Ceramic breeder materials: Status and needs

The tritium breeding blanket is one of the most important components of a f usion reactor because it directly involves both energy extraction and triti um production, both of which are critical to fusion power. Because of their overall desirable properties, lithium-containing ceramic solids are recogn ized as attractive tritium breeding materials for fusion reactor blankets. Indeed, their inherent thermal stability and chemical inertness are signifi cant safety advantages. In numerous in-pile experiments, these materials ha ve performed well, showing good thermal stability and good tritium release characteristics. Tritium release is particularly facile when an argon or he lium purge gas containing hydrogen, typically at levels of about 0.1%, is u sed: However, the addition of hydrogen to the purge gas imposes a penalty w hen it comes to recovery of the tritium produced in the blanket. In particu lar, a large amount of hydrogen in the purge gas will necessitate a large m ultiple-stage tritium purification unit, which could translate into higher costs. Optimizing tritium, release while minimizing the amount of hydrogen necessary in the purge gas requires a deeper understanding of the tritium r elease process, especially the interactions of hydrogen with the surface of the lithium ceramic. This paper reviews the status of ceramic breeder rese arch and highlights several issues and data needs. (C) 1998 Elsevier Scienc e B.V, All rights reserved.