# Flattop k-eff sensitivity example

From Serpent Wiki

This example demonstrates some basic sensitivity calculation capabilities for the Popsy (Flattop) critical experiment (PU-MET-FAST-006 in the ICSBEP handbook).

## Description

The experimental configuration consists of a plutonium alloy sphere (radius 4.5332 cm) reflected by a natural uranium blanket (outer radius 24.1420 cm). The multiplication factor of the system is close to unity (being a critical experiment). This input calculates the sensitivity of the multiplication factor to perturbations applied to the cross sections of ^{235}U, ^{238}U, ^{239}Pu and ^{240}Pu. A processing script for MATLAB/OCTAVE is provided for printing and plotting out the sensitivities.