scholarly journals More Weight on the Job

2010 ◽  
Vol 132 (07) ◽  
pp. 36-38
Author(s):  
Harry Hutchinson
Keyword(s):  
Radioactive Waste ◽  
Treatment Plant ◽  
Chemical Waste ◽  
Hanford Site ◽  
Geological Repository ◽  
Processing Plants ◽  
Stable Glass ◽  
Waste Transfer ◽  
Under Construction ◽  
High Level

This article discusses that new methods and heavier equipment are expected to hasten the nuclear waste transfer at the Hanford Site’s tank farms. The site includes old processing plants, groundwater that exceeds safe levels of radioactivity, and high-level radioactive waste held in 149 aging tanks—some more than 60 years old—that lie underground just 10 miles from the Columbia River. The objective is to remove the highly radioactive waste from the old tanks, which have a single shell construction, and transfer it to 28 newer, more-secure double-shell tanks nearby, where the waste will safely reside until it can be treated in facilities now under construction. There are approximately 53,000,000 gallons of nuclear and chemical waste stored in the tanks at the Hanford Site. Bechtel National Inc., another of the prime contractors for Office of River Protection, is building a treatment plant that will process the wastes being stored in the underground tanks into a stable glass form for permanent disposal in a federal geological repository.

Repository Site Characterization: Comparing International Experience

2009 ◽  
Author(s):  
Martin Goldsworthy ◽  
Till Popp ◽  
Knut Seidel ◽  
Johannes Bruns
Keyword(s):  
Radioactive Waste ◽  
Selection Process ◽  
International Experience ◽  
Geological Repository ◽  
Clay Cover ◽  
Under Construction ◽  
High Level ◽  
A Site ◽  
Hlw Repository ◽  
The Ideal

An important part of the work described here was a study of existing international experience in investigating deep geological repository sites. The objective of this study was to derive a basis for planning the content and extent of investigations which might be carried out in Germany in the future. Such investigations would be required in the course of a site selection process for a repository for HLW (high level radioactive waste). For this purpose information on suitable sites was gathered, mainly from literature sources. Suitable in this context meant two things. Firstly, the investigated site should be in rock similar to four being considered in Germany (salt, clay, crystalline and other hard rock under a clay cover). Secondly, the investigations carried out could reasonably be considered as being intended to lead to the use of the site as a repository. The investigation processes were presented, analysed and compared. The comparison was based on the quality and the intensity of the methods employed to obtain the information necessary for deciding between candidate repository sites in terms of safety and the feasibility of construction. In the final stage of the work the analysis and presentation method developed for the international sites was applied to the investigations already carried out at three German sites (Gorleben — a prospective HLW repository, Morsleben — an existing but now not operational repository for radioactive waste and Konrad — a repository currently under construction). The reported investigatory work was compared with the ideal investigations developed on the basis of the existing international experience.

Validating CFD Models of Multiphase Mixing in the Waste Treatment Plant at the Hanford Site

2006 ◽  
Author(s):  
Brigette Rosendall ◽  
Chris Barringer ◽  
Feng Wen ◽  
Kelly J. Knight
Keyword(s):  
Radioactive Waste ◽  
Waste Treatment ◽  
Fluid Dynamic ◽  
Experimental Studies ◽  
Treatment Plant ◽  
Cfd Models ◽  
Waste Treatment Plant ◽  
Stable Glass ◽  
Treatment Facilities ◽  
Pre Treatment

The Columbia River in Washington State is threatened by the radioactive legacy of the cold war. Two hundred thousand cubic meters (fifty-three million US gallons) of radioactive waste is stored in 177 underground tanks (60% of the Nation’s radioactive waste). A vast complex of waste treatment facilities is being built to convert this waste into stable glass (vitrification). The waste in these underground tanks is a combination of sludge, slurry, and liquid. The waste will be transported to a pre-treatment facility where it will be processed before vitrification. It is necessary to keep the solids in suspension during processing. The mixing devices selected for this task are known as pulse-jet mixers (PJMs). PJMs cyclically empty and refill with the contents of the vessel to keep it mixed. The transient operation of the PJMs has been proven successful in a number of applications, but needs additional evaluation to be proven effective for the slurries and requirements at the Waste Treatment Plant (WTP). Computational fluid dynamic (CFD) models of mixing vessels have been developed to demonstrate the ability of the PJMs to meet mixing criteria. Experimental studies have been performed to validate these models. These tests show good agreement with the transient multiphase CFD models developed for this engineering challenge.

Corrosion Behavior of Simulated LLW Glass in Deionized Water

2009 ◽  
Vol 1193 ◽  
Author(s):  
Toshikatsu Maeda ◽  
Tetsuji Yamaguchi ◽  
Katsutoshi Hotta ◽  
Tsuyoshi Mizuno ◽  
Tsunetaka Banba
Keyword(s):  
Radioactive Waste ◽  
Volume Ratio ◽  
Deionized Water ◽  
Water Volume ◽  
Dissolution Mechanism ◽  
Chemical Compositions ◽  
High Concentration ◽  
Geological Repository ◽  
One Year ◽  
High Level

AbstractStatic leach tests were conducted for simulated low-level radioactive waste (LLW) glass in deionized water at 90 °C for up to one year to investigate the dissolution mechanism of LLW glass. Widely studied leaching behavior of high-level radioactive waste (HLW) glass is referred in discussing the dissolution mechanism. LLW glass is characterized by higher sodium (Na) and aluminum (Al) contents than HLW glass, about twice as high as R7T7, with its SiO2 content close to HLW glass. Powdered simulated LLW glass of three different chemical compositions was tested with the glass-surface-to-water-volume ratio of 2,000 m−1. The release rates of boron (B), widely used as an indicator of dissolution for HLW glass, decreased with time during leaching, as commonly observed in similar tests for HLW glass. The pH of the leachate was stable around 11.3 - 11.6, which is higher than those in similar tests for HLW glass by one pH unit or more. The concentrations of Al in the leachates were higher compared to data for HLW glass by two orders of magnitude. The high concentration seems to be caused by higher pH. In the leachate condition of the present tests, a zeolitic mineral (analcime) is thermodynamically more stable than amorphous silica (SiO2(am)) which is known to control the concentration of dissolved silica (Si) with respect to HLW glass. The present results imply that dissolution of the LLW glass is accompanied with formation of analcime under virtually closed systems such as geological repository where the groundwater flow rate is quite low.

Sign in / Sign up

Export Citation Format

Share Document