Abstract: This report is a brief description of a general purpose logarithmic counting rate meter developed at the Knolls Atomic Power Laboratory. The theory of operation and the circuit design are discussed. The use of a diode as a logarithmic element in the integrating circuit allows extremely accurate counting rate determinations over a five decade range.

Introduction. As stated in Report KAPL 116, one of the objectives of the KAPL reactor is "to provide a prototype demonstration of the practical general of electrical power from Nuclear energy using molten sodium as the primary coolant. The reactor will generate steam at a temperature of 550 degrees F and 465 psia, including 90 degree superheat potentially capable of an efficiency of twenty-eight per cent in electrical output." The work reported here is intended to increase the scope and supply an independent check on the heat transfer system analysis that has previously been done. The purpose of these analyses is to investigate the effects on load rating and top reactor temperature.