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Retention of Pu, Am, Np and Tc in the Corrosion of COGEMA Glass R7T7 in Salt Solutions

Objective

The subject of this investigation is to study the chemical durability of the highly radioactive French borosilicate glass R7T7 in one of the three German "standard" salt solutions as a function of time and temperature. This work complements previous investigations on the durability of a very similar but non-radioactive CEA glass by measuring the release behaviour of Pu, Am, Np and Tc.

A detailed understanding of the glass performance must be obtained for all conceivable accidental conditions including contact with water. The respective results shall be used to describe source terms in the framework of safety analyses.
The repository constitutes a system of technical and natural barriers (multibarrier system) against the release of radionuclides. Glass can be one of the technical barriers. A detailed understanding of the glass performance must be obtained for all conceivable accidental conditions including contact with water. The respective results shall be used to describe source terms in the framework of safety analyses. The subject of this investigation is to study the chemical durability of the highly radioactive French borosilicate glass R7T7 in one of the three German 'standard' salt solutions as a function of time and temperature. This work complements previous investigations on the durability of a very similar but nonradioactive glass by measuring the release behaviour of plutonium, americium, neptunium and technetium.

2 hot cells were equipped with the necessary insturments to perform the corrosion experiments. One cell was prepared to perform the crushing and sieving of the glass. The second cell will contain the equipment to perform the corrosion tests in autoclaves. The radioactive glass block was destroyed in 3 steps. Chunks were produced by impact and subsequently crushed mechanically to produce grains which could then be milled to produce powder.
Work programme:

Installation and equipping hot cells.
Modification of analytical techniques : Tc, Pu, Am and Np have to be separated from concentrated salt solutions for activity measurements (a, beta, g spectrometry).
Equipment for corrosion tests : tests shall be performed in autoclaves in various corrosion conditions. Solutions will be analyzed and corrosion layers investigated.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Forschungszentrum Karlsruhe Technik und Umwelt GmbH
Address

76021 Karlsruhe
Germany