The Department is involved in the design and the safety analysis of advanced reactors, through the development and the application of models for predicting the thermal-hydraulic behaviour of light water nuclear reactors during accident conditions. Both experimental and theoretical activities have been performed in this frame. Among the relevant past experimental activities, the construction and operation of the PIPER-ONE experimental facility, a 1/2200 downscaled thermal-hydraulic simulator of BWR, can be mentioned, which has been mainly used for performing tests simulating Small LOCAs and thermal-hydraulic instabilities. More recently, the passive cooling of innovative reactor containments by falling water film evaporation has been studied (EFFE facility). Both the aspects related to heat and mass transfer and to the film fluid-dynamics have been addressed, under sponsorship by the European Community and the Italian Ministry of University and Research.
In addition, the Department, on behalf of ENEL, performed the analysis of experimental tests conducted on the LSTCF facility installed at Westinghouse to analyse passive containment systems, setting up a scaling methodology for interpreting experimental results.
The traditional activity of development and application of codes for simulating the thermal-hydraulic behaviour of nuclear reactors lead the Department to take part in independent analyses of AP600, SBWR, EPP and EPR reactors, in cooperation with ENEL and ANSALDO, by the use of RELAP, FUMO and ECART codes.
Another relevant application in this field is the use of the Nuclear Plant Analyzer (NPA), both for displaying calculation results obtained by different codes (ECART, RELAP, MELCOR, SCDAP/RELAP) and in the analysis of the different phases of tests performed in experimental facilities (LSTCF, SPES-2).
Presently, the Department is participating in the design of the IRIS reactor, under coordination by Westinghouse and the sponsorship by the US DOE, in cooperation with BNFL (UK), CEA (F), MIT and Univ. California Berkeley (USA), JAPC, Mitsubishi and Tokyo Institute of Technology (Giappone), Nuclep (Brasile) and Politecnico di Milano. Studies in relation to Accelerator Driven reactor Systems (ADS) are also developed in cooperation with Ansaldo and ENEA. The studies on condensation in conditions relevant for nuclear reactors, provided the Department with a specific know-how in the field, resulting in its involvement in international projects (e.g., EU INCON Project). An experimental facility for studying condensation in the presence of noncondensable gases (CONAN) is presently being designed to provide further knowledge on this subject.
Computational fluid-dynamic (CFD) studies are underway, also in cooperation with European research groups, as the University of Manchester, through a specific agreement, and the French Commissariat à l’Energie Atomique (CEA). In the frame of an informal cooperation with the Autoridad Regulatoria Nuclear of Argentina (ARN), a numerical methodology has been developed for the analysis of instabilities in single-phase thermosyphon loops and in boiling channels. The methodology allowed studying in a systematic way the effect of finite difference discretisation of governing PDEs on stability predictions obtained by system codes.

Contact persons
Prof. F. Oriolo E-mail This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Prof. W. Ambrosini E-mail This e-mail address is being protected from spambots. You need JavaScript enabled to view it