RadNet Supports Radiation Monitoring Efforts for the Nuclear Industry

Extensive monitoring programs are in place to protect the air, soil and water around nuclear sites, as well as ensure adherence to state and federal regulations and internal policies. The nuclear industry’s unique fuel source and related operations makes monitoring radiation levels a central focus. While the nuclear industry itself is responsible for many of the radiation monitoring systems, ensuring the public’s health and safety is a collective effort among the industry and agencies. In addition to establishing guidelines, state and federal regulators have programs that support environmental monitoring. One example is the U.S. Environmental Protection Agency’s (EPA) RadNet system.

The nationwide RadNet system monitors the air, precipitation, drinking water and pasteurized milk to track radiation in the environment. Over time, RadNet sample testing and monitoring results show the normal background levels of environmental radiation. The system will also detect higher than normal radiation levels during a radiological incident. The RadNet system has been used to detect and track radioactive material associated with foreign atmospheric nuclear incidents such as the Chernobyl disaster in Ukraine and the accident at the Fukushima nuclear power plant in Japan.


RadNet has more than 100 stationary radiation air monitors in 48 states. Monitors are distributed across the U.S. according to population and geography. Another 40 portable monitors can be deployed to any location in the U.S. RadNet runs 24 hours a day, 7 days a week, and sends near-real-time measurements of beta and gamma radiation to EPA’s National Air and Radiation Laboratory (NAREL). If there is a meaningful increase in radiation levels, laboratory staff investigate immediately.

By looking at this data over time, scientists recognize what is "normal" or "background" radiation in that location. Any reading above normal will trigger an alert to scientists to review the data. In the event of a radiological incident, RadNet data can be used to confirm that no excess radiation is present in an area or to help decision-makers decide whether appropriate actions need to be taken to protect the public.


RadNet and its forerunners have been collecting environmental radiation data for more than 50 years. The first samplings took place in the late 1940s when above ground nuclear blasts occurred in the U.S., Russia and Great Britain. Nuclear reactor incidents in Europe in the 1950s increased concerns about radiation releases and lead to the establishment of additional monitoring programs. The Tritium Surveillance System (TSS) was set up in 1964 to monitor concentrations in major river systems downstream of nuclear facilities and later expanded to drinking water. By 1973, the data collected was being reported in quarterly Environmental Radiation Data (ERD) reports. Programs and data evolved in conjunction with state and industry efforts. By 2002, RadNet data became available on the EPA website.

The health and safety of the environment and communities is a top priority for the nuclear industry. Resources such as RadNet supplement and enhance the industry’s efforts to ensure safe levels of radiation and the ability to manage any radiological events. To learn more about RadNet, click here to visit the website.

RadNet in Action
RadNet has been an important part of monitoring global nuclear incidents. Following the 1986 Chernobyl incident in Russia, there was almost no data available on the extent of radioactive fallout, so the U.S. monitored radioactivity levels to provide information and ensure the food supply was safe. The EPA also monitored the plume from Chernobyl using data from the Environmental Radiation Ambient Monitoring System, a forerunner of RadNet. The system first detected radiation from the accident at ground level on the West Coast one week after the accident. Radioactivity levels were somewhat higher than usual. However, they were well below levels that would have required any action to protect public health.

In 2011 following the Fukushima incident in Japan, RadNet deployed portable monitors in Alaska, Hawaii and the Pacific Territories. RadNet detected miniscule quantities of radionuclides associated with the Fukushima incident. A review of the data showed the levels were thousands of times below any level of public health concern and continuing to decline, so RadNet resumed its routine sampling schedule. To keep the public informed about Japan, a website was launched which displayed near real-time radiation monitoring results.

Access RadNet Data:
Envirofacts' RadNet Database - Laboratory analysis results from air monitor filters and samples of precipitation, drinking water, and milk. Includes both current and historical data needed to estimate long-term trends.

The RadNet Database in EPA's Central Data Exchange - Near real-time environmental radiation data from fixed and deployable monitors.

Environmental Radiation Data (ERD) - Electronic and print journal of EPA's National Analytical Radiation Environmental Laboratory (NAREL).

Click here for the Nuclear Energy Institute’s website and the industry’s perspective on the environment.
Click here for an NRC fact sheet on environmental monitoring.
Click here for a previous NIC article on groundwater monitoring programs.

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