Lattice Code Error

User Support
1

Hello everyone,

I am modelling a CANDU reactor using Openmc, and I was able to get one working with a k-eff of 1.15, but it was a very rudimentary one without reactivity devices. I have tried to make some channels with control rods in it, which have been completed below,

As you can see, I was able to plot the individual universes and see everything, but when I implement it into my matrix,

It removes the fuel sections of the new adjuster rod universe, but the rest of the reactor is fine. I have also switched my normal fuel channels with the ones with the adjuster and they suddenly had their fuel sections again. Is there a limit to the number of different universes that can be used within a matrix? If anyone could help me, this seems very fickle and random to me, making me think something is glitching.

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Single Image as I am a new account.

2

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Here is an image of my reactor without the control rods, this was made using only two different universes for the matrix, one with a fuel channel, one completely moderator.

3

So I figured it out myself after learning more about the code. I was unaware that you could not reuse cells in multiple universes, therefore, I had to use the command,

cell1_copy = cell.clone(clone_materials=False, clone_regions=False)

for each of the cells that were being used by multiple universes. I’m kind of shocked that Openmc cannot reuse cells, but now that I know it’s not the biggest issue.