2> NRC Regulatory Information Conference March 12, 2009AREVA NP Inc.

AREVA Perspectives on the Containment Sump Design and Downstream Effects for

U.S. EPRTM Design

Fariba GartlandProject Manager

AREVA NP Inc.

NRC Regulatory Information ConferenceRockville, MD

March 12, 2009

EPR is a trademark of the AREVA Group

3> NRC Regulatory Information Conference March 12, 2009AREVA NP Inc.

> Innovative and comprehensive solution to the concerns of GSI-191

> Defense-in-depth strategy> Supporting test program> Inspections, tests, analyses

and acceptance criteria (ITAAC)

Introduction

Olkiluoto-3 EPR Project, Finland January 2009

4> NRC Regulatory Information Conference March 12, 2009AREVA NP Inc.

US EPRTM ECCS Sump Blockage Mitigation Design Features

Design Detail

5> NRC Regulatory Information Conference March 12, 2009AREVA NP Inc.

> 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

Defense-in-Depth Strategy

6> NRC Regulatory Information Conference March 12, 2009AREVA NP Inc.

> 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

Additional Features

Strainer Retaining Basket

7> NRC Regulatory Information Conference March 12, 2009AREVA NP Inc.

IRWST Cut-away View

ECCSStrainer

ECCS Strainer

Retaining Basket

Trash Rack

RetainingBasket

8> NRC Regulatory Information Conference March 12, 2009AREVA NP Inc.

> 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

Testing

ECCS strainer testing demonstrates effectiveness of three-tiered design

9> NRC Regulatory Information Conference March 12, 2009AREVA NP Inc.

> 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

Downstream Effects

Debris types and design features minimize potential for blockage

10> NRC Regulatory Information Conference March 12, 2009AREVA NP Inc.

> Pre-operational inspections on key design features affecting sump screen performance: Trash racks over floor openings Weir at floor and wall openings Retaining baskets below floor openings IRWST suction strainer

ITAAC

ITAAC provide confirmation that installation of key components meets the design bases

11> NRC Regulatory Information Conference March 12, 2009AREVA NP Inc.

> 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.

Conclusion

GSI-191 concerns addressed through defense-in-depth strategy