Radioactivity level of the ambient environment of Anren bone—coal power station

The radioactivity level of the ambient environment of Anren Bone-coal Power Station(BCPS) was investigated systematically.The γ radiation dose rate level in the environment ,the content of ^238U and ^226Ra in the ambient soil and the farmland in the direction of downwind,the concentrations of ^238U,^232Th,^226Ra,^40K and ^222Rn,as well as α potential energy in air,and the concentrations of natural U and Th in effluent are all higher than the corresponding values of the reference site.The additional annual effective dose equivalent to the residents living in the houses made of bone-coal cinder brick is 2.7mSv.     

Estimation of the resident’s additional dose in bone-coal mining areas of the five provinces

1 Introduction In the National Investigation of Natural Radioac-tive Levels (abbreviated as “investigation of levels” hereinbelow) during 1983 to 1990, it is found that the specific activities of radionuclides in bone-coal are relatively high. The increase of radioactive level in the environment and the rise of the public accepted dose might be caused by some artificial activities, which include mainly mining and utilizing spontaneously bone-coal by local peasants, producing bone-coal cind…     

RADIOACTIVITY LEVEL OF RESIDENTIAL AREAS AROUND XINJIANG NUCLEAR TESTING SITE AND ESTIMATED POPULATION DOSE

Results are reported on a research for the radioactive level in the investigation region and the control region around the Xinjiang Nuclear Testing Site from 1982 to 1987. There are no significant differences on the land γ radiation level, nor in the radioactive level in the soil, food and water between the two regions. The distribution and transfer of 90Sr, 137Cs and Pu in various kinds of soil are also discussed. It is estimated that the effective dose equivalent of radiation, undergone by the residents around the Testing Site is only 2.9% of that of natural radiation taken yearly by people in normal areas.     

Environmental radioactivity level at a mantle factory in eastern Zhejiang

The Y radiation level, alpha potential energy of thoron and alpha surface contamination level at a mantle factory in the east of Zhejiang Province are reported. The measured results show that the additional annual effective dose equivalent absorbed by the worker in some workshops of the factory was higher than 15 mSv-management limit. The alpha surface contamination on the workers' hands in some workshops was 10 times more than the management limit of National Standard (0.04 Bq/cm2). The mantle factory s main danger to body was internal irradiation of a rays from thoron aerosol.     

Approach to reducing the effect of bone—coal power station on radiation environment

The effect of two bone-coal power stations(6MWe) on environment was investigated within the scope of the dose contribution caused by various radionucildes in different ways.It is found that the best measures to reduce the effect of bone-coal power station on radiation environment include to select a fine boiler system and a comprehensive utilization of the bone-coal cinder(BCC),soot and ash in the catchers.     

Ingestion Dose Estimation in a Typical Area Affected by Natural Radiation in China

<正>In order to study the environmental radiation impact from the germanium mining and processing located in a typical area in China for 40 years,samples of crops were collected in this area, and the activity concentrations of~(210)Pb and~(210)Po in the samples were analyzed.The NORMALYSA software tool recommended by IAEA was used to estimate the ingestion doses of residents living in the research area,while the dietary differences between China and other countries are taken into consideration.     

Measurements of 134Cs and 137Cs in urine and estimation of the inter nal dose of an adult exposed to the Chernobyl Accident

To estimate the internal dose of a Chinese visiting scholar internally contaminated because of the Chernobyl Accident, the contents of 134Cs and 137Cs in urine were measured using a Ge（Li） γ-spectrometer. The internal doses were calculated based on data from the ICRP Publications. The effective doses from ^134Cs and ^137Cs were estimated to be 61 μSv and 98 μ Sv, respectively. The sum of 159 μSv was lower than the total effective dose （310 μSv）, from the inhalation and ingestion of natural radionuclides. The dose of ^131I was also reviewed referring to the UNSCEAR 2000 Report. The equivalent effective dose of ^131I was estimated to be 2.9 mSv, 18 times more than the amount of ^134Cs and ^137Cs. Therefore, it is considered that the earlier estimation of internal doses of ^131I is important in evaluating radiation injuries from a nuclear reactor accident.     

Assessment of the induced radioactivity in the treatment room of the heavy-ion medical machine in Wuwei using PHITS

Carbon-ion radiotherapy(CIRT) offers unique physical and biological advantages over photon radiotherapy. However, some materials and devices in the CIRT treatment room become radioactive under bombardment by therapeutic carbon-ion beams due to nuclear reactions, thereby leading to possible radiation hazards to medical staff and additional and unwanted doses to patients. This study assessed the level of induced radioactivity in the treatment room of the Heavy-Ion Medical Machine(HIMM) in Wuwei. M...     

ENVIRONMENTAL IMPACT OF THE NUCLEAR INDUSTRY IN CHINA

The radiological environmental impact assessment of the nuclear industry in China has been completed. The effective dose equivalents to the critical groups are mainly within the fluctuation range of the average naturhl background radiation dose in the provinces, and below the dose limits. The annual average collective effective dose equivalent from the nuclear industry is approximately 23 man·Sv. According to the nuclear power planning of China, it is estimated that the annual collective effective dose equivalent from the nuclear fuel cycle and the application of radioisotopes is 59 man·Sv in 2000 a.     

Investigation of environmental activity levels of bone-coal mining area in five provinces

During 1991-1993, the activity levels of the bone-coal mines were investigated in Zhejiang, Hubei. Hunan,Jiangxi and Anhui Province, respectively, where the reserve of bone-coal is about 90% of our country‘s total reserve.The average ofγ radiation doserate level measured for bone-coal, bone-coal cinder (BCC) and bone-coal cinder brick (BCCB) in these provinces is about 500 nGy/h, 400 nGy/h and 700 nGy/h respectively, while that for fields, roads and houses made of BCCB in corresponding regions of these provinces is about 200 nGy/h, 260 nGy/h and 300 nGy/h respectively. It is shown that the environmental activity level of bone-coal mining area is about 3 times higher than the reference spots.     

Annual effective dose values from ~(137)Cs activity concentrations in soils of Manisa,Turkey

In this study,the activity concentrations of the fallout radionuclide ~(137(Cs in 150 soil samples collected from 13 districts of Manisa Province were determined using a gamma ray spectrometer with a Na I(Tl) detector.The health risks to people resulting from external exposure were evaluated by estimating the outdoor absorbed gamma dose rate and annual effective dose rate(outdoor and indoor).The activity concentration of ~(137)Cs varied from 3.6 ± 2.0 to 124.1 ± 11.0 Bq kg~(-1),with an average value of43.3 Bq kg~(-1).The average values of the outdoor absorbed gamma dose rate and annual effective dose(outdoor plus indoor) were found to be 1.3 n Gy h~(-1),and 8.0 μSv y~(-1),(6.38 + 1.59 μSv y~(-1)),respectively.The results were compared with internationally recommended values.     

ELECTRON SPIN RESONANCE DATING FOR THE AGE OF PEKING-MAN, LOC.1, ZHOUKOUDIAN, BEIJING

In this paper, we used ESR dating method to measure the accumulative dose of the fossil teeth samples, which are contemporaneous with the Peking-Man. The internal annual dose rate of samples are got by neutron activation analysis and the environmental annual dose rate by highly sensitive TL dosimeters to be embedded in cave deposits in the site. The results of ESR dating are corresponded with the dating results obtained by U-series, FT, TL and paleomagnetic stratigraphical methods on the 3rd, 4th, 7th and 10th layers. Calculation of using different models, the close-equilibrium model, the linear uranium accumulation model and radon loss-linear uranium accumulation model, for travertine, deer teeth and rhinoceros tooth, we obtained the age of the First Peking- Man in the nth layer is 578 ka and gave ages of other layers, from the 1st to the 13th layer in Peking- Man site.     

Radioactive contents and background doses from northern alluvial sediment plains between rivers Ravi and Chenab,Pakistan

Radiometric analysis of soil samples, collected from northern alluvial sediment plains between rivers Ravi and Chenab, has been carried out. Activity concentrations of~(226) Ra,~(232)Th,~(40) K and the artificial radionuclide~(137) Cs were estimated by using high-purity germanium detector. Subsequent values of activity concentrations were used to find terrestrial absorbed dose rate and annual effective doses received by resident of area. The mean radioactivity levels of~(226) Ra,~(232)Th,~(40) K and~(137)Cs were found to be 45.0 ± 1.3,59.6 ± 2.8, 613.8 ± 20.0 and 4.0 ± 0.2 Bq kg~(-1), respectively. Terrestrial absorbed dose rate and annual effective dose received by public were found to be 85.1 n Gy h~(-1)and0.5 m Sv, respectively. The activity concentrations of~(226) Ra,~(232)Th,~(40) K and~(137)Cs and resulting doses obtained for the current study were compared with data available in the literature and with international standards.     

NATURAL BACKGROUND RADIOACTIVITY LEVELS IN THE TERRESTRIAL ENVIRONMENT OF HONG KONG

This paper analyses and summarizes the natural radionuclide contents of soil and building materials, radon concentrations and the penetrating radiation levels in Hong Kong. From these, a thorough and objective assessment for the terrestrial background irradiation level of Hong Kong was made. Finally, the annual effective dose equivalent received by Hong Kong people due to the natural background irradiation was calculated to be 3.2 mSv.     

238U and 232Th concentrations measured in different medical drugs by using solid-state nuclear track detectors and resulting radiation doses to the skin of patients

Urban populations in Morocco receive free medical drugs as prescribed by doctors in district health centres.To explore the exposure pathway of ~(238)U and~(232)Th and their decay products on the skin of patients,these radionuclides were measured in various medical drugs by using solid-state nuclear track detectors(SSNTDs).The measured concentrations range of ~(238)U and ~(232)Th in the medical drug samples of interest vary from(4.3±0.3) to(11.1±0.7) mBq 1~(-1) and(0.49±0.03) to(1.3±0.1)mBq 1~(-1),respectively.A new dosimetric model,based on the concept of specific alpha-dose and alpha-particle residual energy,was developed for evaluating radiation doses to skin following the application of different medical drugs by patients.The maximum total equivalent effective dose to skin due to the ~(238)U and ~(232)Th series from cutaneous application of different medical drugs by patients was found to be 2.8 mSv year~(-1) cm~(-2).     

Assessment of the long-term possible radiological risk from the use of ceramic tiles in Malaysia

This study investigated the level of natural radioactivity and radiological risks of 40 different ceramic tiles through gamma-ray spectroscopy using a high-purity germanium detector. The calculated activity concentrations were evaluated to determine their potential radiological risks to human health. Furthermore, the activity concentrations were subjected to the RESRAD-BUILD computer code to assess the effect of ventilation rate, dweller position, and room size and direction on the total effective dose(TED). The simulated TED received by a receptor when changing the ventilation rate in a room ranged from0.26 ± 0.01 to 0.61 ± 0.01 mSv/y; however,the percentage variations in the TED due to dweller position and room size are 34, 31,and 35% and 33, 27, and 40% for the x-,y-,and z-directions, respectively. The overall TED received by the dweller based on room size and direction is 0.75 mSv/y. The calculated radiological risk parameters were all below the recommended maximum limit. However, the TED received by the dweller is significantly affected by the directions of the measurement, position,room size,and ventilation. Therefore,estimating the TED from one direction would underestimate the total dose received by the dweller.     

Development of a dose-adjustable α-particle irradiation facility for radiobiological studies

Bystander effects induced by low-dose or low dose-rate radiation have put a great challenge to the traditional model for radiation protection. In order to get a better assessment of the adverse effects of radiation, especially the low-dose radiation risk in environment, a radioactive irradiation facility, by which the dose and dose-rate to the biological targets can be controlled by rotating the sample bracket and changing the space between the radioactive source and the targets, was developed. The energy of our α-radioactive source (^241Am) is measured averagely 3.5 MeV at the position of the irradiated sample. The dose rate was measured by using a silicon surface barrier detector and a CR39 particle track detector. A dose rate ranging from 0.045 cGy/s to 1.07 cGy/s can be obtained by changing the space length from the radioactive source to the sample dish.     

Small Punch Test Device Suitable for Radioactive Sample

<正>In order to perform a small punch test on a radioactive sample,and because the small punch test sample is small,it is difficult to complete the test by using mechanical arms in a hot cell,so a small punch test device for radioactive samples is designed,which is easy to operate to reduce the operator's exposure dose.The schematic diagram of the test device is shown in Fig.1.     

Designing a nuclear battery based on the Mo-99 radioactive source soluble in water and aqua regia in order to use in early tests

Today, millions of electrocommunication, electric, medical, and industrial devices use battery. Batteries with long life and high energy density seem to be essential in medical, military, oil and mining, aerospace areas as well as conditions in which access is difficult and in situations where replacement or recharging of battery is costly.In this regard, the use of radiation energy resulting from radioactive materials and its conversion to electric energy can be effective in making batteries. In the present study,various Mo-99 radioisotope values with a half-life of 65.98 h were used as a soluble radioactive source in two materials of water and aqua regia. Then, by comparing the results of the Monte Carlo simulations program MCNPX for these two solutions, it was found that when the water is used instead of aqua regia(for idealization), the values of the superficial current of electrons, the volumetric flux of electrons, and the deposited energy in the volume containing the radioactive solution increased by 10.80, 4.10,and 13.80%, respectively. Also, the short-circuit current and energy conversion efficiency of this battery with a concentration of 0.01 molar, Mo-99 dissolved in the aqua regia are 0.79μA and 16.47%, respectively.     

Dosimetry of chimeric TNT in lung tumor patients

The purpose of this study was to assess the absorbed dose of tumor and main critical organs in 131I labeled chimeric tumor necrotic treatment (chTNT). In 9 patients, a single intravenous dose of (29.6±3.7) MBq/kg was administered. Blood samples were drawn at different time intervals, and urine was collected for up to one week. Tissue distribution of 131I -chTNT was followed for up to one week by gamma camera imaging. Absorbed doses to the whole body and to normal organs were computed according to the MIRD scheme using Mirdose-3 software. S-factors for lung tumors were estimated by comparison with lungs of similar mass and position in the body. It was found that mean serum disappearance half time values for 131I-chTNT were (4.93±9.36) h and (61.7±21.2) h for α, β respectively,while that for whole body was(99±10) h. Mean urine biological clearance half time value was (90±10) h. The absorbed dose to tumor was (8.28±2.65) Gy, and the tumor-to-nontumor dose ratio was 3.95±1.55. And the mean effective dose to patients was (1.02±0.29) mSv/MBq.