Method for dissolving mixture of uranium oxide with plutonium oxide and device therefor

PROBLEM TO BE SOLVED: To reduce the consumption of silver and electric power and to improve the through-put by applying two processes at the time of dissolving a powder consisting of a mixture of uranium oxide and plutonium oxide in a nitric acid solution and using bi-valent silver generated by electrolysis for the time in the same device for circulating an erosive liquid in the inside in a closed circuit. SOLUTION: In the same device for circulating the erosive liquid in the inside in the closed circuit by using the two processes, the powder consisting of the mixture of UO 2 with PuO 2 or a mixed oxide composed of (U,Pu)O 2 is continuously dissolved in the nitric acid solution. (1) The powder P and nitric acid are continuously supplied to the device covering the whole period and the solution S, in which UO 2 is mainly dissolved, is continuously extracted through a filter 5 provided in an accessory division 4. The flow rate is set to circulate so as to keep the concentration constant in the device. (2) After the supply of the powder P and nitric acid A and the extraction are stopped, PuO 2 accumulated in the 1st process is dissolved in the bivalent silver generated by the electrolysis 6 for the time and the dissolved solution is recovered at the time of finishing the process. COPYRIGHT: (C)1997,JPO