Development of Methodology to Evaluate Microbially Influenced Degradation of Cement-Solidified Low-Level Radioactive Waste Forms

1993 ◽  
Vol 333 ◽  
Author(s):  
Robert D. Rogers ◽  
M.A. Hamilton ◽  
R.H. Veeh ◽  
J.W. Mcconnell
Keyword(s):  
Radioactive Waste ◽  
Evaluation Method ◽  
Structural Integrity ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Ion Exchange Resin ◽  
Low Level ◽  
Waste Forms ◽  
Simulated Waste ◽  
Low Level Radioactive Waste

ABSTRACTBecause of its apparent structural integrity, cement has been widely used in the United States as a binder to solidify Class B and C low-level radioactive waste (LLW). However, the resulting cement preparations are susceptible to failure due to the actions of stress and environment. An environmentally mediated process that could affect cement stability is the action of naturally occurring microorganisms. The U.S. Nuclear Regulatory Commission (NRC), recognizing this eventuality, stated that the effects of microbial action on waste form integrity must be addressed.This paper provides present results from an ongoing program that addresses the effects of microbially influenced degradation (MID) on cement-solidified LLW. Data are provided on the development of an evaluation method using acid-producing bacteria. Results are from work with one type of these bacteria, the sulfur-oxidizing Thiobacillus. This work involved the use of a system in which laboratory- and vendor-manufactured, simulated waste forms were exposed on an intermittent basis to media containing thiobacilli. Testing demonstrated that MID has the potential to severely compromise the structural integrity of ion-exchange resin and evaporator-bottoms waste that is solidified with cement. In addition, it was found that a significant percentage of calcium and other elements were leached from the treated waste forms. Also, the surface pH of the treated specimens decreased to below 2. These conditions apparently contributed to the physical deterioration of simulated waste forms after 60 days of exposure to the thiobacilli.

A Procedure to Evaluate the Potential for Microbially Influenced Degradation of Cement-Solidified Low-Level Radioactive Waste Forms

1995 ◽  
Vol 412 ◽  
Author(s):  
R. D. Rogers ◽  
M. A. Hamilton ◽  
R. H. Veeh ◽  
J. W. Mcconnell
Keyword(s):  
Radioactive Waste ◽  
Evaluation Method ◽  
Structural Integrity ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Ion Exchange Resin ◽  
Waste Form ◽  
Low Level ◽  
Waste Forms ◽  
Low Level Radioactive Waste

AbstractBecause of its apparent structural integrity, cement has been widely used in the United States as a binder to solidify Class B and C low-level radioactive waste (LLW). However, the resulting cement preparations are susceptible to failure due to the actions of stress and environment. An environmentally mediated process that could affect cement stability is the action of naturally occurring microorganisms. The U.S. Nuclear Regulatory Commission (NRC), recognizing this eventuality, stated in their Technical Position on Waste Form, Revision 1, that the effects of microbial action on waste form integrity must be addressed. This paper provides recent results from a program that examined the effects of microbially influenced degradation (MID) on cement-solidified LLW. Data are provided which were obtained during the development of an evaluation method using acid-producing bacteria. Results presented here are from work with one type of these bacteria, the sulfur-oxidizingThiobacillus. Commercially prepared, cement-solidified, low-level radioactive waste form samples made from power reactor wastes were evaluated using a new biodegradation test developed for the NRC. Testing demonstrated that MID has the potential to severely compromise the structural integrity and nuclide retentiveness of ion-exchange resin and evaporator-bottoms wastes that have been solidified with cement. It was found that the waste form specimens physically deteriorated after 60 days of exposure to the thiobacilli. Also, the data show that significant amounts of Cs-137, Cs-134, Co-60, C-14, Tc-99, and Sr-90 contained in the waste forms were leached in the presence ofThiobacillus.

The Possibility for Microbially Influenced Degradation of Cement Solidified Low-Level Radioactive Waste Forms

1992 ◽  
Vol 294 ◽  
Author(s):  
Robert D. Rogers ◽  
Melinda A. Hamilton ◽  
John W. Mcconnell
Keyword(s):  
Radioactive Waste ◽  
Structural Integrity ◽  
Nuclear Regulatory Commission ◽  
Waste Form ◽  
Sufficient Evidence ◽  
Reduced Sulfur Compounds ◽  
Burial Site ◽  
Low Level ◽  
Acid Producing Bacteria ◽  
Low Level Radioactive Waste

ABSTRACTThe Nuclear Regulatory Commission (NRC) regulations 10 CFR Part 61, “Licensing Requirements for Land Disposal of Radioactive Waste,” regulate the disposal of radioactive waste and provides, among other stipulations, that class B and C low-level radioactive waste (LLW) be stabilized. This is intended to ensure that solidified waste does not structurally degrade and cause subsidence in the disposal unit's cover system. It is reasoned that deterioration of the waste form could adversely effect the stability of the burial site and lead to the release of radionuclides to the environment. Because of its apparent structural integrity, cement has been widely used as a binder to solidify LLW. However, the resulting preparations called pozzolanic cements are susceptible to failure due to the actions of stress and environment.This paper presents data from the literature that document the significance of biologically mediated chemical attack on concrete, in general. Concrete is susceptible to aggressive reaction with acids (both mineral and organic) of natural and anthropogenic origin. If persistent, such reactions ultimately lead to structural failure. Groups of microorganisms have been identified that are capable of metabolically converting organic and inorganic substrates into organic and mineral acids.The literature supports the conclusions that acid-producing bacteria of one type or another could be prevalent in all soils, even at depths expected for burial of LLW. Given the appropriate conditions of micro-environment and suitable substrate for growth, these bacteria will create conditions conducive to concrete deterioration. Growth substrates used by acid-producing bacteria (i.e., ammonia compounds, other reduced nitrogen compounds, sulfur and reduced sulfur compounds, reduced iron compounds, as well as organic carbon) could be naturally present in the disposal environment or be provided by the contents of the waste form.Sufficient evidence is presented which demonstrates the potential for microbially-influenced deterioration of cement-solidified LLW. These data are the basis for the NRC initiating the development of appropriate tests to determine the resistance of cement-solidified LLW to microbiologically induced degradation.

Identification of Possible High Integrity Containers for Low-Level Nuclear Waste Disposal

1981 ◽  
Vol 6 ◽  
Author(s):  
Jeffrey D. Williams
Keyword(s):  
South Carolina ◽  
Structural Integrity ◽  
Exchange Resin ◽  
Ion Exchange Resin ◽  
Economic Factors ◽  
Burial Site ◽  
Low Level ◽  
High Integrity ◽  
Low Level Radioactive Waste ◽  
Selection Of

ABSTRACTIncreased concern by the State of South Carolina over the condition and capacity of the low-level radioactive waste burial site at Barnwell has prompted them to promulgate new regulations on waste burial containers. As of September 30, 1981, ion exchange resin and filter media waste with an activity of 1 μCi/cc or greater and with isotopes with halflives greater than five years disposed at Barnwell shall be solidified or confined in a “high integrity container”. The materials and designs of these containers are required to provide waste isolation from the environment for a period of 300 years and provide the structural integrity specified in 49 CFR 173.398(b). HITTMAN has been active in the design and development of containers suitable for this purpose with this paper detailing the analyses involved. Material selections were limited to stainless steel, fiberglass, and polyethylenes. Structural concerns focused on overpressure requirements, drop-testing requirements, and lifting capabilities. With a lifetime dose of up to 108 rads, the possibilities of radiation damage were considered. Preliminary selection of polyethylene was based on satisfactory resolution of these issues and economic factors.

scholarly journals Long-term lysimeter field testing of low-level radioactive waste forms

1995 ◽  
Author(s):  
J.W. Jr. McConnell ◽  
R.D. Rogers ◽  
J.D. Jastrow ◽  
W.E. Sanford ◽  
T.M. Sullivan
Keyword(s):  
Radioactive Waste ◽  
Field Testing ◽  
Low Level ◽  
Waste Forms ◽  
Low Level Radioactive Waste

scholarly journals Results after ten years of field testing low-level radioactive waste forms using lysimeters

1997 ◽  
Author(s):  
J.W. Jr. McConnell ◽  
R.D. Rogers ◽  
J.D. Jastrow ◽  
W.E. Sanford ◽  
S.R. Cline ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Field Testing ◽  
Low Level ◽  
Waste Forms ◽  
Low Level Radioactive Waste

Utilization of Radioactive Waste for Solidifying Material to Fill Waste Forms

2001 ◽  
Author(s):  
Takeshi Ishikura ◽  
Daiichiro Oguri
Keyword(s):  
Radioactive Waste ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Filling Ratio ◽  
Improved Method ◽  
Low Level ◽  
Waste Forms ◽  
Disposal Facility ◽  
Low Level Radioactive Waste

Abstract Minimizing the volume of radioactive waste generated during dismantling of nuclear power plants is a matter of great importance. In Japan waste forms buried in shallow burial disposal facility as low level radioactive waste (LLW) must be solidified by cement with adequate strength and must extend no harmful openings. The authors have developed an improved method to minimize radioactive waste volume by utilizing radioactive concrete and metal for mortar to fill openings in waste forms. Performance of a method to pre-place large sized metal or concrete waste and to fill mortar using small sized metal or concrete was tested. It was seen that the improved method substantially increases the filling ratio, thereby decreasing the numbers of waste containers.

scholarly journals Accelerated Leach Test for Low-level Radioactive Waste Forms in the Hungarian NPP Paks

2017 ◽  
Vol 07 (04) ◽  
Author(s):  
Gyorgy Patzay ◽  
Otto Zsille ◽  
Jozsef Csurgai ◽  
Gyula Vass ◽  
Ferenc Feil
Keyword(s):  
Radioactive Waste ◽  
Low Level ◽  
Waste Forms ◽  
Leach Test ◽  
Low Level Radioactive Waste

Guessing and Choosing: A Multicriterion Decision on Disposal Technology for Low-Level Radioactive Waste

1991 ◽  
Vol 11 (3) ◽  
pp. 275-290 ◽  
Author(s):  
Dennis Coates ◽  
Michael Munger
Keyword(s):  
Decision Making ◽  
Radioactive Waste ◽  
Delphi Technique ◽  
Decision Rules ◽  
The United States ◽  
Public Officials ◽  
Low Level ◽  
Full Knowledge ◽  
Low Level Radioactive Waste ◽  
Decision Making Tool

ABSTRACTPublic officials faced with difficult and technologically complex decisions often resort to decision rules that purport to aggregate disparate judgements. Such multicriterion decisions are only as good as the procedures used to perform such aggregation, however. We examine the use of one such decision-making tool, a variant of the Delphi technique, in the choice of a disposal technology for low-level radioactive waste for the Southeast Compact Commission in the United States. The case focuses on the danger when officials guess when they think they are choosing. Choosing occurs when all participants understand the implications, and sensitivities, of the technique used to aggregate judgement; guessing occurs when the participants choose randomly or without full knowledge of the properties of the process.

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