I have been running OpenMC in eigenvalue mode and have now begun running in fixed source mode. I want to extract the subcritical ks value to display the convergence between keff and ks in the approach to criticality between the eigenvalue and fixed source modes. How do I extract the ks value from the run, I don’t see anything in the statepoint file and the only output is the Calculation Rate (active) which I’m going to assume is the multiplication factor. Any help would be appreciated.
In the 2010 paper ‘Subcritical multiplication factor and source efficiency in accelerator-driven system’
ks is identified to be F/(F+S) with F the (total) number of fission neutrons and S the number of source neutrons. (Imo it would be easier to think of both per unit of time).
The whole concept of ks seems a bit far fetched to me but then again, I witness going from deep subritical source range power to critical at full power (1e6 times the sourcestrength) every week at our research reactor.