The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the No. 4 reactor in the Chernobyl Nuclear Power Plant, near the city of Pripyat in the north of the Ukrainian SSR in the Soviet Union. Called the world's worst-ever civil nuclear incident, it is one of only two nuclear energy accidents rated at seven—the maximum severity—on the International Nuclear Event Scale, the other being the 2011 Fukushima nuclear disaster in Japan. The initial emergency response, together with later decontamination of the environment, involved more than 500,000 personnel and cost an estimated 18 billion roubles—roughly US$68 billion in 2019, adjusted for inflation.
The accident occurred during a safety test meant to measure the ability of the steam turbine to power the emergency feedwater pumps of an RBMK-type nuclear reactor in the event of a simultaneous loss of external power and major coolant leak. During a planned decrease of reactor power in preparation for the test, the operators accidentally dropped power output to near-zero, due partially to xenon poisoning. While recovering from the power drop and stabilizing the reactor, the operators removed a number of control rods which exceeded limits set by the operating procedures. Upon test completion, the operators triggered a reactor shutdown. Due to a design flaw, this action resulted in localized increases in reactivity within the reactor (i.e., "positive scram"). This brought about the rupture of fuel channels and a rapid drop in pressure, thereby prompting the coolant to flash to steam. Neutron absorption thus dropped, leading to an increase in reactor activity, which further increased coolant temperatures (a positive feedback loop). This process led to steam explosions and the melting of the reactor core.
The meltdown and explosions ruptured the reactor core and destroyed the reactor building. This was immediately followed by an open-air reactor core fire which lasted until 4 May 1986, during which airborne radioactive contaminants were released and deposited onto other parts of the USSR and Europe.
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The theoretical background and practical aspects of heterogeneous reactions including the basic knowledge of heterogeneous catalysis are introduced. The fundamentals are given to allow for the use of
This course is intended to understand the engineering design of nuclear power plants using the basic principles of reactor physics, fluid flow and heat transfer. This course includes the following: Re
In this course, one acquires an understanding of the basic neutronics interactions occurring in a nuclear fission reactor as well as the conditions for establishing and controlling a nuclear chain rea
In nuclear engineering, prompt criticality describes a nuclear fission event in which criticality (the threshold for an exponentially growing nuclear fission chain reaction) is achieved with prompt neutrons alone and does not rely on delayed neutrons. As a result, prompt supercriticality causes a much more rapid growth in the rate of energy release than other forms of criticality. Nuclear weapons are based on prompt criticality, while nuclear reactors rely on delayed neutrons or external neutrons to achieve criticality.
A nuclear and radiation accident is defined by the International Atomic Energy Agency (IAEA) as "an event that has led to significant consequences to people, the environment or the facility. Examples include lethal effects to individuals, large radioactivity release to the environment, reactor core melt." The prime example of a "major nuclear accident" is one in which a reactor core is damaged and significant amounts of radioactive isotopes are released, such as in the Chernobyl disaster in 1986 and Fukushima nuclear disaster in 2011.
Iodine-131 (131I, I-131) is an important radioisotope of iodine discovered by Glenn Seaborg and John Livingood in 1938 at the University of California, Berkeley. It has a radioactive decay half-life of about eight days. It is associated with nuclear energy, medical diagnostic and treatment procedures, and natural gas production. It also plays a major role as a radioactive isotope present in nuclear fission products, and was a significant contributor to the health hazards from open-air atomic bomb testing in the 1950s, and from the Chernobyl disaster, as well as being a large fraction of the contamination hazard in the first weeks in the Fukushima nuclear crisis.
Learn the basics of plasma, one of the fundamental states of matter, and the different types of models used to describe it, including fluid and kinetic.
Learn the basics of plasma, one of the fundamental states of matter, and the different types of models used to describe it, including fluid and kinetic.
The Supercritical-Water-Cooled Reactor (SCWR) is the Generation IV reactor concept most closely related to current light water reactors (LWRs). The SCWR builds on the vast experience with today's LWRs
EPFL2012
Covers the analysis of heterogeneous reactions, focusing on kinetics and reactor types.
Delves into Ruelle resonances for linear pseudo-Anosov maps, highlighting their importance in dynamical systems theory.
Discusses the Fukushima and TMI nuclear accidents, reactor designs, safety features, and consequences.
Understanding the time-dependent behaviour of a nuclear reactor following an intended or unintended change of the reactor conditions is of crucial importance to the safe operation of nuclear reactors.
The subject of the present PhD thesis is the qualitative, interdisciplinary analysis of the impact of earthquake insurance on earthquake risk territories in Japan. On the one hand, the Japanese Earthq