A trial of tritium water concentration by freezing and thawing processes

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K12226
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental engineering and reduction of environmental burden
• Research Institution: Nagaoka University of Technology
• Principal Investigator: Kamimura Seiji 長岡技術科学大学, Nagaoka, 教授 (70224673)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: Tritium water / Radiation freezing / Radioactive water

Outline of Final Research Achievements

In this study, we tried to develop a technique to separate / enrich tritium water, T2O, contained in radioactively contaminated water, using the difference in melting point from pure water H2O. In order to seperate / concentrate D2O from the D2O solution simulating T2O, an experimental apparatus was assembled, which is composed of a radiation cooling unit, an water freezing inner tank and a temperature stabilizing outer tank, and placed in a constant temperature water tank (range of -20 to 80 C, 0.01 C resolution), covered with a thermal insulating lid. Two approaches was made as follow: a freeze concentration method and a melting concentration method. As a result, it was found that the HDO enrichment to the solid phase tended to increase as the temperature of the water tank in the former case, and the maximum enrichment degree was 40% when the water tank temperature was 1.5 C. . In the latter method, the maximum enrichment to solid phase was 13% at 1.4 C.

Free Research Field

Snow and Ice Engineering