Set the convergence criteria for CMFD in the FIXED case in EigenSolver
Set the convergence criteria for CMFD in the FIXED case in EigenSolver

This makes sure that the CMFD accellerator is at least converging to something
well below the overall convergence criteria. This prevents stagnation

youngmit/mocc,youngmit/mocc,youngmit/mocc,youngmit/mocc