PART B – SAFETY AND RISK ANALYSIS The objective of this part of the course is to provide the students with competences on: (i) techniques for hazard identification; (ii) methodologies for safety (resp., risk) evaluation and analysis; (iii) methods for the control and reduction of the risks associated to the operation of energy (e.g., nuclear) and, in general, industrial systems and plants (preventive and mitigative actions). These multidisciplinary and transversal competences, typical of safety and reliability analysts and managers, are necessary in every field of modern engineering for the design and operation of safe and reliable systems. At the end of the course the students should know: ELO 1 – the (qualitative and quantitative) concepts and definitions of hazard, safety, risk, prevention and mitigation. ELO 2 – the main contents of the legislation about safety and risk of energy and industrial plants. ELO 3 – the systemic and systematic formulation of the safety and risk analysis process. ELO 4 – basic notions on the (qualitative and semi-quantitative) methods for hazard and scenario identification. ELO 5 – the quantitative approach to safety and risk analysis, and the related (analytical and stochastic simulation-based) evaluation techniques. ELO 6 – basic notions on the methodological tools to treat the uncertainty in the reliability and risk assessments and to build confidence in the corresponding results. At the end of the course the students should be able to: ELO 7 – develop and apply the (qualitative and quantitative, analytical, and stochastic simulation-based) methods for the safety and risk analysis of energy and industrial systems and plants. ELO 8 – critically evaluate the results obtained by the application of the methods learned, also in relation to the uncertainty and confidence, with which they can be used to take robust decisions about preventive, protective, mitigative and reactive measures. ELO 9 – communicate the results of their own activity in a technically sound way.

PART B – SAFETY AND RISK ANALYSIS Fundamentals of mathematics and physics. Basic concepts on process (energy) plants. Basic knowledge of MATLAB.

PART B – SAFETY AND RISK ANALYSIS 1. Introduction and description of the contents of the course: general overview of the safety and risk analysis topics offered and importance of the related transversal and multidisciplinary competences within the Master Degree in Energy and Nuclear Engineering (1.5h). 2. Concepts of hazard, safety, risk (and risk tolerability), prevention and mitigation: qualitative and quantitative definitions. (3h) 3. Introduction (basics) on the Italian and European legislation on safety and risk in the design and operation of energy plants [safety of workers, safety of components, machines and systems, safety of plants subject to major accidents (e.g., nuclear plants, refineries, chemical plants, oil&gas installations)]. (3h) 4. Quantitative Risk Assessment (QRA) framework: (11h) a) Comparison between deterministic and probabilistic approaches: respective strengths and weaknesses. b) Basic notions on the qualitative (and/or semi-quantitative) methods for the identification of hazards in the safety (resp., risk) analysis of energy (e.g., nuclear) and, in general, industrial systems and plants: (i) Failure Mode Effect and Criticality Analysis (FMECA) method (for the identification of system failure modes and the corresponding criticality and maintainability analyses); (ii) HAZard and OPerability analysis (HAZOP) method (for the identification of process anomalies). c) Details on the quantitative techniques adopted in the safety (resp., risk) analysis of energy (e.g., nuclear) and, in general, industrial systems and plants: (i) Event Trees, for the identification of the possible accidental sequences (scenarios); (ii) Fault Trees and Reliability Block Diagrams, for the quantification of the probabilities/frequencies of the accidental sequences (scenarios); (iii) Common Cause Failure analysis, for the treatment of dependent failures between components. d) Risk matrices and curves, for a qualitative and quantitative ranking of the criticality of the hazards and scenarios identified. 5. Quantitative (both analytical and stochastic, simulation-based) methodologies for the (time-dependent) reliability, availability and maintainability analyses of equipment and components employed in energy (e.g., nuclear) and, in general, industrial systems and plants: (25.5h) a) Definitions of (time-dependent) system reliability, availability and maintainability. b) Statistical methods for the estimation of reliability, availability and maintainability parameters from field data (and the related confidence): method of moments, method of the Maximum Likelihood Estimation. c) Analysis and mathematical modeling of realistic procedures like inspection, maintenance, repair. d) Importance measures for the assessment of the criticality of industrial (energy) equipment and components. e) Basic examples of Monte Carlo Simulation strategies (see also Part A of the Course) applied to the estimation of (time-dependent) system reliability, availability and maintainability indicators. 6. The problem of uncertainty and its analysis: basic notions on the methodological tools to treat uncertainty in the reliability and risk assessments of industrial (energy) systems and to build confidence in the corresponding results. (3h) 7. Basic notions and examples of application of more advanced and innovative computational techniques for the safety and risk analyses of complex, safety-critical (nuclear) systems. In particular: i) adaptive simulation methods for the dynamic Integrated Deterministic and Probabilistic Safety Assessment (IDPSA); ii) statistical techniques (e.g., supervised and unsupervised clustering) and artificial intelligence methods (e.g., Artificial Neural Networks, AutoEncoders) for the prompt (on-line) detection and diagnosis of faults; iii) soft-computing algorithms, regression techniques and Reduced Order Models (ROMs) for emulating long-running (thermal-hydraulic) codes at a reduced computational cost. (3h) 8. Case studies: lectures will be complemented by examples concerning the safety and risk analyses of realistic energy components, systems and plants exposed to hazards, as well as by quantitative exercise sessions developed by the teachers and/or by the students themselves (on paper or using laptops). (the number of hours is included in the previous bullet items)

PART B – SAFETY AND RISK ANALYSIS Lectures by the teachers will be complemented by examples concerning the safety and risk analyses of realistic energy and industrial components, systems and plants exposed to hazards, as well as by quantitative exercise sessions carried out by the teachers and/or by the students themselves (on paper or using laptops).

PART B – SAFETY AND RISK ANALYSIS MANDATORY MATERIAL - Booklets and slides provided by the teachers. OPTIONAL MATERIAL Safety and Risk analysis (general): - E. Zio, “Introduction to the basics of reliability and risk analysis”, Editore: World scientific, Anno edizione: 2007. - E. Zio, “Computational methods for reliability and risk analysis”, Editore: World scientific, Anno edizione: 2009. - P. Baraldi, F. Cadini, E. Zio, “Introduction to reliability and risk analysis: worked out problems”, Editore: World Scientific, Anno edizione: 2011. - W. Kroger, E. Zio, “Vulnerable Systems”, Editore: World Scientific, Anno edizione: 2011. - T. Aven, P. Baraldi, R. Flage and E. Zio, “Uncertainty in risk assessment”, Editore: Wiley, Anno edizione: 2014. - A.K. Jardine, H.C. Tsang, A. Tsang, “Maintenance, Replacement, and Reliability: Theory and Applications”, Editore: CRC Press, Anno edizione: 2005. - European Safety and Reliability Association, “Maintenance Modeling and Applications”, Editore: ESRA, Anno edizione: 2010. Safety and Risk analysis (“nuclear”-oriented): - M. Modarres, I. S. Kim, “Deterministic and Probabilistic Safety Analysis - Handbook of Nuclear Engineering”, Editore: Springer, Anno edizione: 2010. - IAEA-TECDOC-1200, “Applications of probabilistic safety assessment (PSA) for nuclear power plants”, Anno edizione: 2001. - ASME, “Operation and Maintenance of Nuclear Power Plants”, Editore: ASME book, Anno edizione: 2009.

Lecture slides; Lecture notes; Exercises; Exercise with solutions ; Video lectures (previous years);

Exam: Written test; Compulsory oral exam;

For Part A + B: The exam is carried out separately for the two parts of the course (A+B) and a grade >=18 is to be obtained on both parts. For Part B, the evaluation consists in a written and oral exam. The written test includes both numerical exercises and very brief theoretical questions on all the macro-topics treated (items 2-8 of the Contents section). The exercises are mainly aimed at evaluating the student’s capability of applying the qualitative and quantitative methods for the safety and risk assessment of energy equipment and plants (ELO 7). The theoretical questions will allow verifying the student’s comprehension of the concepts of safety, risk, prevention and mitigation, his/her knowledge of the main legislation related to safety, of the qualitative methods of hazard and scenario identification and characterization, of the fundamentals of the systemic and quantitative approaches to the evaluation of safety and risk of energy plants (ELO 1-6). This part will allow verifying acquired (conceptual, theoretical, and possibly “foundational”) knowledge that cannot be evaluated by numerical exercises. The theoretical questions can be of different nature: (very brief) open questions (e.g., definitions of relevant concepts), or true/false or multiple-choice. The duration of the written exam is 2h-2h15' (max). The use of any learning resource (books, handouts, etc.) is not allowed. This part of the exam will contribute 65% of the final score. The oral exam (duration around 30 minutes) will mainly assess the student’s capability of autonomously and critically formulating, in a clear and convincing way, judgments about the confidence and uncertainty in the results of a safety and risk analysis (ELO 8, 9). This part of the exam will contribute 35% of the final score. The minimum score that allows passing the exam is 18/30. Maximum score is 30/30 cum laude. The final grade of the exam is evaluated as the average of the grades obtained in the two parts of the exam, i.e. Monte Carlo Methods (part A) and Safety and Risk Analysis (part B), rounded to the upper integer.

In addition to the message sent by the online system, students with disabilities or Specific Learning Disorders (SLD) are invited to directly inform the professor in charge of the course about the special arrangements for the exam that have been agreed with the Special Needs Unit. The professor has to be informed at least one week before the beginning of the examination session in order to provide students with the most suitable arrangements for each specific type of exam.