Development of a Monolith-Type Package for Transport and Storage of Radioactive Steel with Particular Respect to Volume Reduction

NUCLEAR WASTE METAL RECYCLING/REUSE The Community's technological research aims at promoting the setting up of a regulatory framework to protect humans and environment within which industrial activities can develop. An example where particular efforts have been undertaken is the reuse/recycling of nuclear metallic waste. One of the most promising (particularly in Germany) recycling routes is the use of lowlevel radioactive steel to produce items for the nuclear industry, eg, packages for transport and/or storage of nuclear waste, which would save costly storage volume and, at the same time, the consumption of raw steel. This route is strongly considered for the possible German Konrad disposal site where packages of a maximum total weight of 20 Mg may be stored. Before casting large packages, specific knowledge was needed with respect to problems occurring in the presence of radionuclides, as well as knowledge on technical characteristics of the cast product. MELTING OF RADIOACTIVELY CONTAMINATED STEEL Melting of low-level radioactive steel has essentially been sponsored by the CEC during the last ten years in the framework of research shared-cost contracts, mainly with British Steel Corporation and Siempelkamp GieBerei. Whereas British Steel researched the possibility of retaining cesium in the acid slag by trials in industrial furnaces, Siempelkamp GieBerei has developed a melting facility authorised to process nuclear scrap with activity levels up to 74 Bq/g in a 20 Mg capacity induction furnace. After having molten 1500 Mg of this scrap, a single-purpose plant of 3.2 Mg capacity was built, authorized to melt scrap up to 200 Bq/g. Various series of specific melting tests have been performed from 1982 until now and over 5000 Mg of low radioactive steel have been processed by melting, the results of which have been or will be published by the CEC. A recent contract concluded with the CEA-UDIN at Marcoule aims at the melting of larger steel components from the primary circuit of the French G2/G3 GCRs in a 15 Mg arc furnace with respect to waste volume reduction and/or free release. DEVELOPMENT OF TRANSPORT AND STORAGE PACKAGES In the framework of the 1984-88 EC research programme, the development, qualification and testing of a Konrad VI type container (1.6 x 2 x 1.7 m) has been carried out by Siempelkamp Giesserei. About 20% ( 4.22 Mg) of steel < 10 Bq/g is reused for each container. Results of these developments were presented at PATRAM'89 in Davos, Switzerland. In 1986 investigations started within the framework of a research contract concluded with KRB Gundremmingen, Siempelkamp and GNS to develop a compact Konrad-type steel package, capable of storing steel up to 500 Bq/g. This paper mainly relates to these developments and shows its application to the KRB-A pilot dismantling project.