Portal:Nuclear technology

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This symbol of radioactivity is internationally recognized.
Nuclear technology is technology that involves the nuclear reactions of atomic nuclei. Among the notable nuclear technologies are nuclear reactors, nuclear medicine and nuclear weapons. It is also used, among other things, in smoke detectors and gun sights.
Nuclear power is the use of nuclear reactions that release nuclear energy to generate heat, which most frequently is then used in steam turbines to produce electricity in a nuclear power plant. As a nuclear technology, nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions.

Presently, the vast majority of electricity from nuclear power is produced by nuclear fission of uranium and plutonium. Nuclear decay processes are used in niche applications such as radioisotope thermoelectric generators. Generating electricity from fusion power remains at the focus of international research. This article mostly deals with nuclear fission power for electricity generation.

Civilian nuclear power supplied 2,488 terawatt hours (TWh) of electricity in 2017, equivalent to about 10% of global electricity generation. As of April 2018, there are 449 civilian fission reactors in the world, with a combined electrical capacity of 394 gigawatt (GW). As of 2018, there are 58 power reactors under construction and 154 reactors planned, with a combined capacity of 63 GW and 157 GW, respectively. As of January 2019, 337 more reactors were proposed. Most reactors under construction are generation III reactors in Asia.

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Decay Chain Thorium.svg
Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately hard, malleable, and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided.

All known thorium isotopes are unstable. The most stable isotope, 232Th, has a half-life of 14.05 billion years, or about the age of the universe; it decays very slowly via alpha decay, starting a decay chain named the thorium series that ends at stable 208Pb. In the universe, thorium, bismuth, and uranium are the only three radioactive elements that still occur naturally in large quantities as primordial elements. It is estimated to be over three times as abundant as uranium in the Earth's crust, and is chiefly refined from monazite sands as a by-product of extracting rare-earth metals.

Thorium was discovered in 1829 by the Norwegian amateur mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jacob Berzelius, who named it after Thor, the Norse god of thunder. Its first applications were developed in the late 19th century. Thorium's radioactivity was widely acknowledged during the first decades of the 20th century. In the second half of the century, thorium was replaced in many uses due to concerns about its radioactivity.

Thorium is still being used as an alloying element in TIG welding electrodes but is slowly being replaced in the field with different compositions. It was also material in high-end optics and scientific instrumentation, and as the light source in gas mantles, but these uses have become marginal. It has been suggested as a replacement for uranium as nuclear fuel in nuclear reactors, and several thorium reactors have been built.

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Castle Bravo 003.jpg
Credit: Federal government of the United States

Castle Bravo nuclear test.

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Ernest Lawrence.jpg
Ernest Orlando Lawrence (August 8, 1901 – August 27, 1958) was a pioneering American nuclear scientist and winner of the Nobel Prize in Physics in 1939 for his invention of the cyclotron. He is known for his work on uranium-isotope separation for the Manhattan Project, as well as for founding the Lawrence Berkeley National Laboratory and the Lawrence Livermore National Laboratory.

A graduate of the University of South Dakota and University of Minnesota, Lawrence obtained a PhD in physics at Yale in 1925. In 1928, he was hired as an associate professor of physics at the University of California, Berkeley, becoming the youngest full professor there two years later. In its library one evening, Lawrence was intrigued by a diagram of an accelerator that produced high-energy particles. He contemplated how it could be made compact, and came up with an idea for a circular accelerating chamber between the poles of an electromagnet. The result was the first cyclotron.

Lawrence went on to build a series of ever larger and more expensive cyclotrons. His Radiation Laboratory became an official department of the University of California in 1936, with Lawrence as its director. In addition to the use of the cyclotron for physics, Lawrence also supported its use in research into medical uses of radioisotopes. During World War II, Lawrence developed electromagnetic isotope separation at the Radiation Laboratory. It used devices known as calutrons, a hybrid of the standard laboratory mass spectrometer and cyclotron. A huge electromagnetic separation plant was built at Oak Ridge, Tennessee, which came to be called Y-12. The process was inefficient, but it worked.

After the war, Lawrence campaigned extensively for government sponsorship of large scientific programs, and was a forceful advocate of "Big Science", with its requirements for big machines and big money. Lawrence strongly backed Edward Teller's campaign for a second nuclear weapons laboratory, which Lawrence located in Livermore, California. After his death, the Regents of the University of California renamed the Lawrence Livermore National Laboratory and Lawrence Berkeley National Laboratory after him. Chemical element number 103 was named lawrencium in his honor after its discovery at Berkeley in 1961.

Nuclear technology news

17 June 2019 – Iran nuclear deal
Iran announces that within ten days, it will stop abiding by the agreement and will exceed the limit on its stockpile of uranium. (NPR)
Iranian President Hassan Rouhani tells the Fars News Agency "the time is short for Europe to save the international nuclear deal", and calls on France to take the lead. Reuters reports that Rouhani added the collapse of the nuclear deal would not be in the interests of the region and the world. (BBC) (NPR)
12 June 2019 – Japan–United States relations, Iran–Japan relations, Iran–United States relations
Japan offers to mediate between Iran and the U.S.; officials say the Japanese government hopes to rescue the landmark 2015 international nuclear deal. (Financial Tribune) (Reuters)
31 May 2019 – North Korea–United States relations
According to South Korean media, North Korea executed five officials back in March, including Kim Hyok-chol, its nuclear envoy to the United States, for their part in the failed second summit in Hanoi. In addition, three other officials involved in the summit have reportedly been sent to a camp for political prisoners. (Reuters) (Fox News)

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