United States Nuclear Regulatory Commission - Protecting People and the Environment

News and Correspondence About Reactor Coolant System Weld Issues

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Date Description
09/19/2008 St. Lucie Retired PZR Safety "A" Nozzle DMW Destructive Examination Report
06/27/2008 DMBW status of activities
02/21/2008 Temporary Instruction 2151/172: Reactor Coolant System DMBW
11/01/2007 MRP-139 Interim Guidance on Bare Metal Visual Exam Requirements
09/07/2007 Safety Assessment on the Advanced FEA Related to Growth of Postulated PWSCC Flaws in Pressurizer Nozzle DMBW
08/13/2007 Advanced FEA Evaluation of Growth of Postulated Circumfrential PWSCC Flaws in Pressurizer Nozzle DMBW
12/18/2006 Letter from Christine King, EPRI, to Tanya Mensah, NRC, regarding PWR Fleet Survey MRP-139 Implementation Plans for Pressurizers - Revision 1
11/09/2006 Letter from King, C., to Mensah, T., concerning PWR fleet survey – MPR-139 implementations plan for pressurizers.
08/23/2006 Letter from Grobe, J., to Riley, J., concerning reporting of MPR-139 inspection findings.
03/29/2006 Letter from John A. Grobe, NRC, to Alex Marion, NEI, regarding teleconference between NRC Staff and NEI representatives concerning spring 2006 dissimilar metal butt welds inspection results.
03/02/2006 Letter from Grobe, J., to Marion, A., request for cooperation in ASME Code process to revise code requirements for inspection of dissimilar metal butt welds.
02/17/2006 Letter from Kenneth Balkey, ASME, to James Dyer on ASME actions to address Alloy 82/182/600 materials
12/20/2005 Letter from James Dyer, NRC, to Gary Park, ASME, on PWSCC in RCS Nickel-Based Alloy Butt Welds
10/12/2005 Letter from Michael E. Mayfield, NRC, to Alex Marion, NEI, regarding questions & comments to MRP-139, "Primary System Piping Butt Weld Inspection and Evaluation Guidelines".
07/27/2005 Letter from Alex Marion, NEI, regarding the Materials Reliability Program inspection plan for piping butt welds.
07/14/2005 Materials Reliability Program: Primary System Butt Weld Inspection and Evaluation Guideline (MPR-139).
11/30/2004 Materials Reliablility Program:  Crack Growth Rates for Evaluation PWSCC of Alloy 82, 182 and 132 Welds (MRP-115NP)
10/19/2004 Materials Reliability Program: Probabilistic Risk Assessment of Alloy 82/182 Piping Butt Welds (MRP 116NP)
07/31/2004 Materials Reliability Program: Alloy 82/182 Pipe Butt Weld Safety Assessment for US PWR Plant Designs (MRP-113NP)
06/12/2003 MRP A600 ITG Butt Weld Working Group slides from public meeting to discuss industry management of various materials degradation issues
04/22/2003 Letter from Brian W. Sheron, NRC to Alex Marion, NEI, regarding Pressurized Water Reactor (PWR) Materials Reliability Project Interim Alloy 600 Safety Assessment for U.S. PWR Plants (MRP-44), Part 1: Alloy 82/182 Pipe Butt Welds
07/18/2002 Materials Reliablility Program:  Crack Growth Rates for Evaluation PWSCC of Thick-Wall Alloy 600 (MRP-55)
06/14/2001 Letter from Dr. Brian Sheron, NRC, to Mr. Alex Marion, NEI, regarding Staff Findings Regarding "PWR Materials Reliability Project Interim Alloy 600 Safety Assessment for U.S. PWR Plants (MRP-44), Part 1: Alloy 82/182 Pipe Butt Welds"
05/04/2001 Letter from Peter Wen, NRC, to Dr. Theodore Marston, EPRI, regarding "Request for Withholding Information from Public Disclosure, EPRI Letter of April 24, 2001."
04/27/2001 Letter from Mr. Alex Marion, NEI, to Dr. Brian Sheron, NRC, regarding "PWR Reactor Piping and Head Penetrations," providing EPRI Report TP1001491 NP, Part 1, "PWR Materials Reliability Project Interim Alloy 600 Safety Assessment for U.S. PWR Plants (MRP-44), Part 1: Alloy 82/182 Pipe Butt Welds," April 2001
03/15/2001 NRC Special Inspection Team Report
02/20/2001 Safety Evaluation Report - WCAP-15615, "Integrity Evaluation for Future Operation: Virgil C. Summer Nuclear Plant Reactor Vessel Nozzle to Pipe Weld Regions" (TAC NO. MB0251)
02/09/2001 NRC Special Team Meeting with Summer Plant Officials to Discuss Hot Leg Weld Crack Findings
01/02/2001 NRC Staff to Meet with Summer Plant Officials to Discuss Pipe Repair Prior to Plant Restart
12/29/2000 WCAP-15615, Revision 0, "Integrity Evaluation for Future Operation Virgil C. Summer Nuclear Plant: Reactor Vessel Nozzle to Pipe Weld Regions;" (Non-Proprietary Class 3)
12/26/2000 Letter from SCE&G submitting copies of WCAP-15615, "Integrity Evaluation for Future Operation Virgil C. Summer Nuclear Plant: Reactor Vessel Nozzle to Pipe Weld Regions"
12/14/2000 Nuclear Energy Institute (NEI) letter to NRC: Reactor Coolant Pipe Cracking Experience
11/16/2000 NRC Information Notice (2000-17), Supplement 1 - Crack in Weld Area of Reactor Coolant System Hot Leg Piping at V. C. Summer
11/03/2000 NRC's expectations and information needs - V. C. Summer crack in the weld area of the reactor coolant system
10/23/2000 NRC's request for information - V. C. Summer crack in the weld area of the reactor coolant system
10/18/2000 NRC Information Notice (2000-17) - Crack in Weld Area of Reactor Coolant System Hot Leg Piping at V.C. Summer
10/13/2000 Licensee Event Notification (#37423) - Initial discovery of boron on the floor and identification of a 4"long hairline crack

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Page Last Reviewed/Updated Wednesday, May 08, 2013