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Radiation Protection

What is the effect on the DCGLW when I decrease or increase the survey unit size?

Generally, more measurements than are necessary could be taken if the survey unit size is smaller than the modeled survey unit size. However, if the size is not significantly smaller, it is usually simpler to make the number of measurements calculated, rather than re-deriving a new DCGLW with new modeling. If the survey unit is larger than what was modeled, dividing the survey unit into sizes that conform to the model will address the difference. Alternatively, the DCGLW can be recalculated to conform with the larger survey unit size by inserting the larger survey unit size into the model. In either case, approval from the regulator is recommended before making changes to survey unit sizes.

For more information on the MARSSIM process, visit Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM).

Return to Frequent Questions about Radiation Regulations, Guidance and Compliance.