Models and Strategies for Blending Nuclear Wastes to Minimize Immobilized Waste Volume

1995 ◽  
Vol 412 ◽  
Author(s):  
M. Hoza
Keyword(s):  
High Level Waste ◽  
Nuclear Wastes ◽  
Low Level ◽  
Wide Variability ◽  
Stable Glass ◽  
High Level ◽  
Tank Waste

AbstractHanford tank waste will be separated into high-level and low-level portions; each portion will then be vitrified to produce a stable glass form for disposal. Because of the wide variability in the tank waste compositions, blending is being considered as a way to reduce the number of distinct compositions that must be vitrified and to minimize the resultant volume of vitrified waste.This paper discusses several approaches to blending and models developed to formulate blends for each approach. The models produce optimized blends which minimize the volume of glass required such that all composition and property constraints on the glass are satisfied. The paper will discuss several blending strategies, and will provide the results of calculations comparing the approaches and strategies. Finally, an overall strategy for retrieving, blending, and vitrifying Hanford tank waste will be briefly discussed.Results of the calculations for high-level waste show that an effective blending strategy can greatly reduce the volume of glass required to immobilize the waste.

High-level Waste, Low-level Logic

1994 ◽  
Vol 50 (6) ◽  
pp. 40-45
Author(s):  
Kristin Shrader-Frechette
Keyword(s):  
High Level Waste ◽  
Low Level ◽  
High Level

scholarly journals A Transport Code for Radiocolloid Migration: With an Assessment of an Actual Low-Level Waste Site

1984 ◽  
Vol 44 ◽  
Author(s):  
Bryan J. Travis ◽  
H. E. Nuttall
Keyword(s):  
High Level Waste ◽  
Waste Site ◽  
Low Level ◽  
Transport Code ◽  
Experimental Laboratory ◽  
Rapid Transport ◽  
High Level ◽  
Waste Repositories ◽  
Low Level Radioactive Waste

AbstractRecently, there is increased concern that radiocolloids may act as a rapid transport mechanism for the release of radionuclides from high-level waste repositories. The role of colloids is, however, controversial because the necessary data and assessment methodology have been limited. To quantitatively assess the role of colloids, the TRACR3D transport code has been enhanced by the addition of the population balance equations. The code was tested against the experimental laboratory column data of Avogadro et al. Next a low-level radioactive waste site was investigated to explore whether colloid migration could account for the unusually rapid transport of plutonium and americium observed. The nature and modeling of radiocolloids are discussed along with site simulation results from the TRACR3D code.

TN™ 81: A Challenging Design

2003 ◽  
Author(s):  
Yves Chanzy ◽  
Camille Otton
Keyword(s):  
Spent Nuclear Fuel ◽  
High Heat ◽  
High Level Waste ◽  
Heat Output ◽  
Dual Purpose ◽  
Stable Glass ◽  
Environmentally Sound ◽  
High Level ◽  
Interim Storage ◽  
And Storage

With increasing burn-up, reprocessing of spent nuclear fuel yields higher quantities of radionuclides, with a powerful source term and high heat output. Improvement in the vitrification process and environmentally sound thinking have been drivers to reduce the number of transports of vitrified residues (High Level Waste) to interim storage facilities in their owner’s country: this results in higher concentrations of nuclides in the stable glass matrix. The challenge was to create, with almost the same allowable mass and dimensions, a transport/storage casks able to transport glass canisters with this new specifications. Improving the environmental performance of the glass canisters would be of no avail without the corresponding means of transport and storage. This is why COGEMA LOGISTICS introduced the TN™ 81 concept; a dual purpose cask able to handle the most demanding canisters from reprocessing: 56 kW instead of 41 kW, and to shield with efficiency greater gamma and neutron sources, which regulations have been made more stringent regarding the neutron quality factor. The paper will comment the choices made, the drop test campaigns run specifically, and report on the loading of the first TN 81 for KernKraftwerk Go¨sgen (KKG), Switzerland.

Treatment and Disposal of the Radioactive Graphite Waste

2010 ◽  
Author(s):  
Lifang Tian ◽  
Mingfen Wen ◽  
Jing Chen
Keyword(s):  
Radioactive Waste ◽  
Radioactive Contamination ◽  
Carbon Material ◽  
Advanced Technology ◽  
High Level Waste ◽  
Graphite Material ◽  
Low Level ◽  
Radioactive Graphite ◽  
High Level ◽  
Low Level Radioactive Waste

A large number of nuclear reactors with graphite as moderator and reflector material are facing to be decommissioned now or later, and the radioactive graphite waste is a large part of the involved wastes. In addition, high temperature gas-cooled reactors being developed rapidly use a large quantity of graphite material (up to 95%) in the nuclear fuel elements, besides graphite material as their moderator and reflector material in the reactor cores. Therefore, it is very critical to manage these graphite wastes from the decommissioned and being decommissioned reactors. The part with low-level radioactive contamination that could not be reused now, may be disposed of as solid waste to reduce its volume, and the possibility of its being retrieved and reused in the future with advanced technology should be considered. The other graphite waste with high-level radioactive contamination requires much more consideration. Due to several factors, such as its large quantity, a lack of available disposal sites and public acceptance, it may not be disposed of directly in the repository any more. An option may be the transformation of the high-level radioactive graphite waste into low-level radioactive waste through physical and chemical processes. The current technologies involve, e.g., thermal treatment to release 36Cl, capture of the 14C from the gases of incineration of carbon material and decomposition of carbon dioxide into solid carbon. After these treatments the carbon material might be decontaminated and separated as low-level radioactive waste and a small amount of residual high-level waste could be disposed of ultimately. In order to achieve a sustainable development of graphite material, the maximum utility and the minimal disposal of radioactive graphite should be considered in the management of radioactive graphite waste. It is urgent to explore new technologies for decontaminating and recycling radioactive graphite.

scholarly journals High level waste characterization in support of low level waste certification. I. HLW supernate radionuclide characterization

1994 ◽  
Author(s):  
M.E. Jamison ◽  
P.D. d`Entremont ◽  
J.S. Clemmons ◽  
C.E. Bess ◽  
D.F. Brown
Keyword(s):  
High Level Waste ◽  
Waste Characterization ◽  
Low Level ◽  
High Level
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