Weapons-grade nuclear materialWeapons-grade nuclear material is any fissionable nuclear material that is pure enough to make a nuclear weapon or has properties that make it particularly suitable for nuclear weapons use. Plutonium and uranium in grades normally used in nuclear weapons are the most common examples. (These nuclear materials have other categorizations based on their purity.) Only fissile isotopes of certain elements have the potential for use in nuclear weapons.
Onkalo spent nuclear fuel repositoryThe Onkalo spent nuclear fuel repository is a deep geological repository for the final disposal of spent nuclear fuel. It is near the Olkiluoto Nuclear Power Plant in the municipality of Eurajoki, on the west coast of Finland. It will be the world's first long-term disposal facility for spent nuclear fuel. It is being constructed by Posiva, and is based on the KBS-3 method of nuclear waste burial developed in Sweden by Svensk Kärnbränslehantering AB (SKB). The facility is expected to be operational in the mid 2020s.
X-10 Graphite ReactorThe X-10 Graphite Reactor is a decommissioned nuclear reactor at Oak Ridge National Laboratory in Oak Ridge, Tennessee. Formerly known as the Clinton Pile and X-10 Pile, it was the world's second artificial nuclear reactor (after Enrico Fermi's Chicago Pile-1), and the first designed and built for continuous operation. It was built during World War II as part of the Manhattan Project.
Pellet stoveA pellet stove is a stove that burns compressed wood or biomass pellets to create a source of heat for residential and sometimes industrial spaces. By steadily feeding fuel from a storage container (hopper) into a burn pot area, it produces a constant flame that requires little to no physical adjustments. Today's central heating systems operated with wood pellets as a renewable energy source can reach an efficiency factor of more than 90%.
Minor actinideThe minor actinides are the actinide elements in used nuclear fuel other than uranium and plutonium, which are termed the major actinides. The minor actinides include neptunium (element 93), americium (element 95), curium (element 96), berkelium (element 97), californium (element 98), einsteinium (element 99), and fermium (element 100). The most important isotopes of these elements in spent nuclear fuel are neptunium-237, americium-241, americium-243, curium-242 through -248, and californium-249 through -252.
North Korea and weapons of mass destructionNorth Korea has a military nuclear weapons program and, as of early 2020, is estimated to have an arsenal of approximately 30 to 40 nuclear weapons and sufficient production of fissile material for six to seven nuclear weapons per year. North Korea has also stockpiled a significant quantity of chemical and biological weapons. In 2003, North Korea withdrew from the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). Since 2006, the country has been conducting a series of six nuclear tests at increasing levels of expertise, prompting the imposition of sanctions.
NeptuniumNeptunium is a chemical element with the symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus. A neptunium atom has 93 protons and 93 electrons, of which seven are valence electrons. Neptunium metal is silvery and tarnishes when exposed to air. The element occurs in three allotropic forms and it normally exhibits five oxidation states, ranging from +3 to +7.
Discovery of nuclear fissionNuclear fission was discovered in December 1938 by chemists Otto Hahn and Fritz Strassmann and physicists Lise Meitner and Otto Robert Frisch. Fission is a nuclear reaction or radioactive decay process in which the nucleus of an atom splits into two or more smaller, lighter nuclei and often other particles. The fission process often produces gamma rays and releases a very large amount of energy, even by the energetic standards of radioactive decay.
Chapelcross nuclear power stationChapelcross nuclear power station is a former Magnox nuclear power station undergoing decommissioning. It is located in Annan in Dumfries and Galloway in southwest Scotland, and was in operation from 1959 to 2004. It was the sister plant to the Calder Hall nuclear power station plant in Cumbria, England; both were commissioned and originally operated by the United Kingdom Atomic Energy Authority. The primary purpose of both plants was to produce weapons-grade plutonium for the UK's nuclear weapons programme, but they also generated electrical power for the National Grid.
Period 7 elementA period 7 element is one of the chemical elements in the seventh row (or period) of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behavior of the elements as their atomic number increases: a new row is begun when chemical behavior begins to repeat, meaning that elements with similar behavior fall into the same vertical columns. The seventh period contains 32 elements, tied for the most with period 6, beginning with francium and ending with oganesson, the heaviest element currently discovered.
