CORVALLIS, Ore. – Nuclear physicists and engineers have developed an important new tool to monitor the operation and use of nuclear reactors, which could play a significant future role in preventing nuclear weapon proliferation, while allowing the peaceful use of nuclear power under safe, verifiable conditions.
The findings are based on the successful use of an “antineutrino” detector, which the National Academy of Engineering has defined as one of the “grand challenges” for engineering.
The research was done by nuclear engineers and physicists from Oregon State University, Lawrence Livermore National Laboratory, and Sandia National Laboratory, and has been published in the Journal of Applied Physics.
In practice, the new device can tell whether a nuclear reactor is operating and the type of fuel that is being used or produced – reactors that produce electrical energy typically use uranium and in the process produce plutonium. There is no way to block the acquisition of data from the antineutrino detector, and it can be obtained at a distance, with or without the cooperation of the reactor operators.
“This innovative new detection technology can give us more confidence that nuclear reactors are being appropriately used for energy production,” said Todd Palmer, an OSU associate professor of nuclear engineering. “If substantial quantities of material were being produced or diverted for nuclear weapons, we could detect this. That’s a pretty strong deterrent to inappropriate uses of nuclear power reactors.”
An antineutrino is a tiny packet of subatomic energy that is produced when a radioactive nucleus decays by emission of a beta particle. They are ordinarily produced in very low numbers, are not routinely present in background radiation, and cannot be easily shielded by lead or other materials.
In a nuclear reactor, antineutrinos are one of the byproducts of the fission of uranium, and are then produced in much higher numbers.
However, they don’t really interact much with other materials, and even then only through gravitational and other very weak forces. Because of that it has been very difficult to detect antineutrinos. The new detector, which its developers say is functional and durable enough for field use, can do that. With continued development, this technology could allow a nuclear safeguarding agency to tell from a substantial distance not only when a nuclear reactor is operating and its power level, but also what the proportional amounts of uranium and plutonium are.
“Prior to this, there was really no certain way to tell what is going on inside a reactor without shutting it down and inspecting it, which is disruptive to the operation of the plant,” Palmer said. “With this new approach, we can tell what is happening, and verify that it is what is supposed to be happening if the reactor is being used for appropriate energy production purposes.”
“This is an important technological advance,” he said. “A lot of people didn’t think it was possible.”
Two prototype antineutrino detectors using this technology are already operating in San Diego and working well, researchers say. Improvements are still possible and needed in detection efficiency and speed, they said.