РефератыИностранный языкToTokaimura Nuclear Accident Essay Research Paper Tokaimura

Tokaimura Nuclear Accident Essay Research Paper Tokaimura

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 b

y


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. Since this facility


was regarded as a low power facility it was not inspected by the proper govermental


officials. The Science and Technology Agency said that it s not the governments


fault when companies fail to meet guidelines. Everyone ended up being in part to


blame for this incident since the government never checked the facility to see if it


made regulations the Science and Technology Agency didn t monitor the radiation


levels, the company who owned the plant rushed their production because of lack of


sales and the workers were at fault since they didn t pay attention to what they were


doing and added to much highly concentrated uranium to the wrong tanks.


Whoever was to blame laws have been put into place in Japan to stop something like


this from happening again.

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