Nuclear powered cars could provide a huge step towards reducing air pollution and resolving the global warming epidemic. Fig. 1 is an attempt by the engineers at Ford to create the first nuclear powered car prototype. Even though this creation looks very interesting, it is no bigger than a foot long and about six inches wide. One of the best advantages to nuclear powered cars would be that it would have to be refilled very rarely, maybe every three to five years. This is because highly concentrated uranium is so energy rich that less than a pound can be used to efficiently power a car. Also, there would be almost no harmful emissions released, and people would not need a key ignition or a button to push in order to start a car; it would constantly be on. Even though this would mean the car would need a battery to store the excess energy, but it would not take up nearly as much space as a gas burning engine.  The only real problem with creating nuclear powered cars would be that the power source is extremely radioactive, so it could possible kill people in or near the car without adequate amounts of shielding.  Large aircrafts and ships would require the most shielding because of their large capacity. Some of the biggest gains, though, would probably come from nuclear-powered cargo ships. The largest container ships, like those operated by Maersk, consume up to about 2,600 US gallons of diesel per hour. It has been calculated that just fifteen large container ships produce as much pollution as all of the world's billions of cars combined, and there are thousands of container ships currently at sea. Nuclear cargo ships would put a serious dent in the reduction of global greenhouse gas emissions. 
In order to safely operate a nuclear-powered vehicle, there must be an appropriate amount of shielding in addition to its containment structure, which is usually made of a several foot thick concrete plating. Because of all the required shielding, the nuclear powered vehicle would most likely be very heavy. This means that reproducing the shielding of a nuclear reactor on an appropriate scale could make the car immobile. One of the major concerns with these cars would be what would happen in a car accident.  Would the shielding hold or will the collision cause a catastrophic release of radiation? Also, an efficient method to safely dispose of used fuel will need to be constructed because the spent fuel is highly radioactive for hundreds of years.  This will add to the already expensive cost of uranium and nuclear power plant startups. The problem is, even as improvements in the super-clean fourth-generation (Gen IV) nuclear power, reactors are still extremely big. A small nuclear reactor is generally classified as anything that generates less than three hundred megawatts of electricity. The combustion engine in a normal car on the other hand, generates one hundred and fifty kilowatts, or about two thousand times less power. Even the smallest of modular Gen IV reactors, which pump out around twenty five megawatts of electrical power, weigh about fifty tons. This is mostly because of all the shielding. If the cars will be driving at one hundred miles per hour with a nuclear reactor in the trunk, some strong shielding is probably the most important safety precaution. 
© Tai Thomas. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 "The Cost-Effectiveness of Nuclear Power for Navy Surface Ships," U. S. Congressional Budget Office, Pub. No. 4028, May 2011.
 T. B. Cochran et al., "Commercial Nuclear Power," Natural Resources Defense council, October 2005.