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BWR Owners’ Group ECCS Suction Strainers Issue Resolution

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BWR Owners’ Group ECCS Suction Strainers Issue Resolution
BWR Owners’ Group
ECCS Suction Strainers
Issue Resolution
Steve Scammon, Chairman
BWROG ECCS Suction
Strainers Committee
Regulatory Information
Conference
March 8, 2011
Bethesda, MD
March 8, 2011
1
Topics
History
BWR Industry Response
BWROG Project Structure
Subcommittee Activities
Recent Interaction with NRC Staff
Current and Near-Term Activities
Acronyms
March 8, 2011
2
History
Boiling Water Reactor (BWR) strainer
concerns first resolved in mid-1990’s
Discoveries from Pressurized Water Reactor
(PWR) sump screen project (GSI
(GSI-191)
191)
prompted new questions for BWR strainers
Emergency Core Cooling System (ECCS)
Suction Strainer performance during accidents
is subject of new analysis
March 8, 2011
3
1/
GE /
BWR Industry Response
BWR Owners’ Group (BWROG) charged with
updating validation of strainer performance
based on recent PWR analyses
ECCS Suction Strainer Committee was
created to drive resolution of new issues
Results of the closure of GSI-191 items drives
strategy for BWROG program
March 8, 2011
4
BWROG Project Structure
Four subcommittees created:
• Source Term
• Downstream Effects – Fuel
• Downstream
D
t
Eff
Effects
t – Components
C
t
• Strainer Head Loss
March 8, 2011
5
Source Term Issues
Latent debris
Zone Of Influence (ZOI) issues
• Size of destructive zone
• Coatings
Chemical effects
March 8, 2011
6
2/
GE /
Downstream Effects – Fuel Issues
BWR industry uses fuel from three vendors; all
must be analyzed for:
• Fuel bundle inlet debris filter plugging
• Local bundle plugging
• Debris deposition on fuel cladding
• Consequences for cladding temperature
March 8, 2011
7
Downstream Effects – Components
Components other than fuel may be affected
by debris traveling past ECCS suction
strainers
BWROG analyzing for:
• Plugging of pumps, valves and fittings
• Long-term effects of abrasion
March 8, 2011
8
Strainer Head Loss Issues
Near field effect
Thin bed effect
Calcium silicate and micro
micro-porous
porous insulations
Non-homogeneous debris beds
March 8, 2011
9
3/
GE /
Recent Interactions with NRC Staff
Resolution strategy meetings covered twelve
resolution topics
• Discussed technical rationale for resolving
safety concerns
• Presented milestones by quarter through
the end of the project
• Held monthly meetings August-November
2010
March 8, 2011
10
Current and Near-Term Activities
Data collection surveys are underway for
details on the following:
• Strainer headloss testing
• Coatings
C ti
assessmentt programs
Determination of applicability of 40% reduction
in damage pressure
March 8, 2011
11
Current and Near-Term Activities
(continued)
Strainer debris bypass testing
Qualified coatings ZOI assessment
Description of debris characteristics
Fuel test planning
March 8, 2011
12
4/
GE /
Acronyms
BWR: Boiling Water Reactor
BWROG: Boiling Water Reactor Owners’ Group
ECCS: Emergency Core Cooling System
GEH: GE Hitachi Nuclear Energy Americas
Americas, LLC
GSI: Generic Safety Issue
NRC: Nuclear Regulatory Commission
PWR: Pressurized Water Reactor
ZOI: Zone Of Influence
March 8, 2011
13
5/
GE /
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