Core heatup and fission product release from an HTGR core in an LOFC accident. [AYERM code]

Abstract

The AYERM code is a conputer program which has been developed for the high-temperature gas-cooled reactor (HTGR) safety research program. It is a conjunction of the heat conduction code, AYER, and a set of special subroutines. This modified AYER code can predict the timedependent release of volatile fission products from a reactor core during a hypothetical loss-of-forced-circulation (LOFC) accident. The computation scheme is based on the finite element method. The function of the AYER code is to compute the temperature distribution and the temperature history of a reactor during an LOFC accident. The subroutines perform two functions. One group of the subroutines provides the essential input data, such as the properties, configuration, initial and boundary conditions, etc., of the reactor core. The other group combines the computed instant local temperature with the fuel model parameters (i.e., the decay and release constants, and the irradiation history of the fuel) to perform the fission product release calculations. I.