Thermal Neutron Scattering Cross Section Measurements of Heavy Water

Abstract

In fission reactor design, high accuracy nuclear cross section data for moderator and coolant materials are essential to perform neutronic transport calculations. For the conceptual Gen-IV supercritical water reactor, only very few and sparse experimental nuclear cross section data for water are available in supercritical states. As the first step towards cross section measurements of light and heavy water in the supercritical states, we have established an experimental setup and tested the feasibility of measuring cross sections using a triple-axis Spectrometer at the NRU reactor, by performing measurements on heavy water (D2O) under ambient conditions. The total cross section σtot , as well as single ( d σ / d Ω ) and double differential (d2 σ / dΩdE ) scattering cross sections were measured. Incident neutron energies from 15 meV to 50 meV, and scattering angles from 10° to 110° were covered. The experimental techniques and the data analysis method to obtain the absolute cross sections will be discussed and the resulting cross sections arecompared with the Evaluated Nuclear Data File.