Start-up of vitrification melting furnace

Abstract

Abstract PURPOSE: To shorten the start-up time of a melting furnace for the vitrification of radioactive wastes, remarkably, by externally heating and melting a mixture of sodium nitrate and sodium borate placed in contact with the material to be molten until the mixture becomes electrically-conductive, and then passing an electrical current through the molten salt mixture and melting the material by the Joule heat. CONSTITUTION: A salt mixture 10 is placed directly on the material 8 to be molten, and heated with the external heater 2. The salt mixture contains at least 5W50% sodium nitrate and 25W50% sodium borate. When a part of the salt mixture is molten and becomes electrically-conductive, electrical curent flows between the auxiliary electrodes 7 to soften the rest part of the salt mixture. When the temperature of the molten salt reaches about 600°C, stationary current flows between the auxiliary electrodes 7, and the material 8 to be molten begins to melt. As the melting of the material 8 proceeds, an electrical current begins to flow between the main electrodes 3 to heat and start up the furnace 1. COPYRIGHT: (C)1982,JPO&Japio

Inventors

• 👤 Naohiko Ogino
• 👤 Noboru Endo
• 👤 Yutaka Nagaki
• 👤 Naoki Tsunoda

Bibliographic Details