Cleaning nuclear facilities during routine maintenance or after unexpected incidents - or urban streets after a dirty bomb detonation - means the exact location of radioactive contaminates must first be determined. This is typically done in a time-consuming manner with personnel scanning with portable count-rate instruments.
This, however, is not always efficacious. Some areas may be too small for counters to reach or too large to be efficient. Contamination may have washed into hard-to-access storm drains.
To address this issue, scientists at the Savannah River National Laboratory have developed an innovative new technology the size of a soccer ball that can locate and map radioactive contamination anywhere in the environment.
According to the researchers, the device, called GrayQb, was developed to allow inexpensive, remote-controlled radiation mapping in harsh environments, such as hot cells and glove boxes to aid in locating contamination. Hot cells and glove boxes have been used in the nuclear industry since the 1950s for production and experimentation.
“The advantage of GrayQb is that the location of contamination inside the cells can be quickly and cost-effectively identified,” said SRNL senior engineer Rusty Coleman. Coleman said having this knowledge allows for quicker decontamination and final disposition of contaminated equipment.
Not only is GrayQb valuable in enclosed spaces, it can be used for outdoor locations such as urban environments, farmland, and storm drain outfalls.
When compared to current technology, if a so-called ‘dirty bomb’ is detonated, the researchers said GrayQb can more accurately locate contaminated areas and locations of concentrated radioactive material.
“The current technique is to perform sweeps of a suspected area of contamination with non-directional detectors,” said principal engineer Eduardo Farfan. “This involves many man-hours and exposes personnel and the public to unnecessary radiation dose.”
Farfan told Homeland1 the SRNL technology uses multiple layers of phosphor storage plates that are highly sensitive to radiation. PSPs are commonly used for imaging when the radiation source and dose rate are known, such as in medical imaging and non-destructive testing. PSPs allow high-resolution, high-sensitivity gamma detection, providing micrometer resolution and revealing milliroentgen dosage levels.
“Even in low dose rate environments, GrayQb can be used to expedite radioactive contamination cleanup operations,” Farfan said.
After radiation is tracked, the PSPs from GrayQb are read on a commercially available scanner in which special software records and translates the exposure data to define the type and location of the radioactive source.