What is Super Piping? ASME B&PV Code Section III Subsection NB

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Discussion Overview

The discussion revolves around the term "super piping" as it relates to the ASME B&PV Code Section III Subsection NB, specifically in the context of nuclear engineering and piping design. Participants explore the definition, application, and safety considerations associated with this term, as well as its relevance to piping construction standards.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that "super piping" refers to the pipe section from the steam generator to the containment isolation valve, highlighting its numerous penetrations for safety and relief valves.
  • Others mention that the term may also apply to the pipe run between the containment penetration and the main steam isolation valves, questioning the rationale behind its designation and the implications of potential pipe breaks.
  • One participant notes that the piping from the steam generator to the main steam isolation valve is typically designed for full primary pressure due to the potential for steam generator tube rupture (SGTR).
  • Another participant clarifies that the design pressure of the steam piping aligns with the secondary design of the steam generator, generally ranging from 1000 to 1200 psi.
  • There is a discussion about the thickness and reinforcement of the pipe section between the containment penetration and the main steam isolation valve, with some participants correcting earlier claims regarding safety classifications and pressure limits.

Areas of Agreement / Disagreement

Participants express differing views on the definition and implications of "super piping," with no consensus reached on its terminology or the specific safety considerations involved. Some agree on aspects of design pressure and safety classifications, while others remain uncertain about the term's usage and relevance.

Contextual Notes

There are unresolved questions regarding the specific definitions and applications of "super piping," as well as the implications of potential pipe failures in the context of safety systems. The discussion reflects varying interpretations of ASME B&PV Code standards and their application in nuclear engineering.

Muti
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The pipe portion from top of steam generator up to containment isolation valve once I heard is called super piping due to number of penetrations in the pipe for safety and relief valves. Is this term correct? Class 1 piping are constructed according to ASME B&PV code section iii, subsection NB. Can I found such terminology (and rules for construction) in subsection NB or somewhere else (if this terminology exist)?
 
I have heard the pipe run between the containment penetration and the main steam isolation valves called super pipe. My understanding was the pipe material certs and fabrication procedures and inspections were such that a pipe break need not be postulated in the section of pipe. I'm not real sure about this though. It seems to me that you could have a break downstream of the MSIV, with failure of MSIV to close as a single failure, and have the same effects as a break in the super pipe. So, what's the point of the super pipe? dynamic effects in the safety valve / MSIV room??

Maybe get more answers in the nuclear engineering section?
 
Thanks gmax so now I know at least this word is said sometimes but not a popular term. From you description it come to my mind piping from SG to MSIV is usually design for full primary pressure because of SGTR. May be due to this connection the pipe length you described might be called super pipe.
 
No, the steam piping design pressure matches the design of the SG secondary, typically 1000 to 1200 psi, depending on the plant.
 
gmax137 said:
No, the steam piping design pressure matches the design of the SG secondary, typically 1000 to 1200 psi, depending on the plant.
Thanks gmax, you are right. The pipe portion between containment penetration and MSIV is thickened and reinforced in design. Pipe portion up to MSIV is Class 2, while rest is non safety class.I was wrong in previous post because I forgot safety valves in SGTR case. Due to safety valves steam line pressure can not rise above design pressure of about 7.5 MPa.
 
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