Cladding hull decontamination process: preliminary development studies

Thermal Impact on Geological Disposal of Hull and End Piece Wastes Resulting from High-Burn-up Operation of LWR and Introduction of MOX Fuels into LWR

“…To select the accompanying ratio of FPs and actinides adhering to hulls, the 2nd TRU report and other reports on the radioactivity of hulls [8][9][10][11] are available, which were determined by dissolution experiments of spent fuel pins taken from an LWR. Since those specimens used in the dissolution experiment may have had different features from hulls generated from reprocessing plant operation, we tentatively used the values adopted in the 2nd TRU report, which were speculated by assuming reprocessing plant operation conditions.…”

“…[8][9][10][11] Figure 13 presents these experimental data and our results calculated with the SWAT code when the accompanying ratios of actinides adhering to hulls are 0.2% (as listed in Table 4) and 0.05%, respectively. The values of alpha-radioactivity obtained by dissolution experiments are markedly lower than the values calculated with 0.2%.…”

“…8,15) Furthermore, removing the actinides in these layers from the base metal of cladding is known to be difficult. 8) However, the alpha-radioactivity of hulls resulting from reprocessing may be dominated by the actinides that adhere to the cladding surface during the dissolution process in the reprocessing plant. 16) Studies have shown that actinides adhering to the cladding surface can be removed using an appropriate reagent.…”

“…16) Studies have shown that actinides adhering to the cladding surface can be removed using an appropriate reagent. 8) Considering these aspects, small amounts of actinides may remain on the surface of the cladding after a dissolution process when the accompanying ratio of actinides adhering to hulls is 0.05%. Therefore, improvement of the dissolution process might be a key issue in reducing the number of waste packages, although some secondary waste may be produced.…”