Proceedings of the conference on molten salts in nuclear technology

The third stage of the Indian nuclear programme envisages extended use of -fuelled reactors with thorium as the fertile material. India is pursuing many concepts of thorium based reactors. One of them is the 300 MWe Advanced Heavy Water Reactor (AHWR). High temperature reactor design options are also being worked out to supply process heat to produce hydrogen by water splitting as a substitute to petroleum based transport fuel. Another option, which is very attractive for large scale deployment and effective thorium utilization, is the molten salt-breeder reactor (MSBR), which can be configured to give significant breeding within thermal energy spectrum of neutrons. DAE is also pursuing metallic fuelled fast breeder reactors with co-located pyrochemical reprocessing plants as an option to increase the breeding gain, reduce the doubling time of the fuel production and reprocess short-cooled and high burnup fuel. In both of these developmental aspects, molten salts play very important role and Bhabha Atomic Research Centre and its sister organization Indira Gandhi Centre of Atomic Research have initiated extensive molten salt research programs. Extensive investigations have been carried out and literature made available by ORNL in the open domain on MSRE and MSBR. These investigations cover almost all aspects of reactor design including, fuel identification, composition, materials of construction, compatibility issues, reactor physics aspects, expected thermal power output etc. Even though the MSBR programme was terminated during 1970, research continued up to as long as 1976. India did contribute to this molten salt reactor concept during early period of 1970s. The research activities were basically focused on solubility studies of actinide fluorides in different salt mixtures. After G-IV initiative, MSBR concept has triggered a re-look and research in this direction has also been revived worldwide. Recent conceptual developments on the design of fast neutron spectrum molten salt reactors (Molten Salt Fast Reactor or MSFR) using fluoride salts open promising possibilities to exploit the 232Th-233U cycle. On the other hand, the MSFR concept can also contribute to significantly diminish the radiotoxic inventory from present-reactors spent fuels in particular by lowering the masses of transuranic elements (TRU). Papers relevant to INIS are indexed separately. (author)