Nuclear lightbulb
Encyclopedia
A nuclear lightbulb is a hypothetical type of spacecraft engine using a Fission reactor to achieve Nuclear propulsion
. Specifically it would be a type of Gas core reactor rocket
that separates the nuclear fuel
from the coolant
/propellant
with a quartz
wall. It would be operated at such high temperature (approx. 25,000°C) that the vast majority of the electromagnetic
emissions would be in the hard ultraviolet
range. Fused silica is almost completely transparent to this light, so it would be used to contain the uranium hexafluoride
and allow the light to heat reaction mass in a rocket or to generate electricity using a heat engine
or photovoltaics
.
This type of reactor shows great promise in both of these roles. As a rocket engine it, like all nuclear rocket designs, can greatly exceed the power density of a chemical rocket. However, it also does not involve the release of any radioactive material from the rocket, unlike other nuclear designs which would cause nuclear fallout
if used in a planetary atmosphere (e.g. Project Orion
). As a method to generate electricity, nuclear lightbulbs are extremely efficient because higher-temperature heat contains more Gibbs free energy
than the low-temperature heat produced in current fossil-fuel plants and water-cooled nuclear reactors.
Nuclear propulsion
Nuclear propulsion includes a wide variety of propulsion methods that fulfil the promise of the Atomic Age by using some form of nuclear reaction as their primary power source.- Surface ships and submarines :...
. Specifically it would be a type of Gas core reactor rocket
Gas core reactor rocket
Gas core reactor rockets are a conceptual type of rocket that is propelled by the exhausted coolant of a gaseous fission reactor. The nuclear fission reactor core may be either a gas or plasma...
that separates the nuclear fuel
Nuclear fuel
Nuclear fuel is a material that can be 'consumed' by fission or fusion to derive nuclear energy. Nuclear fuels are the most dense sources of energy available...
from the coolant
Coolant
A coolant is a fluid which flows through a device to prevent its overheating, transferring the heat produced by the device to other devices that use or dissipate it. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, and chemically inert, neither causing nor...
/propellant
Propellant
A propellant is a material that produces pressurized gas that:* can be directed through a nozzle, thereby producing thrust ;...
with a quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
wall. It would be operated at such high temperature (approx. 25,000°C) that the vast majority of the electromagnetic
Electromagnetic radiation
Electromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...
emissions would be in the hard ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
range. Fused silica is almost completely transparent to this light, so it would be used to contain the uranium hexafluoride
Uranium hexafluoride
Uranium hexafluoride , referred to as "hex" in the nuclear industry, is a compound used in the uranium enrichment process that produces fuel for nuclear reactors and nuclear weapons. It forms solid grey crystals at standard temperature and pressure , is highly toxic, reacts violently with water...
and allow the light to heat reaction mass in a rocket or to generate electricity using a heat engine
Heat engine
In thermodynamics, a heat engine is a system that performs the conversion of heat or thermal energy to mechanical work. It does this by bringing a working substance from a high temperature state to a lower temperature state. A heat "source" generates thermal energy that brings the working substance...
or photovoltaics
Photovoltaics
Photovoltaics is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material...
.
This type of reactor shows great promise in both of these roles. As a rocket engine it, like all nuclear rocket designs, can greatly exceed the power density of a chemical rocket. However, it also does not involve the release of any radioactive material from the rocket, unlike other nuclear designs which would cause nuclear fallout
Nuclear fallout
Fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes...
if used in a planetary atmosphere (e.g. Project Orion
Project Orion (nuclear propulsion)
Project Orion was a study of a spacecraft intended to be directly propelled by a series of explosions of atomic bombs behind the craft...
). As a method to generate electricity, nuclear lightbulbs are extremely efficient because higher-temperature heat contains more Gibbs free energy
Gibbs free energy
In thermodynamics, the Gibbs free energy is a thermodynamic potential that measures the "useful" or process-initiating work obtainable from a thermodynamic system at a constant temperature and pressure...
than the low-temperature heat produced in current fossil-fuel plants and water-cooled nuclear reactors.