Analysis of boron carbide for 10B isotope by thermal ionization mass spectrometer

Natural isotope of boron is 10B and 11B with a relative abundance of 19.78 % for 10B and remaining is 11B. Owing to its high neutron absorption cross section (764 b), 10 B finds an extensive application as shielding material in nuclear industry. Natural boron carbide (B4C) pellets are used as shielding material in shielding assemblies (SA) in Proto Type Fast Breeder Reactor (PFBR). It is also used as axial shield in Fuel blankets and reflector SA. Specifications of these pellets as shielding material for use in inner B4C shielding SA and as axial shielding material in fuel, blanket, reflector SA are different. Also, B4C powder capsules are used in outer boron carbide SA. Enriched boron carbide with 65 % of 10B isotope finds application as control and safety rods (CSR) and Diverse Safety Rod (DSR) sub assembly. The minimum requirement of 19.6 % of 10B isotope in B4C is a pre-requisite for acceptance of the material for nuclear applications. Therefore, a simple method for isotopic assay of B4C for 10B by Thermal Ionization Mass Spectrometry (TIMS) on regular basis has been standardized at Control Laboratory, NFC