Document: NUREG-0800
Document ID: b6b57a00-5b85-4f0c-965c-ca89ef4265e7
Document Type: srp
Title: DETERMINATION OF RUPTURE LOCATIONS AND DYNAMIC EFFECTS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1608/ML16088A041.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.6.2
CFR Part: 
CFR Title: 

Content:
nformation pertaining to dynamic analyses models for jet thrust force and jet impingement load that are included in this SRP Section and ANSI/ANS 58.2. Pending completion of this effort, the NRC staff will review analyses of the jet impingement forces on a case by case basis. These analyses should show that jet impingement loadings on nearby safety related SSCs will not impair or preclude their essential functions. More details related to the potential nonconservatism of ANSI/ANS 58.2 Standard issue are discussed in Appendix A of this SRP. The assumptions are as follows: A. The jet area expands uniformly at a half angle, not exceeding 10 degrees. B. The impinging jet proceeds along a straight path. C. The total impingement force acting on any cross-sectional area of the jet is time and distance invariant, with a total magnitude equivalent to the jet thrust force as defined in Subsection III.5.C(iv), above. D. The impingement force is uniformly distributed across the cross-sectional area of the jet, and only the portion intercepted by the target is considered. E. The break opening may be assumed to be a circular orifice of cross-sectional flow area equal to the effective flow area of the break. F. Jet expansion within a zone of five pipe diameters from the break location is acceptable if substantiated by a valid analysis or testing, i.e., Moody's expansion model (Moody, 1969). However, jet expansion is applicable to steam or water- steam mixtures only and should not be applied to cases of saturated water or subcooled water blowdown. 6. Analyses of pipe-break dynamic effects on mechanical components and supports should include the effects of both internal reactor pressure vessel asymmetric pressurization loads and expanded asymmetric compartment pressurization loads, as appropriate, as discussed for pressurized water reactor (PWR) primary systems in NUREG-0609, “Asymmetric Blowdown Loads on PWR Primary Systems.” 7. For review of a DC application, the reviewer