EVALUATION OF CONTROL LOOP INTERACTION IN LIQUID-METAL COOLED NUCLEAR-REACTORS

Using nonlinear model equations of a liquid metal cooled nuclear react or, effect of magnitude and change in direction of the two manipulated variables on the steady-state gains and time constants are evaluated. The relative gain array (RGA) analysis shows that the interaction bet ween the two feedback loops, one controlling neutron power using contr ol rod position and the other controlling core coolant outlet temperat ure using pump fractional flow, are not significant. Individual loops are tuned for the selection of controller parameters to get a stable r esponse on the nonlinear system. The performance of the two loops for simultaneous step changes in the set points are evaluated.