Direct Radiation Monitoring
NNSA/NSO is responsible for routine radiological monitoring of NTS
operations, air, water, and plants and animals to ensure that the
public, NTS workers, and NTS plants and animals are protected from harm
due to past and present NTS activities.
Energy from radionuclides present in the NTS environment can be
deposited inside humans and animals through inhalation and ingestion.
Air,
water, and game
animals are routinely monitored
for radionuclides in order to estimate the internal radiation dose to
the public via inhalation and ingestion.
Energy absorbed from radioactive materials residing outside the body
results in an external dose. External dose is measured by direct
radiation monitoring. Direct ionizing radiation is monitored both on and
off the NTS from all sources including natural radioactivity from cosmic
and terrestrial sources.
The unit of measure used for direct radiation monitoring is gamma
radiation exposure, expressed as milli-roentgens per year (mR/yr). A
milli-roentgen is a measure of exposure in terms of a specified number
of ionizations in air. Generally, the dose resulting from an exposure to
the most common external radionuclides can be approximated by equating a
1 mR exposure with a 1 milli-rem dose.
Gamma radiation exposure data are used in the calculation of
radiation dose to the public from all internal and external
exposure pathways. Monitoring data are also used to document trends
in gamma radiation exposure rates on the NTS.
Onsite monitoring is performed by
NSTec, the M&O
contractor for the NTS, to determine annual exposure rates from natural
background radiation, from NTS historic contaminated sites (legacy
sites), and from current NTS operations.
Offsite monitoring is sponsored by NNSA/NSO and performed by
the Community Environmental Monitoring Program (CEMP) coordinated by the
Desert Research Institute (DRI) of the University and Community College
System of Nevada. This oversight program monitors direct radiation
within communities adjacent to the NTS. Its purpose is to identify
direct radiation exposure rates to the public which could be attributed
to past or present NTS operations.
Refer to the following Fact Sheet for more information:
What is
Radiation [PDF, 185KB]
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