ML15335A282
| ML15335A282 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 08/10/2015 |
| From: | NRC/OGC |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
| References | |
| RAS 28145, ASLBP 07-858-03-LR-BD01, 50-247-LR, 50-286-LR | |
| Download: ML15335A282 (9) | |
Text
NRC000220 Submitted: August 10, 2015 Global Expertise
- One Voice United States Nuclear Regulatory Commission Official Hearing Exhibit In the Matter of: Entergy Nuclear Operations, Inc.
(Indian Point Nuclear Generating Units 2 and 3)
ASLBP #: 07-858-03-LR-BD01 Docket #: 05000247 l 05000286 Exhibit #: NRC000220-00-BD01 Identified: 11/5/2015 Admitted: 11/5/2015 Withdrawn:
Rejected: Stricken:
Other:
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update Bryan Wilson, Westinghouse June 2014 P R E S S U R I Z E D WAT E R R E A C T O R O W N E R S G R O U P
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - Background Section A-A (Internal Details Removed for Clarity) 2 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - Recent OE Root Cause
- D.C. Cook Issued Root Cause Evaluation (AR 2010-1804-10)
- Root Cause PWSCC of Alloy X-750 with a susceptible heat treatment
- All 29 bolts removed, were either already separated, separated during removal, or had cracks present
- All failures/cracking was at the head-to-shank transition radius
- Fracture mode was essentially 100% intergranular on all bolts
- Industry Impact:
- All Westinghouse and CE plants are potentially susceptible:
- Similar heat treatments are used on all Alloy X-750 clevis insert bolts
- Preload stress in the bolts is similar for all plant
- Visual inspection of bolts alone is not 100% reliable for confirming bolt integrity 3 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - NRC 3/27/14 Meeting Summary
- Overview
- Design Introduction
- Safety Functions
- Design Configurations
- Potential Failure Modes Related to Clevis Insert Bolt Failures
- Why Failure Modes are Unlikely to Occur
- Detection Methods
- Conclusion
- Basic Conclusions
- All design configurations are inherently safe
- Loose parts are captured (with the possible exception of lock bars)
- No single point failure leading to loss of function
- Concerns are primarily commercial in nature
- Visual inspection of wear surfaces and general condition will provide the appropriate level of aging management without the need for bolt inspections
- PWROG project, PA-MSC-1198, will provide utilities the technical basis for the safety case argument presented in the NRC discussion 4 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - Pending Westinghouse Communication
- Technical Bulletin (TB) is the proposed communication tool
- Much of the detail in IG-10-1 will be included
- The TB will also:
- Include a discussion on evaluations performed considering the 4 different Westinghouse and CE clevis insert designs
- Summarize the Root Cause Analysis findings and discuss industry impacts
- Reaffirm that the findings of the RCA do not change the conclusion that this is not an immediate safety concern
- Identify that there are asset management risks that need to be considered
- Provide clear inspection recommendations which can enhance focus of the base aging management program:
- For monitoring conditions directly related to functional performance
- For managing bolt degradation to reduce asset management risk
- Provide optional approaches to support a proactive asset management program 5 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - Potential Inspection Options
- Base Aging Management Program
- Visual examination (VT3) of the following at your next 10-year ISI or earliest opportunity when the lower internals are removed
- For monitoring conditions related to functional performance:
- Radial key / clevis insert interfacing surfaces; look for aggressive or abnormal wear as compared to previous inspection (if available)
- Interface between the clevis insert and vessel lug; look for signs of looseness or dislocation
- For managing bolt degradation to reduce asset management risk:
- Bolt heads; look for wear between the bolt head and lock bar and/or bolt head dislocation (not 100% reliable for confirming bolt integrity)
- Optional Approaches to Support a Proactive Asset Management Program
- UT examination
- Bolt replacement 6 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - Aging Management Requirements Clarification
- Considering the following changes for MRP-227, Rev. 1:
- Recatigorization of the clevis inserts and bolts as Primary components
- Add specifics related to inspection requirements and logic for requiring certain inspections 7 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Questions?
The Materials Subcommittee is established to provide a forum for the identification and resolution of materials issues including their development, modification and implementation to enhance the safe, efficient operation of PWR plants.
8 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Global Expertise
- One Voice www.pwrog.com
NRC000220 Submitted: August 10, 2015 Global Expertise
- One Voice United States Nuclear Regulatory Commission Official Hearing Exhibit In the Matter of: Entergy Nuclear Operations, Inc.
(Indian Point Nuclear Generating Units 2 and 3)
ASLBP #: 07-858-03-LR-BD01 Docket #: 05000247 l 05000286 Exhibit #: NRC000220-00-BD01 Identified: 11/5/2015 Admitted: 11/5/2015 Withdrawn:
Rejected: Stricken:
Other:
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update Bryan Wilson, Westinghouse June 2014 P R E S S U R I Z E D WAT E R R E A C T O R O W N E R S G R O U P
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - Background Section A-A (Internal Details Removed for Clarity) 2 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - Recent OE Root Cause
- D.C. Cook Issued Root Cause Evaluation (AR 2010-1804-10)
- Root Cause PWSCC of Alloy X-750 with a susceptible heat treatment
- All 29 bolts removed, were either already separated, separated during removal, or had cracks present
- All failures/cracking was at the head-to-shank transition radius
- Fracture mode was essentially 100% intergranular on all bolts
- Industry Impact:
- All Westinghouse and CE plants are potentially susceptible:
- Similar heat treatments are used on all Alloy X-750 clevis insert bolts
- Preload stress in the bolts is similar for all plant
- Visual inspection of bolts alone is not 100% reliable for confirming bolt integrity 3 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - NRC 3/27/14 Meeting Summary
- Overview
- Design Introduction
- Safety Functions
- Design Configurations
- Potential Failure Modes Related to Clevis Insert Bolt Failures
- Why Failure Modes are Unlikely to Occur
- Detection Methods
- Conclusion
- Basic Conclusions
- All design configurations are inherently safe
- Loose parts are captured (with the possible exception of lock bars)
- No single point failure leading to loss of function
- Concerns are primarily commercial in nature
- Visual inspection of wear surfaces and general condition will provide the appropriate level of aging management without the need for bolt inspections
- PWROG project, PA-MSC-1198, will provide utilities the technical basis for the safety case argument presented in the NRC discussion 4 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - Pending Westinghouse Communication
- Technical Bulletin (TB) is the proposed communication tool
- Much of the detail in IG-10-1 will be included
- The TB will also:
- Include a discussion on evaluations performed considering the 4 different Westinghouse and CE clevis insert designs
- Summarize the Root Cause Analysis findings and discuss industry impacts
- Reaffirm that the findings of the RCA do not change the conclusion that this is not an immediate safety concern
- Identify that there are asset management risks that need to be considered
- Provide clear inspection recommendations which can enhance focus of the base aging management program:
- For monitoring conditions directly related to functional performance
- For managing bolt degradation to reduce asset management risk
- Provide optional approaches to support a proactive asset management program 5 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - Potential Inspection Options
- Base Aging Management Program
- Visual examination (VT3) of the following at your next 10-year ISI or earliest opportunity when the lower internals are removed
- For monitoring conditions related to functional performance:
- Radial key / clevis insert interfacing surfaces; look for aggressive or abnormal wear as compared to previous inspection (if available)
- Interface between the clevis insert and vessel lug; look for signs of looseness or dislocation
- For managing bolt degradation to reduce asset management risk:
- Bolt heads; look for wear between the bolt head and lock bar and/or bolt head dislocation (not 100% reliable for confirming bolt integrity)
- Optional Approaches to Support a Proactive Asset Management Program
- UT examination
- Bolt replacement 6 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Industry and NRC Coordination Meeting Materials Programs Technical Exchange Clevis Insert Bolt Update - Aging Management Requirements Clarification
- Considering the following changes for MRP-227, Rev. 1:
- Recatigorization of the clevis inserts and bolts as Primary components
- Add specifics related to inspection requirements and logic for requiring certain inspections 7 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Questions?
The Materials Subcommittee is established to provide a forum for the identification and resolution of materials issues including their development, modification and implementation to enhance the safe, efficient operation of PWR plants.
8 P R E S S U R I Z E D WAT E R REACTOR OWNERS GROUP
Global Expertise
- One Voice www.pwrog.com