Speaker
Description
Cement materials have attracted great research interest as potential matrixes for the immobilization of high-level waste (HLW) due to their good mechanical properties and thermal stability. However, the effect of radiation on a cement compound containing HLW has not been enough studied.
Therefore, the purpose of the research is to assess the regulated properties, composition and structure of cement matrixes based on Portland cement and granulated blast furnace slag after exposure to high doses of the ionizing radiation corresponding to HLW. Hot isostatic pressing (HIP) was chosen as a highly promising method for the synthesis of cement matrixes with HLW in an airtight container.
Cement matrixes based on Portland cement and slag with a water-cement ratio 0,2 including imitators of liquid and solid HLW were prepared by HIP at the temperature range 200-300 ℃ and the pressure range 50-100 MPa. Test of cement matrixes for mechanical strength, frost resistance, and chemical resistance were performed. Results showed the compliance of their properties with the regulated requirements for hardened HLW. The effect of temperature (exposure at temperature up to 120 ℃) on the strength of cement matrices was estimated.
The compressive strength of all samples at the 28 day of hardening was higher than the regulated value for cemented liquid radioactive wastes (LRW) (10 MPa). The strength of the samples did not depend on temperature. The reduction in strength after 30 freeze-melting cycles was less than 25%. The rate of leaching of Cs after 28 days was less than 10-6 g/(cm2∙day).
No structural and morphological changes were found after exposure to 120 °C and dose loads up to 109 Gy (electrons) and 1019 decay/g (alpha particles). The rate of Cs leaching on the 28 day of testing did not exceed 10-6 g/(cm2∙day).
The impact of radiation had a greater effect on the strength of cement matrixes based on Portland cement than on the strength of matrixes prepared based on granulated blast furnace slag. The use of slag, i.e. waste from metallurgical production, can be considered as a cheaper substitute for Portland cement.
| Speaker's title | Mr |
|---|---|
| Affiliation | JSC "A.A. Bochvar High-Technology scientific research institute of inorganic materials", 123098, 5a Rogova street, Moscow, Russia. JSC "PRORYV", 107140, 2/8 Malaya Krasnoselskaya street , building 7, office 307, Moscow, Russia |
