Cosmic Rays Help Diagnose Nuclear Reactors
October 18, 2012

Cosmic Rays Help Diagnose Damaged Nuclear Reactors From Space

Brett Smith for - Your Universe Online

They may not be using alien technology, but physicists from Los Alamos National Laboratory are looking to outer space for help in diagnosing a damaged nuclear reactors like the one that caused massive evacuations around the Fukushima Daiichi plant in March 2011.

According to their report in the journal Physical Letters, the research team from Los Alamos National Laboratory has found a way to use cosmic ray radiation to accurately create a detailed image of the inside of a damaged reactor core. This technology could be used to implement more effective cleanup operations, since knowing where radioactive materials are located is key to implementing effective strategies.

In their experiment, the team of scientists compared two methods for detecting hazardous material: a traditional transmission method and the Los Alamos´ scattering method for cosmic-ray radiography. According to the researchers´ report, the latter method proved to be superior.

“Within weeks of the disastrous 2011 tsunami, Los Alamos´ Muon Radiography Team began investigating use of Los Alamos´ muon scattering method to determine whether it could be used to image the location of nuclear materials within the damaged reactors,” explained the study´s lead author Konstantin Borozdin of Los Alamos´ Subatomic Physics Group.

“As people may recall from previous nuclear reactor accidents, being able to effectively locate damaged portions of a reactor core is a key to effective, efficient cleanup,” he said. “Our paper shows that Los Alamos´ scattering method is a superior method for gaining high-quality images of core materials.”

Cosmic-ray, or muon, radiography uses the particles that are generated when radiation from outer space collides with the Earth´s atmosphere. These cosmic rays, known as muons, can be used to create images in the same way as X-rays, expect that muons are produced naturally and constantly come in contact with the human body without any known harmful effects.

Muons are particularly useful in working with radioactive material because “high-Z” materials, like uranium, scatter them differently than the surrounding containment materials — allowing scientists to pinpoint the locations of radioactive material if they know how the muons are being diffused.

Using a computer model, the team was able to simulate a damaged reactor with radioactive material scattered throughout the virtual power plant. They were then able to compare the accuracy of both the traditional scanning methods and the Los Alamos scattering method in finding what material was indeed missing from the model reactor and where it was located over a six-week period.

The Los Alamos method demonstrated that it was able to accurately provide the detailed information that the scientists were looking for.

“We now have a concept by which the Japanese can gather crucial data about what is going on inside their damaged reactor cores with minimal human exposure to the high radiation fields that exist in proximity to the reactor buildings,” Borozdin explained.

“Muon images could be valuable in more effectively planning and executing faster remediation of the reactor complex.”

The researchers noted that this detection technology could also be applied to security measures in the post-9/11 era. They said muon radiation detectors would be non-invasive, yet able to spot heavily shielded contraband in minutes without the need to open a potentially dangerous vehicle or container.