The Uric Database/Model

Abstract

The LIRIC (Library of Iodine Reactions in Containment) database was originally developed as a list of chemical reactions related to the behaviour of iodine in relation to nuclear reactor safety. Although LIRIC began as a compilation of reactions, it has been used as a tool for predicting the behaviour of medium scale integrated experiments and is being developed for use in reactor safety analysis. Three major changes have been necessary. First, a choice of the relevant reactions was needed so the resulting model could run efficiently. Secondly, a better way of handling mass transfer was needed. Thirdly, the capability of dealing with additives and removal of material by the opening and closing of various vents was necessary. The reactions included in the new model, called LIRIC II, are presented and discussed. The original database was run using the Chalk River Nuclear Laboratories' package HAKSIH. Because this package cannot deal with generalized mass transfer or with the "intermittent" reactions mentioned above, MAKSIH was altered, producing a package dubbed MITIMAKS. It accepts ratios of volumes and constructs proper aass transfer equations from them and the rate constants. It also takes starting times for intermittent reactions and stops them using its own conventions. MITIMAKS has been used to simulate data obtained from the Radioiodine Test Facility (RTF), and an example is presented. LIRIC II has also been adapted to run using the more flexible Harvell package FACSIMILE/CHEKMAT. Both MITIMAKS and FACSIMILE/CHEKMAT give virtually identical results for LIRIC II.