AXIAL FLUX PROFILE IN THE ADVANCED TEST REACTOR

This work demonstrates an approach to determine probability of perturbation the axial profile thermal neutron flux in Advanced Test Reactor. The is expected follow a theoretical cosine shape, due minimal use vertically-withdrawn shims. Reactivity normally controlled by rotation Outer Shim Control Cylinders, uniformly affecting at all locations. Reactor routinely accepts for irradiation experiments variety designs. Among analyses required safety basis approved United States Department Energy characterization new experiment’s potential perturbing flux, which could exacerbate power peaking driver fuel. However, this can be more or less severe different locations within Therefore, best requires knowledge baseline flux. Such information obtained measuring decay activated uranium wires irradiated known positions cooling channels plate-type fuel elements. Due variability measured it not usually clear whether given anomalous measurement caused actual perturbation. Assuming normality random errors, quantified.