Convegni ATI - Accesso riservato soci CTI

Autore: F. Castiglia, M. Giardina

Collana: CA - 52 - Cernobbio 1997

Note:
During the last years, the requirement of assuring safe release of dangerous substances in case of accidental situations in nuclear or chemical plant, urged various researchers and research institutions to expend increasing efforts intended at a better understanding of the complex phenomenology of two-phase, multicomponent, chemically reacting fluid, thermalhydraulics. As a result various mathematical models and computer codes have been developed, aimed at the individuation and analysis of most dangerous situations, and at assisting in the project of emergency and mitigation systems, particularly the pressure relief ones. On the other hand, deep experimental activities have been also carried out, both in small as in large-scale apparatus. Among the most engaged organisations, the DIERS institution (Design Institute for Emergency Relief System) and the JRC (Joint Research Centre) of ISPRA, is worthy of being quoted. In particular the JRC developed the RELIEF computer code, which, making use of a one-dimensional model, describes the behaviour of two-phase, multicomponent, chemical reacting fluids during accidental transients and set up the DRACULA large-scale, vertical vessel, experimental apparatus. The present work, refers to the activities devoted to the validation of the RELIEF code, preliminarily, consisting in the execution of saturated water blowdown tests on the DRACULA plant and in the post-test simulations of the transient by means of the code. Still in the framework of validation activities, the RELIEF results are compared with those obtained by using the nuclear code RELAP5MOD3.1 which, as it is well known, is an advanced-thermal hydraulic qualified code, extensively used in the nuclear field.