC-EOS-37PTH-007-B4L, and WC-EOS-37PTH-002-B4L IR 05000277/20230102023-09-15015 September 2023 Biennial Problem Identification and Resolution Inspection Report 05000277/2023010 and 05000278/2023010 and Notice of Violation ML23251A2022023-09-11011 September 2023 Cover Letter W/Report LR-N23-0045, and Peach Bottom Atomic Power Station, Units 2 and 3 - Notice of Proposed Amendment to Decommissioning Trust Agreement2023-09-0808 September 2023 and Peach Bottom Atomic Power Station, Units 2 and 3 - Notice of Proposed Amendment to Decommissioning Trust Agreement IR 05000277/20230052023-08-31031 August 2023 Updated Inspection Plan for Peach Bottom Atomic Power Station, Units 2 and 3 (Report 05000277/2023005 and 05000278/2023005) ML23158A1952023-08-30030 August 2023 R. E. Ginna - Issuance of Amendments to Adopt TSTF-273-A, Revision 2, Safety Function Determination Program Clarifications ML23232A0012023-08-19019 August 2023 Revision of One Procedure That Implements the Radiological Emergency Response Plan (Rerp). Includes EPP 06-009, Rev. 13 IR 05000277/20230112023-08-15015 August 2023 Comprehensive Engineering Team Inspection Report 05000277/2023011 and 05000278/2023011 ML23226A1112023-08-14014 August 2023 10 CFR 50.46 Annual Report IR 05000277/20230022023-08-0808 August 2023 Integrated Inspection Report 05000277/2023002 and 05000278/2023002 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 IR 05000277/20230402023-07-17017 July 2023 95001 Inspection Supplemental Report 05000277/2023040 and Follow-Up Assessment Letter ML23188A0532023-07-0707 July 2023 Registration of Use of Independent Spent Fuel Storage Installation (ISFSI) Casks ML23186A1272023-07-0606 July 2023 Response to Disputed Non-Cited Violation Documented in Peach Bottom Atomic Power Station, Units 2 and 3, Inspection Report 05000277/2022004 and 05000278/2022004 ML23178A0352023-06-27027 June 2023 Senior Reactor and Reactor Operator Initial License Examinations 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 ML23151A4162023-05-31031 May 2023 Revision of One Form That Implements the Radiological Emergency Response Plan (RERP) for Wolf Creek Generating Station (WCGS) ML23150A2052023-05-30030 May 2023 Independent Spent Fuel Storage Installation (Isfsi), Annual Radiological Environmental Operating Report 80 January 1, 2022 Through December 31, 2022 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 ML23142A1602023-05-23023 May 2023 Summary of April 11, 2023, Public Observation Meeting with Constellation Energy Generation, LLC Re Proposed Exemption Request from Work Hour Requirements ML23132A1582023-05-18018 May 2023 Correction to Technical Specification 3.4.7 (Page 3.4-16) Issued in Amendment No. 337 ML23132A1532023-05-12012 May 2023 Transmittal of 2022 Annual Financial Reports WM 23-0009, Financial Assurance Requirements for Decommissioning Nuclear Power Reactors 10 CFR 50.75(f)(1)2023-05-10010 May 2023 Financial Assurance Requirements for Decommissioning Nuclear Power Reactors 10 CFR 50.75(f)(1) IR 05000277/20230012023-05-0808 May 2023 Integrated Inspection Report 05000277/2023001 and 05000278/2023001 ML23114A2522023-04-28028 April 2023 Request to Use a Provision of a Later Edition of the ASME Boiler & Pressure Vessel Code, Section XI 2024-01-05
[Table view] Category:Licensee Event Report (LER)
MONTHYEARML21196A4852021-07-16016 July 2021 LER 2-2021-002-00 for Peach Bottom Atomic Power Station, Unit 2, Safety Relief Valve Inoperability Due to Nitrogen Leakage from Braided Hose Wear 05000278/LER-2017-0012017-12-20020 December 2017 Reactor Pressure Boundary Leakage Due to Weld Failure in One-Inch Diameter Instrument Line, LER 17-001-00 for Peach Bottom Atomic Power Station (PBAPS), Unit 3 Regarding Reactor Pressure Boundary Leakage Due to Weld Failure in One-Inch Diameter Instrument Line 05000277/LER-2017-0012017-03-0808 March 2017 Emergency Diesel Generator Exhaust Stacks Nonconforming Design for Tornado Missile Protection, LER 17-001-00 for Peach Bottom Atomic Power Station (PBAPS), Unit 2 Regarding Emergency Diesel Generator Exhaust Stacks Nonconforming Design for Tornado Missile Protection 05000278/LER-2016-0012016-11-22022 November 2016 Leak in High Pressure Coolant Injection Drain Pipe Results in a Loss of Safety Function, LER 16-001-00 for Peach Bottom, Unit 3, Regarding Leak in High Pressure Coolant Injection Drain Pipe Results in a Loss of Safety Function 05000277/LER-2016-0012016-11-11011 November 2016 Leak in High Pressure Service Water Pipe Results in Condition Prohibited by Technical Specifications, LER 16-001-00 for Peach Bottom, Unit 2, Regarding Leak in High Pressure Service Water Pipe Results in Condition Prohibited by Technical Specifications 05000278/LER-2015-0012016-02-26026 February 2016 Loss of High Pressure Coolant Injection System Function as a Result of Failed Flow Controller Signal Converter, LER 15-001-00 for Peach Bottom, Unit 3, Regarding Loss of High Pressure Coolant Injection System Function as a Result of Failed Flow Controller Signal Converter ML13058A0432013-02-22022 February 2013 Submittal of Independent Spent Fuel Storage Installation (ISFSI) Cask Event Report ML1007702362010-03-12012 March 2010 60-Day Security Event Report 2-10-S01 ML0927401622009-09-30030 September 2009 LER 09-S01-00 for Peach Bottom, Units 2 & 3 Regarding Unescorted Access Granted to Contract Worker Who Did Not Provide Complete Work History Information ML1015505682009-07-10010 July 2009 Event Notification for Peach Bottom on Elevated Tritium Levels Found in On-Site Well ML0434503772004-12-10010 December 2004 LER-04-S01-00 for Peach Bottom Atomic Power Station (PBAPS) Unit 2 and Unit 3, 60 Day Security Event Report 2-04-S01 ML19095A7391976-12-0505 December 1976 Reporting Abnormal Occurrence No. 50-278-74-33 at Peach Bottom Atomic Power Station for Failure of Main Steam Line High Flow Switch dPIS-3-2-116C to Trip During Surveillance Test 2021-07-16
[Table view] |
comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
3. LER NUMBER
2017 - 00 001 Unit Conditions Prior to Discovery of the Event Unit 3 was in Mode 3, Hot Shutdown, when the condition was discovered on 10/23/2017 at approximately 4:00 am. The unit entered Mode 3 at 1:08 am in preparation for the planned refueling outage. There were no structures, systems, or components out of service that contributed to this event.
Description of the Event
On 10/23/2017, with the Unit in Mode 3, at the beginning of a refueling outage, personnel entered the drywell to perform an inspection. At approximately 4:00 am, leakage was identified on a one-inch diameter instrument line socket (EIIS:PSF) weld. The instrument line is for a pressure transmitter from the 'B' Recirculation Pump (EIIS:AD) discharge. Because the leak was misting, the leakage rate could not be quantified. However, the reactor coolant system unidentified leakage prior to plant shutdown was 0.18 gpm.
This line is part of the ASME Class 1 primary coolant pressure boundary. Technical Specification (TS) 3.4.4 does not allow any pressure boundary leakage in Modes 1, 2 or 3. As a result, TS 3.4.4 Condition C was entered, which requires the plant to be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The plant was in Mode 3 at the time of discovery and entered Mode 4, Cold Shutdown, at 12:54 pm on 10/23/2017 (approximately 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> after time of discovery).
Prompt notification to the NRC was made in accordance with 10 CFR 50.72(b)(3)(ii)(A) on 10/23/2017 at 9:35 am (Event Notification #53031).
Analysis of the Event
The leak was determined to be from a crack in the weld connecting the pipe to a tee fitting. The crack extended approximately 60 degrees around the circumference of the weld. Although it could not be determined when the crack developed, it is assumed it existed while operating in Mode 1, prior to shutdown. During such time, the leakage would have been contributing to the total unidentified leakage of 0.18 gpm. This is well below the 5 gpm limit for unidentified leakage as stated in TS 3.4.4.
This event is being reported in accordance with the following:
1. 10 CFR 50.73(a)(2)(i)(B) — Conditions Prohibited by Technical Specifications - TS Limiting Condition for Operation (LCO) 3.4.4 requires there to be no RCS pressure boundary leakage while in Modes 1, 2 and 3. If leakage exists, TS 3.4.4 Condition C requires the unit to be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. Since the leak existed while in Mode 1 for greater than 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />, a condition prohibited by TS existed.
comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Flesource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (31500104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
3. LER NUMBER
2017 - 00 001 2. 10 CFR 50.73(a)(2)(ii)(A) — Degradation of the RCS — Because of the RCS pressure boundary leakage, one of the principal safety barriers of the plant was degraded.
Cause of the Event
The section of the one-inch pipe containing the cracked socket weld was sent to an offsite laboratory for analysis. The pipe was sectioned and lack of fusion defects were identified at the root of the weld. The crack initiated at the location of these defects. The defects would have occurred when the weld was performed during a recirculation system pipe replacement in the late 1980's. It is unknown when the crack began, but normal vibration for the piping likely caused it to propagate to the surface of the weld, resulting in the identified leak.
Corrective Actions
The section of pipe and the associated fitting were replaced. Instrument lines connected to the suction and discharge lines for both of the recirculation pumps with similar configuration and subject to vibration were also replaced during the refueling outage. The new welds were performed with a 2:1 profile, which reduces their susceptibility to vibration-induced failures.
Previous Similar Occurrences A similar event occurred in September of 2005. A crack in a socket weld caused by a lack of fusion defect resulted in a 1 gpm leak in a one-inch equalizing line for a check valve on the 'A' Residual Heat Removal (RHR) injection line. The event is documented in LER 2005-003, dated 10/28/2005. Additional information on this previous occurrence is contained in the corrective action program.