Preliminary Public Dose Evaluation in Support of the Development of the
November 2012
Rare Element Resources Bear Lodge Project
16
3.2.1
American National Standards Institute, Inc.
ANSI Standard N13.53-2009
Control and Release of Technologically Enhanced Naturally
Occurring Radioactive Material (TENORM)
(ANSI, 2009) provides guidance on occupational
exposure to TENORM. This document defines TENORM as:
“Naturally occurring radioactive material disturbed or altered from natural
settings or present in a technologically enhanced state due to past or present
human activities and practices, which may result in a relative increase in
radionuclide concentrations, radiation exposures and risks to the public and threat
to the accessible environment above background level. Technologically enhanced
means that the radiological, physical, and chemical properties of the radioactive
material have been altered such that there exists a potential for:
a)
redistribution and contamination of environmental media (soil, water, air,
biota),
b)
increased environmental mobility in soils and surface and groundwater,
c)
incorporation of elevated levels of radioactivity or increased accessibility
in products and construction material, or
d)
improper disposal or use of disposal methods that may result in
unnecessary or elevated exposures to individuals and populations via the
accessible environment.
TENORM does not include radiation emanating from or radioactivity present in ores, rocks, soils
and materials containing uranium and thorium subject to regulations under the Atomic Energy
Act, as amended” (ANSI, 2009).
Given the above definition of TENORM, all material containing thorium or uranium generated at
the BLP would be considered TENORM unless it is regulated by the NRC as source material.
ANSI-N13-53-2009 provides the following recommendations for occupational radiation
protection:
“Occupational doses received from TENORM shall be controlled under normally
encountered conditions such that the following limits shall not be exceeded:
-
annual dose limit of 100 mrem above background
-
annual average radon-222 concentrations in air of 4 pCi/L”
By providing the above limits for occupational dose, which are similar to the NRC’s dose limits
to members of the public, ANSI is essentially treating any worker potentially exposed to
TENORM as members of the public.
