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:
g transient shock and expansion waves that will cause further unsteadiness in downstream shear layers. Moreover, synchronization of the transient waves with the shear layer vortices emanating from the jet break can lead to significant amplification of the jet pressures and forces (a form of resonance) that is not considered in the ANSI/ANS 58.2 Standard. Should the dynamic response of the neighboring structure also synchronize with the jet loading time scales, further amplification of the loading can occur, including that at the source of the jet.2 Some general observations by past investigators are that strong discrete frequency loads are observed when the impingement surface is within 10 diameters of the jet opening, and that when resonance within the jet occurs, significant amplification of impingement loads can result3. 1 Knowledge Base for Emergency Core Cooling System Recirculation Reliability, February 1996, issued by the NEA/CSNI, http://www.nea.fr/html/nsd/docs/1995/csni-r1995-11.pdf. 2 These feedback phenomena have been described for aircraft that use jets to lift off and land vertically (see, for example Ho, C.M., and Nosseir, N.S., Dynamics of an impinging jet. Part 1, The feedback phenomenon, Journal of Fluid Mechanics, Vol. 105, pp.119-142, 1981). 3 For example, Ho and Nosseir show a factor of 2-3 increase in pressure fluctuations at the frequency of the resonance, but this has not been shown to be a limiting value. 3.6.2-17 Draft Revision 3 – August 2015 Implications for NRC Staff Reviews Given that alternate standards are not yet available to address the topics described above, the staff reviews each new reactor design certification application concerning its dynamic jet load modeling on a case by case basis. As described in this SRP section, the applicant develops a methodology to address the dynamic effects of postulated high energy line breaks and submits it as part of the application. The staff reviews each design certification document (DCD)