National Physical Laboratory

Defining the problem

DiceBefore carrying out any radiation monitoring it is necessary to have some knowledge of the types of radiation that may be encountered and the environmental conditions.

Early planning of the measurements that will have to be made will identify any conditions that could make an apparently simple investigation more difficult. It also provides an opportunity to assess whether it will be necessary to obtain equipment or services that are not readily available.

Establish the extent and nature of the problem

WHO – is  requesting the investigation and measurements? Is the organisation an outside company or an internal group?

WHAT – is being monitored has to be clear. This may affect dose rate range, required levels of detection, the degree of complexity involved and corresponding investigation time. Is the monitoring of sinks and drains required? Is the area controlled, supervised or undesignated?

WHY – is the monitoring needed? Is it a routine contamination assessment, an incident or change of use of area etc? The monitoring strategy will be influenced by the reason for the survey.

WHEN – will influence the measurements as ambient dose rates may vary and other operations taking place in the vicinity may affect the results. Are access times restricted?


Type of Survey:

  1. A benchmark survey can be carried out to establish a level against which further surveys can be compared and confirm any historical information available.
  1. A routine survey can be performed in areas where radiological conditions  are well known and consistent
  1. A non-routine survey may be performed  where radiological conditions are unknown, difficult to predict or highly variable. These require a deeper level of planning.


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