The molten salt system has the usual benefits attributed to fluid fuel systems. The principal advantages claimed over solid fuel elements are: (l) the lack of radiation damage that can limit fuel burn-up; (2) the avoidance of the expense of fabricating new fuel elements; (3) the possibility (partially demon strated in the ARE) of continuous gaseous fission product removal; (4) a high negative temperature coefficient of reactivity; and (5) the ability to add make up fuel as needed, so that provision of excess reactivity is unnecessary. The latter two factors make possible a reactor without control rods, which automati cally adjusts its power in response to changes of the electrical load. The lack of excess reactivity can lead to a reactor that is safe from nuclear power excursions.