AbstractA new type of boronization system has been installed in the JT-60U tokamak. Decaborane B10H14, a material less hazardous than diborane B2H6 for boronization, has been used to deposit a pure boron film on the first wall. The purpose of the boron film is to reduce the levels of impurity contamination in the JT-60U plasmas. The first results indicate that the film produced from decaborane shows a good performance similar to that of layers produced in the conventional way. The new technique thus offers an easier and more convenient way for boronization of the tokamak first wall.