Thorium Candlestick Fission Fragment Starship (original) (raw)

The fission-fragment (FF) rocket is a rocket engine design that directly harnesses hot nuclear fission products for thrust, as opposed to using a separate fluid as working mass. The design can, in theory, produce very high specific impulse of 1,000,000 to 1,500,000 while still being well within the abilities of current technologies. There is a lot of interest in FF rockets due to the high specific impulse but there is one major problem with the concept and that problem is the need to launch radioactive propellant mass into space. The potential solution may be a Thorium " breeder " reactor than can produce more radioactive material than it consumes. This potentially could substantially reduce or possibly even eliminate the need to transport radioactive material into space. Although the mass of the fission fragments are very small, the fragments exit at speeds of a few percent the speed of light and are therefore able to generate a significant thrust force. An FF Rocket burning one hundredth of one gram of fuel per second and ejecting those fragments at five percent of the speed of light would still be able to generate a force of 150 newtons and Clark and Sheldon calculate that their dusty plasma rocket would be able to generate a specific impulse (I SP) of 1.5 million seconds (1). Specific impulse is a measure of the efficiency of a rocket engine and compares the force generated with the mass of propellant used per unit time. A FF rocket therefore offers a huge improvement in efficiency over standard chemical rockets and many proposed advanced propulsion systems. In fact, a fission fragment (FF) engine is one of the few concepts potentially capable of supporting generational (within a human life time) interstellar space flight. This paper will discuss a breeding (FF) rocket using Thorium in a " candlestick " reactor. Thorium Thorium is weakly radioactive: all of its known isotopes are unstable. Thorium-232 (232 Th), which has 142 neutrons, is the most stable isotope of thorium and accounts for nearly all natural thorium, with six other natural isotopes occurring only as trace radioisotopes. Thorium has the longest half-life of all the significantly radioactive elements, 14.05 billion years, or about the age of the universe; it decays very slowly through alpha decay to radium-228 (228 Ra), starting a decay chain named the thorium series that ends at stable lead-208 (208 Pb). Thorium is estimated to be about three to four times more abundant than uranium in the Earth's crust, and is chiefly refined from monazite sands as a by-product of extracting rare earth metals. Thorium Reactor Thorium-based nuclear power is nuclear reactor-based, fueled primarily by the nuclear fission of the isotope Uranium-233 produced from the fertile element thorium. A nuclear reactor consumes certain specific fissile isotopes to produce energy. In this paper I am going to discuss the U-233, transmuted from Th-232 scenario as a way to power a starship. In thermal breeder reactors, the fertile isotope 232 Th is bombarded by slow neutrons, undergoing neutron capture to become