Hi guys,

I am modeling a Nuclear Class 1 pipe.
It is the first time I see reducers with nozzles on it.

Did anyone of you encounter this problem?
How could I model this on Caesar?
How do we calculate the SIF in this case?

attached a two examples of a reducer with nozzles.

Daer Dali

Piping code do not cover this kind of branch connection.
You need to perform finite element analysis to get to SIF value & integrity of this part.
I understand from sketch it is just a drain connection on reducer.
In absence of proper SIF stress % at this location should be kept low.
After hydrotest integrity of total piping system can be confirmed.

Regards

Habib

Dear Habib,

Thank you very much for your response.

Is it possible to use the SIF obtained by finite element methods, in the code fomula to calculate the stress?

SIFs in code are in general only one-half of the theoretical factors (allowable stress has been adjusted accordingly).

Let me ask you please if you have an idea about another problem I have encountered: a branch on an elbow.
How can i calculate the SIF in the branch:
SIF = MAX { SIF(BRANCH) ; SIF(ELBOW)}
or
SIF = SIF(BRANCH) x SIF(ELBOW)

Here another scratch of the branch elbow problem.

Thank you
Dali

Dali,

To get the SIF by FEA, below link would be helpful.

http://65.57.255.42/ubbthreads/ubbthreads.php?ubb=showflat&Number=5545&page=1&fpart=1

As I know, Class 1 nuclear pipe use theoratical SIF rather than Code SIF using 1/2 factor caused by unpolished weld, etc. Isn't it?

I haven't seen those, but recent webinars by Tony Paulin, Paulin Research Group could be helpful to you.

Hope you can solve the problem,

Dear Dali

Elbow in the attached sketch not only increase SIF value but same time reduced flexibility factor. Either you get the value from external finite analysis software or take more conservative figure with client approval.

Regards

ahbib

Thank you very much guys!