Radioactive Waste Disposal: By-Product Material

“By-Product Material” Defined

By-product material is defined in Title 30 Texas Administrative Code (TAC) §336.1105(4)  as “Tailings or wastes produced by or resulting from the extraction or concentration of uranium or thorium from any ore processed primarily for its source material content, including discrete surface wastes resulting from uranium solution extraction processes. Underground ore bodies depleted by such solution extraction operations do not constitute ‘by-product material’ within this definition.”

Sources of By-Product Material

By-product material typically consists of two types:

• Uranium mill tailings. This is ore material that remains after the majority of the uranium has been removed. It contains:
  • residual uranium-238, uranium-235, and their daughter products;
  • other naturally occurring radionuclides, such as thorium-230, radium-226, and their daughter products; and
  • stable metals such as barium, cobalt, copper, lead, nickel, vanadium, and molybdenum.
  The primary radionuclides in these mill tailings are radium-226, thorium-230, radon-222, and lead-210. The radioactivity from radium-226 ranges from 50 picoCuries per gram to over 1,000 picoCuries per gram.
• Thorium mill tailings. Thorium mill tailings differ from uranium mill tailings in that there are typically higher concentrations of thorium radionuclides in the waste material.

Other sources of by-product material include:

• Solution Mining Residues. Sludge-like materials resulting from the processing of uranium ore solutions from the in-situ uranium mining process, these residues contain small amounts of uranium, thorium, and their daughter products (radium-226, lead-210, and thorium-230). Radium-226 is typically the primary radionuclide of interest and is present in activities on the order of 200 picoCuries per gram.
• Uranium Mining and Milling Facility Decommissioning Wastes. Upon completion of operations and subsequent decommissioning of uranium mining and milling facilities, contaminated process piping, equipment, containers, and building material would be classified as by-product waste and should be disposed at a licensed by-product waste disposal facility. The radionuclide constituents in this waste stream will resemble uranium mill tailings. However, this waste could contain significant concentrations of uranium and its daughter products resulting from various phases of the uranium extraction process.

Regulation of By-Product Material

The TCEQ regulates by-product material processing, storage, and disposal under 30 TAC, Subchapter L  , “Licensing of Source Material Recovery and By-Product Material Disposal Facilities” and 30 TAC, Subchapter M , “Licensing of Radioactive Substances Processing and Storage Facilities.”

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