A criticality accident is an uncontrolled nuclear fission chain reaction it is sometimes referred to as a critical excursion critical power excursion or divergent chain reaction any such event involves the unintended accumulation or arrangement of a critical mass of fissile material for example enriched uranium or plutonium criticality accidents can release potentially fatal radiation doses. A nuclear reactor formerly known as an atomic pile is a device used to initiate and control a self sustained nuclear chain reaction nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion heat from nuclear fission is passed to a working fluid water or gas which in turn runs through steam turbines. It is believed by many that this ancient nuclear reactor is around 1 8 billion years old and operated for at least 500 000 years in the distant past.
The site where the uranium originated is an advanced subterranean nuclear reactor that goes beyond the understanding of our current scientific knowledge. But a reactor that must weigh just a few tons is more like the ones that currently power. Low enriched uranium meanwhile is a good alternative and it already powers many nuclear plants on earth.
The phenomenon is named for soviet physicist pavel cherenkov who shared the 1958 nobel prize in physics for its discovery. It s cause is similar to the cause of a sonic boom the sharp sound heard when faster than sound movement occurs. A classic example of cherenkov radiation is the characteristic blue glow of an underwater nuclear reactor.
The radiation is used in particle physics experiments to help identify the nature of the particles being examined. In a pool type reactor the amount of blue glow can be used to gauge the radioactivity of spent fuel rods. Cherenkov radiation is good for more than just making your water glow blue in a nuclear lab.
