Idaho National Laboratory Disposal Facility for Waste Incidental to Reprocessing
Idaho National Laboratory (INL) is a science-based, applied engineering national laboratory dedicated to supporting the mission of the U.S. Department of Energy (DOE) in the areas of nuclear and energy research, science, and national defense. The INL reservation, owned by the U.S. Government, occupies an area of approximately 2,305 km2 [890 mi2] in southeastern Idaho.
Within the INL reservation, the Idaho Nuclear Technology and Engineering Center (INTEC), formerly known as the Idaho Chemical Processing Plant, was established in 1953 to recover fissile uranium by reprocessing spent nuclear fuel (SNF). In reprocessing, INTEC dissolved the SNF, producing an acidic aqueous (water-based) solution, which was then processed through a first-cycle extraction system to separate uranium (or first-cycle extraction waste) from the bulk of the fission products. Finally, the separated uranium was processed through second- and third-cycle extraction systems to remove residual radioactive materials, which included plutonium and transuranic radionuclides.
In 1992, DOE officially discontinued reprocessing SNF at INTEC and, by February 1998, the first-cycle extraction waste stored in the INTEC Tank Farm Facility (TFF) was removed and solidified through calcination (a process in which liquid and solid wastes are heated to a high temperature, oxidized, and converted to a powdery residue). On September 7, 2005, DOE submitted a draft waste determination and supporting performance assessment for residual waste incidental to reprocessing (WIR), including sodium-bearing waste (SBW), in the INTEC TFF. In doing so, DOE intended to demonstrate compliance with the WIR criteria, including the related performance objectives. For additional detail, see the following topics on this page:
History of the INTEC TFF
Historically, the TFF tanks were used to store various INTEC wastes, including those from SNF reprocessing (first-, second-, and third-cycle reprocessing wastes), as well as decontamination waste, laboratory waste, and contaminated liquids from other INTEC operations. In general, because of significantly higher radioactivity levels, first-cycle reprocessing wastes were segregated from the other types of liquid waste. Those other tank wastes, referred to as sodium-bearing waste (SBW) because of their high sodium levels, had a significantly different chemical compositions (and lower radioactivity levels) than first-cycle reprocessing wastes.
DOE intends to close the TFF in phases to support continued INTEC operations. The closure plan includes a variety of tank system cleaning and stabilization activities. The TFF structures, systems, and components (SSCs) that are potentially contaminated with reprocessing wastes as a result of past INTEC reprocessing operations include the stainless steel tanks, encasements, concrete vaults, sand pads, piping, valve boxes, and instrumentation lines. These SSCs will be isolated and grouted as a part of the INTEC TFF final closure plan.
In its consultative role, the NRC staff reviewed DOE's draft waste determination and performance assessment, and concluded with reasonable assurance that the WIR criteria could be met at the INTEC TFF. The staff documented the results of its review in a Technical Evaluation Report (TER) for INL, which the NRC issued in October 2006. DOE then issued its final waste determination in November 2006, taking into consideration the assumptions, conclusions, and recommendations documented in the NRC's TER. The NRC subsequently issued its Monitoring Plan for the INTEC TFF in April 2007.