The difficulties of instrument monitoring are technical complexity, the need for highly qualified personnel, and the cost of the apparatus. Quantitative monitoring is no less complex. All other forms of monitoring are indirect and liable to error, indicating the presence of something, but not revealing what. Whereas in the past total confidence was placed in the monitoring of facilities, the new conditions require that monitoring principles be changed so as to exclude individual access to nuclear materials by all service personnel, as has been done at the Physics and Power Engineering Institute, the Kurchatov Institute, and a number of other Russian facilities. The process of inventorying nuclear materials, as a form of monitoring nonproliferation of nuclear weapons and nuclear technologies, is very complex, especially when the materials are contained in waste, because the presence of radioactive impurities complicates stocktaking and monitoring.
Special monitoring takes place when nuclear materials are transported.
During legal transportation both the inspector and the person accompanying the load have to rely entirely on the accompanying documentation. It is only permissible to open containers and identify their contents precisely in laboratory conditions. The whole country has only tens of such laboratories, but hundreds of customs points. So an appropriately camouflaged load of radioactive material will pass through all stages of transportation without even arousing suspicion. The monitoring services try to keep well away from such loads, instinctively protecting themselves from radiation by means of time and distance.