Chernobyl
This article discusses how uranium dioxide nuclear fuel behaves both during normal nuclear reactor operation and under accident conditions, such as overheating. The cost of work in this area is usually very expensive, so it has often been done in collaboration with other countries, usually under the leadership of the Committee on the Safety of Nuclear Installations (CSNI).
The fuel can swell and the cladding that covers it and forms a fuel rod can deform as a result. It is normal to fill the gap between the fuel and cladding with helium gas to allow better thermal contact between the fuel and the cladding. During use the amount of gas inside the fuel rod may increase due to the formation of noble gases (krypton and xenon) produced by the fission process. If a Loss-Of-Coolant Accident (LOCA) (as in the case of Three Mile Island) or a Reactivity Initiated Accident (RIA) (as in the case of Chernobyl or SL-1) occurs then the temperature of this gas may increase. As the fuel rod is sealed the gas pressure will increase (PV = nRT) and this will possibly deform and burst the cladding. It has been noted that both corrosion and irradiation can alter the properties of the zirconium alloy normally used as a cladding, making it brittle. As a result, experiments using non-irradiated zirconium alloy tubes can lead to misinterpretations.
Graphite nuclear power plant
This article will deal with tritium, its different forms of presentation in radioactive effluents and the presentation of different technologies for its possible treatment. This treatment is particularly complex today in the nuclear industry. Tritium is produced in the fission reactions of a nuclear reactor and can diffuse as a gas, as tritiated water molecules and as the [31H]+ and [O31H]- ions themselves. A case in point is the treatment of the tritium problem in the Fukushima accident. The company that operates the liquid effluent treatment at Fukushima has been using a filtration system to clean up the thousands of tons of radioactive water generated every day by the plant as a consequence of the accident caused by the earthquake and tsunami of March 2011.
In order to comply with this recommendation, the IAEA has held expert meetings to examine the problems involved. In this article, different types of actions proposed for the treatment in particular of tritium as a gas and in its tritiated water form will be presented.
How a nuclear power plant works
Following TMI, protocols have been established that must be followed by operators in various scenarios. In addition, standardized checklists have been established to monitor the status of the different reactor systems.
On April 26, 1986, a series of tests were carried out at the plant to see if the emergency generator was capable of supplying electricity so that all the systems would continue to function in the event of an accident. The generator should have been tested before the plant was commissioned, as were other systems which were also not tested because the plant had to be operational by March 1984 to meet the one million kWh production. The tests were delayed by 10 hours on that April 26th and were performed after the shift change of the operators, who were less trained to perform them. At least these six errors were made during the tests:
There are also within a radius of 30 km around Chernobyl about 800 radioactive waste stores, which were collected in the decontamination work. These storage sites are poorly controlled and monitored. It is known that the safety and isolation measures of many of them are more than precarious, due to the speed and the distressing circumstances in which they were built.
What is corium
This article discusses how uranium dioxide nuclear fuel behaves both during normal nuclear reactor operation and under accident conditions, such as overheating. The cost of work in this area is usually very expensive, so it has often been done in collaboration with other countries, usually under the leadership of the Committee on the Safety of Nuclear Installations (CSNI).
The fuel can swell and the cladding that covers it and forms a fuel rod can deform as a result. It is normal to fill the gap between the fuel and cladding with helium gas to allow better thermal contact between the fuel and the cladding. During use the amount of gas inside the fuel rod may increase due to the formation of noble gases (krypton and xenon) produced by the fission process. If a Loss-Of-Coolant Accident (LOCA) (as in the case of Three Mile Island) or a Reactivity Initiated Accident (RIA) (as in the case of Chernobyl or SL-1) occurs then the temperature of this gas may increase. As the fuel rod is sealed the gas pressure will increase (PV = nRT) and this will possibly deform and burst the cladding. It has been noted that both corrosion and irradiation can alter the properties of the zirconium alloy normally used as a cladding, making it brittle. As a result, experiments using non-irradiated zirconium alloy tubes can lead to misinterpretations.