• Oregon State University, Corvallis

• NSE 452

 1. (D&H 5-30, modified) We can define the power peaking factor for a given reactor core as a ratio between the maximum power density and the average power density in the core. Recognizing that power density is proportional to neutron flux in the one-speed approximation, compute the power peaking factor for for a 1D slab reactor. Graduate students: compute the power peaking factor for a spherical reactor in addition to the slab reactor. First, we need to mathematically describe what we are trying to solve. The problem statement asks us to find: Fp = φmax φavg (1) This is called the power peaking factor because it is a measure of the ”flatness” of the flux and thus, reactor power in the one-speed approximation. The closer to 1 this value is, the more evenly distributed power and flux is throughout the core. To solve equation 1, we need time-independent flux shape functions. Rather than try to derive these ourselves, we will reference flux shape functions for common geometries from D&H: Figure 1: Flux profile functions of common geometries (D&H pg. 209). Note that it is appropriate in this problem to ignore the extrapolation distance because it has little to no meaning in terms of computing the power peaking factor and we are not looking for a critical geometry or mass. Also note that we are calculating this power peaking factor purely in terms of geometry, and this problem does not consider materials effects on Fp like