1. RadNet Update: What’s New, What’s Next?
Lowell Ralston
Radiation Protection Division
Office of Radiation and Indoor Air
U.S. Environmental Protection Agency
Low-Level Radioactive Waste Forum Meeting,
Alexandria, Virginia, October 2017

2. Overview Brief Review of RadNet System
RadNet History and Key Lessons Learned
Recent System Enhancements
Future System Enhancements
RadNet Update

3. What is RadNet?
Provides federal, state, and local governments and the public with continuous real-time radiation monitoring
Provides emergency responders with data in support of homeland security assessments during radiological and nuclear incidents
Informs public officials and the general public of the impacts resulting from major incidents and on ambient levels of radiation in the environment
To learn more, visit
RadNet Update

4. Description of the RadNet System
Air Monitoring Program - provides continuous air sampling and near-real-time radiation monitoring
Sampling and Analysis Program – provides quarterly (and more frequent) analyses of air, precipitation, and drinking water sample
Managed by EPA’s Office of Radiation and Indoor Air (ORIA):
National Analytical Radiation Environmental Laboratory (NAREL) in Montgomery, Alabama
National Center for Radiation Field Operations (NCRFO) in Las Vegas, Nevada
Radiation Protection Division (RPD) in Washington DC
Operated by volunteers from EPA Regions, and state, local, and tribal health services
Provides publically-available data
RadNet Update

5. RadNet Air Monitoring Program
Fixed Air Monitors
139 monitors nationwide
Each monitor has a high-volume air sampler and a 2” x 2” NaI(Tl) detector with gamma spectrometry capability
Monitors provide continuous air sampling and real-time monitoring of gamma radiation emitted from particulate radionuclides collected on the air filter
Air filters are sent to NAREL for additional analyses
RadNet Update

6. RadNet Air Monitoring Program (continued)
Deployable Air Monitors
40 deployable monitors are stored in a state of readiness at NCRFO
Each deployable monitor has both a high-volume and a low-volume air sampler for collection of radioactive particulates and gases.
Dual energy-compensated Geiger-Muller (GM) detectors measure ambient gamma exposure rate
Air filters and cartridges are sent to NAREL for analyses
RadNet Update

7. RadNet Air Monitoring Program (continued)
Near-Real-Time Data Reporting
NAREL receives over 3,000 fixed monitor reports each day (> 1 million annually)
NAREL relies on a combination of automatic software analyses and manual reviews to evaluate and approve or disapprove the publication of these reports
Fixed (and deployable) air monitors continuously record and store radiological measurements and other parameters in real-time
Each hour (or more frequently) monitors transmit encrypted data reports to NAREL by satellite telemetry or cell phone modem
RadNet Update

8. RadNet Air Monitoring Program (continued)
Near-Real-Time Data Reporting
Approved fixed and deployable air monitor hourly data reports are published on EPA’s Central Data Exchange (CDX) / RadNet website (
Data are updated every few hours
Users can select and download radiological data (as comma separated value or CSV files) from all operating monitors for various time ranges
Users can also display the data online as plots
RadNet Update

9. Air Monitoring Program (concluded)
Near-Real-Time Data Reporting
Users can also find near-real-time and laboratory data by State on EPA’s RadNet website (
Depending on the monitoring site, users may also be able to review air filter data and/or precipitation and drinking water analysis data previously available only in EPA’s Envirofacts
Air data may include gamma gross count rates, exposure rates, and air filter analyses
Precipitation and drinking water analysis data may provide gross beta/alpha concentrations and/or radionuclide-specific concentrations.
RadNet Update

10. RadNet Sampling Program
Air Filters, Precipitation, and Drinking Water
Air
Air sampling occurs continuously at 139 locations
A gross beta analysis of each filter is conducted at NAREL
Annual composite samples are analyzed by gamma spectrometry, and for isotopic Pu and U on a rotating schedule
During a major incident, samples are analyzed for radionuclide-specific concentrations
Precipitation
Sampling as precipitation occurs at 34 locations
Analyses on monthly composites for gamma, tritium and gross beta
During a major incident, sample are analyzed for radionuclide-specific concentrations
Drinking Water
Sampling occurs quarterly at 77 locations
Analyses include gamma, tritium and gross alpha/beta, and may include radioiodine and Sr-90
Additional analyses undertaken if values exceed pre-described levels (e.g., Ra-226, if gross alpha exceeds 2 pCi/L)
Results available at ( and at EPA’s Envirofacts website (
RadNet Update

11. RadNet History* Early Time Phase (1945-1970) Date(s) Events 1945-1962
The U.S., the Soviet Union, and Great Britain conduct hundreds of above ground nuclear weapons tests
1959
The Department of Health, Education, and Welfare (HEW) becomes responsible for monitoring radioactive fallout
1963
U.S., Russia, and England stop above ground testing (in accordance with the Limited Test Ban Treaty)
France and the People's Republic of China begin above ground nuclear testing
1970
EPA is founded and inherits radiation monitoring responsibilities from HEW
*Source:
RadNet Update

12. RadNet History (continued)
Middle Time Phase ( )
Date(s)
Events
France and China continue above ground nuclear testing
1973
EPA establishes ERAMS (Environmental Ambient Monitoring System)
France stops and China continues above ground testing
EPA uses ERAMS to respond to:
Chinese nuclear weapons tests (1976)
Three Mile Island (U.S.) nuclear power plant accident (1979)
Chernobyl (Soviet Union) nuclear power plant accident (1986)
Tokaimura (Japan) criticality accident (1999)
Hanford wildfires (U.S.) threatening the Los Alamos Nat. Lab (2000)
2001
Following the terrorist attacks on 9/11, EPA’s emergency response mission changes to support Homeland Security
RadNet Update

13. RadNet History (concluded)
Recent Time Phase (2002-Present)
Date(s)
Events
EPA begins system upgrades to better reflect new mission:
ERAMS sample data become available on the EPA website (2002)
ERAMS renamed RadNet (2005)
First near-real-time RadNet fixed air monitor was placed in service in San Diego, CA (2006)
Additional monitor are installed in major populations and in other geographical areas in the continental U.S., Alaska, Hawaii, and Puerto Rico ( )
2011
The Fukushima Daiichi Nuclear Power Plant accident in Japan is the first, real-world test of the new RadNet System
2011-present
EPA continues RadNet system enhancements, including:
Expansion and upgrade of the RadNet Air Monitoring Network
Enhanced data production, storage, and sharing
Increased use of RadNet data by other federal, state, local emergency responders, and the general public
RadNet Update

14. Key Lessons Learned What’s Important? How Can RadNet Help?
Decision makers, emergency responders, modelers, dose assessors, and the general public demand (and deserve) quality data, frequent updates, and clear messaging
RadNet fixed and deployable monitors provide continuous air monitoring and near-real-time data in major U.S. population centers and in wide geographical areas
Environmental sampling and analysis procedures and adequate measurement capabilities ensure timely results
RadNet programs follow strict quality assurance and quality control procedures
EPA staff ensure that RadNet data are fully explained and provide clear messages
Data sharing and collaboration with other federal, state, local, and tribal responders is vital
Homeland Security is a team effort, requiring the complete, comprehensive, and coordinated involvement of all responders to ensure the health and safety of Americans
Constant maintenance and system upgrades are crucial
Since RadNet is always “on,” EPA must ensure that aging components are quickly repaired or replaced
EPA constantly evaluates new technologies and upgrades to enhance capabilities
RadNet Update

15. What’s New?
RadNet Update

16. Recent RadNet System Enhancements
What’s New?
How Can Enhancements Help?
Exposure rate measurement capability has currently been added to 32 RadNet fixed air monitors
Exposure rate is easier to put in perspective than gamma count rate
The addition of RadNet exposure rate data will help radiation professionals communicate radiation data to the public
GM detectors will be added to all fixed air monitors during routine maintenance and repair
Access to RadNet air monitoring data on the CDX website has been greatly accelerated
New cloud-based servers and software continuously retrieve RadNet data from the NAREL server
Data are compiled for each monitoring location and are available for rapid download
Air filter and near-real-time monitoring data have been consolidated on the RadNet website
Air filter analysis results were previously only available on EPA’s Envirofacts website
Data can now be sorted, filtered and printed from can easy access toolbar
Air filter data tables can be used as teaching tools/visual aids, and provide context when looking at the RadNet system as a whole
RadNet Update

17. Recent System Enhancements (continued)
What’s New?
How Can Enhancements Help?
Simplified air filter tables display results for radionuclides typically seen after a radiological event
Simplified air filter data tables reduce the opportunity for confusion by indicating if the finding was a result, non-detect, or not analyzed
Data tables also help radiation professionals communicate radiation data to the public
Air filter data are now downloadable in multiple formats
Download formats now include CSV, Excel, and PDF, making it easier for users to obtain and analyze RadNet data
EPA and NOAA (National Oceanic and Atmospheric Administration) staff have launched a joint research project to refine and improve abilities to model the global-scale effects of a foreign nuclear incident
EPA and NOAA scientists hope to improve air modeling capabilities for foreign nuclear incidents by running NOAA’s HYSPLIT atmospheric transport and dispersion model using EPA’s RadNet data
Improved modeling will help EPA respond more quickly and effectively to future events similar to the Fukushima nuclear power plant accident
RadNet Update

18. Recent System Enhancements (concluded)
What’s New?
How Can Enhancements Help?
EPA is now receiving data from U.S. IMS (International Monitoring System) radionuclide stations supporting the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO) in Vienna, Austria
IMS data are produced by continuous monitoring of radionuclide particulate and gas releases at 11 locations within the U.S. and its territories
The U.S. Air Force Tactical Air Command National Data Center is responsible for sending the data to EPA
During an emergency, EPA will use the U.S. IMS data to check RadNet data, expand coverage and inform environmental modeling
EPA has expressed a strong commitment to collaborating with the Department of Energy (DOE) and Department of Defense (DoD) on radiation monitoring data and projects
EPA will shortly be providing interactive graphs showing gross beta air filter data and downloadable, near-real-time RadNet data compiled monthly for each monitoring location
Air filter results graphs will present new and historical beta count rate data over time with reference lines for major radiological incidents
Compiled files will greatly facilitate user access and assessment of RadNet data
RadNet Update

19. What’s Next?
RadNet Update

20. Future RadNet System Enhancements
What’s Planned?
How Can Enhancements Help?
Improve communications capabilities of RadNet fixed monitors
Upgrading cell phone modems to 4G technology will provide faster data download speeds and better two-way communication between NAREL and the monitors
Upgrading to a new, high-speed internet satellite system will permit two-way communication, faster downloads, and redundancy in the communications system
Improve detection capabilities of RadNet fixed monitors
Current NaI(Tl) detectors have limitations, including temperature instabilities, the need for gain stabilization using Am-241, and low resolution of gamma peaks
EPA will evaluate suitable replacement detector systems that address limitations
Address limitations of current RadNet deployable monitors
Current deployable monitors are heavy and bulky, lack spectrometric capability, and lack reliability in control and communication systems following transportation
EPA is considering alternatives to the current deployable monitors
RadNet Update

21. Future System Enhancements (concluded)
What’s Planned?
How Can Enhancements Help?
Improve RadNet data sharing with federal, state, local, and tribal responders
EPA will explore ways to export RadNet near-real-time monitoring data and sample analysis results automatically during major radiological events to a number assessment organizations, including the:
RadResponder Network (
Federal Radiological Monitoring and Assessment Center (FRMAC) (
RadNet Update

22. Thank you!
Special thanks to Dan Askren (NAREL), Jessica Wieder (RPD), and Angela Shogren (RPD)
RadNet Update