The thesis presents the problem of the aging of electrical cables in nuclear power plants. Electrical cables are one of the most important components of any nuclear power plant. The main goal is to present their role in the operating process of nuclear power plants. It describes the mechanisms of aging and ways of evaluating the ability of cables to aging, despite successfully preserve their functionality.
The functionality of cables, their use and the related of ageing are explained in the introduction. There is also the description of the aging mechanisms depending on the specific conditions in nuclear power plants.
The second chapter presents an introduction to the problems described through systems important for safety, the security features of structures, systems and components and their detailed descriptions followed by the criteria for safe operation of nuclear power plants. The environmental and seismic qualification standards are described at the end of the chapter.
Electrical cables, their purpose and use in nuclear power plants are described in third chapter. The composition of the cables is shown in two cases. The section on insulating materials which are used for cables in nuclear power plants is at the end of the chapter. This section serves as an introduction to the content of the fourth chapter where a more detailed analysis of the effects of aging on the used electrical cables is presented.
The fourth chapter is the central part of the thesis. The focus is on the mechanisms of aging. It includes types of radiation, their sources and consequences on cables. The effects of temperature and mechanical stressors from the environment are also included. Operation management of aging cables and descriptions of accelerated aging under the influence of elevated temperatures and radiation as well as descriptions of measuring the temperature and the intensity of radiation in nuclear power plants is at the end of chapter.
The fifth chapter focuses on the method of elongation at break. This is one of the most common methods for cables aging management. It is described by the way of its implementation, and a brief description of the code in Matlab. The code is the author's own work and serves as an aid in data analyzing.
The last two chapters present the results of the analysis and the conclusions. It turns out that the method elongation at break can be very effective with enough data available.