Solving of transient fixed source problem

[Tristan Song]

Hello! Everyone. I has some questions about OpenMOC.
I'm currently trying to solve a transient fixed source problem with a slight modification of OpenMOC, after updating the cross section and transient source at each time step I call solver.computeEigenvalue() to solve new equations. But I encountered a problem, that is, the calculated flux at each step is normalized, which allows me to get the change of the neutron flux distribution  (shape function)  at each step, but not the change of the total power (amplitude function) with time. And after directly canceling the normalization of the flux, the iteration cannot converge.

Although it seems that this problem can be solved in quasi-static methods, I still wonder if there is a direct solution to this problem. I am a beginner in both OpenMOC and transient computing. I would really appreciate if someone can answer my question!

Best Regards
Song

[Guillaume Giudicelli]

Hello

IIRC, the shape function should be normalized in a quasi static method, and the amplitude function should be obtained from the PKE.

If you are trying to build a direct time solver rather than one based on a time-space shape decomposition, you'll want to look at the computeFlux in the Solver class

Guillaume

[Tristan Song]

Merci beaucoup! I am going to try to use computeFlux to solve it directly. Then try the quasi-static method.