Decontamination of Cs from Japanese cedar (Cryptomeria japonica) via kraft cooking

To investigate the possibility of decontaminating 137 Cs-contaminated Cryptomeria japonica wood, kraft pulping was conducted and the Cs behavior in the reaction process was examined. 133 Cs-treated or 137 Cs-contaminated bark, sapwood, and heartwood chips of Cryptomeria japonica were digested using an aqueous solution of NaOH and Na 2 S. The pulp was washed with ultrapure water and filtered, after which the filtrate (black liquor) was collected. The black liquor was acidified to separate the supernatant and precipitation. The Cs ( 133 Cs and 137 Cs) concentrations in the chip and reaction products were measured. As for wood samples, the majority of Cs was present in black liquor, while only a minor amount of Cs was retained in the pulp (