Resistance of class C fly ash belite cement to simulated sodium sulphate radioactive liquid waste attack.

The resistance of class C fly ash belite cement (FABC-2-W) to concentrated sodium sulphate salts associated with low level wastes (LLW) and medium level wastes (MLW) is discussed. This study was carried out according to the Koch and Steinegger methodology by testing the flexural strength of mortars immersed in simulated radioactive liquid waste rich in sulphate (48,000 ppm) and demineralised water (used as a reference), at 20 degrees C and 40 degrees C over a period of 180 days. The reaction mechanisms of sulphate ion with the mortar was carried out through a microstructure study, which included the use of Scanning electron microscopy (SEM), porosity and pore-size distribution and X-ray diffraction (XRD).

Radioactively contaminated electric arc furnace dust as an addition to the immobilization mortar in low- and medium-activity repositories.

Electric arc furnace dust (EAFD), generated by the steel-making industry, is in itself an intrinsic hazardous waste; however, the case may also be that scrap used in the process is accidentally contaminated by radioactive elements such as cesium. In this case the resulting EAFD is to be handled as radioactive waste, being duly confined in low- and medium-activity repositories (LMAR). What this paper studies is the reliability of using this radioactive EAFD as an addition in the immobilization mortar of the containers of the LMAR, that is, from the point of view of the durability.

Efficiency of a blast furnace slag cement for immobilizing simulated borate radioactive liquid waste.

The efficiency of a blast furnace slag cement (Spanish CEM III/B) for immobilizing simulated radioactive borate liquid waste [containing H3BO3, NaCl, Na2SO4 and Na(OH)] has been evaluated by means of a leaching attack in de-mineralized water at the temperature of 40 degrees C over 180 days. The leaching was carried out according to the ANSI/ANS-16.1-1986 test.

Nondestructive decontamination of mortar and concrete by electro-kinetic methods: application to the extraction of radioactive heavy metals.

Because the service lives of nuclear power plants are limited to a certain number of years, the need for the management of quite a large volume of radioactive contaminated concrete arises, which, in most cases, was not taken into account when the capacities of the low and medium activity repositories were designed. Therefore, the decontamination of these structures would be of great interest in order to declassify the wastes as radioactive and manage them as conventional ones. This research studies the reliability of the application of electrical fields to decontaminate radioactive contaminated concrete.

Spanish LLW and MLW disposal: durability of cemented materials in (Na, K)Cl simulated radioactive liquid waste.

The microstructural stability or durability of a specific backfilling pozzolanic-cement mortar, which is employed in Spain, in concrete containers for the storage of low level liquid wastes (LLW) and medium level liquid wastes (MLW), has been studied by means of the Koch-Steinegger test at the temperatures of 20 and 40 degrees C during a period of 365 days. Mortar samples were immersed in salt solutions of 3.46 M NaCl and 3.