Background
Many practices involving radioactive substances generate materials with potential or known radioactive contamination. Clearance of materials means a decision that such materials can be released from regulatory control and used or disposed of without restrictions from a radiation protection point of view. According to regulations issued by the SSM, such decisions must be based on thorough measurements of the activity content and it must be shown that the activity content is below certain values, so called clearance levels. Clearance of metals for recycling is a well-established part of the system for management of radioactive waste in Sweden. Metals are being cleared both directly from the practices or facilities and after treatment in the waste treatment facilities in Studsvik.
In accordance with international recommendations and requirements, the SSM regulations on clearance of materials are based on the criterion that no member of the public should receive a yearly radiation dose that exceeds in the order of 10 microsieverts. In this context, workers that handle cleared materials are regarded as members of the public.
Both the clearance levels in the SSM regulations and in the permission for clearance of metallic ingots from the Studsvik melting facility are based on recommendations from the European Commission (RP 122 part 1 and RP 89, respectively). The clearance levels in the regulations will soon be changed to the values given in the new European directive on radiation protection (Directive 2013/59/Euratom). No change is foreseen concerning the recommendation RP 89.
Dismantling of nuclear power reactors in expected to generate large amounts of cleared scrap metals in Sweden in the near future. In this context, SSM has identified a need to review the applicability of the European recommendations in Sweden and to investigate if the clearance levels give a sufficient level of protection for members of the public. SSM therefore initiated the study that is presented in this report.
Results
The project has given valuable information on the current procedures for handling and treatment of scrap metals and on the possible dose consequences when applying the clearance levels of Directive 2013/59/ Euratom and the recommendation RP 89.
Objectives
The study indicates that the clearance levels of Directive 2013/59/Euratom give sufficient protection for people handling cleared scrap metals and by-products of metal recycling. For some gamma-emitting radionuclides, the study indicates that the clearance levels of the European Commission recommendation RP 89 do not give sufficient protection when transporting large amounts of scrap metals.
The study can serve as a basis for SSM:s continued work on regulation and supervision of clearance of materials.