ML13010A282
| ML13010A282 | |
| Person / Time | |
|---|---|
| Site: | Palisades |
| Issue date: | 01/10/2013 |
| From: | NRC/RGN-III |
| To: | |
| References | |
| Download: ML13010A282 (31) | |
Text
NRC Public Webinar NRCs Perspectives on Leaks January 12, 2013 1
Welcome Welcome Cynthia Pederson Deputy Regional Administrator NRC R i
III NRC Region III 2
Introductions - NRC
- Cynthia Pederson, Deputy Regional Administrator, Region III Administrator, Region III
- Jack Giessner, Chief, Project Branch 4 (Presenter)
Branch 4 (Presenter)
- Elba Sánchez-Santiago, Reactor Inspector RIII (Presenter)
Inspector, RIII (Presenter)
- Thomas Taylor, Palisades Senior Resident Inspector 3
Resident Inspector
Meeting Agenda g
g
- Meeting Purpose
- Through-wall leaks overview
- Classifications Classifications
-Examples
- Q&A Session
- Closing Remarks 4
- Closing Remarks
Meeting Purpose
- Provide a perspective on leaks and how they are regulated by the NRC.
- Provide examples of leaks that have occurred at Palisades and actions taken to address these leaks.
- Answer questions from the public.
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What is a leak?
- A leak is generally an opening in a pipe a component or a structure pipe, a component or a structure from which a fluid escapes.
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- Examples:
- Metallic portion of a component (Through-Wall) 6
Leaks Covered by NRC Regulations
- Leaks from safety related piping and components components.
- Leaks that have an impact on safety related components.
- For example, a leak from a non safety related system that falls onto a safety related component.
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- Leaks from components important to safety. (e.g. Fire Protection) 7
Leaks Not Covered by NRC Regulations
- Leaks that have no impact on safety-related equipment related equipment.
- For example most of the non-essential service water systems.
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- Through-wall leaks originate from a crack or material loss that goes all the way or material loss that goes all the way through the wall of the pipe or component.
- All through-wall leaks that are in safety All through wall leaks that are in safety related components are required to be repaired.
- The actions taken and the timeliness are dependant on the safety significance (component class).
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Classifications
- Safety Related systems are divided into three American Society of Mechanical three American Society of Mechanical Engineers (ASME) Code categories (Class 1 Class 2 or Class 3)
(Class 1, Class 2, or Class 3).
- The system Code Class is determined by
- The system Code Class is determined by application of a methodology endorsed by the NRC (Regulatory Guides and the the NRC (Regulatory Guides and the Code of Federal Regulations).
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Class 1 Systems
- Are safety related systems.
- Consists of the pressure retaining boundary of the reactor coolant
- It includes all RCS connections up to the outermost containment isolation valve.
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Class 1 Systems
- Repair Requirements
-Must be repaired immediately after discovery.
-No RCS Pressure Boundary Leakage permitted.
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Control Rod Drive Housing Leak -
Palisades Example p
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Control Rod Drive Housing Leak - Palisades 14
Control Rod Drive Housing Leak -
Palisades Palisades
- Through-wall leak in control rod drive housing #24 found on August 12 housing #24 found on August 12.
- The housing is part of the primary coolant system boundary.
- Area is not allowed ANY leakage per Technical Specifications.
- Required repair prior to start-up.
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Class 2 Systems
- Are safety related systems.
- Typically systems that are relied upon directly to mitigate an accident.
- Examples include: Safety Injection system, residual heat removal system and the safety related portions of the main steam system.
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Class 2 Systems
- Repair Requirements
- Leakage must be evaluated to determine the effect on the system.
- The repair may occur at a later time dependent on the results of the evaluation which must follow an NRC evaluation which must follow an NRC approved method.
17
Main Steam Leak -
Palisades Example Steam Leak 18
Main Steam Leak - Palisades Example
- Small un-isolable through-wall steam leak leak.
- Technical Specifications required a plant shut down.
- Repair was required prior to start-up (November 2012).
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Safety Injection Refueling Water Storage Tank (SIRWT) - Palisades Storage Tank (SIRWT) Palisades C t b
Catacombs
- Image for demonstration purposes only 20
Safety Injection Refueling Water Storage Tank (SIRWT) Area - Palisades g
(
)
- Through-wall leak identified.
- Tanks structure was determined to be sound based on an NRC accepted methodology.
- Confirmatory action letter (CAL) was issued to Palisades in order to track their commitments.
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Class 3 Systems
- Are safety related systems.
- Generally consist of cooling water systems that support the reactor f
shutdown function.
- An example of a Class 3 System is Service Water.
Class 3 Systems
- Repair Requirements:
- Similar to Class 2, leakage must be evaluated to determine the effect on the system system.
- The repair may occur at a later time dependent on the results of the dependent on the results of the evaluation which must follow an NRC approved method.
approved method.
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Service Water Leak -
Palisades Example 24
Service Water Leak - Palisades
- The NRC resident inspector discovered water leaking from a service water valve water leaking from a service water valve.
- The leak rate was about 11/2 cups per hour and did not affect system functions and did not affect system functions.
- NRC inspectors monitored the leak on a daily basis.
daily basis.
- The valve was repaired in November 2012 25
Summary of Through Wall Leaks
- All through-wall leaks that are in safety related components are safety related components are required to be repaired.
- Repair requirements depend on the component Code Class and/or evaluation results.
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Conclusion
- Palisades is operating safely.
- The NRC has noted a number of technical issues for which initial NRC f
f review identified no immediate safety concerns.
- Proper maintenance of the facility is necessary to ensure safe plant operation.
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Conclusion
- NRC continues to monitor licensees activities related to leaks to ensure activities related to leaks to ensure that regulatory requirements are met.
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Questions Questions 29
M ti Cl Meeting Closure Cynthia Pederson Deputy Regional Administrator NRC R i
III NRC Region III 30
Meeting Contacts g
- Followup Questions - Contact the NRC Region III Offi f P bli Aff i Office of Public Affairs Viktoria Mitlyng / Prema Chandrathil T l (630) 829 9500 Tel: (630) 829-9500 OPA3@nrc.gov 31