| Neptunium isotopes are prepared by long time of Uranium neutron irradiation in nuclear reactors as byproduct of plutonium production. 237U is produced via an (n, 2n) reaction with 238U in quantities approximately 0.3% of those of plutonium or 10-6-10-4 mass% of uranium concentration. In reactors which utilize uranium enriched by 235U the 237Np isotope is produced via the reaction 235U (n, g) 236U (n, g) 237Np; highly radioactive wastes of plutonium processing produced through uranium reactor irradiating become the main source of Neptunium-237. The world production volume is 0.5-1 tons annually. Neptunium-237 of high isotope purity is extracted as a product of Americium-241 fission. Short-lived Neptunium-239 isotope with T1/2= 56.5 hours is an intermediate product of plutonium production and a daughter product of Americium-243. The light (neutron-deficient) neptuniums' isotopes are usually obtained in reactors via uranium vary energy deuteron irradiation. Neptunium is separated by precipitation, ion exchange, extraction, as well as via extraction chromatography. Neptunium metal is produced via NpF4 reduction by Barium or Calcium vapours at temperature more than 700°C. |