Laboratory Investigation into the Radiolytic Gas Generation from Rock Salt. A Study Related to the Disposal of High Level Radioactive Waste

1988 ◽  
Vol 127 ◽  
Author(s):  
Norbert Jockwer ◽  
Jörg Monig
Keyword(s):  
Dose Rate ◽  
Rock Salt ◽  
Absorbed Dose ◽  
Polar Compounds ◽  
Gas Production ◽  
Gas Generation ◽  
Γ Irradiation ◽  
Gaseous Products ◽  
Air Atmosphere ◽  
High Level

ABSTRACTSalt samples of two different mineralogical compositions were subjected to 60Co-γ-irradiation under an air-atmosphere. The resulting gaseous products were analysed from the gas phase above the salt. Additionally, the salt was subsequently heated up to 300 °C in order to liberate adsorbed, less volatile, and polar compounds. The gases CO2, CO, N2O, H2S, SO2, and Cl2 were identified whereas H2 was notably absent. The influence of various parameters, i. e. the total absorbed dose, the dose rate, and the temperature, on the radiolytic gas production was studied in some detail, increasing dose leads to increasing yields in CO2 and N2O. Carbon monoxide is radiolytically destroyed. Since CO2 and CO occur naturally in rock salt, they desorb thermally to some extent during the irradiation. The dose rate does not affect the yields, while the temperature during irradiation has a big effect on the radiolytic CO2 yields. At 250 °C and a radiation dose of 1×106 Gy a maximum CO2 yield of 70 mg gas per kg irradiated salt was observed. Upon heating the sample to 300 °C for 30 min. 47 mg per kg salt are additionally released.

Parametric Investigation of Rock Salt Behaviour Resulting from Disposal of High Level Radioactive Waste

1990 ◽  
Vol 212 ◽  
Author(s):  
D. Caramelle ◽  
M.T. Gaudez ◽  
J. Monig ◽  
G. Ouzounian ◽  
G. Simonet
Keyword(s):  
Grain Size ◽  
Rock Salt ◽  
Absorbed Dose ◽  
Gas Production ◽  
High Level Waste ◽  
Spent Fuel ◽  
Salt Composition ◽  
Gas Atmosphere ◽  
High Level ◽  
Fuel Elements

ABSTRACTThe liberation and generation of gases from rock salt due to heat and gamma irradiation is investigated in order to obtain some of the data needed for the development of the concept for the disposal of high level waste in rock salt.Our work is concerned with the influence of various parameters on gas production, e.g. salt composition and grain size, total absorbed dose, dose rate, temperature and gas atmosphere. Some of these parameters have not been studied previously in detail.The original gamma irradiator employing spent fuel elements and capable of exposing samples at temperatures up to 250°C will be described. Experimental results from some 150 experiments will be given. The two major gases found were CO2 and N2O.CO, H2, CH4, Hydrocarbons, CI2, HCl and SO2 were also detected. The dependence of the gas yields on the various parameters will be presented and discussed.

Radiolytically-Induced Gas Production in Plutonium-Spiked Wipp Brine

1992 ◽  
Vol 294 ◽  
Author(s):  
D. T. Reed ◽  
S. Okajima ◽  
L. H. Brush ◽  
M. A. Molecke
Keyword(s):  
Gas Phase ◽  
Alpha Particle ◽  
Particle Deposition ◽  
Gas Production ◽  
Gas Generation ◽  
Gaseous Products

ABSTRACTGas generation due to alpha particle deposition was investigated in four WIPP relevant brines; WIPP brine A, ERDA-6, DH-36 and G8-B. This was done by spiking each brine with plutonium-239 and periodically sampling the gas phase to determine the nature of the gaseous products and the rates of gas generation. The predominant gas generated radiolytically was hydrogen, with yields ranging from 0.6 to 1.5 molec/100 eV for the four brines tested. Plutonium (VI) was stable in two synthetic brines, WIPP brine A and ERDA-6 but was rapidly reduced in the underground collected brines DH-36 and G8-B, although most of the plutonium remained in solution.

HUMAN EXPOSURE TO BACKGROUND RADIATION IN ORTUM, KENYA

2019 ◽  
Vol 188 (1) ◽  
pp. 98-108
Author(s):  
F O Wanjala ◽  
N O Hashim ◽  
D Otwoma ◽  
C Nyambura ◽  
J Kebwaro ◽  
...  
Keyword(s):  
Dose Rate ◽  
Human Exposure ◽  
Activity Concentration ◽  
Background Radiation ◽  
Absorbed Dose ◽  
Threshold Values ◽  
Absorbed Dose Rate ◽  
The World ◽  
Average Activity ◽  
Terrestrial Radionuclides

Abstract The activity concentration of radionuclides 238U, 232Th and 40K in soil and the absorbed dose rate (ADRA) at 1 m above the ground in Ortum was determined. The activity concentration in soils ranged from 33 to 85, 20 to 67 and 148–1019 Bq kg–1, respectively with an average of 40 ± 1.43, 56 ± 1.46 and 425 ± 19.24 Bq kg–1, respectively. The activity concentration of 232Th and 238U was found to reduce with increasing depth while that of 40K increased with increasing depth. The average activity concentration in soil was higher than the world average values. The average ADRA in air at 1 m above the ground was found to be 112 ± 29.6 nGy h–1. The soil and rocks in Ortum are recommended for use because the activity concentration of the terrestrial radionuclides is lower than the recommended threshold values.

Assessment of natural radioactivity levels and the associated radiological hazards in some building materials from Mayo-Kebbi region, Chad

2018 ◽  
Vol 53 (4) ◽  
pp. 265-278 ◽  
Author(s):  
S. Penabei ◽  
D. Bongue ◽  
P. Maleka ◽  
T. Dlamini ◽  
Saïdou ◽  
...  
Keyword(s):  
Dose Rate ◽  
Natural Radioactivity ◽  
Building Materials ◽  
Hazard Index ◽  
Absorbed Dose ◽  
Radiation Hazard ◽  
Absorbed Dose Rate ◽  
Activity Concentrations ◽  
Radiological Hazards ◽  
Radiation Hazard Index

In order to assess the levels of natural radioactivity and the associated radiological hazards in some building materials of the Mayo-Kebbi region (Chad), a total of nineteen samples were collected on the field. Using a high resolution γ-ray spectrometry system, the activity concentrations of radium (226Ra), thorium (232Th) and potassium (40K) in these samples have been determined. The measured average activity concentrations range from 0.56 ± 0.37 Bq kg−1 to 435 ± 7 Bq kg−1, 1.3 ± 0.6 Bq kg−1 to 50.6 ± 1.1 Bq kg−1 and 4.3 ± 2.0 Bq kg−1 to 840 ± 9 Bq kg−1, for 226Ra, 232Th and 40K, respectively. The highest 226Ra average activities is found in soil brick samples of Zabili. The highest mean value of 232Th and 40K concentrations are found in soil brick samples of Madajang. The activity concentration and the radium equivalent activity (Raeq) have been compared to other studies done elsewhere in the world. Their average values are lower than most of those of countries with which the comparison has been made. Were also evaluated, the external radiation hazard index, the internal radiation hazard index, the indoor air absorbed dose rate, the outdoor air absorbed dose rate, the activity utilization index, the annual effective dose, the annual gonadal dose equivalent, the representative level index, as well as, the excess lifetime cancer risk. In accordance with the criterion of the Organization for Economic Cooperation and Development, our results show that soil brick samples of Zabili and Madajang increases the risk of radiation exposure, thereby the possibility of developing cancer by people living in this environment. Based on these findings, brick samples from Zabili and Madajang are not recommended for construction purposes. All other sample materials have properties that are acceptable for use as building materials in terms of radiation hazard.

Kinetics of nonisothermal dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate

2019 ◽  
Vol 107 (2) ◽  
pp. 165-178
Author(s):  
Noura Mossaed Saleh ◽  
Ghada Adel Mahmoud ◽  
AbdelRahman AbdelMonem Dahy ◽  
Soliman Abdel-Fadeel Soliman ◽  
Refaat Mohamed Mahfouz
Keyword(s):  
Absorbed Dose ◽  
Isoconversional Methods ◽  
Gas Diffusion ◽  
Conversion Degree ◽  
Monoclinic System ◽  
Air Atmosphere ◽  
Dehydration Reactions ◽  
Γ Ray ◽  
Acetate Hydrate ◽  
Kinetics Of

Abstract Kinetics of dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate with 103 kGy total γ-ray dose absorbed in air atmosphere were studied by isoconversional nonisothermal method. The dehydration proceeds in two steps with the elimination of 0.8 and 0.4 mol of H2O, respectively. This result indicates that the investigated neodymium (III) acetate hydrate contains 1.2 mol of crystalline water in its structure. The dehydration reactions are best described by nucleation (A2 model) and gas diffusion (D4 model) for unirradiated and γ-ray irradiated samples, respectively. Analysis of the kinetic data using linear and nonlinear isoconversional methods showed that the apparent activation energy, Ea (kJ/mol) is dependent on the conversion degree, α, of the dehydration process. The Ea−α plots for both unirradiated and γ-ray irradiated neodymium (III) acetate hydrate showed that the dehydration is a complex process and contains multistep reactions. The results showed that γ-ray irradiation has a significant effect on the kinetics and thermodynamic parameters of the dehydration reaction. Powder X-ray diffraction showed that neodymium (III) acetate hydrate has a monoclinic system (SG P2/m) and no phase transformation was detected by γ-ray irradiation up to 103 kGy absorbed dose. The system maintains the same crystal structure before and after dehydration.

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