Neutron Absorption Properties of Geopolymeric Composite used Taftan Mountain Volcanic Ash

Neutron absorbers materials must have the ability to slow down the fast neutrons and absorb the thermal neutrons. In recent years, geopolymers have used as a replacement for cements and used to store nuclear waste. In this study, neutron absorption properties of geopolymer samples were investigated. In this regard, Taftan Mountain volcanic ash was used for synthesis of the samples. Sodium hydroxide and sodium silicate were used as alkaline activators. The samples were cured at 65°C for 24 hours and then kept at ambient temperature for seven days in order to geopolymerisation reactions were completely done. The fast neutrons were retarded by light elements such as hydrogen or carbon and boron absorb thermal neutrons In order to improve the absorption properties of the samples boron oxide and boron carbide (by 5-10 wt%) were added to them. The x-ray diffraction (XRD) and Fourier transformation spectroscopy (FTIR) were performed to investigate the phase and chemical bond, properties of the samples respectively. The compression strength and absorption properties of the samples were studied by compression and absorption tests. The XRD results confirmed the existence of geopolymer phases and the FTIR results showed the existence of a geopolymer network. The sample without any additive had maximum compressive strength 37.5 MPa. The absorption test results showed that the samples containing boron carbide had higher neutron absorption than the samples containing boron oxide due to existence of carbon in them.