Characterisation of residues and reprecipitates from dissolver solution of highly burnt LWR fuel
The residue remaining after dissolution of spent fuel under PUREX type conditions has metallic and oxide components. The amount and composition of the metallic part of the residue depend mainly on the irradiation conditions of the fuel; the oxide part is largely influenced by the dissolution process conditions, especially by the nitric acid concentration. The amount of residue left after dissolution is about 2 wt % of the fuel and is lowest for the fuel which was dissolved in HNO(3) of high concentration. In comparison to other studies carried out on low burn-up BWR and PWR fuels, an exponential increase of the residue amount with burn-up is observed. Apart from these primary residues, secondary residues are found in the dissolver solution, due to reprecipitation phenomena. The influence of the parameters studied (HNO(3) concentration, storage temperature and storage time) on the composition of the precipitate is evident. A lower acidity favours the precipitation of all elements, except I. Storage at higher temperature sometimes reduces considerably the amount of precipitate except for a few elements such as Zr, Mo, Ba and Pu. These elements continue to precipitate in significant amounts even after one week.
Bibliographic Reference: Paper presented: RECOD '94 - 4th International Conference on Nuclear Fuel Reprocessing and Waste Management, London (GB), April 24-28, 1994
Availability: Available from (1) as Paper EN 38127 ORA
Record Number: 199410300 / Last updated on: 1994-11-28
Original language: en
Available languages: en