Hello, I am running an OpenMC eigenvalue simulation on 128 openMP threads coupled with a point burnup calculation code considering online reprocessing for a single assembly from a Molten Salt Reactor. In each burnup step, the online feed rates of fissial and fertile nuclides would be adjusted until the nuclide densities satisfy the criticality at the end of this burnup step.
So in one burnup step, the nuclide densities from the previous step and guessed online feedrates for fissial are input into a point burnup calculation code MODEC(DOI: 10.1016/j.anucene.2018.09.032, which can be called in Python). Once the nuclide number densities of burnup results are got, they would be input into OpenMC to get the keff. If keff is not within pre-set margin (like 0.990 to 1.010), the feed rates will be adjusted and the above process will be repeated.
In order to acquire the one-group cross sections for burnup calculation, I have used the NJOY to make incident neutron cross sections for 781 nuclides. When running OpenMC, if one of these 781 nuclides is not loaded, I make it 1.0e-30 to tally the one-group cross section. Hence, there are 781 nuclides in every OpenMC calculation.
Now I have a question that with my code running, the OpenMC simulation time becomes longer. In the first step, it takes 2 minutes to run an OpenMC eigenvalue simulation. In the second step, it takes about 10 minutes to run an OpenMC eigenvalue simulation, and 6-time simulations are needed to guess the suitable online feed rates, so in total I spent about 60 minutes operating the second burnup step.
I have attached my burnup file in the forum, of which the number represents the burnup step. Also, I get the screenshot of my CPU use when I run a single assembly sample in burnup step 13. Is there any way to solve this problem? Such as releasing the runtime memory and so on.
Thank you so much!
Here is 0 step file:
geometry_0.xml (1.0 KB)
materials_0.xml (31.0 KB)
model_0.xml (39.1 KB)
settings_0.xml (252 Bytes)
tallies_0.xml (5.3 KB)
Here is 1 step file:
model_1.xml (78.0 KB)
settings_1.xml (252 Bytes)
tallies_1.xml (39.3 KB)
geometry_1.xml (1.1 KB)
materials_1.xml (35.7 KB)
input_burnup_1.xml (38.4 KB)
output_burnup_1.xml (142.1 KB)
Here is 2 step file:
tallies_2.xml (73.4 KB)
geometry_2.xml (1.1 KB)
materials_2.xml (35.7 KB)
model_2.xml (112.3 KB)
settings_2.xml (252 Bytes)
input_burnup_2.xml (43.1 KB)
output_burnup_2.xml (142.1 KB)
Here is 3 step file:
materials_3.xml (35.7 KB)
model_3.xml (131.9 KB)
output_burnup_3.xml (142.1 KB)
settings_3.xml (252 Bytes)
tallies_3.xml (92.9 KB)
input_burnup_3.xml (43.1 KB)
geometry_3.xml (1.1 KB)
Here is CPU screenshot:
