ML18340A013

July 24, 2018, Summary of Category 1 Public Teleconference with Nuscale Power, LLC, Design Certification Application Section 3.7, Seismic Design, and 3.8, Design of Category I Structures.

ML18340A013
Person / Time
Site:	NuScale
Issue date:	04/17/2019
From:	Vera M NRC/NRO/DLSE/LB1
To:	Samson Lee NRC/NRO/DLSE/LB1
Vera A M/NRO/5861
References
Download: ML18340A013 (9)

Text

/RA/

"-.. Based on these results, an average pressure of 4.20 psi was added as static pressure to the SAP2000 RXB model. This added pressure accounts for the missing 3D effects of fluid-impulsive pressure on the pool walls and foundation.

The pressure at the bottom of the pool due to gravity loading of the water is approximately 30 psi (62.4 lb/ft3

• 69 ft depth *1/144 ft2/in2). Consequently, the average pressure on the wall is half this amount, or 15 psi. The pressure of 4.20 psi is 28 percent of the average pressure (4.20 psi/15 psi = 0.28). Therefore, a 1.28g vertical static loading was added to the SAP2000 model to ensure this additional pressure is accounted for in the design. See Figure 3.7.2-129. Increasing the downward acceleration by a factor of 1.28 corrects for the underestimated fluid pressure, due to mass lumping, in the SSI model.

Horizontal hydrostatic load is a function of fluid density and depth. Fluid density can be altered by changing the acceleration due to gravity.

Increasing the vertical gravitational acceleration increases the horizontal

hydrostatic pressure.

"