Belgoprocess (Belgium)

The EUROCHEMIC reprocessing plant, established by an international consortium of 13 OECD countries, operated from 1966 to 1974 to process fuel from power reactors and research reactors.

Abstract Up to 1998, spent ion exchange resins have been fed to the incinerator in combination with various other solid combustible wastes at Belgoprocess. However, thanks to sustained efforts to reduce radioactive waste production in all nuclear facilities in Belgium, the annual production of solid combustible waste is now much too small to allow this practice to be continued. Since the incinerator at Belgoprocess is not capable of treating spent ion exchange resins as such, it was decided to adopt the use of foam as a carrier to feed the resins to the incinerator. The mixture is a pseudohomogeneous charged foam, ensuring easy handling and allowing incineration in the existing furnace, while a number of additives may be included, such as oil to increase the calorific value of the mixture and accelerate combustion. The first incineration campaign of spent ion exchange resins in a triphasic foam mixture, in conjunction with other liquid and solid combustible wastes, will be started in January 2000. The foam, comprising 70% by weight of resins, 29% by weight of water and 1% by weight of surfactant will be pulverized in the incinerator through an injection lance, at a feed rate of 40 to 100 kg/h. The incinerator and associated off-gas treatment system can be operated at standard conditions. Belgoprocess is the subsidiary of the Belgian national agency for the management of radioactive waste, known by its Dutch and French acronyms, NIRAS and ONDRAF respectively. The company ensures the treatment, conditioning and interim storage of nearly all radioactive waste produced in Belgium.

Abstract Governments and the nuclear sector realize more and more the importance of waste characterization in the end cycle. Several methods are available for radiological characterization. Each method has his advantages and disadvantages in regard to the definition of the operational range based on the waste characteristics and the knowledge of the waste. The decision on what technique(s) to be used will be based on the required precision, accuracy, detection limit and isotopes to be declared for a certain purpose and on the related costs. Recently Belgoprocess, the Belgian waste treatment facility, has performed large efforts and investments to assure a good waste characterization.

A survey is given of the main activities of the Belgoprocess Company, with special emphasis on safety precautions. The routine sampling program for internal contamination consists of urinary and faecal sampling, among others. Faecal samples sometimes reveal low contamination levels. This contamination can be considered as low-level, frequent, and intermittent. No distinct correlation is found with another control technique. A survey is given about uncertainties that might hamper a representative sampling and/or a correct interpretation of the obtained data. Reference is made to the dosimetric models regarding complexity and uncertainties.

Simulated Annealing and a variant we call Locally Optimized Simulated Annealing are applied to an industrial problem : a collection of small containers of nuclear fuel have to be grouped in subsets that are as homogeneous as possible with respect to several criteria. The two algorithms are compared on real data and the sensitivity to parameter choice is explored.KeywordsGroupingSimulated AnnealingCombinatorial Optimization