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Open Journal of Geology 2017年第1期7卷 93-117页

作者： Khairiya M. Fawzy Geology Department Faculty of Science Aswan University Aswan Egypt

The alkali feldspar granite of Gabal El Atawi is post orogenic granite originated from subalkaline magma in extensional suite. It is developed within plate tectonic setting and has A2-type character which generated from apparent crustal source. The petrographic, geochemical and radioactive characteristics of El Atawi granite meet and fulfill the requirements of being fertile granite and it can be considered as promising uraniferous granite. Fluid inclusion studies of the altered granite elucidated two different solutions acting on the host granitic pluton. The first is NaCl-CaCl low temperature fluid with a wide range of salinity. The second is high temperature and salinity Fe-Mg-Na chloride solution. Different fractures in the granite acted as good channels for the hydrothermal fluids that leached uranium from its bearing minerals disseminated all over the host granite and redeposited it in the alteration zones.

关键词： radioactivity Geochemistry Post-Orogenic A-Type Granite Gabal El Atawi Central Eastern Desert Egypt

An Analysis for Distribution of Natural Radionuclides in Soil, Sand and Sediment of Potenga Sea Beach Area of Chittagong, Bangladesh

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Journal of Environmental Protection 2014年第17期5卷 1553-1563页

作者： Sabina Yasmin Bijoy Sonker Barua Masud Kamal Md. Abdur Rashid Department of Physics Chittagong University of Engineering and Technology Chittagong Bangladesh Atomic Energy Centre Bangladesh Atomic Energy Commission Chittagong Bangladesh

A HPGe (High Purity Germanium) detector based, low background gamma-ray counting system was used for activity measurement in soil, sand and sediment samples collected from Potenga sea beach area of Chittagong, Bangladesh. The specific radioactivities of Radium (226Ra), Thorium (232Th) and Potassium (40K) were measured in the above samples. The investigation reflects the lower deposition of minerals exist in the collected samples. From the measured specific radioactivities of the above three natural radionuclides, the radium equivalent activity (Raeq), the external hazard index (Hex), the external gamma absorbed dose rate and the annual effective dose were calculated. The obtained mean values of gamma absorbed dose rate in soil and sand samples and annual effective dose in soil, sand and sediment samples were found higher than the worldwide average as reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2000). The Raeq values were in the range of 47.86 to 293.76 Bq·kg-1 and the Hex varied from 0.13 - 0.81, which indicated that the study area was radiologically safe for human being.

关键词： Natural radioactivity Specific radioactivity HPGe γ-Ray Detector Radiation Hazard Index Dose Rate Potenga Sea Beach

High-Level Nuclear Wastes and the Environment: Analyses of Challenges and Engineering Strategies

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World Journal of Nuclear Science and Technology 2012年第3期2卷 89-105页

作者： Mukhtar Ahmed Rana Physics Division Directorate of Science PINSTECH Islamabad Pakistan

The main objective of this paper is to analyze the current status of high-level nuclear waste disposal along with presentation of practical perspectives about the environmental issues involved. Present disposal designs and concepts are analyzed on a scientific basis and modifications to existing designs are proposed from the perspective of environmental safety. A new concept of a chemical heat sink is introduced for the removal of heat emitted due to radioactive decay in the spent nuclear fuel or high-level radioactive waste, and thermal spikes produced by radiation in containment materials. Mainly, UO2 and metallic U are used as fuels in nuclear reactors. Spent nuclear fuel contains fission products and transuranium elements which would remain radioactive for 104 to 108years. Essential concepts and engineering strategies for spent nuclear fuel disposal are described. Conceptual designs are described and discussed considering the long-term radiation and thermal activity of spent nuclear fuel. Notions of physical and chemical barriers to contain nuclear waste are highlighted. A timeframe for nuclear waste disposal is proposed and time-line nuclear waste disposal plan or policy is described and discussed.

关键词： High-Level Nuclear Waste Nuclear Waste Containment and Disposal Environment Conceptual Model Designs radioactivity Damage Chemical Heat Sink

Rhythmic and Spоradic Changes in the Rate of Beta Decays: Possible Reasons

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Journal of Modern Physics 2018年第8期9卷 1617-1632页

作者： Alexander G. Parkhomov Russian Academy of Natural Sciences Moscow Russia

In a number of experiments, when detecting particles emitted in beta decays, periodic oscillations of count rate with an amplitude up to tenths of a percent and short bursts vastly exceeding the usual count rate are found. At the same time, several experiments did not detect any differences from the “normal” course of beta decays greater than 0.01%. The article shows that the inconsistency of the experimental results is due to different measurement technique. The assumption is made of the possible participation in the beta decay processes of cosmic slow neutrinos, which makes it possible to explain in a comprehensive manner not only periodic and sporadic changes in the beta decay rate, but also a number of other incomprehensible phenomena associated with beta radioactivity. On the basis of the experiments carried out, an estimate is made of the flux density of slow cosmic neutrinos.

关键词： Beta radioactivity Nuclear Decay Rate Solar Neutrinos Relic Neutrinos Variations of radioactivity Rhythmic Oscillations

Gamma Radiation Measurements of Naturally Occurring Radioactive in Igneous Rocks and Its Radiological Complications

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World Journal of Nuclear Science and Technology 2017年第3期7卷 136-144页

作者： Jamilah Al-Zahrani Physics Department Faculty of Science King Abdulaziz University Jeddah Saudi Arabia

The concentrations of natural radioactivity were measured in igneous rock samples collected from Albaha region in the south west of Saudi Arabia. A high purity germanium (HPGe) detector was used for analysis. The average activity concentrations for 226Ra, 232Th and 40K were 35, 31.52 and 843.63 Bq kg−1, respectively. The average absorbed dose rate was 70.86 nGy⋅h−1 with a corresponding average annual effective dose 0.09 mSv⋅y−1. The average radium equivalent activity value was 145.84 Bq⋅kg−1, lower than the international limit 370 Bq⋅kg−1. The external and internal indices average values were 0.39 and 0.49, respectively. The average results obtained in this study are lower than the average national and world recommended values, therefore, there is no health risk to the populace of the area. This study provides a baseline map of background radioactivity levels in the Saudi environment and will be used as reference information to assess any changes in the level background due to geological processes.

关键词： Natural radioactivity Radium Thorium and Potassium Concentrations Hazard Index

Delayed Neutrons Energy Spectrum Flux Profile of Nuclear Materials in Ghana’s Miniature Neutron Source Reactor Core

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World Journal of Nuclear Science and Technology 2011年第2期1卷 26-30页

作者： R.B.M. Sogbadji R.G. Abrefah E. Ampomah-Amoako S.A. Birikorang S.E. Agbemava B.J.B. Nyarko H.C. Odoi Ghana Atomic Energy Commission National Nuclear Research Institute P.O. Box LG80 Legon Ghana

A slightly prompt critical nuclear reactor would increase the neutron flux exponentially at a high rate causing the reactor to become uncontrollable, however due to the delayed neutrons, it is possible to leave the reactor in a subcritical state as far as only prompt neutrons are concerned and to also sustain the chain reaction when it is going to die out. The delay neutron flux spectrum of the compact core of the Ghana’s miniature neutron source reactor (MNSR) was studied using the Monte Carlo method. 20,484 energy groups combined for all three categories of the energy distribution, thermal, slowing down and fast regions were modeled to create small energy bins. The moderator, the inner irradiation channels, the annulus beryllium reflector and the outer irradiation channels were the regions monitored. The delay thermal neutrons recorded its highest flux in the inner irradiation channel with an average flux of (4.0127 0.0076) × 1008 n/cm2?s, followed by the outer irradiation channel with an average flux of (2.4524 0.0049) × 1008 n/cm2?s. The beryllium reflector recorded the lowest flux in the thermal region. These values of the thermal energy range occurred in the energy range (0 – 0.625× 10 – 07) MeV. The inner irradiation channel again recorded the highest average flux of (1.2050 ± 0.0501) × 1007 n/cm2?s at the slowing down region in the energy range (0.821 – 6.94) MeV. The outer irradiation channel recorded the lowest flux in this region. In the fast energy region, (6.96 – 20) MeV, the core, where the moderator is found, the same trend was observed with the inner irradiation channel recording the highest flux at an average flux of (2.0647 ± 0.3260) × 1006 n/cm2?s .The outer irradiation channel recorded the second highest flux while the annulus beryllium reflector recorded very low flux in this region. The final k-effective contribution from only delay neutrons is 0.00834 with the delay neutron fraction being 0.01357 ± 0.00049, hence the Ghana MNSR has good safety inherent feature.

关键词： radioactivity Doses water Gamma Spectroscopy Oil Areas Nigeria

Solidification of Spent Ion Exchange Resin Using ASC Cement

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Tsinghua Science and Technology 2002年第6期7卷 636-640页

作者：周耀中云桂春叶裕才 Institute of Nuclear Energy Technology Tsinghua University Beijing 100084 China

Ion exchange resins (IERs) have been widely used in nuclear facilities. However, the spent radioactive IERs result in major quantities of low and intermediate level radioactive wastes. This article describes a laboratory experimental study on solidification processing of IERs using a new type of cement named ASC cement. The strength of the cementation matrix is in the range of 1820 MPa (28 d); the loading of the spent IER in the cement-resin matrix is over 45% and leaching rates of 137Cs, 90Sr and 60Co are 7.92×10 -5, 5.7×10 -6, and 1.19×10 -8 cm/d. The results show that ASC cement can be a preferable cementation material for immobilization of radioactive spent IER.

关键词： radioactivity spent ion exchange resins cementation solidification

High Heat Producing Volcano-Plutonic Rocks of the Siner Area, Malani Igneous Suite, Western Rajasthan, India

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International Journal of Geosciences 2012年第5期3卷 1137-1141页

作者： Laishram S. Singh G. Vallinayagam Department of Geology Kurukshetra University Kurukshetra India

he volcano-plutonic rocks of the Siner area of the Malani Igneous Suite (MIS) are characterized by high content of radioactive elements (U, Th, K) and are classified as high heat producing felsic volcano-plutonic rocks of A-type granitoid. Microgranite shows highly comparable heat production (26.07 HP) and total heat generation value (62.06 HGU in average) as compared to other granite (HP = 12.73;HGU = 26.57), rhyolite (HP = 4.98;HGU = 11.85) and trachyte (HP = 5.00;HGU = 11.91). The volcano-plutonic rocks of the present show higher average value of total HGU than the average value of 3.8 HGU for the continental crust, which suggests a possible linear relationship among the crustal heat generation of the MIS.

关键词： radioactivity Volcano-Plutonic Rocks Malani Igneous Suite

Gamma Radiation Measurements in Tunisian Marbles

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World Journal of Nuclear Science and Technology 2012年第3期2卷 80-84页

作者： Kais Manai Chiraz Ferchichi Mansour Oueslati Adel Trabelsi National Center for Nuclear Sciences and Technologies Sidi-Thabet Tunisia Physics Department College of Science King Faisal University Hofuf KSA Research Unit of Nuclear and High Energy Physics Faculty of Sciences of Tunis Tunis El-Manar University Tunis Tunisia

The radioactivity of 15 kinds of different granites collected in Tunisia was determined by gamma-ray spectrometry using hyper-pure germanium (HPGe) detector. The average activity concentrations for primordial radionuclides 238U, 232Th and 40K were respectively 33.24, 8.01 and 116.98 Bq/kg. The activity concentrations ranged from 3.59 to 87.37 Bq/kg for 238U, from 0.45 to 25.34 Bq/kg for 232Th and from 24.06 to 380.23 Bq/kg for 40K. The measured activity concentrations were used to assess of the radium equivalent activity ranged from 22.2 to 995.8 Bq/kg, the absorbed dose rate in air from 7 to 1209 nGy/h and the internal (0.1 to 2.8) and external (0.1 to 2.7) hazard indices. The data obtained in this study may be useful for natural radioactivity mapping.

关键词： radioactivity Marble Radium Equivalent External and Internal Hazard Indices

Sun, Earth, radioactive ore: Common periodicity

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Natural Science 2013年第9期5卷 1001-1005页

作者： O. B. Khavroshkin V. V. Tsyplakov Institute of Physics of the Earth RAS Moscow Russia

The study of natural radioactivity of objects which are able to change their temporal timing feature is presented. It is of interest to compare the latest data on the activity of the Sun and the periodicity of solar neutrinos and the temporal characteristics of the radioactive source. That is, to conduct a search for the possible influence of external sources for radioactivity. There are cycles 5 min, 18 min and 53 min found in solar physics. The cycle of 27 days corresponds to the activity of the Sun. During of the solar activeity these temporal pulsations are lost in a strong variation of solar wind (Neugebauer, NASA). The Stanford University scientists (P. Starrek, G. Valter and M. Vitlend) have found the cycle of 28.4 days as pulsations of the solar neutrinos. Neutrinos come from the depths of the Sun and they tell about the frequency of oscillations of solar bowels. It is also seen online: Kostyantynivska L. V. Solar activity. Search experiment is better to have a known but modified experiment. Experiments on monitoring natural radioactivity and the possible influence from the Sun were previously carried out by measuring the variations of the gamma-ray sample of ore from the TransBaikal uranium deposit;the characteristics of the sample are known. The spectrum of temporal variations in the activity of the sample Zabaikalskaya radioactive ore contains peaks which coincide with the period of natural oscillations of the Sun. The capture cross section of the radioactive heavy deformed nucleus in time decay increases in many orders and is able to interact with the stream of solar neutrinos which are modulated by own oscillations of the Sun. The picks of spectrum of long-period oscillations of the Earth exceed its own contain peaks that match the value with an accuracy of 1% 3% with peaks of its own oscillations of the Sun. The mechanism of excitation of these oscillations is similar to the nature of variations in the activity of a radioactive sample of ore. These effects are included in the mechanisms of interacti

关键词： Solar R-Index Radioactive Source Periodicity of radioactivity Solar Neutrino Oscillations Super-Long Oscillations of the Earth Abnormal Capture Cross Section of Neutrino