Centrifugal Separation of Boron Isotopes Using Boron Trichloride as Processing Gas

Abstract

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.

Keywords

• boron isotopes stable isotope separation gas centrifugal separation boron trichloride overall separation factor