A study concerning tritium concentration evolution in the CANDU reactor moderator system coupled to an on-line detritiation facility

The tritium extraction from tritiated heavy water is of key importance for the owners of CANDU type reactor NPPs since the tritium, which in this case occurs as a by product, is radioactive and being carried by water, presents an important radiological risk to NPP operators, population and the environment. Since several years the experimentation of a detritiation technology was initiated at ICSI Rm Valcea and promising results were obtained so far. The design of a detritiation facility coupled on-line to the moderator system of a CANDU reactor, that is the main source of tritium, must fulfil several requirements imposed by: the characteristics of the NPP systems, owner requirements, technical feasibilities of building detritiation facilities, legislation, etc. To meet these requirements an analysis of the evolution of the concentration of tritium in the heavy water moderator and the way these evolution is affected by the design parameters was undertaken in this work. (authors)