Molecular Dynamics of Supercritical Water for Nuclear Data Development

The Canadian supercritical water-cooled reactor (SCWR) was selected as one of the Generation-IV International Forum initiatives for reactor design. It uses supercritical light water as a coolant under operating conditions of 250 bar and 623-898 K. However, the simulation codes used to assess the performance and safety of such a design depend upon the accuracy of available nuclear data parametrizations, which currently do not include models of light water in the supercritical regime. In this paper, we present a study of supercritical water (SCW) through molecular dynamics simulations. Flexible variants of the TIP4P/2005 and SPC models for H2O are assessed to determine their ability to reproduce experimental measurements of SCW properties, and their suitability for the future development of nuclear data parametrizations for thermal neutron scattering from SCW. Planned experiments measuring thermal neutron scattering from SCW to inform nuclear data development are also summarized.