Vitrification of Simulated LILW Using Induction Cold Crucible Melter Technology
- Nuclear Environment Technology Institute (NETEC), Korea Hydro and Nuclear Power Co., LTD, 150 Dukjin, Yuseong, Daejeon 305-600 (Korea, Republic of)
Vitrification destroys hazardous organics, and immobilizes heavy metals and radioactive elements to form a chemically durable and highly leach-resistant vitrified form. The vitrification process provides exceptional volume reduction and is attractive for minimizing disposal volume. A pilot plant test using an induction Cold Crucible Melter (CCM) fitted with an off-gas treatment system (OGTS) has been conducted to vitrify a simulated low-and intermediate-level radioactive waste (LILW) generated from Korean nuclear power plants. The CCM process is based on the use of a water-cooled metallic structure assembled in sectors which is transparent to the electromagnetic field supplied by a high-frequency generator. A solidified glass layer because of the water-cooled structure of the CCM protects the structure against corrosion. By creating the solidified glass auto-crucible on the inner surface of the wall, corrosion damage to the steel in contact with the molten glass is prevented. In order to start-up the CCM, the glass frits were loaded in the CCM. The glass melting was initiated by heating of a short-circuited titanium ring in an electromagnetic field followed by ring burnout and incorporation of the titania in the glass frits. The melter has one drain that exits through the bottom. It is a direct bottom drain from the floor of the melt tank. It is sealed by the solidified glass layer and can be activated by removing the water cooling system. This drain is used if it is desired to drain the melter. The melter employs oxygen bubbling to promote mixing and to increase the melting rate. The bubblers are desired to produce a curtain of bubbles rising from the melter floor. In addition to mixing, the bubbling of oxygen tends to keep the melt well oxidized. The top of the melter is equipped with a number of ports. These provide access for feed, viewing, off-gas discharge, etc. The normal method of feeding is dry feeding through a feed pipe mounted through the top of the melter. The HFG power and operating frequency were applied in the ranges of 100{approx}200 kW and 250{approx}270 kHz, respectively. The simulated mixed waste vitrification test using the pilot scale plant consisting of the CCM and the OGTS at NETEC has demonstrated its good workability, reliability, and high productivity. The mixed waste was easily vitrified at a maximum rate of 20 kg per hour. The product quality of the glass such as chemical durability, phase stability, etc. was satisfactory. All regulated gases in the stack were well below the environmental regulation limits. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 13023, Tucson, AZ, 85732-3023 (United States)
- OSTI ID:
- 21210722
- Report Number(s):
- INIS-US-09-WM-06461; TRN: US09V1150081184
- Resource Relation:
- Conference: Waste Management 2006 Symposium - WM'06 - Global Accomplishments in Environmental and Radioactive Waste Management: Education and Opportunity for the Next Generation of Waste Management Professionals, Tucson, AZ (United States), 26 Feb - 2 Mar 2006; Other Information: Country of input: France; 3 refs
- Country of Publication:
- United States
- Language:
- English
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