PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Radioactive Waste”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2001

Foaming in simulated radioactive waste.

Radioactive waste treatment process usually involves concentration of radionuclides before waste can be immobilized by storing it in stable solid form. Foaming is observed at various stages of waste processing like SRAT (sludge receipt and adjustment tank) and melter operations. This kind of foaming greatly limits the process efficiency. The foam encountered can be characterized as a three-phase foam that incorporates finely divided solids (colloidal particles). The solid particles stabilize foaminess in two ways: by adsorption of biphilic particles at the surfaces of foam lamella and by layering of particles trapped inside the foam lamella. During bubble generation and rise, solid particles organize themselves into a layered structure due to confinement inside the foam lamella, and this structure provides a barrier against the coalescence of the bubbles, thereby causing foaming. Our novel capillary force balance apparatus was used to examine the particle-particle interactions, which affect particle layer formation in the foam lamella. Moreover, foaminess shows a maximum with increasing solid particle concentration. To explain the maximum in foaminess, a study was carried out on the simulated sludge, a non-radioactive simulant of the radioactive waste sludge at SRS, to identify the parameters that affect the foaming in a system characterized by the absence of surface-active agents. This three-phase foam does not show any foam stability unlike surfactant-stabilized foam. The parameters investigated were solid particle concentration, heating flux, and electrolyte concentration. The maximum in foaminess was found to be a net result of two countereffects that arise due to particle-particle interactions: structural stabilization and depletion destabilization. It was found that higher electrolyte concentration causes a reduction in foaminess and leads to a smaller bubble size. Higher heating fluxes lead to greater foaminess due to an increased rate of foam lamella generation in the sludge system.

Chemical Phenomena↗
PubMed1995

A methodology for evaluating the toxicity of radioactive waste and its application to the radioactive waste generated in Pennsylvania.

Communicating with the public on the risks of low-level radioactive waste disposal is difficult due to the lack of comparisons that are understandable to the public. This paper presents a methodology for analyzing the intrinsic toxicity of radionuclides in waste and comparing it to that for soil or other wastes that may contain naturally-occurring radionuclides. The intrinsic toxicity of each radionuclide is normalized by dividing its specific activity in the waste by an appropriate ingestion risk standard, such as the U.S. EPA proposed drinking water limits. To illustrate the usefulness of this method, it was used to analyze Pennsylvania's commercial low-level radioactive waste inventory. The results are presented along with an indication of the usefulness of this method for screening purposes to analyze and identify problematic constituents in various waste streams.

Evaluation Studies as Topic↗
PubMed2006

Warren K. Sinclair keynote address: contemporary issues in risk-informed decision making on the disposition of radioactive waste.

A consistent and transparent risk-informed approach to managing nuclear waste is plagued with different regulators, different rules and regulations for different waste types, different compliance requirements, and indecisions about probabilistic vs. deterministic models. Low-activity waste management is particularly void of a path forward with respect to being risk-informed. Risk assessment is not referenced in the statutes on low-activity waste even though both the U.S. Environmental Protection Agency and U.S. Nuclear Regulatory Commission (U.S. NRC) have policies to apply consistent risk management approaches to all of their programs. The U.S. NRC has developed guidance on the preparation of probabilistic performance assessments for low-activity waste facilities, but there have been no serious takers and a lack of initiative on the part of licensees. Thus, little to no experience exists on risk-informing low-activity waste. The missed opportunities include establishing a risk basis that would allow for simpler, safer, and much less costly alternatives for low-activity waste disposal while enabling society to have the full benefit of radiation technologies. There is hope that congressional action or regulatory rule making will address some of these issues with the result being the adoption of a more general and unified approach to risk-informed regulation of all types of waste. Just as much of the initiative for risk-informed nuclear power came from industry, it must also be the case for nuclear waste. A start would be the adoption of a basic framework of risk assessment in waste management applicable to all types of waste--radioactive and nonradioactive. The "set of triplets" risk assessment framework that is applicable to any kind of risk is an established alternative. It is believed that such a framework with the support of a regulatory structure made compatible through appropriate rulemaking or congressional action, and the experience of the probabilistic performance assessments for the Waste Isolation Pilot Plant and the proposed Yucca Mountain high-level waste repository, could result in the right path forward for the regulation and management of low-activity waste.

Decision Making↗
PubMed2006

Improving radioactive waste management: an overview of the Environmental Protection Agency's low-activity waste effort.

Radioactive waste disposal in the United States is marked by a fragmented regulatory system, with requirements that often focus on the origin or statutory definition of the waste, rather than the hazard of the material in question. It may be possible to enhance public protection by moving toward a system that provides disposal options appropriate for the hazard presented by the waste in question. This paper summarizes aspects of an approach focusing on the potential use, with appropriate conditions, of Resource Conservation and Recovery Act Subtitle-C hazardous waste landfills for disposal of "low-activity" wastes and public comments on the suggested approach.

Decision Making↗
PubMed2006

International standards related to the classification and deregulation of radioactive waste.

Although solid radioactive waste management is mainly a national concern, there are some aspects that have international implications. One important example is the decommissioning of nuclear facilities, which results in the release of materials that could be reused and recycled. It is possible that these materials could enter international trade, especially if the material is a metal. It is clearly desirable, therefore, to have appropriate international standards to help regulate trade. This paper describes recent international developments relating to the establishment of radiological criteria for the release of materials from regulatory control (clearance). There have already been some experiences of clearance and the transfer of recycled materials within Europe, and this paper reviews that experience. It also discusses recent developments in relation to the international classification of radioactive waste.

Decision Making↗
PubMed1995

[Management and storage of radioactive waste].

Management of radioactive waste is a matter of public concern. Such management, however, is today handled industrially in France, and when these techniques are well applied, it is possible to create storage centres. Waste having a short half-life is now stored in the Centre de l'Aube, which replaces the one begun in 1969 in the Department de la Manche. For waste with a long half-life, following the law passed in 1991, ANDRA is pursuing its programme of site prospection to establish two underground laboratories for studying geological storage.

Drug Storage↗
PubMed2006

Risk-informed radioactive waste classification and reclassification.

Radioactive waste classification systems have been developed to allow wastes having similar hazards to be grouped for purposes of storage, treatment, packaging, transportation, and/or disposal. As recommended in the National Council on Radiation Protection and Measurements' Report No. 139, Risk-Based Classification of Radioactive and Hazardous Chemical Wastes, a preferred classification system would be based primarily on the health risks to the public that arise from waste disposal and secondarily on other attributes such as the near-term practicalities of managing a waste, i.e., the waste classification system would be risk informed. The current U.S. radioactive waste classification system is not risk informed because key definitions--especially that of high-level waste--are based on the source of the waste instead of its inherent characteristics related to risk. A second important reason for concluding the existing U.S. radioactive waste classification system is not risk informed is there are no general principles or provisions for exempting materials from being classified as radioactive waste which would then allow management without regard to its radioactivity. This paper elaborates the current system for classifying and reclassifying radioactive wastes in the United States, analyzes the extent to which the system is risk informed and the ramifications of its not being so, and provides observations on potential future direction of efforts to address shortcomings in the U.S. radioactive waste classification system as of 2004.

Decision Making↗
PubMed2006

[Hight-temperature matrices to immobilize radioactive waste].

To immobilize liquid radioactive waste with medium activity level, specialists of "RADON" Industrial Research Association use borosilicate glass incorporating up to 30-35 mass percent of radioactive waste, with sulfate and chloride ions content up to 1 mass percent. To increase those concentrations, the authors suggest putting phosphate or vanadate additives into borosilicate glass or using phosphate glass. In vitrification of solid waste, for instance burning oven slag, sodium silicate or dolomite and bentonite mixture are suggested as additives.

Bentonite↗
PubMed1978

[Draining of radioactive waste water from departments working with radioactive material after introduction of the law for radiation protection (author's transl)].

In order to establish the drainage of radioactive waste water 1976 in the Federal Republic of Germany a new law for radiation protection was introduced. In this paper a concept is introduced how to determine specifications for constructing a decay plant using the given data of a department for nuclear medicine. The given boundary conditions were to secure a low concentration of radioactive material in order to establish the drainage of extreme low activities without diluting it.

Berlin↗
PubMed1986

Disposal of low-level radioactive wastes.

The generation of low-level radioactive waste is a natural consequence of the societal uses of radioactive materials. These uses include the application of radioactive materials to the diagnosis and treatment of human disease and to research into the causes of human disease and their prevention. Currently, low level radioactive wastes are disposed of in one of three shallow land-burial disposal sites located in Washington, Nevada, and South Carolina. With the passage in December 1980 of Public Law 96-573, "The Low-Level Radioactive Waste Policy Act," the disposal of low-level wastes generated in each state was identified as a responsibility of the state. To fulfill this responsibility, states were encouraged to form interstate compacts for radioactive waste disposal. At the present time, only 37 states have entered into compact agreements, in spite of the clause in Public Law 96-573 that established January 1, 1986, as a target date for implementation of state responsibility for radioactive wastes. Recent action by Congress has resulted in postponement of the implementation date to January 1, 1993.

Radioactive Waste↗
PubMed1982

Radionuclide export and elimination by coyotes at two radioactive waste disposal areas in southeastern Idaho.

Coyote fecal samples were collected near a radioactive waste leaching pond and a solid radioactive waste disposal facility and analyzed for radioactivity. Elevated concentrations of 137Cs, 90Sr and 238Pu in the samples from the liquid radioactive waste leaching area were attributed to coyotes ingesting contaminated pond water and/or small mammals. Elevated 241Am concentrations in coyote fecal samples collected around the solid radioactive waste disposal facility were due to ingestion of contaminated small mammals. Assumptions relative to the coyote use of these areas permitted an estimate of the maximum quantity of radioactivity exported and eliminated around the facilities. An annual total of 7.2, 31.4 and 1.8 microCi (90Sr, 137Cs, 238Pu, 239,240Pu, 241Am, 242Cm and 244Cm) was eliminated by coyotes within a 6.3 km radius of the solid radioactive waste disposal facility, liquid waste leaching pond, and control area, respectively. These quantities of radioactivity eliminated by coyotes were similar or less than quantities transported by other mechanisms such as waterfowl and vegetative uptake of radioactivity. Coyotes are a mode of radionuclide transport from the two radioactive waste disposal areas; however, due to the low radionuclide concentrations and low yearly radionuclide inventories in coyote fecal samples, it is doubtful that any significant environmental consequences occur as a result of this transport mechanism.

Animals↗
PubMed2005

The UK Committee on Radioactive Waste Management.

The UK Committee on Radioactive Waste Management is charged with recommending to Government, by July 2006, options for the long term management of the UK's radioactive waste legacy. These options should inspire public confidence. Now, more than halfway into the time allotted, we, as two former members of the Committee, express our concerns at the wayward approach that has been adopted. The Committee has placed emphasis on gaining public confidence but this has been done at the expense of recruiting the best scientific expertise in the management of radioactive waste, an act which we believe will actually undermine public confidence. Furthermore, given also the immense importance of this decision to public safety, national security and the national interest, we believe urgent steps should be taken to review the Committee's process, its management and its sponsorship.

Humans↗
PubMed2004

Radioactive waste disposal implications of extending Part IIA of the Environmental Protection Act to cover radioactively contaminated land.

A short study has been carried out of the potential radioactive waste disposal issues associated with the proposed extension of Part IIA of the Environmental Protection Act 1990 to include radioactively contaminated land, where there is no other suitable existing legislation. It was found that there is likely to be an availability problem with respect to disposal at landfills of the radioactive wastes arising from remediation. This is expected to be principally wastes of high volume and low activity (categorised as low level waste (LLW) and very low level waste (VLLW)). The availability problem results from a lack of applications by landfill operators for authorisation to accept LLW wastes for disposal. This is apparently due to perceived adverse publicity associated with the consultation process for authorisation coupled with uncertainty over future liabilities. Disposal of waste as VLLW is limited both by questions over volumes that may be acceptable and, more fundamentally, by the likely alpha activity of wastes (originating from radium and thorium operations). Authorised on-site disposal has had little attention in policy and guidance in recent years, but may have a part to play, especially if considered commercially attractive. Disposal at BNFL's near surface disposal facility for LLW at Drigg is limited to wastes for which there are no practical alternative disposal options (and preference has been given to operational type wastes). Therefore, wastes from the radioactively contaminated land (RCL) regime are not obviously attractive for disposal to Drigg. Illustrative calculations have been performed based on possible volumes and activities of RCL arisings (and assuming Drigg's future volumetric disposal capacity is 950,000 m3). These suggest that wastes arising from implementing the RCL regime, if all disposed to Drigg, would not represent a significant fraction of the volumetric capacity of Drigg, but could have a significant impact on the radiological capacity with respect to 226Ra plus 232Th. The government's decision-making programme for managing solid radioactive wastes in the UK may possibly achieve a general consensus that the use of landfill for LLW from the RCL regime has a fundamental role to play. However, this is unlikely to change the situation within the next few years. No new national facility arising from this programme is likely to be available during the first decade of the operation of a new RCL regime. Hence it appears that Drigg will need to play an important role for some years to come.

Humans↗