Radiation shielding of premises
The radiation shielding of radiation appliances and the premises of use of radioactive substances must be planned and constructed in a way that ensures that use of radiation does not cause a hazard. The workload and usage methods of the equipment and sources as well as the use of the premises must be taken into account already at the planning stage. Unauthorized acquisition of radiation appliances and radioactive materials must be prevented.
The radiation shielding of the premises of use and the surrounding rooms must be planned and constructed in a way that minimizes radiation exposure as much as reasonably possible and ensures compliance with the dose limits set forth in the Radiation Decree. The planning of the premises must also take into account the potential exposure from multiple radiation sources.
Based on the Radiation Act, STUK specifies the safety requirements that must be considered in the planning. Some of these requirements are presented in Guide ST 1.10, and additional instructions for radionuclide laboratories are presented in Guide ST 6.1.
The shielding and other arrangements of the premises must be demonstrated to STUK when applying for a safety licence. If necessary, STUK can issue a preliminary statement on the shielding of the premises of use and the surrounding rooms. The shielding at the place of use will be verified at a commissioning inspection by the STUK.
The radiation appliances, radioactive substances and their usage and storage locations must be marked with the appropriate warning signs. Warning and prohibition signs are available on the STUK website.
Protection of workers
The radiation exposure of workers must be determined in advance, and the assessment must take into account the possibility of abnormal incidents. Based on the possible exposure, the working areas must be classified as controlled and supervised areas, and the workers must be classified to the applicable radiation work category.
Controlled area refers to an area where special precautions must be taken for protection against radiation and for preventing the spread of radioactive contamination. The working conditions at supervised areas are monitored for protection against radiation. Detailed instructions on the classification of premises are presented in Guide ST 1.6.
The responsible party must provide the workers with the necessary instructions on working in controlled and supervised areas and on protection against radiation.