scholarly journals The effect of irradiation on the atomic structure and chemical durability of calcite and dolomite

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Yi-Hsuan Hsiao ◽  
Bu Wang ◽  
Erika Callagon La Plante ◽  
Isabella Pignatelli ◽  
N. M. Anoop Krishnan ◽  
...  
Keyword(s):  
Atomic Structure ◽  
Nuclear Power ◽  
Power Plants ◽  
Chemical Properties ◽  
Chemical Durability ◽  
Mineral Dissolution ◽  
Alkaline Solutions ◽  
Carbonate Minerals ◽  
Minimal Damage ◽  
Physical And Chemical

Abstract When exposed to irradiation—e.g., in nuclear power plant environments—minerals may experience alterations in their atomic structure which, in turn, result in changes in their physical and chemical properties. Herein, we mimic via Ar+ implantation the effects of neutron irradiation on calcite (CaCO3) and dolomite (CaMg(CO3)2) – two carbonate minerals that often find use as aggregates in concrete: a material that is extensively used in the construction of critical structural and safety components in nuclear power plants. By a pioneering combination of nanoscale quantifications of mineral dissolution rates (i.e., a proxy for chemical durability) in alkaline solutions, vibrational (infrared and Raman) spectroscopy, and molecular simulations, we find that irradiation minimally affects the atomic structure and properties of these carbonate minerals. This insensitivity to radiation arises from the predominantly ionic nature of the interatomic bonds in these minerals which can relax and recover their initial configuration, thus ensuring minimal damage and permanent alterations to these minerals following radiation exposure. The outcomes have significant implications on the selection, use, and specification of mineral aggregates for use in nuclear concrete construction.

Silver Nanoparticles Supported on Ordered Mesoporous Carbon for Formaldehyde Electrooxidation

2011 ◽  
Vol 110-116 ◽  
pp. 508-513
Author(s):  
Ling Bin Kong ◽  
Ru Tao Wang ◽  
Xiao Wei Wang ◽  
Zhen Sheng Yang ◽  
Yong Chun Luo ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Mesoporous Carbon ◽  
Chemical Reduction ◽  
Chemical Properties ◽  
Ordered Mesoporous Carbon ◽  
Alkaline Solutions ◽  
Cyclic Voltammograms ◽  
Peak Current Density ◽  
Ordered Mesoporous ◽  
Physical And Chemical

Metal nanocatalysts, as the anodic materials, have become increasingly important in fuel cells due to their unique physical and chemical properties. Here we report the ordered mesoporous carbon (CMK-3) supported silver nanocatalysts have been prepared through the wet chemical reduction by using the reduction of formaldehyde. The electrochemical properties of the Ag/CMK-3 nanocatalysts for formaldehyde oxidation are studied by cyclic voltammograms (CV) and chronoamperometric curves (i-t) in alkaline aqueous solutions. The results show that the peak current density (from CV) of the Ag/CMK-3 electrode is 112 mA cm-2, above 2 times higher than that of Ag/XC-72 at the same Ag loading (14.15 μg cm-2). Furthermore, the i-t curves demonstrate that the Ag/CMK-3 nanocatalysts are efficient and stable electrocatalysts for anodic oxidation of formaldehyde in alkaline solutions. Our results indicate that the application potential of Ag/CMK-3 nanocatalysts with the improved electrocatalytic activity has far reaching effects on fuel cells and sensors.

Experimental Investigation on the Volume Reduction of Irradiated Graphite Arising From the Decommissioning of KRR-2

2007 ◽  
Author(s):  
D. G. Lee ◽  
Y. J. Cho ◽  
H. C. Yang ◽  
K. W. Lee ◽  
C. H. Jung
Keyword(s):  
Fluidized Bed ◽  
Nuclear Power ◽  
Power Plants ◽  
Chemical Properties ◽  
Volume Reduction ◽  
Efficient Technology ◽  
Processing Technologies ◽  
Radioactive Graphite ◽  
Irradiated Graphite ◽  
Fluidized Bed Incineration

Graphite has been used as a moderator and reflector of neutrons in more than 100 nuclear power plants as well as many experimental reactors and plutonium production reactors in various countries. Most of the older graphite moderated reactors are already shut down and are awaiting decommissioning planning and preparation. The graphite waste has different characteristics than other decommissioning waste due to its physical and chemical properties and also because of the presence of tritium and carbon-14. Therefore radioactive graphite dismantling, handling, conditioning and disposal are a common part of the decommissioning activities. A volume reduction of the waste is needed to reduce disposal cost of radioactive waste. However the existing processing technologies are based mostly on the isolation of radioactive graphite from the environment, they are not able to provide for a significant volume reduction. For this reason, the high-temperature thermal treatment process such as an incineration or a pyrolysis is considered as promising technologies, since it provides a substantial volume reduction. Currently, the fluidized bed incineration is considered as efficient technology for the treatment of radioactive graphite waste. In this study, the fluidized bed incineration condition and the radioisotopes behavior were experimentally investigated by using irradiated graphite waste which has arisen from the decommissioning of Korean Research Reactor 2 (KRR-2).

scholarly journals Criteria of medical response to radiological emergencies in the Republic of Belarus

2021 ◽  
Vol 14 (2) ◽  
pp. 48-55
Author(s):  
C. N. Buzdalkin ◽  
N. G. Vlasova ◽  
A. V. Rozhko ◽  
V. N. Bortnovsky
Keyword(s):  
Radiation Exposure ◽  
Nuclear Power ◽  
Chemical Properties ◽  
Medical Intervention ◽  
The Body ◽  
Emergency Plans ◽  
Specialized Treatment ◽  
Medical Response ◽  
The Republic ◽  
Physical And Chemical

The Republican Research Center for Radiation Medicine and Human Ecology in the Internal and External Emergency Plans of the Belarusian nuclear power plant is specified as an institution that provides specialized treatment for personnel, as well as persons from the population living in the emergency zone of the station. The plant is the first facility in the Republic that used nuclear energy. There is no experience in treating radiation injuries in Belarus. This is the first time that the National Health Service has been assigned the task of ensuring readiness for the reception and specialized treatment of people who have been exposed to emergency or unplanned radiation. The purpose of the work is to establish criteria for radiation exposure for use in a Belarusian specialized medical institution in case of medical response to radiological accidents. As a result of the analysis of publications of international organizations, the criteria of radiation exposure that can be applied in the conditions of Belarusian specialized medical institutions were selected. Assessment of the criteria was made taking into account existing national technical regulations and the available capabilities of emergency response participants. To account for the quality of radiation in relation to deterministic effects “Gy-equivalent” is used. The criteria include both dosimetric values for cases of external and internal accidental and unplanned exposure, and levels of radioactive substances with unknown physical and chemical properties entering the body that require urgent medical intervention. Criteria for cases of surface contamination of skin and wounds require separate consideration.

scholarly journals PHYSICAL AND CHEMICAL PROPERTIES OF GROUNDWATER IN BANJARARUM AREA AND ITS VICINITY, WEST PROGO

KURVATEK ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 111-116
Author(s):  
Sri Ning Peni ◽  
. . T. Listyani R.A.
Keyword(s):  
Volcanic Rocks ◽  
Chemical Properties ◽  
Mineral Dissolution ◽  
Special Treatment ◽  
Test Results ◽  
Chemical Test ◽  
Animal Dung ◽  
Groundwater Samples ◽  
Laboratory Test Results ◽  
Physical And Chemical

 Groundwater in the Banjararum area is found in various rocks that build  the West Progo Hills, including the Nanggulan and the Andesite Breccia Formations. Groundwater can be found in dug wells and springs. Field surveys show that the groundwater is generally clear, tasteless and odorless, except for the well at Ngipikrejo. Chemical test results from four samples showed that groundwater in limestone has Ca, Mg - HCO3 type, whereas in volcanic rocks of type Ca - HCO3 and Ca, Na - HCO3. Groundwater chemistry type is generated from the soil, mineral dissolution in sedimentary rocks and igneous rocks as well as the atmosphere through rainwater. The considerable content of NO3 in the Ngipikrejo area indicates pollution from human activities, plants or animal dung. In general, groundwater in the study area is suitable for use as clean water or drinking water, characterized by a measurable pH in the field of 6.6 - 7.2 and TDS 54 - 155 ppm. Nevertheless, laboratory test results show that groundwater samples are water-filled, with a hardness of 135,866 - 778,048 (moderately hard - very hard), so special treatment is required before drinking.

New Construction of an In-Drum Drying Plant in the Central Decontamination and Water Treatment Facility (ZDW)

2013 ◽  
Author(s):  
Martin Hoffmann ◽  
Ingmar Koischwitz ◽  
Jörg Viermann
Keyword(s):  
Water Treatment ◽  
Nuclear Power ◽  
Power Plants ◽  
Chemical Properties ◽  
Waste Waters ◽  
Treatment Facility ◽  
Final Disposal ◽  
Nuclear Plants ◽  
Processing Plants ◽  
New Construction

During the operation and dismantling of nuclear plants, a variety of radioactive liquid wastes accumulate, which must be supplied to a disposal chain suitable for final disposal. In the initial conditioning step, with regard to their chemical properties these waste waters are usually adjusted by water treatment systems (predominantly evaporation facilities) permanently installed in nuclear power plants, and then, they are concentrated up to a predefined content of solids. Afterwards, the developing evaporator concentrate is desiccated locally and suitable for final disposal by own permanently installed conditioning installations or by means of mobile plants. For a mobile conditioning of evaporator concentrates, GNS uses the drying plant of the type FAVORIT proven over decades. Each of the mobile FAVORIT processing plants is provided with a handling licence for Germany valid nationwide according to § 7 of the German Radiation Protection Ordinance (StrlSchV).

Seismic Damage Indicating Parameters at Nuclear Power Plants Affected by the 2011 Tohoku-Oki Earthquake and Plant Shutdown Criteria

2017 ◽  
Vol 33 (1) ◽  
pp. 109-121
Author(s):  
Fred F. Grant ◽  
Yuchuan Tang ◽  
Greg S. Hardy ◽  
Robert Kassawara
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Free Field ◽  
Seismic Damage ◽  
Damage Potential ◽  
Ground Shaking ◽  
Minimal Damage ◽  
Current Threshold ◽  
Plant Shutdown

A rational and quantitative shutdown criterion is required for a nuclear power plant in response to seismic shaking to determine whether the plant must be shut down for inspection. The shutdown criterion is generally defined in terms of seismic damage indicating parameters. This paper presents seismic damage indicating parameters of the recorded free-field and in-structure motions at the Onagawa, Fukushima Daiichi, Fukushima Daini, and Tokai Daini nuclear power plants during the 2011 Tohoku-oki earthquake. The observed seismic damage indicating parameters largely exceed the current U.S. and Japan shutdown thresholds for nuclear power plants, while minimal damage due to ground shaking was observed at the four Japanese plants. These observations indicate a potential for raising the current threshold without introducing any significant additional seismic risk to nuclear power plants. The insights presented in this paper can be used to guide regulation and industry methods for quickly evaluating the damage potential of future earthquakes that affect nuclear power plants. With some adjustment, a similar methodology and criterion could be applied to conventional structures and lifeline infrastructure.

Methodical Apparatus for the Development of Typical Scenarios of Beyond Design Basis Accidents with VVER Reactors in the Planning and Implementation of Protective Measures for the Population

2018 ◽  
Vol 63 (6) ◽  
pp. 27-33
Author(s):  
Б. Галушкин ◽  
B. Galushkin ◽  
С. Горбунов ◽  
S. Gorbunov ◽  
В. Клочков ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Protective Measures ◽  
Fuel Rod ◽  
Radioactive Substances ◽  
Containment Shell ◽  
Safety Systems ◽  
Radionuclide Release ◽  
Physical And Chemical

To develop a simple methodological apparatus for constructing typical scenarios of accidents and estimate of emissions of radioactive substances from nuclear power plants with VVER reactors in the planning and implementation of protective measures for the population.Material and methods_ To build the model of release of radionuclides into the environment in case of an accident used literary experimental data of outputs of the radioactive substances from the fuel when it is heating and melting, the destruction of the fuel rod cladding, the use of technical means retention of radioactive substances in the containment of the reactor and their behaviour in the containment (sedimentation, sorption, etc.).Results_ Mathematical apparatus has been developed to quantify the magnitude of emissions of radioactive substances at nuclear power plants with VVER reactors depending on the time for dose-forming radionuclides in the instantaneous rupture of cooling pipelines in the presence of additional failure of NPP safety systems. The amount of emission of each deterministic of an accident correspond to the level 4 to 7 of the INES scale. Radionuclide release into the environment was calculated in the following physical and chemical processes_ heating and melting of fuel, depressurization of fuel rod claddings, peculiarities of the behavior of radionuclides in the containment shell (deposition, etc.) and operation of technical means to ensure radiation safety, structural leakages of the buildings. As an example, the assessment of the release of radionuclides into the environment depending on the time for level 5 of the INES accident scale is given. Conclusion_ Methodical apparatus can be used in the construction of typical scenarios for the development of basis accidents and assessment of radioactive emissions at nuclear power plants with VVER reactors in the planning and implementation of protective measures for the population and emergency exercises and training_

Sensitivity Analysis on Safety Functions of Engineered and Natural Barriers for Fuel Debris Disposal

MRS Advances ◽  
2017 ◽  
Vol 2 (12) ◽  
pp. 687-692
Author(s):  
Taro Shimada ◽  
Yuki Nishimura ◽  
Seiji Takeda
Keyword(s):  
Sensitivity Analysis ◽  
Nuclear Power ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Radionuclide Migration ◽  
Power Station ◽  
Safety Function ◽  
Fukushima Daiichi ◽  
Physical And Chemical ◽  
And Chemical Properties

ABSTRACTA disposal measure for fuel debris generated at the accident in the Fukushima Daiichi Nuclear Power Station has been studied so far. However, physical and chemical properties of the fuel debris located in reactor containment vessels have not yet been obtained. In order to investigate the safety function of barriers required for disposal of fuel debris, sensitivity analysis for radionuclide migration was carried out, considering with uncertainty of the properties. As a result, it is indicated that it was important for evaluation of fuel debris disposal to obtain the physical and chemical properties of 14C and 129I during release to groundwater, in addition to 238U.

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