Reliability of Nuclear Power Plants
- Josef Dušek
- Josef Dušek
- Department of Nuclear Reactors
Course is the introduction to basics of reliability theory, especially to reliability of NPP systems. It familiarize with evolution, basic procedures and practical applications of modern approach to safety assessment of nuclear facility using probabilistic safety assessment method both in Czech Republic and in the world. The stress is put on methodology of buildup and assessment of fault trees for NPP systems important to safety and on understanding of such systems. Students are further familiarized with events tree method and within the course they independently buildup these trees for selected initiatory events. Finally, some operational experience and data on failures of Czech and foreign NPPs ((Three Mile Island, Chernobyl, Paks) and basic information on international information systems IRS and INES are given.
- Syllabus of lectures:
1.Reliability analysis of complex systems and NPP probabilistic safety assessment (PSA) - basic terms, approaches to nuclear safety and reliability
2.Evolution of probability analysis in the field of nuclear energy in the world and in Czech Republic ((Rassmussen?s studies - its origin, content, contribution, deficiencies, German risks studies), preparation of PSA for NPP, PSA for Dukovany NPP and Temelin NPP, state and evolution of PSA in the world, IAEA activities in the field of PSA
3.Basic reliability indicators and their importance, terms from probability theory (conditional probability, Bayes formula, probability density, distribution function, intensity of failures, exponential and Weidbull distribution, Gauss distribution, median, fractile, failure trend parameter, probability of failure-free operation, failure intensity, preparedness), potential to increasing system reliability, importance of qualitative and quantitative reliability analysis, nature of decision-making process (e.g. depth of analysis and external effects, effect of maintenance strategy on system reliability, etc.), failure concept and success concept, relation between block diagram and failure tree reliability analyses, transition from logical diagram to failure tree.
4.Block diagram preparation, systems important to safety in NPPs with VVER reactors, practical applications of reliability analysis, failure tree method (tree of failure states), choice of top event, system reliability analyses procedure using failure tree, basic graphic symbols used in failure trees, their meaning, and means for their quantitative and qualitative assessment, rules for failure tree construction, means of failure tree description, advantages and disadvantages of failure tree
5.Analysis of human factor effect and its application to reliability analysis of nuclear power plants /MSc. K. Matejka jr./
6.Qualitative and quantitative evaluation of failure tree, Boole algebra rules and potential of their use in failure tree analyses, Shannon method, probability-table method, Gray?s code, Karnaugh table, Renk?s method, methods of searching the minimum critical sections, additive theorem and its use, principle and potential of failure tree simulation assessment, pseudo-random numbers, Monte Carlo method.
7.Possibilities of inclusion of component behaviour variability into failure tree analysis, computer codes for reliability analyses, input data for reliability analysis (incl. Input data for computer code), NPPs? information systems, used types of probabilistic distributions, recovery principle and means of it assessment , effect of periodical checks, maintenance, and tests on reliability and possibilities of their inclusion to reliability analysis, failures on requisition, common cause failures (CCF), uncertainty and sensitivity analysis
8.Event tree methodology, event tree method application on units with VVER reactors
9.Selective systems, their use, meaning, and way of assessment, practical exercise with reliability assessment on specific examples, international information systems IRS and INES.
10.Approach of SONS to PSA and use of PSA within work of state surveillance, Risk monitor with practical example /MSc. K. Matejka jr./
11.Operational experience and data on failures of Czech and foreign NPPs (Three Mile Island, Chernobyl), feedback, PSA practical application (risk oriented operational limits and conditions, emergency preparedness), tuition to lectures
12.Tuition to lectures
- Syllabus of tutorials:
Practical training in assessment the specific model examples from the field of reliability.
- Study Objective:
Knowledge: basics of reliability theory, and, especially, of system reliability of NPPs, probabilistic safety assessment methods
Abilities: buildup and assessment of failure tree for NPPs systems important to safety and recognition of these systems
- Study materials:
1.Probabilistic Safety Assessment, workshop proceedings, NRI Řež 1987 (in Czech)
2.Procedures for Conducting PSA of NPP (level 1), Safety Series No.50-P-4, IAEA, Vienna, 1992
3.Fullwood R.R., Hall R.E. : Probabilistic Risk Assessment in the Nuclear Power Industry - Fundamentals and Applications, Pergamon Press, 1988
- Further information:
- No time-table has been prepared for this course
- The course is a part of the following study plans:
- Jadarné inženýrství (elective course)