IP4NA -Investigation of the use of inorganic polymers in nuclear applications: Influence of irradiation

Abstract

Inorganic Polymers (IPs) are interesting alternative binder materials to Ordinary Portland Cement (OPC). Using these binders as an alternative for Portland cement-based materials in nuclear applications offers promising properties as chemical resistance and high temperature resistance. The micromechanical properties of the IP and the effect of gamma irradiation on the micromechanical properties (Hardness, Young’s modulus and creep modulus) of the individual IP constituents (unreacted particles and binder) is investigated in this study. The IPs were cured for 1 h, 24 h or 28 days prior to irradiation at a dose rate of 8.85 kGy/h up to a total absorbed dose of 200 kGy. Nanoindentation grid tests were used to evaluate the micromechanical response. The results of the irradiated samples are compared to these of non-irradiated samples. It is indicated that the binder phase as well as the unreacted particles in samples of only 1 hour old prior to irradiation are more sensitive to gamma irradiation than the hardened samples. A decrease in Young’s modulus of 13% was recorded for the unreacted particles and a decrease of 32% for the binder phase, indicating that the binder is more sensitive to gamma irradiation then the unreacted particles. However, the IPs studied show a different behaviour when irradiated immediately after casting or after 24 h of hardening. It is therefore thought that the mechanism behind the effect of irradiation is different for the non-hardened samples compared to hardened samples. IP samples seem to withstand irradiations up to 200 kGy without any changes in micromechanical properties as hardness, Young’s modulus and creep. In most cases, the creep modulus is lower for irradiated samples compared non-irradiated samples. A significant increase of 39% in the binder creep modulus for the non-hardened samples could be found.