Abstract

Recycling of slightly radioactively contaminated steel scrap from nuclear installations to waste containers, shieldings or any other components for the nuclear cycle is practice in Germany since the early 90ies.

To qualify the process, characterization of the radiological inventories in metal, slag and filter dust as well as metallurgical analysis is necessary. Therefore samples from the melt, slag and filter dust are taken to be analyzed by gammaspectroscopy. Alpha and beta emitting radionuclide inventories are calculated based on the typical nuclide ratio of the nuclear facility where the scrap results from. Activity distribution factors for each radio element are empirical values based on the melting of about 10,000 t of steel scrap with various nuclide ratios. High decontamination of the metal can be achieved for uranium, thorium, plutonium, cesium and strontium, which allows free release of the metal in most cases. For Co60 — the main radionuclide in reactor scrap — the decontamination by melting is limited and in most cases the strong criteria for free release can not be yielded. Such metal can be used for manufacturing cast iron components like containers or shieldings.

To manage the expected large amount of metallic waste resulting from the decommissioning of nuclear facilities recycling is well developed and accepted in Germany. By the high cost of intermediate and final storage of nuclear waste recycling is a very economical alternative (3, 4).

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