Document: NUREG-0800
Document ID: 919b8fa0-8b11-41bd-9694-2c62120b843b
Document Type: srp
Title: Revision 7 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0636/ML063600403.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6
CFR Part: 
CFR Title: 

Content:
ams, 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 Pmax = the temporal maximum of pressure acting on the projected area of the structure, psi t = time, sec τ = duration of impact, sec For both cylindrical and flat structures, the maximum pressure Pmax and pulse duration τ will be 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 Table B-1 Mark II LOCA-related hydrodynamic loads Summary table 6.2.1.1.C-25 Revision 7 - March 2007 where: Ip = impulse per unit area, psi-sec MH __ = hydrodynamic mass per unit area, lbm/ft2, from (a) above A V = impact velocity, ft/sec, determined according to Section A.2. (c) The pulse duration will be obtained from the equation 0.0463D τ = V (cylindrical target) 0.0011W τ = V V $ 7 ft/sec (flat target) 0.0016W τ = V V < 7 ft/sec (flat target)116 where: τ = pulse duration, sec D = diameter of cylindrical pipe, feet W = width of the flat structure, feet V = impact velocity, ft/sec (d) The value of Pmax will be obtained using the following equation: Pmax = 2Ip/τ For both cylindrical and flat structures, a margin of 35% will be added to the Pmax values (as specified above) to obtain conservative design loads. The load acceptance criteria, as specified above, corresponds to impact on rigid structures. The effect of finite flexibility of real structures will be accounted for in the following manner: When structural dynamic analysis is performed, the "rigid body" impact loads will be applied; however, the masses of the impacted structures will be adjusted by adding on the hydrodynamic masses of impact. The numerical values of