Aggressive chemical decontamination tests on small valves from the Garigliano BWR
In order to check the effectiveness of direct decontamination on small and complex components, usually considered for storage without decontamination because of the small amount, tests were performed on the DECO experimental loop. Four small stainless steel valves from the primary system of the Garigliano BWR were decontaminated using mainly aggressive chemicals such as HCl, HF, HNO(3) and their mixtures. Preliminary treatment with soft chemicals (oxalic and citric acid mixture) was assessed on two valves. Two valves were also decontaminated using ultrasound in aggressive chemical solutions. The main results of the experimental activities are: (i) the residual radioactivity in the valve is strongly dependent on the features of the valve, such as structural complexity; (ii) before deciding whether or not to decontaminate a small and complicated component, it is necessary to establish how to measure the residual radioactivity after treatment; (iii) after treatment with aggressive chemicals, the residual radioactivity is independent of the initial dose rate level; (iv) whatever the decontamination process may be, some hot spots remain; these may be higher than 1 Bq/g or 1 Bq/cm2.
Bibliographic Reference: EUR 12878 EN (1990) 61 pp., FS, ECU 6.25
ISBN: ISBN 92-826-1594-4
Record Number: 199011318 / Last updated on: 1994-12-01
Original language: en
Available languages: en