Nuclear salt-water rocket


Nuclear salt-water rocket

A nuclear salt-water rocket (or NSWR) is a proposed type of nuclear thermal rocket designed by Robert Zubrin that would be fueled by water bearing dissolved salts of Plutonium or U235. These would be stored in tanks that would prevent a critical mass from forming by some combination of geometry or neutron absorption (for example: long tubes made out of boron in an array with considerable spacing between tubes). Thrust would be generated by nuclear fission reactions from the nuclear salts heating the water and being expelled through a nozzle. The water would serve as both a neutron moderator and propellant.

In a conventional chemical rocket, chemical reactions of the fuel and oxidizer (e.g. Oxygen and Kerosene) heat the byproducts of the chemical reaction (e.g. CO2 and H2O) to high temperatures as they are forced through a rocket nozzle. The fast moving molecules in the exhaust focused in one direction create thrust. In a nuclear thermal rocket (or NTR) a nuclear fission reactor would serve as a source of heat which would be transferred to a propellant that is then exhausted through a rocket nozzle. The propellant in this case can be any material with suitable properties, it need not react during the operation of the rocket, it is simply a source of mass to be heated up and exhausted out of the rocket at high speeds. In an NSWR the nuclear salt-water would be made to flow through a reaction chamber and out an exhaust nozzle in such a way and at such speeds that the peak neutron flux in the fission reaction would occur outside of the vehicle. This has several advantages relative to conventional NTR designs. Because the peak neutron flux and fission reaction rates would occur outside of the vehicle, these activities could be much more vigorous than they could be if it was necessary to house them in a vessel (which would have temperature limits due to materials constraints). Additionally, a contained reactor can only allow a small percentage of its fuel to undergo fission at any given time, otherwise it would overheat and meltdown (or explode in a runaway fission chain reaction). Because the fission reaction in an NSWR is dynamic and because the reaction products are exhausted into space it doesn't have a limit on the proportion of fission fuel that reacts. In many ways this makes NSWRs like a hybrid between fission reactors and fission bombs.

Because of their ability to harness the power of what is essentially a continuous nuclear fission explosion, NSWRs would have both very high thrust and very high exhaust velocity, a rare combination of traits in the rocket world, meaning that the rocket would be able to accelerate quickly as well as be extremely efficient in terms of propellant usage. One design would generate 13 meganewtons of thrust at 66 km/s exhaust velocity (compared to ~4.5 km/s exhaust velocity for the best chemical rockets of today). Another design would achieve much higher exhaust velocities (4,700 km/s) and use 2,700 tonnes of highly enriched Uranium salts in water to propel a 300 tonne spacecraft up to 3.6% of the speed of light.

NSWRs share many of the features of Orion propulsion systems, except that NSWRs would generate continuous rather than pulsed thrust and may be workable on much smaller scales than the smallest feasible Orion designs (which are generally large, due to the requirements of the shock-absorber system and the minimum size of efficient nuclear explosives).

The vessel's exhaust would contain radioactive isotopes, but these would be rapidly dispersed after traveling only a short distance; the exhaust would also be travelling at high speed (in Zubrin's scenario, faster than Solar escape velocity, allowing it to eventually leave the Solar System). This is however, little use on the surface of a planet, where a NSWR would eject massive quantities of superheated steam, still containing fissioning nuclear salts. This is extremely dangerous from an ecological point of view, and such engines could not be used on the surface of a planet without terrible environmental damage occurring.

See also

References

  • R. Zubrin, "Nuclear Salt Water Rockets: High Thrust at 10,000 sec ISP", Journal of the British Interplanetary Society 44, 371-376 (1991)

External links


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • 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. Contents 1 Surface ships and submarines 2 Cars 3 Aircraft …   Wikipedia

  • Nuclear marine propulsion — is propulsion of a ship by a nuclear reactor. Naval nuclear propulsion is propulsion that specifically refers to naval warships (see Nuclear navy). Only a very few experimental civil nuclear ships have been built; the elimination of fossil fuel… …   Wikipedia

  • Nuclear thermal rocket — Sketch of nuclear thermal rocket …   Wikipedia

  • Rocket engine — RS 68 being tested at NASA s Stennis Space Center. The nearly transparent exhaust is due to this engine s exhaust being mostly superheated steam (water vapor from its propellants, hydrogen and oxygen) …   Wikipedia

  • Nuclear photonic rocket — In a nuclear photonic rocket, a nuclear reactor would generate such high temperatures that the blackbody radiation from the reactor would provide significant thrust. The disadvantage is that it takes a lot of power to generate a small amount of… …   Wikipedia

  • Nuclear pulse propulsion — An artist s conception of the Project Orion basic spacecraft, powered by nuclear pulse propulsion. Nuclear pulse propulsion (or External Pulsed Plasma Propulsion, as it is termed in one recent NASA document[1]) is a proposed method of spacecraft… …   Wikipedia

  • Nuclear electric rocket — In a nuclear electric rocket, nuclear thermal energy is changed into electrical energy that is used to power one of the electrical propulsion technologies. Technically the powerplant is nuclear, not the propulsion system, but the terminology is… …   Wikipedia

  • Nuclear aircraft — This article is about Aircraft nuclear propulsion. For the US Air Force program, see Aircraft Nuclear Propulsion. For the crystallographic feature known as an atomic plane, see crystallography. A nuclear aircraft is an aircraft powered by nuclear …   Wikipedia

  • Nuclear lightbulb — 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… …   Wikipedia

  • Nuclear reprocessing — technology was developed to chemically separate and recover fissionable plutonium from irradiated nuclear fuel.[1] Reprocessing serves multiple purposes, whose relative importance has changed over time. Originally reprocessing was used solely to… …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.