An experimental technique was devised in conjunction with a new type of ; counting device, which permits the direct measurement of local to reactor core ; average power density. The unique feature of this system is the manner in which ; the core average power density is determined. By placing a large number of ; activated fuel plates on the circumference of a cylinder, on the axis of which ; is
... [Show full abstract] located a gamma ray detector, the integrated induced gamma ray activity of the ; group of fuel plates is measured. Since the gamma ray activity is directly ; proportional to the power developed in the set of fuel plates being counted, the ; total activity of all of the fuel plates in a reactor may be measured by counting ; all of the reactcr fuel plates in groups, and a number proportional to the core ; average power density can then be obtained by dividing the total counts for all ; of the fuel plates by the volume of fuel counted. The cylindrical platform, ; called the " Cylindrically Loaded Integrating Platform," in conjunction with a ; tab counter and an axial scanning counter comprise the complete counting system. ; This system has been used extensively to measure three dimensional power ; distributions for a variety of critical assembly cores. The results were found ; to be consistent and reproducible to within 3%. (auth)