Hanford tank clean up: A guide to understanding the technical issues

Abstract

The public is being asked for their input to the decisions about how Hanford cleanup should progress. This input requires a basic understanding of the technical issues related to cleanup. Public input and involvement is critical to developing cleanup approaches and practices.

Hanford waste blending and the value of research: stochastic optimization as a policy tool

“…The US Department of Energy's Hanford, WA site is one of many government facilities now confronting the emerging effects of this legacy. Buried beneath Hanford are 177 storage tanks, with capacities ranging from 50 thousand to one-million gallons, holding waste from nearly two-thirds of the weapons grade nuclear fuel produced in the US following World War II (3). Mixed into this chemical waste is high-level radioactive material, including strontium, cesium, and plutonium isotopes -the latter with a half-life of tenthousand years.…”

“…The current -but evolving -remediation strategy consists of a multistage process, beginning with characterization and preprocessing of the tank contents, separation of low-and high-level radioactive components, and conversion of both waste streams into glass "logs" for permanent disposal in a national repository (3,6). The blending problem, on which this paper focuses, applies to the glass formation process -referred to as "vitrification" -and seeks combinations of tank wastes that minimize the amount of glass produced.…”

“…A non-homogeneous mixture of gases, liquids, slurries, and solids, the tank contents include: salts, organic complexants and their aging products, different metals, low-and high-level nuclear waste, and water (3). In order to convert these substances into glass, various oxides (e.g., SiO 2 , B 2 O 3 , Na 2 O, Li 2 O, CaO, and MgO) -collectively referred to as "frit" -must be added to the waste as it melts.…”

f-Element Ion Chelation in Highly Basic Media - Final Report

“…As a result, the radioactive elements in many storage tanks (e.g., at the Hanford facility) reside in complex solid and liquid matrices. 3,4 It has been proposed that the permanent disposal of the waste will require partitioning of low and high activity components while minimizing their volumes, particularly for the HLW fraction. The initial treatment may involve physical separation of the solid and liquid fractions, and there may be some washing of the solid fraction.…”

Environmental monitoring of leaks using time-lapsed long electrode electrical resistivity

“…The waste was generated from plutonium production for nuclear weapons. Of these, 67 single shelled tanks are known or suspected as having leaked, possibly releasing an estimated 4x10 6 L of radioactive fluids into the vadose zone [Gephart and Lundgren 1998]. The Department of Energy is currently conducting liquid waste retrieval to temporarily house the waste into safer double shelled tanks and eventually into a vitrified waste matrix for permanent disposal.…”