Estimation of Radioactive Waste Quantities Arising During Decommissioning

Summary

The quantities of radioactive waste arising from the decommissioning of nuclear power plants, which are in operation, under construction or ordered in the countries of the European Community, have been roughly estimated.

As compared to earlier evaluations, measurements and decontamination work at the 237 MWe Boiling-Water Reactor KRB-A Gundremmingen, which has been shut down since 1977 after 11 years of operation, allowed a more precise forecast in two fields, penetration of contamination in walls and floors, and decontamination of metallic components and piping at a large scale.

The penetration of contamination has been measured at selected locations. The surfaces of almost all of the restricted area are covered by a protective layer as in most of the European nuclear power plants. 90% of the activity has been found to be cumulated in the coatings. An extrapolation to the total plant surface showed, that only about 500 Mg of waste would be generated during dismantling in the process of decontaminating walls and floors to values for unrestricted release.

Electrochemical decontamination of metallic components to unrestricted release has been demonstrated successfully at KRB-A at a large scale. The treatment of the decontamination solutions allowed the estimation of the quantities of secondary waste produced in the event of a decontamination of the whole machine-house equipment.

Supposing that, in the average, reactors will be dismantled definitively after a decay-time of at least 30 years after final shut-down, the arising quantities of medium- and low-level radioactive waste have been estimated for the different types of reactors.

Cumulation of the quantities shows, that only after the year 2050 an annual quantity would be reached, which is of the same order of magnitude than the waste produced annually by normal reactor operation (including reprocessing of fuel elements) in the years 1990 to 2000.