Criticality Control Fissile of Materials. Proceedings of the Symposium on Criticality Control of Fissile Materials

Criticality control comprises all the administrative and technical procedures which enable the storage and processing of fissile material to be carried out under conditions of nuclear safety. It is of particular importance in the safe design and operation of chemical and metallurgical plants processing fissile material, in the handling and storage of enriched fuel for reactors, and in transportation of fissile material. The growth of nuclear power, with its increasing use of fissile material and production of plutonium, is leading to an ever widening need for this discipline. This Symposium was held 4½ years after the only other international meeting on this topic, at which the first broad exchange of ideas and theories enabled a comparison to be drawn between the various ways in which the subject is handled in the different countries. That meeting showed that criticality safety was often achieved by procedures known to be ultra-safe, as there was a great lack of useful experimental data with which to check theoretical models. Since that time the quantities of material being processed have increased, and with the now urgent necessity of achieving economic, and hence commercially competitive, operation, the procedure of using arbitrary factors of safety is no longer adequate. Plant Managers now require good data on the basis of which they can choose a suitable factor of safety, and design a process to be safe under any foreseeable circumstances. The present Symposium showed the great increase in the amount of available experimental data and its importance in checking the now highly sophisticated computer calculations. There are many diagrams in these Proceedings with curves from which critical parameters for various configurations can be taken. The dearth of data for plutonium systems is causing some difficulty in plutonium processing plants, which are becoming commercially important. The excellent safety record of the atomic energy industry was highlighted, and a strong case was put forward for educating administrators, governments and the general public to realizing that an accident could be assessed in a way similar to that in any other industry. A criticality incident tends to remain localized; an analysis of all the incidents that have occurred since the start of the industry confirms this view. There has never as the result of a mishap been any danger to a member of the public, nor has there been damage to neighbouring property. Of interest also is the comparison made available between the differing philosophies for achieving safe operation practised in the various countries- with, however, close agreement regarding the basic safety data and requirements.