Tokaimura Nuclear Accident Essay Research Paper Tokaimura

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Tokaimura Nuclear Accident Essay, Research Paper Tokaimura Nuclear Accident To understand what happens in accidents you must first understand how reactors work. All nuclear accidents are unique and are not usually caused by the same problem some for example some are caused by equitment failure like in the Three Islands Plant in Pennsylvania, and some are caused by ignoring a simple test which was not administered correctly at Cherynobyl. Whatever the cause may be nuclear energy is still too cost effective to stop for a few accidents. Tokaimura is another accident which was caused by human error and is the focus of this research paper. Tokaimura is the worst nuclear accident ever to occur in Japan How does a nuclear reactor work you might say well a reactor produces and

controls the release of energy from atoms, by splitting the atomic nuclei nuclear fission: fission is the splitting of one atom usually of uranium or plutonium to produce two smaller but equally massive parts. The fission process releases a large quantity of thermal energy as well as gamma rays and two or more free neutrons. These free neutrons fission other uranium nuclei which in turn give off neutrons that split still more nuclei this is called a chain reaction. In a nuclear power reactor the energy released is used to generate electricity which then in turn is spread to anyone who needs power. This is where Einsteins theory of relation comes in a little mass times the speed of light squared yields lots of energy. Now what went wrong at Tokaimura on the morning of September

30th 1999? This morning was a normal morning not unlike any other in the past three workers at the plant were finishing up purifying the uranium oxide they were processing to mke fuel rods the fast Japan Joyo research reactor. The three were working with a 18.8 percent pure concentration of uranium 235 instead of the normal 5 percent pure so they were unexpierienced with the higher concetrated uranium. Since the company who owns the plants sales had dropped 47% they tried increasing production by using an unsafe cheaper method using more uranium. The uranium -nitric acid mixture being used was supposed to be homogenized in safe storage tanks these tanks were extremely small and narrow so the homogenized process took a longer time. Once again the workers violated standard

procedure by used the precipitation tanks instead of the typical storage tanks. Pouring a large amount of the solution into the tanks; about 9.2 kilograms and soon exceeded the amount of uranium that the safety mechanism that they bipassed would normally allow. Not knowing what a criticality was or the enriched 18.8 percent concentrated uranium mixture the workers added the same amount of uranium as they normally would for the weaker 5 percent concentrated mixture. Since the percipitation tanks cooling water circulated around the jacket encasing it was reflecting neutrons and facilitating heat removal so in other words they had created a low power nuclear reactor and didn t even know about it. The chain reaction started when the enriched uraniums level reached 16.1 kilograms

which was almost 7 times the authorized level of 2.4 kilograms. Emergency alarms blared at the release of gamma radiation and the plant was evacuated immediately. The village of Tokai was very poorly prepared not having neutron detectors which would have let the employees that the chain reaction was not over yet which allowed others to be exposed who didn t have to be. Paramedics on the scene received doses of about 1.3 rem constuction workers were believed to have taken in 1.5 rem and the power plant employees received upto 4.7 rem. It was later found that only about 207 people were actually exposed to the radiation given off by the plant. Who was to blame in this accident? the workers were blamed as trying to be creative but this was put down after the secret manual was found.