Centrifugal Separation of Boron Isotopes Using Boron Trichloride as Processing Gas

Stable isotopes had been widely used in the industrial production, health care, fundamental physics research, and so on. Natural boron has two stable isotopes: ¹⁰B (19.9%) and ¹¹B(80.1%). The thermal neutron cross section of ¹⁰B isotope is 3835 barns, while that of ¹¹B isotope is only 0.005 5 barns. With high cross section for thermal neutron, ¹⁰B isotope gains important applications in nuclear industry, radiation therapy and other fields. In the third-generation nuclear power plants, it’s required that the primary coolant should use enriched boric acid with ¹⁰B isotope in abundance of 30%-60%. Boron carbide with ¹⁰B isotope in abundance of 92% is used in fast neutron reactors as the control rod. ¹⁰B isotope can also be used for boron neutron capture therapy (BNCT) in cancer treatments. In order to obtain high-abundance ¹⁰B isotope, the study on gas centrifugal separation of boron isotopes was carried out based on domestic centrifuges, with boron trichloride as processing gas. Single-centrifuge experiments of different feed flows and cuts were done. Samples of each experiment were analyzed by the gas mass spectrometer to calculate separation performance. As a result, the overall separation factor of boron trichloride was about 1.08. Furthermore, the influence of feed flow and cut on overall separation factor was studied. Finally, based on the single-centrifuge experiments, parameters of centrifugal cascades for high-abundance ¹⁰B isotope production were carried out by numerical calculation. Cascade parameters of square cascade and matched abundance ratio cascade were worked out separately. ¹⁰B isotope production in abundance of 60% and 90% could be obtained by cascades with suitable parameters. The single-centrifuge experimental study and cascade calculation proved the feasibility of boron isotope separation by gas centrifugation method, with boron trichloride as processing gas. It laid a foundation for enriched boron isotopes production.