A probability approach to estimating the safety of a reactor installation

Autor: V. S. Emel'yanov, V. I. Morozkin, O. G. Kamyshnikov, V. S. Golubev
Rok vydání: 1993
Předmět:
Zdroj: Atomic Energy. 74:36-39
ISSN: 1573-8205
1063-4258
DOI: 10.1007/bf00750972
Popis: The necessary condition for establishing that the functioning of a reactor installation is safe is an investigation of the quantitative characteristics of the safety in order to confirm that the standard technical and guiding documentation requirements are being met [1, 2]. The problem is usually solved by a probability analysis of the safety [3]. Here, in addition to problems of choosing and proving the probability models, based on a consideration of a tree of breakdowns and a tree of events, correct and objective usage is of considerable importance, and, when necessary, the acquisition of initial data on the functioning reliability of individual parts of the reactor installation and effect of the human factor on safety, and also on the effectiveness of the organizational and technical means of monitoring the state of the elements of the reactor equipment as a whole. The correct acquisition and use of information enables the possibility of an emergency (or accident-free operation) in a reactor installation to be reliably estimated. As regards the procedure for a probability analysis of safe operation, the method of estimating the reliability characteristics of individual parts and of the installation as a whole, which are discussed in detail in the technical documentation [1, 2, 4, 5], and in other publications [4, 6-10], we will consider the factors which, in our opinion, must be taken into account in any probability analysis of failue-free operation when designing, setting up and using a reactor installation. An analysis of the publications [1-4, 6, 7, 10-12] enables us to present and quantitatively estimate the probability of an emergency occurring using a model which includes the following components (Fig. 1): failure of the reactor-equipment components, personnel error, failure for a common reason, and failure of the safety system, i.e., the probability of an emergency (or an accident) occurring can be estimated from the probability of the failure of the components, the reactorinstallation systems, operator error, failure of the emergency protection, and external action on the installation (Fig. 2). A considerable amount of experimental material has accumulated at the present time regarding the reliability of different critical components, particularly typical reactor installations [4, 5, 10-13]. Information on the reliability of both the components and the installations as a whole has also been given in several publications [ 10, 14, 15]. The basis of the procedure is the principle of obtaining and confirming the reliability characteristics of a reactor installation and its systems from the reliability characteristics of the equipment, and when such information is not available it is necessary to analyze the reliability characteristics during the experimental development with a wide use of an accelerated time basis and prediction [14-16]. This principle requires a check of the correctness of the estimate, which is confirmed by demonstration experiments on trial or pilot models. A systematic approach to such an analysis is described, for example, in [ 15], and is based on monitoring and analyzing the change in a characteristic parameter during testing and use and its prediction by successive prediction and, if possible, experimentally under forced operation [14, 16]. When making a probability analysis of the extent to which a reactor installation is safe, particular attention must be devoted to estimating the quantitative characteristics of the action of the personnel and the probability of external actions [ 10]. Here, although a certain amount of data on the probability of the occurrence of emergency situations due to personnel error is available, and the standard documentation requires that such an analysis should be made, quantitative estimates depend very much on various factors and have a considerable spread. To reduce the risk of an accident or emergency situations occurring, the standard technical and operating documents require the compulsory presence of special monitoring and diagnostic systems in the reactor installation, enabling one to estimate and predict the technical state of its
Databáze: OpenAIRE
Externí odkaz: