Liquid fuels are liquids containing dissolved nuclear fuel and have been shown to offer numerous operational advantages compared to traditional solid fuel approaches.
Liquid-fuel reactors offer significant safety advantages due to their inherently stable "self-adjusting" reactor dynamics. This provides two major benefits: virtually eliminating the possibility of a runaway reactor meltdown, and providing an automatic load-following capability which is well suited to electricity generation and high-temperature industrial heat applications.
Another major advantage of some liquid core designs is their ability to be drained rapidly into a passively safe dump-tank. This advantage was conclusively demonstrated repeatedly as part of a weekly shutdown procedure during the highly successful 4 year Molten Salt Reactor Experiment.
Another huge advantage of the liquid core is its ability to release xenon gas, which normally acts as a neutron absorber ( is the strongest known neutron poison and is produced both directly and as a decay product of  as a fission product) and causes structural occlusions in solid fuel elements (leading to the early replacement of solid fuel rods with over 98% of the nuclear fuel unburned, including many long-lived actinides). In contrast, molten salt reactors (MSR) are capable of retaining the fuel mixture for significantly extended periods, which not only increases fuel efficiency dramatically but also incinerates the vast majority of its own waste as part of the normal operational characteristics. A downside to letting the  escape instead of allowing it to capture neutrons converting it to the basically stable and chemically inert , is that it will quickly decay to the highly chemically reactive long lived radioactive , which behaves similar to other alkali metals and can be taken up by organisms in their metabolism.