A Department of Health inspector examines each shipment of waste prior to disposal in the trench. Each shipment is checked for compliance with requirements and regulations of the U.S. Department of Transportation, U.S. Nuclear Regulatory Commission, and the state of Washington, as well as the site operators license. Packages are randomly selected and opened to ensure contents comply with all requirements.
Waste is generally packaged in metal drums or metal boxes, and is usually put directly into the trenches. It is classified as A, B, or C. U.S. Nuclear Regulatory Commission (USNRC) regulation 10 CFR 61 went into effect on December 27, 1983. Part 61 requires that all low-level radioactive waste be classified based upon mobility, half-life, and radiological hazard. Class A waste has the lowest concentration of radionuclides and must meet only the minimal waste form requirements. Approximately 95 percent of the waste received at the disposal facility is Class A.
Class B and C contain higher concentrations and must meet both the minimum and stability waste form requirements. Class C waste must also be disposed by methods that provide additional protection against inadvertent intruders.
Stability of Class B and C wastes can be provided by the waste form itself, processing the waste to a stable form or placing the waste in containers that provide stability. To the extent possible, Class B and C waste forms must retain their gross physical properties and identity for a minimum of 300 years under expected disposal conditions. In practice, stability is achieved by the use of high integrity containers (HIC), Engineered Concrete Barriers (ECB), or media that has proven to meet the requirements set forth by the USNRC. Both HIC's and stabilization media must pass tests that have been prescribed by the USNRC.