Production of Cf-252 and other transplutonium isotopes at Oak Ridge National Laboratory

Abstract

In 1957 Glenn T. Seaborg conceived and advocated for the construction of the High Flux Isotope Reactor (HFIR) and the Transuranium Processing Plant (since then renamed the Radiochemical Engineering Development Center, or REDC) at Oak Ridge National Laboratory. Heavily shielded hot cells, glove boxes, and laboratories allow recovery of transuranium elements produced in substantial quantities. Seaborg’s vision of HFIR and REDC producing milligram quantities of berkelium, californium, and einsteinium has been fulfilled beginning in 1966 through May 2019 with 78 production campaigns yielding a cumulative totals of 1.2 g of 249Bk, 10.2 g of 252Cf, 39 mg of 253Es, and 15 pg of 257Fm. Notably, 252Cf is a neutron source used in many industrial applications including oil exploration; process control systems for the cement industry, coal analysis, and power production; sources to start nuclear reactors and perform nondestructive materials analyses; homeland security and national defense detection devices; and medical research. Isotopes made available through transplutonium production at HFIR/REDC have enabled scientists to study the nuclear properties and reactions, chemical properties, optical properties, and solid-state properties of transplutonium elements. Long-lived isotopes have served as targets in heavy ion accelerators to produce heavier elements leading to the discovery of 104Rf, 105Db, 106Sg, 113Nh, 114Fl, 115Mc, 116Lv, 117Ts, and 118Og. This paper reviews the evolution of the processing flowsheets to produce, separate, and purify transplutonium isotopes, which have evolved over 50 years of operation at HFIR and REDC, and summarizes directions of future work to improve the efficiency of the production operations.

Measurement of Ac227 Impurity in Ac225 using Decay Energy Spectroscopy

“…Spectra were obtained from four sample types: 1) a pure sample of 225 Ac from a 229 Th generator; 2) a pure sample of 227 Ac; 3) synthetic mixtures of the above to simulate 1% and 10% 227 Ac/ 225 Ac activity ratios; and 4) an 225 Ac production sample, which is from a 232 Th target irradiated at LANL with an 100 MeV proton beam for 46 hours and chemically purified at ORNL [19]. ORNL also sourced the 229 Th and 227 Ac for samples 1-3.…”

Experimental and theoretical studies on the extraction behavior of Cf(iii) by NTAamide(C8) ligand and the separation of Cf(iii)/Cm(iii)

“…the HFIR at Oak Ridge National Laboratory), and its purication process involves the separation of californium from other actinides and impurities. [6][7][8][9] 252 Cf is the main product of Cf production by this method, and its alpha decay half-life is 2.645 years, so the chemical purity of 252 Cf will also be affected by its decay product 248 Cm. 10,11 Therefore, it is of great practical signicance to conduct basic chemical experiments on californium for further research and to obtain data with practical value.…”

Advancing Radiation-Detected Resonance Ionization towards Heavier Elements and More Exotic Nuclides

“…To study these heavy elements, synthetic production of respective atoms is necessary as they do not naturally occur on earth. While the actinides up to fermium (Z = 100) can still be produced in macroscopic sample sizes from breeding processes in nuclear reactors [4], the transfermium elements (Z > 100) are exclusively produced in atom-at-a-time quantities in fusion-evaporation reactions at large-scale accelerator facilities. Therefore, measurements of their atomic properties are very challenging.…”