Uranium U

An improved solvent extraction process, PUREX, utilizes an organic mixture of tributyl phosphate solvent dissolved in a hydrocarbon diluent, typically dodecane. This was used at Savannah River, Georgia, ca 1955 and Hanford, Washington, ca 1956. Waste volumes were reduced by using recoverable nitric acid as the salting agent. A hybrid REDOX/PUREX process was developed in Idaho Falls, Idaho, ca 1956 to reprocess high bum-up, fuUy enriched (97% u) uranium fuel from naval reactors. Other separations processes have been developed. The desirable features are compared in Table 1. 

Marine sediments can be both sources and sinks for U. Uranium has repeatedly been shown to be scavenged from solution into reducing sediments. 

The nucleus """U (uranium) does not fission spontaneously, but It can be induced to fission through interaction with a neutron. Pictorially, a typical neutron-induced fission of " U producing two nuclei and three neutrons is depicted in Figure 2. 

Resource category Extraction cost ranges ( /kg U) Uranium resources (kt) Individual Total Data reliability... 

Th Thorium 232.03S1 91 Pa Protactinium 92 U Uranium 93 Np Neptunium 94 Pu Plutonium 95 Am Americium 96 Cm Curium 97 Bk Berkelium 98 Cf Californium 99 ES Einsteinium 100 Fm Fermium 101 Md Vlendelevium 102 No Nobelium Lr Lawrencium... 

SRM 979), Ni (nickel metal isotopic standard NIST SRM 986), Rb (rubidium chloride isotopic standard NIST SRM 984) and Sr (strontium carbonate isotopic standard NIST SRM 987). In addition, isotope reference materials are available for heavy elements such as T1 (thallium metal isotopic standard NIST SRM 997), Pb (NIST lead standard reference materials SRM 981-983) or U (uranium oxide NIST isotope standard U 005, U020, U350, U500 or U930) and others. The most important isotope standard reference materials applied in inorganic mass spectrometry are summarized in the table in Appendix V.17... 

EBWR Core Alloy U(uranium) 93-5, Zr (zirconium) 5.07 Nb(niohium) 1,5%... 

As appears from the table, exotic elements , i.e. uncommon elements are also used, e.g. Y (yttrium), Th (thorium), U (uranium) and Eu (europium). We already learnt in chapter 3 that the most electron-... 

Ho Holmium Er Erbium Tm Thulium Yb Ytterbium Lu l.utetium f Hf Hafnium Ta Tantalum W Wolfram f Re Rhenium Os Osmium Ir Iridium Pt Platinum Au Gold Hg Mercury Tl Thallium Pb Lead Bi Bismuth Po Polonium At Astatine f Rn Radon Fr Francium f Ra Radium Ac Actinium Th Thorium Pa Protactinium U Uranium Np Neptunium f Pu Plutonium f Am Americium f Cm Curium f Bk Berkelium f Cf Californium i... 

---