[frithguild]

I have seen the MSRE depictions many times. The MSRE operated at a 650c deg peak for 1.5 years. Just because they used that much concrete in an experiment does not mean that you need that much shielding material. So please.

Ok 8 grams is ridiculous - I'll bite. Why is the mass of the fuel a factor for criticality? I thought the primary factor in achieving criticality was the proximity of the fuel materials, not the volume.

[TexasGator]

“Just because they used that much concrete in an experiment does not mean that you need that much shielding material. So please.”

Please see the below link. It shows the shielding studies for the MSRE.

“Ok 8 grams is ridiculous - I’ll bite. Why is the mass of the fuel a factor for criticality? I thought the primary factor in achieving criticality was the proximity of the fuel materials, not the volume.”

Please see the below link. It contains the criticality studies for the MSRE.

http://web.ornl.gov/info/reports/1964/3445606043171.pdf

I will be happy to entertain questions after you have had time to absorb the material.