helium cooled reactor
61Nuclear fusion — Nuclear physics Radioactive decay Nuclear fission Nuclear fusion Classical dec …
62Nobel Prizes — ▪ 2009 Introduction Prize for Peace The 2008 Nobel Prize for Peace was awarded to Martti Ahtisaari, former president (1994–2000) of Finland, for his work over more than 30 years in settling international disputes, many involving ethnic,… …
63Nuclear fission — For the generation of electrical power by fission, see Nuclear power. Splitting the atom redirects here. For the EP, see Splitting the Atom. Nuclear physics Radioactive decay Nuclear fission Nuclear fusio …
64Nuclear weapon design — The first nuclear weapons, though large, cumbersome and inefficient, provided the basic design building blocks of all future weapons. Here the Gadget device is prepared for the first nuclear test: Trinity. Nuclear weapon designs are physical,… …
65Neutron poison — For information on biological effects of excessive ionizing radiation, see radiation poisoning. A neutron poison (also called a neutron absorber or a nuclear poison ) is a substance with a large neutron absorption cross section in applications,… …
66Atomic nucleus — A figurative depiction of the helium 4 atom with the electron cloud in shades of gray. In the nucleus, the two protons and two neutrons are depicted in red and blue. This depiction shows the particles as separate, whereas in an actual helium atom …
67rare-earth element — /rair errth /, Chem. any of a group of closely related metallic elements, comprising the lanthanides, scandium, and yttrium, that are chemically similar by virtue of having the same number of valence electrons. Also called rare earth metal. [1955 …
68crystal — crystallike, adj. /kris tl/, n., adj., v., crystaled, crystaling or (esp. Brit.) crystalled, crystalling. n. 1. a clear, transparent mineral or glass resembling ice. 2. the transparent form of crystallized quartz. 3. Chem., Mineral. a solid body… …
69Crystal — /kris tl/, n. 1. a city in SE Minnesota, near Minneapolis. 25,543. 2. a female given name. * * * I Any solid material whose atoms are arranged in a definite pattern and whose surface regularity reflects its internal symmetry. Each of a crystal s… …
70dating — I In geology and archaeology, the process of determining an object s or event s place within a chronological scheme. Scientists may use either relative dating, in which items are sequenced on the basis of stratigraphic clues (see stratigraphy) or …
