NAIADQ, a computer program for calculating reactivity transients in low power experimental water reactors.

Abstract

The computer code NAIADQ is designed to simulate the course and consequences of non-destructive reactivity accidents in low power experimental water-cooled reactor cores fuelled with metal plate elements. It is a coupled neutron kinetics-hydrodynamics-heat transfer code which uses point kinetics and one-dimensional thermohydraulic equations. Nucleate boiling which occurs at the fuel surface during transients is modelled by the growth of a superheated layer of water in which vapour is generated at a non-equilibrium rate. It is assumed that this vapour is formed at its saturation temperature and that it mixes homogeneously with the water in this layer. The code is written in FORTRAN IV and has been programmed to run as a catalogued procedure on an IBM operating system such as MVT or MVS with facility for the inclusion of user routines.