In this paper new measures of joint importance of two and three components for repairable multistate systems based on the classical Birnbaum measure, are proposed. By considering repairable system, first joint relevancy conditions of two and three components are given. Then probabilities of each of the relevancy are measured. The proposed method is applied on a data set. An illustrative example is given. As in the Birnbaum measure, the proposed measures are generic since they depend on the probabilistic properties of the components and the system structure. These measures are useful when consider repairable system.

Aim. For the purpose of substantiating the safety of further operation of the IIN-1 pulsed solution research reactor beyond the design service life, its dependability has been evaluated for the future operation period. The paper aims to describe the criteria and show an example of IIN-1 vessel dependability evaluation.

Method. At the stage of IIN-1 design, no dependability criteria were defined, therefore, based on the NP-009-17 general norms of research nuclear reactor safety, an original dependability criterion, the vessel seal, has been chosen. A reactor vessel that, over the period of operation, is subject to cyclic thermomecanical and radiation loads at the moments of nuclear fuel fission pulse, corrosion damage at the moments of solution heating, dynamic forces of chemical microexplosion of the explosive mix during physical experiments, is a hazardous structural element of IIN-1 that is exposed to the highest loads in terms of emergency tolerance and a priority contributor to the overall nuclear and radiation safety of the research installation. The IIN-1 vessel seal and its general dependability define the efficiency of its safety barriers for the environment and personnel over the long operation of the research installation. IIN-1 vessel dependability is evaluated using experimental methods of non-destructive testing aimed at verifying the seal and state of the metal exposed to corroding media, such as metallographical observation of surveillance specimens, mechanical testing, etc. The strength and plastic properties of the vessel’s metal were tested by static tension.

Results. The ultimate stress limit, yield strength, impact resistance and percent elongation of the vessel’s material under temporal degradation of its service properties in the course of life ageing have been defined. Based on the results of specimen tests, tables have been drawn up and conclusions have been made regarding the emergency tolerance of the reactor vessel for the future operation period of IIN-1. Metallographic research in terms of the tendency to intercrystalline corrosion were conducted using the AM method according to GOST 6032-58. The key factors have been defined that affect the ageing of the vessel material of a pulsed reactor: fast neutron flux and their integral values in the reactor vessel’s most vulnerable elements and formation of explosive mix (consisting of hydrogen and oxygen) that causes immediate boiling of the fuel and, subsequently, significant cyclic stress in the vessel’s material that can cause permanent deformation. They can eventually disrupt the vessel seal and destroy the reactor. The dependability of the vessel of such nuclear reactor is evaluated through recurrent in-service inspections of the degradation of the metal’s properties, including in terms of corrosion resistance and mechanical strength by examining surveillance specimens. The paper describes the surveillance specimens and the procedure of their examination.

Conclusion. The approach suggested in the paper enables predictive assessment of the operational dependability of a solution nuclear reactor in the course of a long operation. The authors suggest key criteria for evaluating the characteristics of a vessel’s safety and dependability state that allow accurately defining the safe life of a research nuclear reactor and verifying the extendibility of its design life.

Aim. We suggest a method of using the fatigue test in case of irregular loading for studying the key subject matters related to material fatigue, specifically those to do with fatigue limit. It is important to know the fatigue limit characteristic in order to speed up tests; in order to ensure stable and reliable servicing of machines.

Methods. Comparative examinations in cases of block and random loadings enable researchers to make corresponding conclusions without excessively extending the duration of tests and without recurring to supersonic frequency tests that are to a certain degree controversial. An example of applying the proposed method is given. The second stage of fatigue, specifically the crack propagation stage, is also considered. The key idea is similar. Testing under irregular loading allows making conclusions regarding the maximum among small amplitudes that do not cause damage.

Conclusions. The proposed method allows using special testing methods to obtain information that is valuable to engineers and researchers. The tests are also closer to the field conditions of machinery operation.

A Markov model of wind farm reliability based on the example of the station on the island of Anholt, Denmark, is constructed. Reliability indexes of equipment of one turbine as a function of wind velocity are calculated. Based on hourly measurements of wind speed and electricity consumption, the durations of periods of satisfied and unsatisfied demand are estimated. It is found that the distributions of these periods can be approximated by a mixture of exponential distributions. The plant operation process is approximated by a Markov process with 5 states and continuous time. As a result, estimates of non-stationary and stationary probabilities of electricity demand being met by wind power are obtained.

Aim. The paper aims to solve the problem of objective and confident functional safety (FS) evaluation of intelligent control systems (ICS). As regards ICS, the conventional methods, due to their particular features, do not allow for a sufficiently confident estimation of the actual state of FS. The above features include primarily the nondistinct architecture of ICS and the changing connections between the system elements.

Methods. Substantiating ICS FS requires using the complete arsenal of known methods and means recommended in GOST 33432-2015 [1], including managerial measures defined by the requirements for the safety policy, program and case. The authors have analysed the capability to prove ICS FS using experimental, expert, analytical, technological, and simulation-based methods. The limitations of some methods as regards ICS FS substantiation have been established.

Results. The authors suggest a heuristic graph-based semi-Markov (Markov) method of proving system FS. For the purpose of substantiating ICS FS, it is recommended using the heuristic graph-based method combined with the technological method defined in GOST R IEC 61508 [2–4]. They don’t only allow confidently evaluating the FS of intelligent systems, but developing recommendations for achieving acceptable safety levels of such systems.

In advance of the revision of GOST 33433-2015. Functional safety. Risk management on railway transport, a basic standard that defines the approach and general rules for managing risks in railway transportation that are associated with the functional safety of infrastructure facilities and rolling stock, it is imperative that we refine the definitions in the area of assessment and handling of risks associated with the operation of railway transportation as a technical system. This paper aims to conduct a comparative analysis of the key notions and their definitions as applied to risk management that have become part of national standards and regulatory documents in the Russian Federation. The risks that arise from the effects of various uncertainties on the achievement of the specified goals serve as a qualitative and quantitative estimation of the threats that manifest themselves in the process of technical systems operation. The absence of a single definition of risk and generally accepted concept of risk management complicates the introduction of the risk-oriented principles in business management and causes conflicts and misunderstanding between different levels of management and responsibility. Using the example of an analysis of regulatory support of risk management in railway transportation, the paper discusses the requirement of mutual coordination of the existing regulatory documents and guidelines that regulate the corporate risk management process as part of a single concept for the purpose of ensuring a single understanding of the conceptual and practical aspects of the used terms and concepts. The authors touch upon the definition of the basic concept of “risk”. They also discuss the harmonisation of the approaches and terminologies used in the Russian and foreign risk management standards.

Aim. The paper aims to tests and analyse the results of application of an intelligent system for constructing metro train driver working schedules that is intended for automatically improving the efficiency of utilisation of the working time of metro train drivers. In this case, depending on the task at hand and the chosen criterion, efficiency is understood as a reduction of the number of drivers involved in the implementation of the specified standard train schedule, improved uniformity of alternation of driver work and rest periods, as well as reduction of the duration of down time within work shifts.

Methods. The study presented in the paper uses the graph theory, recursive and heuristic algorithms.

Results. The authors have developed recursive algorithms for preparing work schedules for main metro train drivers and substitute drivers that operate during main drivers’ lunch breaks. The developed algorithms are used in the intelligent system for metro train driver work schedule planning. The algorithm for generating main driver work schedule includes driver allocation to a number of work lines preliminarily defined based on the rolling stock operation schedule for the purpose of ensuring traffic according to the planned metro train schedule. The algorithm for generating substitute driver work schedule involves substitute driver work time planning based on the possibility of arranging lunch breaks for main drivers.

Conclusion. The paper presents the results of a trial of the developed intelligent system for train driver work planning for the Moscow Metro using the example of the Zamoskvoretskoye Depot of the Zamoskvoretskaya Line, the Vykhino Depot of the Tagansko-Krasnopresnenskaya Line, as well as the results of the system’s adaptation to the Moscow Central Circle. It also presents a comparative analysis of driver work schedules, i.e., the actual one and one obtained using the developed intelligent system. The application of the developed system may enable as much as a 28% improvement of the efficiency of metro train drivers’ work hour use.

Aim. An analysis of the distinctive features of the functional dependability of software that are common to critical real-time applications in respect to microprocessor protections. Dependability indicators are among the primary operational characteristics of relay protection. As such protections migrate to microprocessor technology, it became necessary to characterise their operation and dependability with software dependability along the hardware dependability. The importance of the tasks it solves in the process of operation puts it into the category of programs used in critical real-time applications. That, in turn, toughens the requirements for their dependability evaluation.

Methods. The comparative analysis allowed evaluating the unity of the examined operational dependability factors of the software as part the examined applications, while identifying certain distinctive features that are common to relay protections that use microprocessors.

Results. The paper provides an example of such estimation that shows that, given all the complexity of testing microprocessor protection programs, the contribution of software errors still is 2,5% from the overall contribution.

Conclusion. It is shown that microprocessor protection programs fall into the category of critical real-time application programs, which allows using the experience and characteristics of such software as part of relay protection. Nevertheless, the paper cites certain distinctive features that are common only to microprocessor-based relay protection. Further tasks are specified.