Methods for the developmente of the safety analysis of nuclear power plants’. The course consists of lectures and numerical evaluations.

At the end of the course, the students will have a deep knowledge of the characteristics and safety requirements of nuclear power plants, of phenomena occurring in both Design Basis Accidents and Severe Accidents; moreover, the students will have the knowledge necessary to the design of safety features and to the development of Probabilistic Risk Assessment.

Basis concepts of reactor physics, nuclear plants, single-phase and two-phase fluid dynamics and heat transfer.

1. Design criteria for protection system, engineered safety features and auxiliary systems. Critical accident sequences and safety classes. 2. Phenomena and simplified models of typical accidents in Light Water Reactors. 2.1 Loss of Flow Accidents (LOFA): pump coast-down and heat removal by natural circulation. 2.2 Loss of Heat Sink: loss of feedwater, steam line break; 2.3 Reactivity Insertion Accidents (RIA) 3. Loss of Coolant Accidents (LOCA): subcooled blowdown, water hammer, saturated blowdown, dryout, flooding and refilling. 4. Probabilistic Risk Assessment (PRA): 4.1 Aims and results of the three levels of PRA. 4.2 PRA level 1: Master Logic Diagram for the determination of initiating events, event tree and fault trees for the evaluation of the occurrence probability of accidental sequences. 4.3 PRA Level 2: in-vessel and ex-vessel phenomena in severe accidents, loads on containment system and modes of failure, release of radioactive fission products from fuel, coolant system and containment system. 4.4 PRA level 3. Results of WASH 1400.

The theory is complemented by numerical evaluations of the time behaviour of the most important thermal-hydraulic parameters during LOFA, LOHS and LOCA accidents, ; during the PC Lab session the student will both implement analytical models and use system codes typically developed for nuclear fission plants.

- N.E.Todreas and M.S.Kazimi,"Nuclear systems",Vol.I ,II,Hemisphere,1990. - R.T.Lahey and F.J.Moody,"The thermal-hydraulics of a boiling water reactor",American Nuclear Society, New York, 1993. - L.S.Tong and J.Weisman,"Thermal analysis of pressurized water reactors",American Nuclear Society, La Grange Park,1996. - E.E. Lewis, Nuclear power reactor safety, Wiley, New York, 1977. - N.J. McCormick, Reliability and risk analysis, Academic Press, London, 1981..

Modalità di esame: Prova orale obbligatoria; Elaborato scritto individuale;

Exam: Compulsory oral exam; Individual essay;

... The exam at the end of the course is oral: it regards all the theoretical topics and includes a discussion of the results obtained in the computing laboratory sessions. To be admitted to the exam, the reports of the numerical evaluations must be provided to the teacher at least 5 working days before the exam date. Contributions to the final grade: oral 80%, projects reports 20%.

Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.