Hi everyone:
I have a question. If I have a Lead-Bismuth reactor at full power with 30 fuel assemblies. Now, I want to simulate the reactor with 3 fuel assemblies in OpenMC 0.10. Can OpenMC accurately simulate it? OpenMC: A state-of-the-art Monte Carlo code for research and development) said that “subcritical multiplication problems are not yet supported” in fixed source. The k-eigenvalue should is lower than 1 for non-full power. So, can OpenMC accurately simulate it?
That is why I ask the question.
Yes, OpenMC can handle such a problem. You can either run a k-eigenvalue calculation with the three fuel assemblies (in which case you’ll get a keff less than 1), or you can run a fixed source problem with subcritical multiplication which is now supported. If you run a fixed source problem, just be careful if keff is less than but close to 1 as the multiplication factor (M=1/(1-k)) can get quite large, resulting in long run times.