For our Contemporary Science and Innovation course, our professor took us to visit MIT’s Nuclear Reactor. This nuclear reactor is one of the oldest still running and has been operating since 1958. It was upgraded in 1975 and again in 2010. It shuts down once a month for refuel (shuffle fuel around). This research reactor operates 24/7 at up to 6 MW (megawatts) thermal power. It demonstrates fission technology which is when neutrons hit a hard atom which splits apart and makes more neutrons causing a chain reaction (235 Uranium->Neutron->Fission Product). The stray neutrons are absorbed by 235 Uranium.

In the nucleus of each atom of Uranium-235 fuel, there are 92 protons and 143 neutrons, which adds up to a total of 235 particles. They are so incredibly tiny that their size is hard to even fathom. Around this nucleus spin 92 electrons, which are even tinier particles. It’s said that if the nucleus were as large as a baseball, an electron on its outer rim would be nothing more than a speck about a mile away. The MIT Research Reactor is used principally for the production of neutrons. When it is in operation, the central active core holds an authentic swarm of neutrons moving in every direction at extremely high speeds. The amount of fission in the uranium nuclei is monitored essentially by six control blades of boron-stainless steel which are added vertically alongside the fuel elements. Boron has the property of absorbing neutrons without transferring any. When the control blades are completely added, they absorb so many neutrons from the uranium that there are not enough to cause a chain reaction. To put the reactor into action, the control blades are elevated very slowly. As they absorb less and less neutrons, more and more neutrons are available to element the breaking apart of uranium nuclei, until there are enough neutrons that are being completely discharged to maintain a chain reaction.

The nuclear reactor is a heavy-water reflected, light-water cooled and moderated nuclear reactor that uses flat, plate-type, finned, aluminum-clad fuel elements. It uses water as a coolant and produces no greenhouse gases. It is dedicated for peaceful applications, R&D (Research and Development). There are 2,000 gallons of cool water being pumped a minute through the pumps in the equipment room. The electrons coming out of the reactor move faster than the speed of light. Experimental facilities accessible at the MIT Research Reactor contain two medical edification rooms, beam ports, automatic transfer facilities (pneumatic tubes), and graphite-reflector edification facilities. In addition to that, many  in-core experimental facilities(ICSAs) are also accessible.The MIT Reactor surrounds a number of basic safety features, including negative reactive temperature coefficients of both the fuel and moderator and a negative void coefficient of reactivity. Another safety feature is the location of the core within two concentric tanks. More safe characteristics it contains are the use of anti-siphon valves to set apart the core from the result of breaks in the coolant piping, a core-tank design that advances natural circulation in the occurrence of a loss-of-flow accident; and the occupancy of a full containment. All of these aspects make MIT’s Nuclear Reactor a  particularly safe facility.

http://web.mit.edu/nrl/www/reactor/reactor.htm