Comparison of decontamination techniques for reactor coolant system applications. Final report

This report presents the results of a comparison study of a group of cleaning techniques for possible in-place and off-system decontamination of the subsystems that make up the TMI-2 reactor coolant system. A matrix format was developed which permitted comparison of the techniques using a set of criteria, grading factors, and weighting factors which relate to the performance of the technique and importance of the criteria. Comparisons of applicability are made for the following groupings of reactor coolant system components: heat exchanger tubing; pipe one to 20 in. I.D.; tanks, filter housings, and pipe 28 in. I.D. and larger; tanks with internal components; and valves and pumps. The study indicates that the most promising in-place decontamination techniques are: fluid propelled scrapers, brushes, and pigs; rotating brushes/hones; and pressurized water jets. The most promising techniques for off-system decontamination include: pressurized water jets, ultrasonics, vibratory cleaning, rotating brushes and hones, FREON cleaning, and electropolishing