I wondered how stable our LFTR design might be and I quickly exceeded my knowledge. We have some thermal-reactivity coefficients. ondrejch wrote:Feedback -9.53 pcm/K. That means dk/dT is -95.3*10-6/K to me. That is the ratio of neutrons from one generation to another.

If we knew the time from one generation to the next, the equivalent neutron lifetime, then we could calculate the rate of power change if our LFTR were one degree K above equilibrium;

power change per second= k^(1/apparent neutron lifetime)

Does anyone have a good number for the apparent neutron lifetime when used for control calculations? I know the real calculation has to include multiple neutron energy groups and delayed neutrons. The "apparent neutron lifetime" is only an affine approximation. I'm assuming the design is thermal and carbon moderated with the fuel/moderator ratio selected to maximize k.

Thanks in advance,

Rob

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It is good to be splitting atoms again on the weekend.