More than 20 years of evaluation work on various radiological/nuclear detection devices has given the Technical Testing and Analysis Center (TTAC) an opportunity to secure an array of specialized equipment in its lab space, with the result that the center at the US Department of Energy’s Oak Ridge National Laboratory (ORNL) can perform a full range of testing on-site.
The advantage of not having to send devices out to other locations for evaluation is one that users ranging from federal agencies to private manufacturers appreciate. “We are the only national laboratory in the country with all of our capabilities under one roof,” said Christina Forrester, R&D staff member at ORNL.
TTAC, a part of ORNL’s Electrical and Electronics Systems Research Division, had its genesis in the former instrumentation and controls division at ORNL; it was first known as the Environmental Effects Laboratory, and its purpose was to make sure that radiation protection instruments could function in the environments they were expected to operate in.
Today, TTAC ensures that devices sent by various users are fully operational and conform to established standards, with the ability to perform climatic, electromagnetic, mechanical, and functional testing of devices with industrial radionuclides, medical isotopes, or special nuclear material.
The center’s climatic testing evaluates devices in various temperatures, humidity levels, air pressures, dust, and even salt fog to simulate a maritime environment. Electromagnetic tests evaluate how devices may operate around electrical conditions such as radio frequencies and magnetic fields—especially important now with widespread cell phone use—as well as line noise and voltage variation, Forrester noted. Mechanical testing may involve shocks and drops, vibrations, and other conditions a device may experience inside environments such as cars, airplanes, and helicopters. TTAC’s lab space also allows for aerial systems and materials testing, as well as full standup testing of large systems.
The lab maintains a large inventory of radiological sources, and has the means to procure short-lived sources as well as the ability to lease large industrial sources. “When testing the short-lived radiological materials, it is extremely important that we test in the most efficient way to capture any susceptibilities the device under test may have, while completing the work in a limited amount of time due to the decay rate of the source,” Forrester said.
For instance, the center requests the arrival of medical isotopes like Technetium-99m early in the morning because it decays within 6 hours. “If the source doesn’t arrive early enough, we may end up being here after hours in order to meet the required testing activity,” she said. “This means we may have to adjust our schedule very quickly, but the staff is flexible and always willing to accommodate.”
Testing along Old Bethel Valley Road
Earlier in 2016, TTAC tested seven vehicle-mounted mobile detection systems against technical standards in its labs and also along Old Bethel Valley Road on the ORNL campus under the sponsorship of the Department of Homeland Security’s (DHS’s) Domestic Nuclear Detection Office. Federal, state, local, and tribal agencies typically use such mobile systems in detecting illicit trafficking of radioactive materials.
The researchers moved radiological sources past detection devices at varying speeds and conducted static testing with sources in a spherical pattern.
Researchers performed a portion of the testing using industrial sources such as those that might be routinely shipped, notably cesium-137 and cobalt-60, which were leased from a third party. The sources were contained in standard Department of Transportation shipping containers, and then certified transportation personnel strapped the containers in and operated the vehicles.
The test was complex but successful, with all data collected and reports produced for the device manufacturers and users on schedule.
One technical challenge for the researchers was that although some of the devices were off-the-shelf, others were still in final development and did not have user interfaces. The TTAC staff worked around that issue by writing their own scripts for capturing data and packaging it in a way that allowed for sorting, Forrester said. Vendors also provided on-site training for the TTAC staff to ensure that the parameters of the large systems were properly set for accurate operation.
Other projects for TTAC include working with the Nuclear Material Detection and Characterization Group on their efforts to evaluate radiation portal monitor panels for potential degradation in equipment deployed around the world; this work is sponsored by the Nuclear Smuggling Detection and Deterrence program at the National Nuclear Security Administration. TTAC is using its environmental chambers to perform humidity tests, as well as vibration testing of those panels.
There is also electromagnetic compatibility/interference testing to determine if equipment is susceptible to radio frequencies, emissions testing to determine which frequencies the equipment may emit, conducted disturbances, and electrostatic discharge testing, Forrester explained.
TTAC also works with the Defense Threat Reduction Agency (DTRA) to test prototype devices developed specifically for DTRA and their users. This can include backpack systems, mobile radiation detectors, imaging systems, and handheld radiation detectors.
The work TTAC does is important to its sponsors and ultimately demonstrates weaknesses that manufacturers can use to improve their systems, Forrester noted. For example, TTAC found flaws in a system deployed overseas that would have allowed electrical transients and potentially caused a failure of the device over time.
Closer to home, TTAC also performs tests for ORNL researchers. In one example, a scientist sought testing on six samples of substrates with different coatings to see how they responded to a salt environment, Forrester said.
Standards development, validation
Because of the center’s long experience in testing, TTAC test engineers have become involved in standards development and validation of those standards.
TTAC researchers have helped establish the qualification requirements and test protocols for all International Atomic Energy Agency electrical equipment that the agency fields for detection and monitoring—for instance, uninterruptible power supplies, battery chargers, and other critical functionality for equipment used to safeguard or monitor nuclear materials.
In the United States, TTAC members routinely sit on the working committees for the flagship radiation detection standard for the DHS—ANSI N42. The ORNL center has evaluated all of the ANSI N42 standards and was a key participant in DHS’ ITRAP+10 (illicit trafficking radiation assessment program) to evaluate mobile systems, radiation portal monitors, and spectroscopy-based radiation portal monitors, Forrester explained.
“Through that testing, we identified several areas where the standard had weaknesses or needed to be changed. So those standards went back into revision, and in the last year or so, we have been reviewing those and are heavily involved in validation,” she said.
“Rather than just publishing standards based on our committee work, we validate them using our equipment here and devices borrowed from vendors,” most of whom have offices just outside the ORNL campus, Forrester added. In one instance, technicians discovered that a test could not be performed as written, so a change in wording was suggested and then adopted by the standards committee.
The TTAC group has patented its own technology as well: a laser-based item monitoring system that tracks stored material—not necessarily nuclear in nature.
Forrester noted that the center can also conduct user training, including the production of videos for use in training personnel to properly operate detection devices.
