Turning the scale towards nuclear reactor safety
In certain technological areas, such as in nuclear reactor technology, experimental investigations cannot be performed in the plant but only in the laboratory and under conditions that deviate from the real ones. In such cases, a mathematical approach, known as scaling analysis, may be applied in order to indicate how the experimental results can be applied to the prototype, in a systematic and reliable manner. The SCACEX Thematic Network, a group of European experts, has conducted scaling analyses for reactor safety experiments aimed at identifying its requirements and shortcomings and assessing its significance and applicability. Although scaling methods are being used in several projects, a systematic and regular application, in the form of guidelines for engineering needs, had not been established. The network activities included a compilation of scaling methods and the documentation of case studies in order to serve as a reference report. The analyses, applied to a selected nuclear safety area related to reactor containment, demonstrated a universal range of applicability for the existing scaling methods. Scaling analysis gives insight on the transfer limitations of experimental results and sheds light on the processes under investigation. In this way, it comprises an important tool for the specification and design of more cost-effective experiments. However, scaling methods necessitate a strong knowledge of the phenomena involved in an experiment. This can be achieved through its identification and ranking through a Phenomena Identification and Ranking Table (PIRT). PIRT is a method whereby experts agree on the important phenomena underlying an experiment and rank them in terms of existing knowledge, assigning numerical values. SCACEX report can serve as a valuable handbook for future scaling analyses in nuclear reactor technology. Furthermore, scaling analysis concepts may be implemented in different application fields.
