Operational Safety Performance Indicator System at the Dukovany Nuclear Power Plant — Experience with Indicator Aggregation

The operational safety performance indicators serve as an important tool of performance monitoring and management at the Dukovany NPP. A software-supported system has been developed, which has included: data collection, central data storage, graphic output production and periodical report generation. Analyses of performance indicator trends together with evaluation in respect of annually updated target values and acceptance criteria is used for operational safety reviews forming an integral part of continual self-assessment process. This contribution has been focused on experience obtained during development of the operational safety assessment model using indicator aggregation. It summarises problems that had to be paid specific attention in the development process. Thanks to their solution, the model has become a synoptic monitor and a useful tool for operational safety assessment. 1. NEW SYSTEM DEVELOPMENT Based on our own experience with use of performance indicators since the beginning of Dukovany NPP operation and according to the latest IAEA recommendations [1], we have revised the existing performance indicator system and developed a safety performance indicator system. From the bulk of indicators hitherto used by the individual departments of the plant, we have selected all indicators concerning safety and meeting given criteria. These indicators have been included in a new centralized system. To maintain compatibility with international performance indicator systems, all WANO performance indicators and some IAEA-PRIS performance indicators have been included as well. This effort has resulted in a group of 184 specific indicators. Each of these indicators has been assigned the following attributes: definition, targets and criteria, frequency of data collection, data provider and responsible system engineer. In the first step, the indicators were divided in four main areas indicating: (1) safe, reliable operation; (2) barrier reliability and tightness; (3) environmental effect; (4) activities of state regulatory body. In the scope of IAEA Coordinated Research Project, the Dukovany NPP has been revising the system and a software support. The choice and the basic hierarchy of the operational safety performance indicators has been revised so that it was in accordance with three attributes of safe operation: smooth operation, low risk and positive safety attitude. Also the lower levels of the indicator hierarchy (overall and strategic indicators) reflect the recommendations provided in [1]. Specific indicators are tested according to recommended selection criteria. An important part of the centralized system of operational safety performance indicators is a computer network application providing for data inputting and storage. It is a 32-bit Windows application cooperating with an SQL Oracle server. The main characteristics of the application include: • openness of the system for setting a group of specific indicators; • possibility to create any hierarchic structure of the indicators and display the structure on the screen; • distributed system of data collection (individual data providers can input ‘their’ indicator values directly from their computer); • automatic requesting of missing data;