STUDY OF THE REQUIREMENTS OF INTERNATIONAL STANDARDS IEC60880 AND IEC62138 FOR THE DEVELOPMENT OF SOFTWARE FOR INFORMATION AND CONTROL SYSTEMS OF NPPS IMPORTANT FOR SAFETY

Abstract

Today, a significant part of electrical energy is produced by nuclear power plants. Atomic energy is a cheap, economically beneficial and ecological way of meeting people's needs with electricity. At the same time, this production is connected with the need to ensure the protection of people and the environment from ionizing radiation of nuclear fuel during normal operation of the plant and in case of emergency situations. Nuclear power plants (NPP) contain a large amount of equipment to ensure technological processes and perform safety functions. The purpose of the work is to study the requirements for the formation of the life cycle, the main stages of design and documentation of the software of the computer control systems of nuclear power plants (software CCS NPP), which perform safety functions of categories "A", "B" and "C". Requirements for software performing category A functions are given in the international standard IEC 60880 "Nuclear power plants – Instrumentation and control systems important to safety – Software aspects for computer-based systems performing category A functions", software requirements , performing category "B" and "C" safety functions, specified in the international standard IEC 62138 "Nuclear power plants – Instrumentation and control important for safety – Software aspects for computer-based systems performing category B or C functions". The object of research is the process of developing software for computer control systems of nuclear power plants. The subject is a study of the requirements of international standards IEC 60880 and IEC 62138 for the development of software for information and control systems of NPPs, important for safety. As a result of the study, the general structure of the requirements of the IEC 60880 and IEC 62138 standards was considered, the groups of participants who participate in the development of the software of the NPP CCS and the distribution of software development activities among these groups were determined, the analysis of the requirements of the general requirements and the requirements for the stage was carried out development of the software specification, requirements for the stage of design and implementation of software, requirements for the stage of verification, integration and validation and requirements for the stage of installation, operation and modification, a table of distribution of requirements for software was formed, means of implementation of requirements were studied, the problem of assessment of compliance with the standard was determined. Conclusions. The international standards IEC 60880 and IEC 62138 contain important requirements for all stages of the development of the safety-critical NPP control system software. The requirements concern both organizational issues and technical aspects. According to these standards, each enterprise engaged in the development of NPP CCS software must define working groups that will implement various stages of the NPP (design, implementation, verification, etc.). The standards do not contain requirements for software user interfaces. Therefore, one of the directions of further research will be the requirements of other international standards – IEC 61772 "Nuclear power plants – Control rooms – Application of visual display units (VDUs)" ("Visual display units") and IEC 62646 "Nuclear power plants – Control rooms – Computer -based procedures" ("Computerized procedures"), as well as the requirements of industry regulatory documents, such as NUREG-0700 "Human-System Interface Design Review Guidelines" – "Construction of human-machine interfaces" (U.S. Nuclear Regulatory Commission, USA ). The standards do not define generally accepted metrics that indicate the degree of compliance of the software with these standards. Based on this, each organization that performs an assessment of the compliance of software and CSU as a whole with the requirements of the standards must create its own methodology for such an assessment. Therefore, the goal of the following research is to study the means of evaluating requirements specifications, software code metrics, completeness criteria of software testing, which can be used for the development of formal software evaluation methods for the requirements of standards.