Graphite and INOR materials are swapped in sample basket

[paulromano]

I've been comparing the MSRE CAD model with the reference CSG model from IRPhEP handbook. One difference I noticed recently is that the graphite and INOR materials in the sample basket appear to be reversed. Here is a plot of the sample basket from OpenMC (orange is graphite, green is salt, purple is INOR):

An MSRE report says the following:

Each basket contains four 0.250-in. -dim x 5-1/2-ft long samples of INOR-8 and five graphite sample bars, 0.250 in. x 0.470 in., as shown in Figure 5.8.

Based on this description, the cylinders should be INOR and the bars should be graphite. Here's the corresponding figure from the report:

[paulromano]

I should also add that this does appear to have a pretty big impact on k-effective. If I take the CSG model (which has the correct assignment of graphite and INOR) and swap those materials within the 4 cylinders / 5 sample bars, the k-effective drops more than 1000 pcm. That implies that fixing this in the CAD model will raise k-effective by that amount.

[church89]

hey @paulromano thanks for reporting this, that seems to be an error in assigning materials during the step export. I'll fix it right away and point you to the correct files.

[aslakstubsgaard]

hey paul, your right, this is an error in the part naming.
i can see in the cad (onshape) that it's correctly named where the parts are drawn but were later rename incorrectly.

also note that they changed the sample basket many times throughout the reactor operation, and we just expect that this design was the one that was used for the criticality experiments in the beginning, but if you're doing burnup calculation for the msre then it's a approximation to assume that this model of sample holder stayed in there.
see section 5 in the msre core cad model documentation, that for some reason isn't loading properly right now:
https://github.com/openmsr/msre/blob/master/core/docs/msrecore.pdf