eat-resistant enough to contain any heat the fuel could produce. Graphite fuel elements and reactor internals which make up the reactorcore have a high heat capacity and maintain their strength at temperatures beyond 2760 C (5000 F). As a result, temperature changes in the core occur very slowly and without damage to the core structure in the event of design basis transients and accidents.The coolant of the M.H.T.G.R. is another interesting idea. Instead of water which is used in the current nuclear reactors and could eventually corrode the pipes it flows through, the M.H.T.G.R. uses helium. The principle of the reactor is the same, a stream of helium is superheated in the core, and then has the same type of heat exchange with a stream of water that is heated to steam and turns the turbine in the same way as a normal rector. However the helium is not necessary as a coolant because the reactor can never get hot enough to melt. The third and possibly most important thing, the thing that makes the M.H.T.G.R. so safe is it's fuel. An article in Time magazine, July 21, 1986 explains the fuel pellet. "In the MHTGR, bits of uranium fuel are encapsulated in tiny grains made of carbon and silicon compounds. The fuel particles, which are embedded in racquetball-size ''pebbles'' of graphite, will remain intact up to 3600 F. But the configuration of the core and the reactor's size (it generates only 80 megawatts of power, compared with 1,000 megawatts for large conventional reactors) ensure that temperatures never rise above 2900 F."The fuel and the reactor itself completely eliminate the possibility of a reactor meltdown. Because the fuel pellets themselves keep radiation from escaping there is no problem with storing spent fuel.Not only does the M.H.T.G.R. present a nuclear reactor that is inherently safe, it brings advantages along with it. The reactor is small and can be mass-produced. It can then be set up at different sites all around ...
