Japanese researchers test detection devices at West Valley

Two research scientists from Japan's Kyoto University and Kochi University of Technology visited the West Valley Demonstration Project in western New York state earlier this fall to test their novel radiation detectors, the Department of Energy's Office of Environmental Management announced on November 19.

Kyoto University's Minoru Tanigaki brought the KURAMA-II (Kyoto University radiation mapping system) to West Valley for testing, while Sadao Momota with Kochi University of Technology tested his soil gamma-ray measurement system at the site. The KURAMA-II is a portable detector system that monitors air dose rate and radioisotope concentration levels in the ground at the same time. Momota's system, meanwhile, can be used in the field to provide real-time soil contamination data.

According to DOE-EM, Tanigaki and Momota envision expanding use of their equipment from nuclear accident response to radioactivity surveying at industrial nuclear sites undergoing decommissioning and decontamination.

KURAMA-II: Developed in response to the Fukushima Daiichi nuclear accident, KURAMA is a GPS-linked system that measures information on radiation as well as positional information during mobile surveys. The system led to the development of KURAMA-II, a fully automated system capable of collecting spectral data in real time.

According to the KURAMA website, the systems are different from other mobile radiation detectors in that they are designed to be used in large-scale surveys in emergencies, and they can reduce the burden on users and minimize data damage and loss of measuring instruments through real-time data sharing and full automation (KURAMA-II) using cloud computing.

Hundreds of KURAMA-II have been deployed in Fukushima and the surrounding areas, providing air dose rate maps over the past decade.

As the emergency period following the Fukushima Daiichi accident passed, evacuees returned to their communities and air dose rates in the region decreased. The focus on radioactivity monitoring in the region shifted to tracking radioactive materials deposited in residential areas and farmland. KURAMA-II, which is small enough to fit in a backpack, was redesigned for such purposes.

Soil measurements: With fellow researchers, Momota helped develop a tractor-based robot with the capability of real-time assessment and visualization of radioactive material density and fertility in farmlands. The device is intended to help accelerate the recovery process of the farmlands suffered by the Fukushima accident.

With Momota's device, a soil sample is collected down to a one-foot depth and placed on the measurement system. The results of gamma spectroscopy are automatically displayed on an attached monitor. Such real-time data enables farmers to understand the condition of their fields without waiting weeks for laboratory analysis, according to DOE-EM.

Further collaboration: DOE-EM is currently demolishing the Main Plant Process Building at West Valley, a project scheduled for completion next year. As West Valley moves to the next phase-contaminated soil remediation and disposition, and demolition of remaining Main Plant components and other facilities-there may be an opportunity for further collaboration among the two research scientists and West Valley, according to Jennifer Dundas, West Valley assistant director of the Office of Technical Services.

"The visit to West Valley by Minoru Tanigaki and Sadao Momota was successful in that both agreed that their collaboration would be mutually beneficial," Dundas said. "That is, radioactivity measurement technology development for the researchers and safe decommissioning planning for West Valley."