In response to radiological accidents, first responders and expert staff can be exposed to high radiation doses of up to 500 millisieverts. In training this is neither permitted nor justified.
Thus, realistic training with real radiation sources is impossible.
The revolution in radiological training is VirtuRAD. VirtuRAD allows the staff to observe doserates of any order exactly as if they really measured them. The simulated doserate is calculated based on the position of the measurement device and is shown on its screen. The staff can realize the inverse-square law, use shields and apply advanced methods for spotting radiation sources - without receiving a single microsievert of dose.