Washington nuclear sensors capable of detecting faintest amounts of radiation

The radiation detectors developed by the Pacific Northwest National Laboratory (PNNL) in Washington are so sensitive that they can detect trace amounts of radioactive material from hundreds of thousands of miles away.

The recent nuclear crisis in Japan has proven the system’s efficacy as the sensors were able to detect minute amounts of radiation in the atmosphere.

Far from being a public health concern, the amount of radiation from Japan detected on the west coast of the United States was far less than what individuals receive from natural sources and is testament to the sensors extraordinary sensitivity.

One PNNL scientist estimates that the levels of radioactive materials detected from Japan in Washington are about 18,000 times lower than what an average person gets on a daily basis from rocks and cosmic rays.

Harry Miley, a physicist with PNNL, further eased fears by explaining exactly how little radiation was detected. In an analogy he said imagine if every atom of air was a single BB and there were 260 Olympic-sized swimming pools filled with them. The amount of cesium-137 picked up by the sensors was equal to fifty BBs, while the amount of iodine-131 amounted to a single BB.

In addition, the Washington Department of Health has said that the levels of radioactive material detected from Japan have been steadily decreasing.

Kathryn Higley, head of Oregon State University’s Department of Nuclear Engineering and Radiation Health, said, “It’s kind of a blessing and curse to be able to detect this stuff at orders of magnitudes below where we would expect any health effects. It can scare the crap out of people when there’s really no need to be concerned.”

While not part of the Comprehensive Test Ban Treaty Organization’s network of radiation sensors around the world, the PNNL facility helps the organization track any radiation detected from nuclear weapons tests.

“Our stations are 100 times more sensitive than any other equipment out there,” said Lassina Zerbo, the chief scientist for the international nuclear treaty organization.

PNNL scientists have been providing the Environmental Protection Agency with constant updates on radiation reading levels as roughly half of the agency’s radiation sensors were not functioning at the time of the Japanese earthquake.

PNNL’s sensitive radiation monitors were developed after nearly ten years of research.

Several days after the incident at Japan’s nuclear reactors, minute amounts of Xenon-133 were first detected on the west coast of the United States.

According to Tony Peurrung, PNNL’s associate director, xenon-133 is the ideal indicator to catch nations conducting clandestine nuclear weapons tests as it is a gas that travels long distances unchanged. But the difficulty lies in sniffing out the gas from the vast amounts of air across the world.

Scientists developed technology that relies on xenon’s tendency to stick to cold surfaces and passed air over charcoal chilled to nearly minus 200 degrees.

PNNL also operates instruments that can detect fission products generated at the core of nuclear reactors like iodine-131 and cesium-137.

While the levels detected by these sensors are far too low to pose a public health threat, PNNL’s facilities have proven to be a valuable asset in detecting nuclear activity when it occurs around the world.