Environmental Health and Safety UG-RSOG -025-2004
A Guide to Nuclear Radiation Shielding
at U of Guelph
Prepared November 11th, 2005
1. Introduction to the revision 001 Document
This Guide was written in order to address the need for information on the appropriate shielding of personnel against external ionizing radiation fields during the conduct of their work with nuclear substances and other radiation sources. This Document focusses on ionizing radiation from "nuclear sources", meaning radioactive and artificial radiation sources such as accelerators, but is NOT directly intended for X-ray system users. A separate guide, RSOG-026 (in preparation) addresses protection from radiation fields arising from X-ray system operation. Further, with the exception of thermalized neutrons, protection from radiations of such high energy or character that may induce nuclear transmutations is also not addressed here: see RSOG-027, (in preparation.) Policy and regulation are also NOT explicitly addressed in this document. However, various threshold values indicated by statute or regulation may be mentioned for expository purposes. Further, one is always expected to follow and respect the ALARA principle in implementing and radiation protection measure, such as shielding. What this may mean in practice is that, in some circumstances, shielding as a method alone may not be sufficient for protection of personnel, and that one must also not disregard or overlook any possible INTERNAL exposure (i.e., contamination) concerns. While trustworthy shielding values are presented for many common situations in this Document, the best test of shielding effect is ultimately a survey with a trustworthy exposure meter. Double checking any estimated shielding for appropriate protective value on an actual system rounds out a diligent radiation protection design. Such testing is deemed a necessity, and will, as a side benefit, reveal any initial contamination in an experimental setup.

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