At the Eurochemic site, 800 kg of combustible alpha waste containing ∼7 kg of plutonium were treated from March 1983 to July 1985 with the aim of concentrating the plutonium by oxidating the waste and converting it into a soluble form so that the established purification processes could be applied. In a batch process, shredded waste is oxidized with nitric acid in sulfuric acid. The digester content is then kept for several hours at digestion temperature to complete the dissolution of plutonium dioxide. The cold digester content is then filtered and the plutonium-containing filter cake is sent to the plutonium purification system. The off-gases generated are freed from the acids by scrubbing. The process is demonstrated in a plant with a daily throughput of 10 kg of waste. For the oxidation of waste and the dissolution of plutonium dioxide, a ring-type digester made of technical glass is used. The following principal results have been obtained: 1. Complete oxidation of the waste material is achieved within 15 min at a digester acid temperature of 250°C under oxidizing conditions provided by nitric acid. 2. At 250°C and with constant stirring of the digester content, a plutonium oxide to plutonium sulfate conversion rate of up to 99% is obtained within 8 h. 3. The average waste throughput achieved has been 4.1 kg per run (maximum of 10.4 kg). The plutonium decontamination factors were 1010 for the cleaned off-gas and 106 for the liquid secondary waste.