I have a problem with the depletion calculation. I have generated the chain file with openmc-make-depletion-chain, below is the code of depletion section I am using. I am simulation a whole reactor core. with over 16000 fuel rods.
import openmc
import openmc.deplete
import numpy as np
import matplotlib.pyplot as plt
batches = 60
inactive = 10
particles = 1000
Sharif,
It is difficult to determine the exact cause, but I believe a likely candidate is the volumes and/or power normalization. When you are computing the volume of your fuel “st_fuel”, you take the area of a bundle and multiply it by 200, assuming that is the number of assemblies in your core. The issue could be that the area computed with “area[Bundle_A_fuel] = np.pi * fuel_A_fuel.coefficients[‘r’] ** 2” is only the area of a single fuel rod, not of all the fuel rods in a single assembly (usually ~250 rods / PWR assembly). This causes your core to be depleted about much faster than anticipated.
This also leads to the negative densities you are seeing, since the solution method used by OpenMC (CRAM) does not ensure positivity of compositions. The negative values could be consistent with your over depletion as well.
I would recommend ensuring the volume of your burnable materials, “st_fuel” are indeed correct. Regards,
Drew