Summary of doctoral thesis of Materials science: Assessment of natural radioactivity in some building materials used in Laos PDR

The objectives of the thesis is: Determination of the concentration of the Naturally Occurring Radioactive Materials (NORM) in some building materials commonly used in Lao PDR such as cement, sand, etc. by gamma spectrometers using NaI(Tl) and HPGe detectors.
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Summary of doctoral thesis of Materials science: Assessment of natural radioactivity in some building materials used in Laos PDR MINISTRY OF EDUCATION AND TRAINING VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY ---------------------------- SONEXAY XAYHEUNGSY PROJECT NAME: ASSESSMENT OF NATURAL RADIOACTIVITY IN SOME BUILDING MATERIALS USED IN LAOS PDR Major: ATOMIC AND NUCLEAR PHYSICS Code: 9440106 SUMMARY OF DOCTORAL THESIS OF MATERIALS SCIENCE HANOI - 2019 The doctoral thesis was completed at Institute of Physics, Graduate University of Science and Technology Supervisors: Prof. Dr. Le Hong Khiem Reviewer 1: …………………… Reviewer 2: …………………… Reviewer3: …………………… This doctoral thesis will be defensed at Graduate University of Science and Technology, Vietnam Academy of Science and Technology on … hour…, date…. month … year… The dissertation can be referred at: National Library of Vietnam LIST OF PUBLISTIONS 1. Sonexay Xayheungsy, Le Hong Khiem. Measurement of natural radioactivity in some cements of Lao PDR by using NaI(Tl) gamma-ray spectrometer, Advance in applied and engineering Physics IV, Publishing House for Science and Technology,2016, 231 2. Sonexay Xayheungsy, Le Hong Khiem, Phương pháp xác định hoạt độ của các nguyên tố phóng xạ tự nhiên bằng phổ kế gamma dùng detector NaI(Tl), Advance In Applied And Engineering Physics V, Publishing House for Science and Technology, 2018, 295 3. S. Xayheungsy, L.H. Khiem, L.D. Nam, Radiation dose estimation of cement samples used in Lao PDR, Communications in Physics, 27, No. 3, 2017,193-203. 4. Sonexay Xayheungsy, Le Hong Khiem, Le Dai Nam. Assessment Of The Natual Radioactivity And Radiological Hazards In Lao Cement Samples. Radiation Protection Dosimetry, 2018, Vol. 181, No. 3, 208–213. 5. Sonexay Xayheungsy, Le Hong Khiem. Natural Radioactivity In The Soil Of Thoulakhom District In Vietiane Province, LaoPDR, Tạp Chí Phát Triển Khoa Học Và Công Nghệ- Đại Học Quốc Gia TP. HCM, ngày 21 tháng 3 năm 2018. 6. X.Sonexay, L.H.Khiem, L.D.Nam, Assessment of Natural Radioactivity Levels and Radiation Hazards of Building Materials of Lao PDR. International Journal Of Modern Engineering Research (IJMER), 14.04.2018 7. Sonexay Xayheungsy1,3, N.C.Thanh2, L.D.Nam2, V.H.Giang2 and L.H.Khiem2,3*, Measurement of natural radioactivity in some sand and brick in Vietiane province, Lao PDR. IJRDO - Journal of Applied Science, Volume-4, Issue, 11, Nov, 2018. INTRODUCTION 1. Thesis necessity There are various sources that contain radiation, especially in the earth, rocks with different amounts. An amount of radiation that is higher than the safety threshold can be a cause of many diseases including cancer, which is dangerous for people. Building materials such as cement, brick, sand, soil, etc. are mainly made from raw materials such as soil and rock. As a result, they can break down into radioactive gas radon. According to statistics of the UN, a person spends 70% his lifetime in-door (houses, offices, or public buildings, etc.). If the construction materials contain an extremely high amount of radiation, it will be hazardous. For the safety of humankind, The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has given a radiation safety threshold for building materials. In most countries, it is mandatory to check radioactivity of the materials for construction before they are used. In Laos PDR , up to now there has not been any inspection of radiation carried out (due to lack of skilled personnel). Laos has officially become a member of the IAEA since 2011. Since then, Lao government have requested Vietnam to give a hand in training highly qualified personnel in the field of radioactive control in construction materials. The objective of this thesis is to understand the method of assessment of natural radioactivity in some building materials for better implementation of constructions in Laos. 2. Objectives of the study The objectives of the thesis is: - Determination of the concentration of the Naturally Occurring Radioactive Materials (NORM) in some building materials commonly used in Lao PDR such as cement, sand, etc. by gamma spectrometers using NaI(Tl) and HPGe detectors. - To assess the radiological hazard associated with the natural occurring radioactive isotopes in the building materials used in Laos PDR. These data are extremely important for the radiation dose assessment for residents, and making proper warning and necessary recommendations to production facilities so that they can make necessary adjustments to ensure the absolute safety in radioactive aspects for construction materials used in the market. 3. Main research contents of the thesis - The research is to analyze the amount of concentration of natural occurring radioactive isotopes including 238U, 235U, 232Th and 40K in the building materials used in Laos PDR by using gamma-ray spectroscopy technique. For our measurements, both NaI(Tl) and HPGe detectors have been used for gamma-ray detection. - For analyzing the gamma-ray spectra obtained with NaI(Tl) detector, a mathematical method has been used for determining the areas of overlapping spectral regions due to the poor energy resolution of NaI(Tl) detector. - To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the air absorbed dose rate, the annual effective dose rate, the representative in ...