Problem about using Moltres to solve an EigenValue benchmark #201
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Hi, everyone. I'm using Moltres to do a IAEA2D benchmark. My understanding of this benchmark is to solve a two-group steady-state neutron diffusion equation for four materials and the group constants for the materials are given. First, given a hypothetical eigenvalue, the neutron flux is obtained by solving the diffusion equations. Then use the neutron flux calculated in the previous step to correct the new eigenvalues. This iteration goes on to get a final eigenvalue. With @smpark7 's advice, I wrote a new input file today referring to the input file: moltres/problems/2021-cnrs-benchmark/phase-0/nts.i. The distribution of materials and corresponding group instants are here. The other group constants are all set zero, including reciprocal of speed of neutrons(INVV), delayed fission spectrum But the result is incorrect and strange, the hypothetical eigenvalue is 1.5, but the final eigenvalue is 276.7433. Do I set any wrong parameters in the input file? Besides that input file, I found an input file: moltres/problems/022317_test_critical_neutronics_only_reactor/k-eigen-problem.i. And I plan to write a new input file by referencing this input file. Do you think this approach is feasible? |
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Replies: 1 comment 9 replies
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Hey Xu. Your zip link is broken but I think you're on the right track with your current input file. Some of the issues I can think of are:
You can choose not to provide any normalization parameters. The |
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Hey Xu. Your zip link is broken but I think you're on the right track with your current input file. Some of the issues I can think of are:
ElmIntegTotFissPostprocessor
requiresFISS
to calculate the total number of fissions, whileElmIntegTotHeatPostprocessor
requiresKAPPA
to calculate the total power output. If you're using either of these postprocessors for the normalization factor in theExecutioner
section, you have to…