Safety_Series_025_1968 - gnssn - International Atomic Energy ...

This publication is no longer validPlease see http://www.ns-iaea.org/standards/A more precise evaluation of persistent internal contaminationcan be made quite indirectly from the results of environmental monitoring.If the atmospheric contamination at. any particular placeand time is known accurately, the quantity of radionuclides whichan individual worker has absorbed by inhalation can be deduced fromthese data. In practice an attempt is made, by judicious and fr e ­quent sampling, to obtain a fairly accurate picture of the atm osphereof the work place, a procedure which requires, great skill andcare. The method may be applied in uranium mines or radiochemicalplants. For every worker, the type of work done and the time spentover each operation must be known, and as representative data aspossible on the atmospheric pollution of the work place must be derivedfrom samples in flasks or on filters and from continuous recordingequipment. These data are weighted according to the typeand duration of the work done by the individual concerned. By determining,for an average individual, the quantities of air inhaledand the modes of absorption, the body burden at the end of a day,a week or a month may be deduced. These methods are undoubtedlycapable of offering excellent crosschecks in determining the bodyburden of radioactive substances which are difficult to measure directlyand slow in elimination, as is the case with alpha emitterssuch as radium or plutonium.4. 1. 2. Radiological monitoring organizationPersonnel monitoring should be carried out to determine thelevels of external irradiation and of radioactive contamination towhich the worker has been subjected. The methods described inearlier paragraphs are to be applied for this purpose.4. 1. 2. 1. Monitoring of external irradiation4.1. 2. 1. 1. Factors governing the organization of monitoring. Personnelmonitoring for external irradiation can and should be carriedout in a completely systematic manner, and the available methodsyield perfectly reliable data on the radiation doses to which personnelare exposed. However, the choice of method is governed by certainfactors, the principal of which are the following:(1) Spatial distribution. Irradiation of the body may be either wholeor partial, and among cases of whole-body irradiation some may bepractically homogeneous, such as exposure to gamma rays. In the91