Document: NUREG-0800
Document ID: a28650b3-fa03-428d-a2bd-4a27f583710b
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070484.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6
CFR Part: 
CFR Title: 

Content:
he pool-swell zone of the wetwell shall be calculated for grating with open area greater than or equal to 60% by forming the product of the pressure differential as given in Figure 4-40 of NEDO-21061, Revision 2, and the total area of the grating. To account for the dynamic nature of the initial loading, the load shall be increased by a multiplier given by: where: F = static equivalent load SE W = width of grating bars, in. f = natural frequency of lowest mode, Hz D = static drag load NOTE 3 Impact Loads on Small Structures The hydrodynamic loading function that characterizes pool impact on small horizontal structures shall have the versed sine shape. Small structures are defined as pipes, I-beams, and other similar structures having one dimension less than or equal to 20 inches. The acceptance criteria are not applicable to the determination of ovaling stresses in cylindrical pipes. where: p = pressure acting on the projected area of the structure, psi P = the temporal maximum of pressure acting on the projected area max of the structure, psi t = time, sec = duration of impact, sec Ip MH A V x 1 (32.2)(144) Table B-1 Mark II LOCA-related hydrodynamic loads Summary table 6.2.1.1.C-23 DRAFT Rev. 7 - April 1996 For both cylindrical and flat structures, the maximum pressure P and pulse duration will be max determined as follows: (a) The hydrodynamic mass per unit area for impact loading will be obtained from the appropriate correlation for a cylindrical or flat target in Figure 6-8 of NEDE-13426P. (b) The impulse will be calculated using the equation where: I = impulse per unit area, psi-sec p MH a) above __ = hydrodynamic mass per unit area, lbm/ft , from ( 2 A V = impact velocity, ft/sec, determined according to Section A.2. (c) The pulse duration will be obtained from the equation 0.0463D = V (cylindrical target) 0.0011W = V V 7 ft/sec (flat target) 0.0016W = V V < 7 ft/sec (flat target)116 where: = pulse duration, sec D = diameter of cylindrical pipe, feet W =