Gas nuclear reactor

A gas nuclear reactor ( English Nuclear Gas Core Reactor - NGCR) is a nuclear reactor in which the nuclear fuel is in gaseous form. Such a reactor has not yet progressed beyond the experimental stage. Possible applications are powerful rocket motors for interplanetary flights as well as nuclear power plants with significantly better efficiency in power generation.

Rocket engine

In the gas nuclear reactor for spacecraft , the uranium fuel, which has been vaporized and compressed into gas, is heated by the nuclear fission . The plasma of the gas core is prevented from flowing apart by magnetic confinement similar to the fusion reactor , while the reaction chamber is protected. This gas core is now surrounded by liquid hydrogen , whose energy absorbed by the heating is used for propulsion when it flows out of a nozzle. With such an arrangement, which for reasons of the released radioactivity can only be operated in space, a very high specific impulse could be achieved.

In October 2009, the Russian space agency Roskosmos announced that it would resume the development of such a drive that had begun in 1954. The engine uses highly enriched uranium in a plasma gas phase at a pressure of around 1,000 atm (100 MPa ) and temperatures of up to 70,000 Kelvin. Hydrogen is to be used as a fuel , supplemented by alkali metals such as lithium to promote the transfer of energy from radiation. Costs of 17 billion rubles ($ 580 million) are budgeted. The engine is supposed to create the conditions for a manned Mars mission .

Power generation

A container with a coil wrapped around its outside is filled with gaseous uranium hexafluoride , the uranium of which is enriched . The arrangement is filled to just under critical mass . The uranium hexafluoride is compressed so strongly at one point by a pressure wave generated (for example by a blast capsule) that a chain reaction occurs. This creates a lot of heat at this point, which leads to the expansion of the uranium hexafluoride. Since this cannot escape, there is condensation in other places where a chain reaction occurs again. The result is a plasma wave traveling through the container . This is surrounded by magnetic fields that induce a voltage in the coil wound on the container. The efficiency of this arrangement is approx. 20 percent.

To cool the reaction chamber with the uranium hexafluoride and the coil, a coolant flows around them. With the heated coolant, a conventional thermal power generation with an efficiency of 35%, similar to today's nuclear power plants , can be carried out, so that with this arrangement an efficiency of 48% would be possible.

Since uranium hexafluoride is chemically very reactive, strong corrosion of the components must be expected. To date, no reactor has been built according to this scheme.

Individual evidence

1. ↑ Koroteev, Son: Development Nuclear Gas Core Reactor in Russia ( Memento from September 30, 2007 in the Internet Archive ) (PDF; 91 kB), 45th AIAA Aerospace Sciences Meeting, January 2007
2. ↑ dailytech.com: Russia is Developing Nuclear Fission Spaceship to Reach the Red Planet ( Memento of the original from August 20, 2017 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , October 29, 2009  

literature

• Paul A. Czysz / Claudio Bruno: Future Spacecraft Propulsion Systems . Praxis Publishing, Chichester 2006, ISBN 978-3-540-88813-0 . P. 332ff.
• Brown, LC (2001). Direct Energy Conversion Fission Reactor: Annual Report For The Period August 15, 2000 Through September 30, 2001
• Knight, T. Shield Design for A Space Based Vapor Core Reactor ( September 7, 2004 memento in the Internet Archive )