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In the laboratory there are measurement instruments that can to be used to check the amount of radioactivity and where it is. Hence you can verify that neither you nor your fellow students are exposed to irradiation above the safe limits.
For people who are pregnant the rules for exposure are especially strict, nevertheless the amount of activity in most student course exercises are so small that there are no health concerns. In exercises which use larger amount of radioactivity, you will be specially briefed and this will be made quite clear to everybody participating. Do not hesitate to discuss any safety concerns with either your supervisor or radiation protection officer.
The ALARA (As Low As Reasonably Achievable) principle is the main guideline for all rad. work and should be followed at all times: No person should be exposed to more radiation than absolutely necessary to carry out the work. Therefore all work done with radioactivity should be done meticulous and planned in advance. Mistakes or carelessness could easily contaminate yourself and/or persons around you. To avoid this keep equipment that has been in contact with activity separated from equipment that is not contaminated and keep workbenches etc. tidy and clean.
When planning the exercise one should always think about the precautions one must use so that no active material is spread. Therefore certain rules must be followed:
Before you start your exercise, you are required to think through the work and operations you are going to perform and evaluate the associated likelihood of having an accident and how serious such an accident could be. This evaluation is required to be written in your journal and signed by yourself and your supervisor before you start any practical work.