Internal irradiation of the thyroid gland in residents of Kaluga Oblast from results of <Superscript>131</Superscript>I content measurements performed in May 1986

The content of ¹³¹I in the thyroid gland of approximately 30000 residents of Kaluga oblast was measured in May 1986. The work was supported by calibration and verification of the measurement means and procedure. The data making it possible to evaluate the individual, average, median, and collective dose of internal irradiation of the thyroid gland in people of different ages in the populated points of the oblast are presented. The irradiation dose to the thyroid gland in children is much higher than for adults. It is found that the individual dose of internal irradiation to the thyroid gland is described by a nearly log-normal distribution. Some of the individuals examined have an individual dose which is several-fold higher than the average and median dose. This indicates the presence of groups with an elevated radiation risk; attention should be focused on this group first when medical-prophylactic and protective measures are taken. The data from Kaluga oblast, combined with similar results from Bryansk oblast and Belarus, have served as basis for reconstructing the individual absorbed irradiation dose to the thyroid gland and as dosimetric support of radiation-epidemiological studies using the case-monitoring procedure. Translated from Atomnaya énergiya, Vol. 105, No. 2, pp. 97–103, August, 2008.     

Thyroid-Gland Irradiation Dose in the Russian Population Due to the Fallout of Radioactive Iodine After the Chernobyl Accident

The average irradiation dose to the thyroid gland is estimated for the people living in 4105 populated points in the Bryanskaya, Tul'skaya, Orlovskaya, and Kaluzhskaya oblasts. The basic principles of the method used to reconstruct the dose are presented. The people living in Bryanskaya oblast have the highest irradiation dose to the thyroid gland: in children less than 3 yr old the individual dose reached 10 Gy; the average dose exceeded 2.5 Gy in 12 populated points. In children living in Bryanskaya oblast, for populated points with soil contamination density above 37 kBq/m² the irradiation dose exceeded 0.05 Gy. The highest average irradiation dose to the thyroid gland in children living in Tul'skaya, Orlovskaya, and Kaluzhskaya oblasts is 0.3–1 Gy. The collective irradiation dose for the four most strongly contaminated oblasts is estimated to be as follows: Bryanskaya – 60, Tul'skaya – 20, Orlovskaya – 13, Kaluzhskaya – 3.5 thousand·people·Gy.     

Retrospective Individual Dosimetry at a Populated Point with a High Degree of Radioactive Contamination

The results of a reconstruction of the individual accumulated absorbed dose of internal and external whole-body irradiation (from 1986 to 2000) for the residents in the village of Zabor'e in the Krasnogorsk rayon of Bryansk oblast – the most highly contaminated populated point in Russia as a result of the Chernobyl accident (4329 kBq/m^{2 137}Cs) – are presented. The total individual accumulated absorbed dose is 50–490 mGy. For 18 of the 42 individuals examined, the dose exceeds 200 mGy. It is found that the protective countermeasure (elimination of the family milk cows) taken in 1986 was ineffective, since in 1987 the villagers began to reacquire family cows. Measures are proposed for limiting the consumption of local contaminated food products. The computational methodology adopted, based on questioning the population and assessing the running radiation conditions, is verified by comparing with data from individual EPR dosimetry on tooth enamel for some of the individuals examined (10 samples). The agreement with the EPR data is good.     

Radiation conditions in the Moscow Region in the period 1957–2005

Information about the radiation conditions in the Moscow region in 1957–2005 is presented. It is shown that the total activity of the β-emitting radionuclides, ⁹⁰Sr and ¹³⁷Cs, in atmospheric air, fallout, and food products changes. These data are used to estimate the total individual irradiation dose to the public, which does not exceed 0.2 mSv/yr. This is much less than the dose limit (1 mSv/yr) established in NRB-99. It is concluded that the radiation conditions in the Moscow region are satisfactory in the period studied. __________ Translated from Atomnaya énergiya, Vol. 100, No. 3, pp. 225–231, March, 2006.     

Statistical characteristics of the collective dose

A statistical approach for estimating the yearly effective collective dose is proposed. The distribution law for the collective dose is proposed on the basis of the assumption that the distributions of the number of people in the controlled group and the individual irradiation dose are random. It is shown that the distribution law for the collective dose has a quasiexponential form and is characterized by an average value and a variance. It is shown for a statistical analysis of the multiyear data from individual dosimetric monitoring of workers at the Moscow Scientific and Industrial Association Radon that the hypothesis advanced is consistent with observations. Practical recommendations are given for calculating collective dose statistics. 3 figures. 8 references. Moscow Scientific and Industrial Association Radon. Translated from Atomnaya énergiya, Vol. 88, No. 3, pp. 213–217, March, 2000.     

Prediction of the radiation effect resulting from the contamination of water in marine fisheries

The planning and implementation of various projects involving possible radioactive contamination of seawater require a prediction of the effect of radiation on the public. The main pathway for a radiation effect is the consumption of seafood from contaminated fisheries. A method is proposed for assessing the radiation effect due to the consumption of seafood. A special feature of the method proposed is that it uses dose coefficients to convert the volume activity of seawater in the area of a fishery into the effective irradiation dose to an individual from the general public. The computed dose coefficients for 57 radionuclides and seven types of seafood are presented. __________ Translated from Atomnaya énergiya,Vol. 100, No. 2, pp. 83–86, February, 2006.     

Swelling and radiation creep of austenitic corrosion-resistant steel irradiated by neutrons in wide dose and temperature ranges

The results of a study of the swelling and in-reactor creep of EI-847, EP-172, and ChS-68 austenitic steel after irradiation in materials science assemblies in the range 330–700°C and damaging dose 20–96 dpa are presented. The temperature dependences of the volume change of steel were obtained from measurements of the diameter of unloaded ampuls. It is shown that the swelling of the steel increases linearly with increasing tangential stress. The modulus of in-reactor creep in the interval 410–630°C for the steel investigated in the cold-deformed state varies in the range (0.5–3)·10^–6 MPa^–1·dpa^–1. For lower and higher temperatures, the creep modulus increases to (5–8)·10^–6 MPa^–1·dpa^–1.     

Effect of prior structural defects in quartz fiber lightguides on defect formation by γ radiation

The absorption spectra of unirradiated and irradiated (to fast neutron fluence 10¹² and10¹⁴ cm⁻² in VVR-SM) quartz-quartz fibers after additional irradiation with ⁶⁰Co γ rays to 10⁸ rad are investigated. It is shown that neutrons transform E′ centers into ≡Si-Si≡ centers. The kinetics of accumulation of bridge oxygen atoms under the action of γ radiation exhibits two stages. The first stage is due to neutron irradiation and the manifestation of preliminary potential centers of nonbridge oxygen atoms. The second stage is associated with the creation of additional nonbridge oxygen atoms under the action of γ radiation. The γ-ray dose for the onset of the second stage decreases as the fluence of the preliminary neutron irradiation increases. __________ Translated from Atomnaya énergiya, Vol. 104, No. 1, pp. 23–26, January, 2008.     

Calculation of the characteristics of the external irradiation of a human being as a result of <Superscript>137</Superscript>Cs contamination of soil

Monte Carlo estimates of the effect of certain characteristics of the external irradiation of a human being standing on the surface of soil contaminated with ¹³⁷Cs are presented. The spectrum and angular distribution of gamma rays in air and the effect of the height of the individual’s position above the soil surface, the area of the contaminated surface, the contamination depth in the soil, the snow cover, and the walls of a room are estimated. The effect of a change in certain computational parameters on the results is examined. It is shown that the density of the phantom material and soil have the strongest effect on the computational results. __________ Translated from Atomnaya énergiya, Vol. 104, No. 2, pp. 111–115, February, 2008.     

Remediation of zones of local radioactive contamination

A methodology remediating zones of local radioactive contamination is presented. It is based on a classification of the zones taking account of the contribution of external and internal irradiation to the total dose load to the public. The criteria for identifying such loads and the steps required for their remediation are identified. A radiation-ecological validation of the decrease in the external irradiation dose to the public in zones of local radioactive contamination is given. __________ Translated from Atomnaya énergiya, Vol. 100, No. 2, pp. 125–134, February, 2006.     

Radiation Conditions in Obninsk

Monitoring data are used as a basis to examine the radiation conditions in Obninsk, including an analysis of the radioactive emissions from the Physics and Power-Engineering Institute and the Scientific-Research and Physicochemical Institute, the content of technogenic radionuclides in atmospheric air, soil, surface waters, and the components of agricultural natural ecosystems, and an estimate of the dose and radiation risk to the public. The monitoring results show relatively low levels of technogenic radionuclides in the environment, much lower than the admissable values. It is recommended that regular radiation monitoring of the content of tritium in surface and underground waters and also iodine isotopes in air near the ground at Obninsk be continued. The total estimated dose, taking account of numerous pathways of technogenic irradiation of the public in Obninsk, is on the average about 10⁻⁵ Sv/yr, which corresponds to a negligibly low radiation risk, less than 10⁻⁶ under standard operating conditions of nuclear objects. __________ Translated from Atomnaya Energiya, Vol. 99, No. 3, pp. 214–221, September, 2005.     

Incorporation of bottoms from nuclear power plants into a matrix based on portland cement and silicic additives

The solidification of partially evaporated bottoms of RBMK and VVER with salt concentration 500–650 g/liter by compositional binders consisting of Portland cement and silicic additives – aerosil, microsilica, opoka, silicic acid, liquid glass, and diatomite is examined. The additions were used to obtain matrices that satisfy the requirements of safe storage of cemented radwastes. The partition coefficients of ¹³⁷Cs in partially evaporated bottoms are determined for all additives studied. The most effective additive for solidification of partially evaporated bottoms of VVER is diatomite. Matrices with diatomite have strength 50–81 kg/cm², the rate of leaching of ¹³⁷Cs ~ 10^–3–10^–4 g/(cm²·day) and the fill with respect to salts reaches 20.9 wt.%. On the solidification of partially evaporated RBMK bottoms the most effective hardening additives are aerosil and microsilica and the most effective sorbing additives are bentonite, opoka, and diatomite. The matrices so obtained have strength 59–93 kg/cm², ¹³⁷Cs leach rate ~ 10^–3–10^–4 g/(cm²·day) and contain to 25.1 wt.% salts.     

Measurement of the individual dose of external irradiation

The relation between the dose recorded with an individual tissue-equivalent luminescence dosimeter and the effective dose obtained by the human body is calculated. The scattering of γ rays in the human body and the surrounding space is taken into account. It is shown that for the conditions under which the dose load is formed, which exist under the normal operating conditions of a nuclear power plant, the effective dose obtained by the worker is related with the dose measured with an individual tissue-equivalent dosimeter by the relation D_eff=0.56±0.125D_equiv where D_eff is the effective dose, in Sv; D_equiv is the measured dose. in Gy. 4 tables, 2 references. All-Russia Scientific-Research Institute of Nuclear Power Plants. Translated from Atomnaya énergiya, Vol. 87, No. 3, pp. 222–226, September, 1999.     

Radiation intensity and expansion saturation of the crystal lattice of irradiated diamond

It is shown that the saturation of the expansion of the diamond crystal lattice during irradiation in a reactor depends not only on the temperature but also on the intensity of the irradiation. Expansion saturation decreases with decreasing irradiation intensity. The temperature influences saturation expansion indirectly via an increase of the effectiveness of the annealing of defects, and the intensity of irradiation stimulates additional annealing by increasing its duration. The same level of the saturation of expansion of the diamond lattice, specifically, 2.75%, can be attained at irradiation temperatures 80 and 300°C if the diamond is irradiated with neutron flux density 10¹² and 10¹⁴ sec^–1·cm^–2, respectively.     

Radiation dose to providers of brachytherapy with microsources of <Superscript>125</Superscript>I for prostate cancer

The results of measurements of the local irradiation dose to the most highly irradiated sections of the body of a therapy provider — the skin on the fingers and palm and regions of the chest — are presented. The measurements were performed by the method of thermoluminescence dosimetry using highly sensitive TLD-500K detectors. It was established that even for the highest total activity of these sources (1221 MBq) and the longest period of work without the use of x-ray protective gloves the maximum dose (minus the natural background and take the account to the energy dependence of the sensitivity of the detector) to the provider is 0.18 ± 0.01 mGy (the large finger on the right hand was exposed to the highest irradiation level) and 0.01 ± 0.0004 mGy (the outer side of the palm of the left-hand was exposed to the lowest irradiation level), which does not present a radiation hazard even when working repeatedly with the sources. __________ Translated from Atomnaya énergiya, Vol. 103, No. 2, pp. 125–128, August, 2007.     

Results of SM reactor tests of dysprosium hafnate

Models of absorbing elements with a promising material for the control organs of nuclear reactors have been tested in the SM reactor – pelleted and powder kernels with different composition based on dysprosium hafnate in a mixture with boron carbide. The neutron fluence with energy >0.1 MeV averaged over a kernel volume was (0.9–1.3)·10²² cm^–2 at the moment the tests were completed for different samples. The temperature at the center of the kernels of the absorber element models during irradiation was 620–1100°C in channel No. 4 and 400–500°C in channel No. 9. The results of the materials science studies show that on the whole the serviceability of the absorbing elements based on pellets and powders of dysprosium hafnate is high.     

吸入性210Pb内照射剂量估算方法研究

本文通过建立包含沉积模型、生物动力学模型和剂量学模型的一整套内照射模型,计算得到吸入环境中的²¹⁰Pb对男女成年人各器官的当量剂量系数,从而得到有效剂量系数为1.1×10^-6 Sv/Bq。计算结果对²¹⁰Pb防护工作的开展提供了参考数据。     

Formation of Helium Porosity in Different Materials during Post-Radiation Annealing

The characterisitics of the development of helium porosity in bcc and fcc alloys and structural steel after irradiation with 40-keV He⁺ up to dose 5⋅10²⁰ m⁻² at 20°C and subsequent annealing at 650°C for 1 h and 5 h are studied by transmission electron microscopy. It it found that under these conditions smaller bubbles with high density are formed in bcc than in fcc materials. It is shown that for an annealing time of 5 h higher porosity is formed in all materials, except nickel, than with 1 h annealing. This is due to the inflow of thermal vacancies from the free surface. The data obtained are discussed from the standpoint of the formation of various helium-containing complexes, their thermal stability, and the diffusion mobility of the matrix atoms. __________ Translated from Atomnaya Energiya, Vol. 99, No. 2, pp. 115–120, August 2005.     

Irradiation dose for personnel during brachytherapy of malignant neoplasms with 32P microsources

Experimental measurements of the local absorbed radiation dose in the most irradiated parts of the bodies of personnel (the skin of the hands and palms, eyes, thorax, and abdomen of operators) by means of high sensitivity TLD-500K thermoluminescence detectors are reported. It is found that, for ³²P microsources with a total activity of 100 MBq, after 6 hours of work without protective x-ray gloves during a simulation of placing a real preparation in the region of the liver of an adult phantom, the maximum local irradiation dose to the hands (the skin of the left middle finger and thumb) from bremsstrahlung with deduction of the natural background and without special protective measures is 0.54 ± 0.001 mGy, the minimum dose (skin on the palm of the right hand) is 0.1 ± 0.01 mGy, and the irradiation of the thorax, abdomen, and eyes of the operator is less than 0.12 mGy. This presents no radiation hazard, even for repeated work with these sources. Translated from Atomnaya énergiya, Vol. 105, No. 4, pp. 233–235, October, 2008.     

Evaluation of the irradiation dose rate for marine biota in the region of the destroyed fukushima reactor (japan) in march–may 2011

The irradiation dose rate in March–May 2011 is evaluated for marine biota in the coastal zone near the destroyed Fukushima reactor and in the open sea. It is shown that for representative marine organisms (fish and mollusks) the irradiation dose rate did not exceed the safe level 0.4 mGy/h (10 mGy/day). In the open sea, 30 km from the nuclear power plant, the irradiation of marine biota is much lower than in the coastal zone near the nuclear power plant. A comparative evaluation is made of the irradiation dose rate for water organisms in the exclusion zones of the Eastern-Urals track of radioactivity and the Chernobyl and Fukushima nuclear power plants.