Plutonium Chemische Eigenschaften,Einsatz,Produktion Methoden
Beschreibung
Plutonium was first isolated and produced in 1941 at the
University of California-Berkeley, by nuclear chemist Glenn T.
Seaborg and his colleagues, Joseph W. Kennedy, Edwin M.
McMillan, and Arthur C. Wahl. Minute amounts of plutonium
exist naturally, but large amounts are produced in nuclear
reactors when uranium absorbs an atomic particle such as a
neutron.
Natural occurrences of plutonium are very rare, but it can
occur in a reaction called spontaneous fission. This type of
reaction occurs when ores of uranium with a high localized
concentration decay in the right conditions and produce small
amounts of plutonium. Synthetic plutonium is produced in
a controlled nuclear reactor when uranium-238 absorbs
a neutron and becomes uranium-239, ultimately decaying to
plutonium-239. Plutonium has at least 15 different isotopes.
Different isotopes of uranium and different combinations of
neutron absorption and radioactive decay create the different
isotopes of plutonium. Plutonium was discovered during
wartime; therefore, the majority of plutonium production was
for nuclear weapons. Other plutonium applications range from
being energy sources on deep space probes to small amounts
providing power to heart pacemakers.
Chemische Eigenschaften
silvery white metal; highly reactive; αform: monoclinic, a=0.6183 nm, b=0.4822 nm, c=1.0963 nm; ionic radius of Pu++++ is 0.0887nm; stable form from room temp to 115°C; enthalpy of vaporization 333.5kJ/mol; enthalpy of fusion 2.82kJ/mol; discovered in 1940–1941; prepared in ton quantities in nuclear reactors; 238Pu produced in kg amounts from 237Np; important fuel for producing power for terrestrial and extraterrestrial applications [MER06] [KIR78] [CRC10]
History
The name of Pu derives from the planet Pluto, (the Roman god of the underworld). Pluto was selected because it is the next planet in the solar system beyond the planet Neptune and the element plutonium is the next element in the period table beyond neptunium. Plutonium was first synthesized in 1940 by American chemists Glenn T. Seaborg, Edwin M. McMillan, Joseph W. Kennedy and Arthur C. Wahl at Berkeley, California, in the nuclear reaction
238U(
2H, 2n)
238Np → β − →
238Pu. The longest half-life associated with this unstable element is 80 million year
244Pu.
Verwenden
The principal plutonium isotopes,
239Pu and
240Pu, were
produced as ingredients for nuclear weapons. It is estimated
that the United States produced 400 kCi of plutonium for
nuclear weapons testing, and approximately 325 kCi was
dispersed globally into the environment from conducted
aboveground tests. Overall, an estimated 500 aboveground
nuclear tests were conducted between 1945 and 1963 by the
Soviet Union, Britain, France, and the United States. From these
tests, it is estimated 100 000 kCi of plutonium were dispersed
into the environment.
Applications for 238Pu include using it as a heat source for
thermoelectric power devices. Radioisotope thermoelectric
generators (RTGs) have been used to provide a source of power
in remote locations, such as deep space probes. This plutonium
isotope generates a large amount of heat through its decay
process. The generated heat is converted into electric power via
a thermocouple in the RTG. Small-scale application of
238Pu is
also used to provide power to heart pacemakers. The concept behind the use of this material is a result of the half-life of the
isotope, since its half-life is extremely long, changing out the
power source is not necessary.
Plutonium Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte