Time changes of dose equivalent rate above the soil surface as indication of natural attenuation processes

Abstract. Eight sites in the Fukushima contaminated area were surveyed for long-term changes in D-shuttle dose equivalent rate above the soil surface during 2015–2017. D-shuttle readings in most cases decreased faster than if due to radioactive decay only. More rapid decrease can be explained by natural attenuation processes, such as erosion of the topsoil, the vertical migration of radionuclides in the soil and the deposition of cleaner sediments transported by surface runoff. According to the time dependencies of D-shuttle dose rate readings integral rate constants of the natural attenuation were estimated using the exponential trend-line. Estimated rate constants of natural attenuation ranged from 7.3×10-3 to 0.48 yr−1, while the correspondent a half-dose rate decrease was 1.4–95 years.

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Calculating radiation dose rate from online real-time environmental -spectrum using NaI(Tl) detector

Nuclear Science and Technology ◽

10.53747/jnst.v11i1.128 ◽

2021 ◽

Vol 11 (1) ◽

pp. 16-25

Author(s):

Thu Bac Vuong ◽

Hoang Tuan Truong ◽

Duc Thang Duong ◽

Dac Dung Bui ◽

Duc Viet Cao ◽

...

Keyword(s):

Radiation Dose ◽

Dose Rate ◽

Real Time ◽

Specific Activity ◽

Radioactive Isotopes ◽

Dose Equivalent ◽

Radiation Dose Rate ◽

Equivalent Rate ◽

Ambient Dose Equivalent ◽

Ambient Dose

Calculating gamma radiation dose rate from online real-time environmental gamma spectrum using NaI(Tl) detector has been developed into a software named RADAPROC V.1 in the Center for Operating the National Network of Environmental Radiation Monitoring And Warning (CONNERMAW). Currently, hundreds of online gamma spectra per day from online monitoring stations are processed to calculate the total ambient dose equivalent rate and the ambient dose equivalent rate of typical natural radioactive isotopes such as K-40, Bi-214, Tl-208 according to the method of using the function G(E) and the photo-peak area method. The calculated results have been compared with the results of calculating the dose rate from the specific activity of radioactive isotopes in soil samples collected at the same monitoring location and analyzed in the laboratory. The difference between the methods is less than 25%. The ambient dose equivalent rates of typical natural radioactive isotopes are a bit higher than those calculated with SARA-NMC software. The software will be improved shortly for better results.

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Rainfall Intensity and Quantity Estimation Method Based on Gamma-Dose Rate Monitoring

Sensors ◽

10.3390/s21196411 ◽

2021 ◽

Vol 21 (19) ◽

pp. 6411

Author(s):

Valentina Yakovleva ◽

Grigorii Yakovlev ◽

Roman Parovik ◽

Aleksey Zelinskiy ◽

Aleksey Kobzev

Keyword(s):

Dose Rate ◽

Time Derivative ◽

Estimation Method ◽

Radioactive Decay ◽

Atmospheric Precipitation ◽

Ground Surface ◽

Soil Surface ◽

Radiation Dose Rate ◽

Γ Radiation ◽

Average Value

The features of the atmospheric γ-background reaction to liquid atmospheric precipitation in the form of bursts is investigated, and various forms of them are analyzed. A method is described for interpreting forms of the measured γ-background response with the determination of the beginning and ending time of precipitation, the distinctive features of changes in the intensity of precipitation and the number of single (separate) events that form one burst. It is revealed that a change in the intensity of precipitation in one event leads to a change in the γ-radiation dose rate increase speed (time derivative). A method of estimating the average value of the intensity and amount of precipitation for one event, reconstructing the intensity spectrum from experimental data on the dynamics of the measured dose rate of γ-radiation, is developed. The method takes into account the radioactive decay of radon daughter products in the atmosphere and on the soil surface during precipitation, as well as the purification of the atmosphere from radionuclides. Recommendations are given for using the developed method to correct for changes (daily variations) in radon flux density from the ground surface, which lead to variations in radon in the atmosphere. Experimental verification of the method shows good agreement between the values of the intensity of liquid atmospheric precipitation, calculated and measured with the help of shuttle and optical rain precipitation gauges.

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Dose rate, dose-equivalent rate, and quality factor in SLS-1

International Journal of Radiation Applications and Instrumentation Part D Nuclear Tracks and Radiation Measurements ◽

10.1016/1359-0189(92)90030-y ◽

1992 ◽

Vol 20 (3) ◽

pp. 447-451 ◽

Cited By ~ 9

Author(s):

Gautam D. Badhwar ◽

Leslie A. Braby ◽

Frank A. Cucinotta ◽

William Atwell

Keyword(s):

Dose Rate ◽

Quality Factor ◽

Dose Equivalent ◽

Equivalent Rate

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Correlation between calculated and measured values of gamma dose rate in air in forests contaminated with 137Cs: the remote period after the Chernobyl accident

Radiatsionnaya Gygiena = Radiation Hygiene ◽

10.21514/1998-426x-2019-12-4-37-46 ◽

2020 ◽

Vol 12 (4) ◽

pp. 37-46 ◽

Cited By ~ 2

Author(s):

Valery P. Ramzaev ◽

Anatoly N. Barkovsky

Keyword(s):

Vertical Distribution ◽

Dose Rate ◽

Chernobyl Accident ◽

Gamma Dose ◽

Dose Equivalent ◽

Air Kerma ◽

Equivalent Rate ◽

Ambient Dose Equivalent ◽

Air Kerma Rate ◽

Ambient Dose

In 2015–2016, 13 forest and 7 virgin grassland plots located in the south-western districts of the Bryansk region were surveyed. The aim of the work was to experimentally test the possibility of using a method for calculating the dose rate of gamma radiation in air in radioactively contaminated forests in a remote period after the Chernobyl accident. According to the results of gamma-spectrometric analysis of soil samples obtained at the sites in another study, the values of inventory and vertical distribution of 137Cs in the upper 20 cm layer were established. In this paper, these data were used to calculate the air kerma rate using a method taken from literature. In addition, at the sites of soil sampling, ambient dose equivalent rate in air was measured, and the contribution of 137Cs to the total gamma dose rate was determined with a field gamma spectrometer-dosemeter. The measured values of the ambient dose equivalent rate from 137Cs correlated positively and statistically significantly with the calculated values of the air kerma rate. The Spearman correlation coefficient was 0.989 (P < 0.01) for the location “forest” and 0.893 (P < 0.05) for the location “grassland”. There was no statistically significant difference between the “forest” and “grassland” locations when analyzing the ratio of the measured dose rate values to the calculated dose rate values (the Mann-Whitney U test, P > 0.05). Results of this work show that, when calculating gamma radiation dose rate in air in forests at a remote stage after the Chernobyl accident, it is enough to know the 137Cs inventory in the upper 20 cm soil layer and a detailed picture of vertical distribution of the radionuclide in this layer. The presence of woody biomass can be neglected. This dose rate estimate is conservative. However, a degree of overestimation of the dose rate in air is small, within +10%, which is quite acceptable for determining the external effective dose rate for an individual in the radioactively contaminated forest.

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A user's manual for ALDOSE: A computer code for calculating absorbed-dose rate, dose-equivalent rate, and dose-weighted LET as functions of depth in water irradiated by an alpha disc source

10.2172/6758265 ◽

1990 ◽

Cited By ~ 1

Author(s):

T.E. Huston ◽

J.E. Turner

Keyword(s):

Dose Rate ◽

Absorbed Dose ◽

Computer Code ◽

Dose Equivalent ◽

Absorbed Dose Rate ◽

Equivalent Rate

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Study the Effect of Scattering and Disperse Radiation on Equivalent Dose Rate for Al & Pb Shields

Baghdad Science Journal ◽

10.21123/bsj.8.2.261-268 ◽

2011 ◽

Vol 8 (2) ◽

pp. 261-268

Author(s):

Baghdad Science Journal

Keyword(s):

Dose Rate ◽

Atomic Number ◽

Equivalent Dose ◽

Secondary Radiation ◽

Dose Equivalent ◽

Equivalent Dose Rate ◽

Equivalent Rate

The effects of scattering and secondary radiation generated inside the material on dose equivalent rate where studied using Co60 and Cs137 sources of activity (199.8 , 177.6) MBq , respectively for different thicknesses of Al , Pb and Pb- glass . The results showed that the equivalent rate increases when the effect of scattering was included for Al and Pb shields with cobalt-60 source of energy 1.25 MeV ; and decreases for Pb shield with Cs-137 source of energy 0.662MeV .The results showed also that the atomic number of The material effects the dose equivalent rate . The Pb-glass shield was found to be more efficient in absorption than other shields.

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Natural restoration of radiopolluted ecosystems and impact on human health

Global NEST Journal ◽

10.30955/gnj.000163 ◽

2013 ◽

Vol 2 (1) ◽

pp. 59-66

Keyword(s):

Human Health ◽

Vertical Migration ◽

Soil Layer ◽

Soil Surface ◽

Migration Velocity ◽

Dose Equivalent ◽

Natural Restoration ◽

Equivalent Rate ◽

Contamination Of Soils ◽

Initial Contamination

The vertical migration velocity of radionuclides and the ability of soils components to immobilise them, as the most important parameters of natural-restoration, was studied. The Dose Equivalent Rate (DER) reduction of external ã-radiation was studied in order to assess its impact on human health. The vertical migration velocities of 137Cs and 90Sr in typical soils of contaminated regions in Ukraine (Chernobyl 30-km zone) and Belarus (Gomel region) have been evaluated annually during the last 8 or 10 years since the accident. In most of these soils the migration rate of 90Sr was found to be higher than this of 137Cs and ranged from 0.71 to 1.54 cm year-1 and 0 to 1.16 cm year-1 respectively. At present the main part of radionuclides is located in the upper 10 cm soil layer. The ability of the soil components to immobilise the radionuclides was also investigated from 1989 to 1994 and was found that approximately 57% of 137Cs was converted in fixed forms. It is expected that this percentage will increase to 80% in the next years. Finally, we studied how the DER of ã-radiation, which changes with the migration of radionuclides in the soil, affects the human health. In comparison with 1986, when 100% of 137Cs was distributed on the soil surface, a significant reduction of DER occurred in the studied areas and about ten years after the Chernobyl accident, it ranges from 17.5% to 45%, depending mainly on the level of initial contamination of soils and its migration velocity.

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Radiation Survey in the Area of Peaceful Nuclear Explosion «Takhta-Kugulta»

Medical Radiology and radiation safety ◽

10.12737/1024-6177-2021-66-2-13-22 ◽

2021 ◽

Vol 66 (2) ◽

pp. 13-22

Author(s):

A. Titov ◽

N. Shandala ◽

D. Isaev ◽

Yu. Bel'skih ◽

M. Semenova ◽

...

Keyword(s):

Specific Activity ◽

Nuclear Explosion ◽

Soil Surface ◽

Mean Value ◽

Surface Contamination ◽

Dose Equivalent ◽

Tritium Content ◽

Equivalent Rate ◽

Ambient Dose Equivalent ◽

Ambient Dose

Purpose: Radiation survey in the area of peaceful nuclear explosion «Takhta-Kagylta» in the Stavropol Region. Material and methods: Radiation survey was performed on the territory of the protected area and on the territory of the 30-km zone from the explosion site. Methods of pedestrian gamma survey with a portable spectrometric complex Multirad-M were used in the course of the survey, along with gamma spectrometric and radiochemical measurements of radionuclide activities in samples and radiochemical separation of 90Sr and 137Cs. The measurement of tritium activity concentration in water was carried out using a low-background liquid alpha-beta radiometer Quantulus-1220. Results: The highest average value of gamma ambient dose equivalent rate was obtained in the area of the peaceful nuclear explosion site. A value of ambient dose equivalent rate at the area between the site and Kevsala village is lower than on the site, but higher than in Kevsala village and in other settlements. The mean value of the surface contamination of soil with 137Cs on the site was 0.43 kBq/m2, while that of 90Sr was 0.055 kBq/m2. Average values of soil surface contamination with radionuclides in the settlements located in the area of the explosion vary over the range between 0.16 and 0.37 kBq/m2 for 137Cs and between 0.035 and 0.066 kBq/m2 for 90Sr. 241Am specific activity values were below the minimum detectable activity (0.01 – 0.04 kBq/m2 at the time of the soil sample measurement of 10–30 h). The contents of 3H, 90Sr and 137Cs radionuclides in drinking water and water of the surface water reservoirs is significantly lower than the intervention levels established in NRB-99/2009. Conclusions: Radiation situation at the location of the technological well complies with the requirements of SanPiN 2.6.1.2819-10 “Radiation Safety and Protection of the Population Living in the Areas of Peaceful Nuclear Explosions (1965 – 1988)”, and does not pose a threat to the health of the population when staying there. It is necessary to arrange the territory of the protection area and technological (charging) well in accordance with the requirements of SanPiN 2.6.1.2819–10. Within the framework of long-term radiation monitoring, it is necessary to provide for the monitoring of the tritium content in the produced gas and in the groundwater of the Krasnogvardeiskoe deposit (located in the direction of the spread of groundwater from the location of the peaceful nuclear explosion).

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