I am simulating a reactor, and I have a warning about a particle missing after passing a lattice boundary, but it’s not the normal issue where it cancels the run because the geometry is incorrectly designed and too many particles are lost. It only happens once, and it’s always the same batch and particle when I run the simulation. I don’t see how I have this issue in the first place, and I am further interested that even though I am running the same simulation, with batch = 200, particles = 2000, and I ignore the first 30 batches, I get the exact same k-eff at each batch. I would have expected for a Monte-Carlo method to have variance between each of the same batches, even when the exact same simulation is ran, especially at a particle amount so low per batch. Attached are two different runs of the same simulation. I don’t believe this is a particularly important issue, but I must be misunderstanding how OpenMc calculates k-eff, is it using a deterministic method, but that wouldn’t make sense as its tracking the particles to calculate the k-eff. My other guess is its a problem with my software not actually running a new simulation, but I don’t that is it as it goes through the steps like it is, and I have no issue with other simulations.
