ML092600643

Handout 3 - Kewaunee Power Station, Agenda Setting Meeting 09/15/09

ML092600643
Person / Time
Site:	Kewaunee
Issue date:	09/15/2009
From:	Dominion Energy Kewaunee
To:	Office of Nuclear Reactor Regulation
Tam P
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ML092600030	List: ML092600018 ML092600376 ML092600643 ML092600899
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TAC MC4691
Download: ML092600643 (7)

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Kewaunee Power Station NRC Agenda Setting Meeting 9/15/2009 ALDEN Solving flow problems since 1894

RAI E9j: Concentrated sources of drainage

• No concentrated spray and drainage sources are located in the immediate vicinity of the strainer

• The closest source is modeled in the transport calculation and the flume wall calculation

• The influence of the source can be seen in the calculated approach velocity profile

• The drainage source influence was represented in the large flume test ALDEN Solving flow problems since 1894

Kewaunee Power Station NRC Agenda Setting Meeting 9/15/2009 ALDEN Solving flow problems since 1894

RAI E9j: Concentrated sources of drainage

• No concentrated spray and drainage sources are located in the immediate vicinity of the strainer

• The closest source is modeled in the transport calculation and the flume wall calculation

• The influence of the source can be seen in the calculated approach velocity profile

• The drainage source influence was represented in the large flume test ALDEN Solving flow problems since 1894

E13a--e: CFD modeling of containment flow E13a

• Simulations were conducted using Fluent and followed the standard calculation methodology

• The standard k- model was used for turbulence calculations

• Debris transport calculations were conservatively performed at the water level for the start of recirculation

• High transport fractions were obtained for most zones up to a tumbling velocity of 0.2 ft/sec ALDEN Solving flow problems since 1894

E13a--e: CFD modeling of containment flow E13a

• Detailed accounting was performed to model spray and break flow drainage into the recirculation pool

• Concentrated sources of falling water were treated ideally converting all water potential energy into kinetic energy

• The debris interceptor curb was modeled with few simplifying assumptions

• No assumptions with regard to debris interceptor debris loading were necessary

• No credit was taken for lift-over-curb transport limitations over the debris interceptor curb ALDEN Solving flow problems since 1894

E15: Turbulence in containment and flume / test configuration

• Flume configuration based on long-term recirculation conditions

- Achieved 14 minutes after recirculation start

• Water level in containment for analysis and test maintained at 40.5

- 40.5 is water level for the start of recirculation

- Actual water depth is more than 2 ft higher for long-term recirculation

• Velocity and turbulence levels in vicinity of strainer are low

• Containment structure divides break flow into three sources distributing break flow momentum Long-term recirculation velocity magnitude (ft/s) Long-term recirculation TKE (ft2/s2)

ALDEN Solving flow problems since 1894

E15: Turbulence in containment and flume / test configuration

• Debris interceptor, despite its low height blocks most break flow from reaching strainer

• Flume Reynolds numbers are in the turbulent range

• Flume effective turbulence is on par with that calculated in containment

• Turbulence levels calculated in containment correspond to a maximum of 0.02 ft/sec RM 0.0025 0.002 Distance from Velocity Flume Width Hydraulic Radius screen (ft) (ft/sec) (in) (ft) Reynolds #

Turbulent kinetic Energy (ft2/s2)

Containment Turbulence Flume Turbulence 0.0015 1 0.10 10.4 0.39 6704 2 0.10 9.9 0.37 6045 3 0.10 11.3 0.41 6644 0.001 6 0.08 14.3 0.51 6435 10 0.09 11.7 0.42 6617 0.0005 21 0.12 8.9 0.33 6821 25 0.13 8.5 0.32 6852 0

0 5 10 15 20 25 30 35 30 0.13 8.4 0.32 6861 Distance Back From Strainer (ft)

ALDEN Solving flow problems since 1894

E16: Pool fill transport & distance traveled by debris

• Preferential pool fill transport is limited except during sump C fill-up

• Sump C fill-up preferentially causes debris to move away from strainer bank

• No credit for this transport is taken in the analysis

• The average distance traveled by debris is greater than 30 when considering calculated zone exit flow splits

• TempMat calculated transport fraction was increased by 20% of debris generated for conservatism in determining test quantity

• Transport testing at Alden showed 3x - 4x approach velocity profile only yielded partial transport of TempMat smalls.

ALDEN Solving flow problems since 1894