Element 93 · Actinide
Neptunium
Neptunium is a synthetic radioactive actinide produced as a by-product of nuclear reactors.
Element Facts
SYMBOL
Np
ATOMIC NO.
93
ATOMIC WEIGHT
237
CATEGORY
Actinide
PERIOD
Period 7
GROUP
Group 3
Background
Neptunium was discovered in 1940 by Edwin McMillan and Philip Abelson at the University of California, Berkeley, by bombarding uranium-238 with neutrons in a cyclotron. It was the first transuranic element to be identified. Named after Neptune, the planet beyond Uranus — following the precedent set by uranium (named after Uranus). Its discovery opened the field of transuranic element research that led to plutonium, americium, and all subsequent synthetic elements.
Industrial Uses
Neptunium-237 is produced as a byproduct of nuclear reactor operation (from irradiated fuel). It is used as a starting material to produce plutonium-238 for radioisotope thermoelectric generators (RTGs) that power deep-space spacecraft (including New Horizons and Voyager probes). Small quantities are used in nuclear physics research and as neutron detectors.
Scrap Viability
Why QuickStop Metals doesn’t buy Neptunium:
Neptunium is a radioactive actinide metal produced and stored exclusively in licensed nuclear facilities under strict international safeguards (IAEA) and UK nuclear security legislation. It is a controlled material under the Nuclear Non-Proliferation Treaty framework and cannot be processed at a scrap yard.
What It's Worth
No commercial scrap market. Neptunium-237 recovered from nuclear fuel reprocessing is managed as controlled nuclear material at national nuclear facilities. No civilian price benchmark exists.