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:
en axial position, on the ratio of the static pressure in the outermost jet flow region to the ambient static pressure. In the ANSI/ANS 58.2 Standard, the asymptotic plane is described as the point at which the jet begins to interact with the surrounding environment. This has been interpreted to mean that the jet is subsonic downstream of the asymptotic plane. As discussed in References 2 and 3, supersonic or not, the jet is highly dependent on the conditions in the surrounding medium and, at a given distance from the issuing break, will spread or contract at a rate depending on the local jet conditions relative to the surrounding fluid pressure. 3.6.2-16 Revision 3 – December 2016 Supersonic jet behavior can persist over distances from the break that are far longer than those estimated by the standard, extending the zone of influence of the jet and the number of SSCs that could be impacted by a supersonic jet. For example, tests in the Seimens-KWU facility in Karlstein, Germany showed that significant damage from steam jets can occur as far as 25 pipe diameters from a rupture.1 Distribution of Pressure within the Jet Plume Appendix C and Appendix D of ANSI/ANS Standard 58.2 describe the assumptions used for defining the special pressure distribution within a jet cross section for various jet conditions. It assumes a uniform pressure distribution over the cross section of a nonexpanding jet. For an expanding jet, the standard assumes variable (not uniform) pressure over the cross section of the expanding jet. In developing the formulas for the spatial distribution of pressure through an expanding jet cross section, the standard generally assumes that the pressure within a jet cross section is maximum at the jet centerline. However, this assumption is valid near the break, but far from the break, the pressure variation is quite different, often peaking near the outer edges of the jet. Therefore, applying the standard’s formulas could lead to nonconservative