Date of Award
Master of Science (MS)
The isotope 10B is a good neutron absorber with a thermal neutron absorption cross section of ~3800 barns. This quality has led to the use of boron as a neutron absorber in the nuclear power industry. In current practice, boric acid is commonly used as a neutron absorber in the water regime of active and passive safety systems. The boron hydride compounds in this study, namely Li2B10H10, Na2B10H10, K2B10H10, Li2B12H12, Na2B12H12, and K2B12H12, have been studied to assess their performance in situations where criticality control needs exceed normal control methods. In this type of situation these compounds have several advantages over commonly used neutron absorbers such as boric acid. The boron content of the previously listed boron hydride salts is up to 80 wt% boron compared to 17 wt% for boric acid. The solubility of these compounds is more than ten times greater than boric acid at 25°C. The pH of these compounds has been shown to be neutral in concentrated aqueous solutions. Thermal stability of these compounds as solids has been observed at temperatures greater than 500°C. Electrochemical impedance spectroscopy studies indicated that these compounds are significantly less corrosive than boric acid. Use of these boron hydride salts can lead to reduction in emergency shutdown pool size, reduce or remove the necessity for pool heating and heat tracing of lines, allow for more rapid introduction of the absorber in emergency situations or be used in other applications where significant neutron control is necessary.
Blake, Alex, "Characterization of Boron Hydride Compunds for Potential use in Pressurized Water Nuclear Reactors" (2015). Electronic Thesis Collection. Paper 30.