Development of High Temperature Reactor Fuel
One of the types of nuclear reactors is the high temperature reactor (RST). This type of reactor can be made modular according to the need of the local electricity. The high temperature reactor besides producing electricity, also makes possible for utilizing the heat of the reactor for processes needing high temperature. The High Temperature Reactor fits with the geographic condition of Indonesia which consists of islands that have not yet any connections to the integrated electrical network.
The modular High Temperature Reactor, is one of the reactors with high level of security because the fuel is anti melting even though it is in accident condition and has an inherent cooling which could cool down by itself without any handling by anyone. The reactor was developed in Germany, South Africa, China and several of the countries use fuel in the form of balls. The ball formed fuel was made of coated particles measuring less than 1 cm which was mixed with a graphite matrix, and molding became a ball measuring 5cm in diameter, therefore forming a fuel element in the form of a 6cm diameter ball.
The coated particles which become the high temperature reactor fuel, consists of small particles of UO2, with 4 layers, one buffer layer and 3 isotropic layer. The first layer is a low density pyrocarbon as a buffer, a place to store the results of fission, the high density pyrocarbon to maintain the fission results, the silica carbide which also functions as a strengthener to further maintain the results of fission which is still coming out of the high density pyrocarbon layer, and the most outer layer of the high density pyrocarbon to protect the silica carbide. The layers of pyrocarbon and silica carbide could withstand temperatures up to 3000 oC.
