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Abstract

The objective of this work was the development of a new model to analyse and to quantify mechanistically tellurium chemical behaviour in the primary system of a light water reactor under severe accident conditions by studying the basic principles of the phenomena which take place. The model is devoted mainly to the chemical processes because there exists a greater uncertainty n this area and the lack of specific experimental evidence suggests a theoretical apprpoach. The model includes the following original contributions: (i) a mechanistic model to quantify the chemical interaction of tellurium vapours with silver aerosols; (ii) a mechanistic model to quantify the chemical interaction of tellurium vapours with stainless steel of the pipes and structural surfaces by taking into account the initial state of the surface (presence or not of an oxide layer). To verify and to validate the model, it has been incorporated in the transport code RAFT 1.1, and the experimental data from the Marviken Aerosol Transport Test 4 have been used. The results obtained after the inclusion of the new model in the code show a clear improvement if they are compared with those obtained with the original version of the RAFT 1.1 code. It is concluded that the new model permits a mechanistic treatment of the chemical interaction of tellurium with silver aerosols and with stainless steel surfaces, and gives very satisfactory results when it is compared with experimental data.

Additional information

Authors: ALONSO A, Catedra de Tecnologia Nuclear, Madrid (ES);GONZALES C, Catedra de Tecnologia Nuclear, Madrid (ES)
Bibliographic Reference: EUR 15209 EN (1993) 94 pp., free of charge
Availability: Available from Joint Research Centre, Publication Department, I-21020 Ispra (Va.) (IT)
Record Number: 199511565 / Last updated on: 1995-12-12
Category: PUBLICATION
Original language: en
Available languages: en