| 摘要 |
<p>1306408 Processing spent nuclear fuel KERNFORSCHUNGSANLAGE JULICH GmbH 26 May 1970 [27 May 1969] 25260/70 Heading G6R [Also in Division C1] Uranium, thorium, and protactinium are separated from an oxide mixture by dissolving the mixture in a pyrosulphate melt, obtaining an aqueous solution from the melt, passing the solution through an adsorbent to adsorb protactinium, concentrating the residual solution to precipitate sulphatothorate, and extracting uranium from the solution with a solution of tributyl phosphate. Nuclear fuel containing uranium and thorium is reprocessed by removing canning material, converting to oxides if necessary, dissolving in potassium pyrosulphate at 800‹ C., forming an aqueous solution of the melt, and removing insoluble fission product sulphates. The solution is then passed through an adsorption column of silica gel or glass to remove protactinium, which may be recovered by means of oxalic acid solution or concentrated H 2 SO 4 . The residual solution is concentrated to precipitate thorium as sulphatothorate which is separated. Aluminium nitrate and nitric acid are added to the remaining solution, from which uranium is extracted with hydrocarbon solution of tributyl phosphate in a multi-stage mixer-settler. Uranium is returned to aqueous phase by re-extraction with dilute nitric acid.</p> |
