Document: NUREG-0800
Document ID: 63f62189-691f-402d-9ac9-41fb60ec2261
Document Type: srp
Title: DETERMINATION OF RUPTURE LOCATIONS AND DYNAMIC EFFECTS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1423/ML14230A035.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.6.2
CFR Part: 
CFR Title: 

Content:
ic jet modeling, including blast wave effects, for new reactor design certification applications. The staff assesses the applicant’s procedures to be used to analyze all loads induced on neighboring SSCs or jet shields by postulated pipe ruptures, along with the dynamic structural analyses of the SSCs. These loads include blast waves emanating from sudden pipe breaks, as well as the static and the dynamic oscillatory jet impingement forces on the SSCs and/or shields throughout the blowdown process (until all source fluid is exhausted). The staff reviews the applicant’s criteria for when and how these oscillatory loads need to be considered and determined to be conservative. For example, the staff has accepted the oscillatory jet loading to be considered for SSCs within 10 pipe diameters of two-phase jets and 25 pipe diameters of steam jets. Beyond these distances, the oscillatory jet force is negligible and therefore, does not need to be considered by the applicant. The state of a jet plume fluid often changes during a blowdown process as the pressure and temperature ratios between source and exterior fluid changes. The jet plume geometry also changes during blowdown, with a wide expansion at high pressure ratios (source pressure/external pressure) and a smaller expansion at lower pressure ratios. The staff determines that the applicant’s proposed methodologies conservatively capture all SSCs that might be impacted by the varying jet plume areas and fluid states throughout blowdown. 3.6.2-18 Draft Revision 3 – August 2015 The staff also determines that the applicant’s methodologies used to assess the loads capture the worst-case static and oscillatory loads that may occur for all possible loading directions, including situations in which instabilities and coupling to acoustic wave reflections lead to amplifications of oscillatory loads, particularly in impinging jets close to nearby SSCs. These amplifications occur at discrete frequencies associated with