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The Fluid Heat Transport Systems (FHTS) extension to the ESATAN thermal analyser was released to industry in 1989. A significant as effort has been directed towards obtaining, far as possible, an error free code which gives results in reasonable agreement with reference data. The first steps to ensure confidence in FHTS have been taken by system testing during software acceptance and by means of a comparison with RETRAN, a US code unique in possessing a US safety evaluation report for reactor licensing applications. RETRAN output data was taken as the a priori reference data to verify FHTS. Two sets of test cases have been defined, one concerning single-phase problems (basically the Columbus water loop), the second set containing models with two-phase conditions (a simple idealised loop and boundary conditions). The paper highlights the difficulties encountered during the comparison work, presents the major results and discusses the main issues involved in FHTS verification/validation.

ECOSIM is a software tool for the simulation of Environmental Control and Life Support (ECLS) systems which has been developed for the European Space Agency. A preliminary model of the Hermes Air Management System has been developed during the ECOSIM testing in order to assess the functionality of the software and to verify its results with those obtained from previous simulation tools. The model represents the Hermes cabin with its crew and it includes submodels for the sub-systems performing the following functions: Temperature and Humidity Control. Total Pressure and Composition Control. Air revitalisation. The interactions between these different subsystem are taken into account by the model, while many of the previous simulations made assumptions to decouple the different subsystems (e.g: a constant cabin temperature has been assumed during cabin depressurization transients, to decouple the pressure control section from the air conditioning section).