Transcript Document 7727057

AREVA Perspectives on the Containment
Sump Design and Downstream Effects for
U.S. EPRTM Design
Fariba Gartland
Project Manager
AREVA NP Inc.
NRC Regulatory Information Conference
Rockville, MD
March 12, 2009
EPR is a trademark of the AREVA Group
AREVA NP Inc.
> NRC Regulatory Information Conference March 12, 2009
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Introduction
> Innovative and
comprehensive solution to
the concerns of GSI-191
> Defense-in-depth strategy
> Supporting test program
> Inspections, tests, analyses
and acceptance criteria
(ITAAC)
Olkiluoto-3 EPR Project, Finland
January 2009
AREVA NP Inc.
> NRC Regulatory Information Conference March 12, 2009
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US EPRTM ECCS Sump Blockage Mitigation
Design Features
Design Detail
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Defense-in-Depth Strategy
> Insulation material
> Four protective weir /
trash rack structures
> Four retaining baskets
in the IRWST
> Large area, low flow
velocity region within
the IRWST
> Four large surface area
three-dimensional flat
screen sump strainers
in the IRWST
AREVA NP Inc.
> NRC Regulatory Information Conference March 12, 2009
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Additional Features
> Also contributing to the overall effectiveness of
the system:
 Retaining basket overlaps trash rack portal area
 Overflow from retaining baskets to IRWST
 Retaining basket screen mesh size is identical to the
strainer screen mesh size
 Inverted side screens on the sump suction strainers
Strainer
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Retaining
Basket
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IRWST Cut-away View
ECCS
Strainer
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Retaining
Basket
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ECCS
Strainer
Trash
Rack
Retaining
Basket
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Testing
> ECCS Strainer Testing
 Test facility
• Scaling: 1:1 vertical and 1:20 for all other parameters
(horizontal, flow rate, screen size, debris amount)
 Test results
• Three-tiered design very effective
• Retaining baskets retained 95% of total debris
ECCS strainer testing demonstrates effectiveness of
three-tiered design
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Downstream Effects
> Potential blockage minimized by:
 The retaining basket and sump strainer screens are the
same mesh size, 0.08 x 0.08 inches
 High debris retention in the baskets (95%)
> Fuel:
 U.S. EPR design uses very little fibrous insulation
 Evaluations of fuel under expected debris load will be
completed according to current industry standards
> Components:
 Downstream components (e.g., ECCS pumps) will be
specified to accommodate expected debris load
Debris types and design features minimize potential
for blockage
AREVA NP Inc.
> NRC Regulatory Information Conference March 12, 2009
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ITAAC
> Pre-operational inspections on key design
features affecting sump screen performance:
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Trash racks over floor openings
Weir at floor and wall openings
Retaining baskets below floor openings
IRWST suction strainer
ITAAC provide confirmation that installation of key
components meets the design bases
AREVA NP Inc.
> NRC Regulatory Information Conference March 12, 2009
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Conclusion
> The potential debris source term is minimized.
> The U.S. EPR sump design has advanced and
redundant features with respect to post-accident
debris accumulation and ECCS recirculation
sump strainer blockage.
GSI-191 concerns addressed through
defense-in-depth strategy
AREVA NP Inc.
> NRC Regulatory Information Conference March 12, 2009
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