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Title: Development of characterization protocol for mixed liquid radioactive waste classification

Abstract

Mixed liquid organic waste generated from health-care and research activities containing tritium, carbon-14, and other radionuclides posed specific challenges in its management. Often, these wastes become legacy waste in many nuclear facilities and being considered as ‘problematic’ waste. One of the most important recommendations made by IAEA is to perform multistage processes aiming at declassification of the waste. At this moment, approximately 3000 bottles of mixed liquid waste, with estimated volume of 6000 litres are currently stored at the National Radioactive Waste Management Centre, Malaysia and some have been stored for more than 25 years. The aim of this study is to develop a characterization protocol towards reclassification of these wastes. The characterization protocol entails waste identification, waste screening and segregation, and analytical radionuclides profiling using various analytical procedures including gross alpha/ gross beta, gamma spectrometry, and LSC method. The results obtained from the characterization protocol are used to establish criteria for speedy classification of the waste.

Authors:
 [1];  [2];  [3];  [4]
  1. Waste Technology Development Centre, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia)
  2. Radioisotop Technology and Innovation, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia)
  3. Radiochemistry and Environment, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia)
  4. Material Technology Group, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia)
Publication Date:
OSTI Identifier:
22391639
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1659; Journal Issue: 1; Conference: NuSTEC2014: Nuclear Science, Technology, and Engineering Conference 2014, Skudai, Johor (Malaysia), 11-13 Nov 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; APPROXIMATIONS; CARBON 14; CLASSIFICATION; DECLASSIFICATION; GAMMA SPECTROSCOPY; IAEA; LIQUID WASTES; MALAYSIA; NUCLEAR FACILITIES; ORGANIC WASTES; RADIOACTIVE WASTE MANAGEMENT; RADIOACTIVE WASTES; RECOMMENDATIONS; TRITIUM

Citation Formats

Zakaria, Norasalwa, E-mail: norasalwa@nuclearmalaysia.gov.my, Wafa, Syed Asraf, Wo, Yii Mei, and Mahat, Sarimah. Development of characterization protocol for mixed liquid radioactive waste classification. United States: N. p., 2015. Web. doi:10.1063/1.4916872.
Zakaria, Norasalwa, E-mail: norasalwa@nuclearmalaysia.gov.my, Wafa, Syed Asraf, Wo, Yii Mei, & Mahat, Sarimah. Development of characterization protocol for mixed liquid radioactive waste classification. United States. doi:10.1063/1.4916872.
Zakaria, Norasalwa, E-mail: norasalwa@nuclearmalaysia.gov.my, Wafa, Syed Asraf, Wo, Yii Mei, and Mahat, Sarimah. Wed . "Development of characterization protocol for mixed liquid radioactive waste classification". United States. doi:10.1063/1.4916872.
@article{osti_22391639,
title = {Development of characterization protocol for mixed liquid radioactive waste classification},
author = {Zakaria, Norasalwa, E-mail: norasalwa@nuclearmalaysia.gov.my and Wafa, Syed Asraf and Wo, Yii Mei and Mahat, Sarimah},
abstractNote = {Mixed liquid organic waste generated from health-care and research activities containing tritium, carbon-14, and other radionuclides posed specific challenges in its management. Often, these wastes become legacy waste in many nuclear facilities and being considered as ‘problematic’ waste. One of the most important recommendations made by IAEA is to perform multistage processes aiming at declassification of the waste. At this moment, approximately 3000 bottles of mixed liquid waste, with estimated volume of 6000 litres are currently stored at the National Radioactive Waste Management Centre, Malaysia and some have been stored for more than 25 years. The aim of this study is to develop a characterization protocol towards reclassification of these wastes. The characterization protocol entails waste identification, waste screening and segregation, and analytical radionuclides profiling using various analytical procedures including gross alpha/ gross beta, gamma spectrometry, and LSC method. The results obtained from the characterization protocol are used to establish criteria for speedy classification of the waste.},
doi = {10.1063/1.4916872},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1659,
place = {United States},
year = {Wed Apr 29 00:00:00 EDT 2015},
month = {Wed Apr 29 00:00:00 EDT 2015}
}
  • Highlights: • Knowledge of wastes in substances will be necessary to assess HP1–HP15 hazard properties. • A new analytical protocol is proposed for this and tested by two service laboratories on 32 samples. • Sixty-three percentage of the samples have a satisfactory analytical balance between 90% and 110%. • Eighty-four percentage of the samples were classified identically (Seveso Directive) for their hazardousness by the two laboratories. • The method, in progress, is being normalized in France and is be proposed to CEN. - Abstract: The classification of waste as hazardous could soon be assessed in Europe using largely the hazardmore » properties of its constituents, according to the the Classification, Labelling and Packaging (CLP) regulation. Comprehensive knowledge of the component constituents of a given waste will therefore be necessary. An analytical protocol for determining waste composition is proposed, which includes using inductively coupled plasma (ICP) screening methods to identify major elements and gas chromatography/mass spectrometry (GC–MS) screening techniques to measure organic compounds. The method includes a gross or indicator measure of ‘pools’ of higher molecular weight organic substances that are taken to be less bioactive and less hazardous, and of unresolved ‘mass’ during the chromatography of volatile and semi-volatile compounds. The concentration of some elements and specific compounds that are linked to specific hazard properties and are subject to specific regulation (examples include: heavy metals, chromium(VI), cyanides, organo-halogens, and PCBs) are determined by classical quantitative analysis. To check the consistency of the analysis, the sum of the concentrations (including unresolved ‘pools’) should give a mass balance between 90% and 110%. Thirty-two laboratory samples comprising different industrial wastes (liquids and solids) were tested by two routine service laboratories, to give circa 7000 parameter results. Despite discrepancies in some parameters, a satisfactory sum of estimated or measured concentrations (analytical balance) of 90% was reached for 20 samples (63% of the overall total) during this first test exercise, with identified reasons for most of the unsatisfactory results. Regular use of this protocol (which is now included in the French legislation) has enabled service laboratories to reach a 90% mass balance for nearly all the solid samples tested, and most of liquid samples (difficulties were caused in some samples from polymers in solution and vegetable oil). The protocol is submitted to French and European normalization bodies (AFNOR and CEN) and further improvements are awaited.« less
  • Plasma arc technology is a high temperature process that completely oxidizes organic waste fractions: inorganic hazardous and radionuclide waste fractions are oxidized and encapsulated in a highly durable slag. The robust nature of the technology lends itself to application of diverse mixed and hazardous wastestreams. Over 500 hours of testing have been completed at the Department of Energy`s Western Environmental Technology Office with a pilot-scale system. This testing was designed to demonstrate operability over a wide range of wastes and provide the data required to evaluate potential applications of the technology on both a technical and economic basis. In additionmore » to characterization of the off gas for typical combustion products, the fate of radionuclide surrogates and hazardous elements within the Plasma Arc Centrifugal Treatment (PACT) system has been investigated extensively. Test results to date demonstrate that cerium, a plutonium surrogate, remains almost exclusively in the slag matrix. Hazardous elements such as chromium and lead volatilize to a greater extent and are captured by the off-gas system. Preliminary design work is underway to develop a minimum emissions off-gas system for demonstration on a engineering-scale plasma unit. The proposed system will filter particulate matter from the hot gas stream and treat them in an electric ceramic oxidizer, which replaces the conventional afterburner, prior to quenching and acid gas removal. 5 refs., 3 figs., 5 tabs.« less
  • A sample of high-level radioactive tank waste was characterized to provide a basis for developing a waste simulant. The simulant is required for engineered-scaled testing of pretreatment processes in a non-radiological facility. The waste material examined was derived from the bismuth phosphate process, which was the first industrial process implemented to separate plutonium from irradiated nuclear fuel. The bismuth phosphate sludge is a complex mixture rich in bismuth, iron, sodium, phosphorus, silicon, and uranium. The form of phosphorus in this particular tank waste material is of specific importance because that is the primary component (other than water-soluble sodium salts) thatmore » must be removed from the high-level waste solids by pretreatment. This work shows unequivocally that the phosphorus present in this waste material is not present as bismuth phosphate. Rather, the phosphorus appears to be incorporated mostly into an amorphous iron(III) phosphate species. The bismuth in the sludge solids is best described as bismuth ferrite, BiFeO3. Infrared spectral data, microscopy, and thermal analysis data are presented to support these conclusions. The behavior of phosphorus during caustic leaching of the bismuth phosphate sludge solids is also discussed.« less
  • The US system of radioactive-waste classification and its development provide a reference point for the discussion of risk-based thinking in waste classification. The official US system is described and waste-acceptance criteria for disposal sites are introduced because they constitute a form of de facto waste classification. Risk-based classification is explored and it is found that a truly risk-based system is context-dependent: risk depends not only on the waste-management activity but, for some activities such as disposal, it depends on the specific physical context. Some of the elements of the official US system incorporate risk-based thinking, but like many proposed alternativemore » schemes, the physical context of disposal is ignored. The waste-acceptance criteria for disposal sites do account for this context dependence and could be used as a risk-based classification scheme for disposal. While different classes would be necessary for different management activities, the waste-acceptance criteria would obviate the need for the current system and could better match wastes to disposal environments saving money or improving safety or both.« less