A preliminary kinetic study of a sodium-beryllium-uranium circulating fuel reactor

Abstract

The initial response of a 1:100:2000 U-Na-Be Reactor, operating at a power density of 1200 cals/cc/sec, to a sudden change in the fuel concentration in the circulating carrier, has been calculated on the assumption of constant inlet temperature and no delayed neutrons. The result confirmed that the peak temperatures and power can be accurately calculated by ignoring the moderator temperature rise, and that the approach to the new steady state values is given by the solution of the linearized equations. The slow moderator heating implies that the departure from the steady state are still large when the carrier and fuel have completed one transit of the external circuit. The assumption that the mean temperature is the arithmetic peak but overestimates the maximum power and outlet temperature excursions by 15 1/2% and 7% respectively.