Territory contamination with the radionuclides representing the fuel component of Chernobyl fallout

Title: Territory contamination with the radionuclides representing the fuel component of Chernobyl fallout

Author: V.A Kashparov, S.M Lundin, S.I Zvarych, V.I Yoshchenko, S.E Levchuk, Y.V Khomutinin, I.M Maloshtan, V.P Protsak

Reference: Science of The Total Environment, Volume 317, Issues 1–3, 30 December 2003, Pages 105-119

DOI: http://dx.doi.org/10.1016/S0048-9697(03)00336-X

Keywords: Chernobyl accident; Terrestrial density of contamination; Plutonium; Radioactive fallout; Fuel particles

Abstract: The data obtained through a series of experiments were used to specify the correlation of activities of the fuel component radionuclides of Chernobyl fallout and to create the maps of the 30-km Chernobyl zone terrestrial density of contamination with ¹⁵⁴Eu, ²³⁸Pu, ^239+240Pu and ²⁴¹Am (on 01.01.2000). In the year 2000, total inventories of the fuel component radionuclides in the upper 30-cm soil layer of the 30-km Chernobyl zone in Ukraine (outside the ChNPP industrial site, excluding the activity located in the radioactive waste storages and in the cooling pond) were estimated as: ⁹⁰Sr—7.7×10¹⁴ Bq; ¹³⁷Cs—2.8×10¹⁵ Bq; ¹⁵⁴Eu—1.4×10¹³ Bq; ²³⁸Pu—7.2×10¹² Bq; ^239+240Pu—1.5×10¹³ Bq; ²⁴¹Am—1.8×10¹³ Bq. These values correspond to 0.4–0.5% of their amounts in the ChNPP unit 4 at the moment of the accident. The current estimate is 3 times lower than the previous widely-cited estimates. Inventories of the fuel component radionuclides were also estimated in other objects within the 30-km zone and outside it. This allowed more accurate data to be obtained on the magnitude of a relative release of radionuclides in the fuel particles (FP) matrix during the Chernobyl accident outside the ChNPP industrial site. It amounts to 1.5±0.5% of these radionuclides in the reactor, which is 2 times lower than the previous estimates. Two-thirds of the radionuclides release in the FP was deposited on the territory of Ukraine.

URL: http://www.sciencedirect.com/science/article/pii/S004896970300336X

Empirical scavenging coefficients of radioactive substances released from chernobyl

Title: Empirical scavenging coefficients of radioactive substances released from chernobyl

Author: Kirsti Jylhä

Reference: Atmospheric Environment. Part A. General Topics, Volume 25, Issue 2, 1991, Pages 263-270

DOI: http://dx.doi.org/10.1016/0960-1686(91)90297-K

Keywords: Chernobyl; radioactive fallout; wet scavenging coefficient; weather radar; Finland

Abstract: After the accident at the Chernobyl power plant on 26 April 1986, most parts of Europe were affected by the associated radiation pollution. In this paper the dependence of the precipitation scavenging coefficient λ (s⁻¹) on the rainfall rate R (mm h⁻¹) is studied on the basis of radioactivity and radar rainfall measurements in Southern Finland after the accident.

URL: http://www.sciencedirect.com/science/article/pii/096016869190297K

Simulation of the chernobyl radioactive cloud over Europe using the eurad model

Title: Simulation of the chernobyl radioactive cloud over Europe using the eurad model

Author: H. Hass, M. Memmesheimer, H. Geiβ, H.J. Jakobs, M. Laube, A. Ebel

Reference: Atmospheric Environment. Part A. General Topics, Volume 24, Issue 3, 1990, Pages 673-692

DOI: http://dx.doi.org/10.1016/0960-1686(90)90022-F

Keywords: Forecast; accidental release; Chernobyl; long-range transport; deposition; radionuclides

Abstract: The opean cid eposition Model (EURAD) is used to investigate the long-range transport (LRT) and deposition of radioactive material in Europe during the first week after the Chernobyl accident. Emphasis is laid on using the model system in a forecast mode as possibly would be done shortly after such an event. Thus, meteorological fields are predicted with the PSU/NCAR mososcale model MM4.The multilayer Eulerian model CTM ( hemistry ransport ) is applied to compute transport and deposition of Cs-137 and I-131 using the predicted meteorological fields. However, the accident scenario was estimated using published data. The model results and performance are discussed by comparison with observations. It is demonstrated that the model can reproduce certain observed characteristics of the radioactive cloud, i.e. trends in surface air concentrations, arrival times and wet deposition patterns. This leads to the suggestion that the predictive capability of the EURAD-system has a relatively high level considering the fact that several simple approaches were used.

URL: http://www.sciencedirect.com/science/article/pii/096016869090022F

Transport of radioactive particles from the Chernobyl accident

Title: Transport of radioactive particles from the chernobyl accident

Author: Roy Pöllänen, Ilkka Valkama, Harri Toivonen

Reference: Atmospheric Environment, Volume 31, Issue 21, November 1997, Pages 3575-3590

DOI: http://dx.doi.org/10.1016/S1352-2310(97)00156-8

Keywords: Chernobyl accident; radioactive particles; long-range transport; particle transport

Abstract: After the Chernobyl accident large and highly radioactive particles were found in several European countries. Particles > 20 μm in aerodynamic diameter were transported hundreds of kilometres from the plant, and they were sufficiently active (> 100 kBq) to cause acute health hazards. Here, a particle trajectory model is used to identify the areas of large particle fallout. Effective release height of the particles and atmospheric phenomena related to their transport are investigated by comparing particle findings with locations given by trajectory calculations. The calculations showed that in the Chernobyl accident either the maximum effective release height must have been considerably higher than previously reported (> 2000 m) or convective warm air currents may have lifted radioactive material upwards during transport. Large particles have been transported to other areas than small particles and gaseous species. The particulate nature of the release plume must be taken into account in dispersion and transport analyses. Air parcel trajectories alone are not necessarily sufficient for identifying the fallout area of radioactive material.

URL: http://www.sciencedirect.com/science/article/pii/S1352231097001568

Transfer of radiocaesium in sensitive agricultural environments after the Chernobyl fallout in Sweden: III. County of Västernorrland

Title: Transfer of radiocaesium in sensitive agricultural environments after the Chernobyl fallout in Sweden: III. County of Västernorrland

Author: K. Rosén, E. Haak, Å. Eriksson

Reference: Science of The Total Environment, Volume 209, Issues 2–3, 19 January 1998, Pages 91-105

DOI: http://dx.doi.org/10.1016/S0048-9697(98)80100-9

Keywords: Radiocaesium; Radioiodine; Chernobyl; Nuclear fallout; Grass; Cereals

Abstract: In 1986 a large number of farms in the Chernobyl-affected area in the county of Västernorrland in northern Sweden were investigated for radiocaesium transfer to grass and cereal grain. The soil surface layer (0–5 cm) in 1986 and the crop products in 1986–1996 were analysed. The aim was to study the impact of soil and crop rotation on sensitivity of ¹³⁷Cs transfer in a short and long term perspective. In the fallout year 1986 the transfer to grass was usually much higher than to cereal grain. In this year the transfer to grass was usually much higher in the first cut rather than the second cut. The reduction in transfer with year was large but variable with site and with crop sequence. Ploughing was effective in decreasing the transfer of ¹³⁷Cs to crops. On arable sites in 1986 the transfer to cereal straw was larger at late stem elongation (LSE) than at the maturing stage. Unexpectedly, there was no clear relationship between transfer of ¹³⁷Cs to the crops and any of the soil characteristics. In 1986 the transfer of ¹³¹I to grass and cereals was also investigated on some of the farms. The results are compared with the transfer of ¹³⁷Cs, 2 months after the Chernobyl fallout.

URL: http://www.sciencedirect.com/science/article/pii/S0048969798801009

Transfer of radiocaesium in sensitive agricultural environments after the Chernobyl fallout in Sweden. II. Marginal and seminatural areas in the county of Jämtland

Title: Transfer of radiocaesium in sensitive agricultural environments after the Chernobyl fallout in Sweden. II. Marginal and seminatural areas in the county of Jämtland
Author: Klas Rosén
Reference: Science of The Total Environment, Volume 182, Issues 1–3, 5 April 1996, Pages 135-145

DOI: http://dx.doi.org/10.1016/0048-9697(95)05059-0

Keywords: Radiocaesium; Grass; Fallout; Chernobyl; Contamination

Abstract: In 1986, two Chernobyl-affected areas in the county of Jämtland, a mountain area and a river valley area, were investigated as to radiocaesium behaviour and transfer to grass. The soil surface layer (0–10 cm) in 1986 and 1989 and grass samples in 1986–1994 were analysed on 9 temporary grassland sites and 8 permanent pasture sites, described individually. The aim of this investigation was to study the sensitivity of different soil types and the influence of normal farming practices, ploughing and K-fertilization on the caesium transfer, in short- and long-term perspectives after the Chernobyl fallout. As expected, the transfer of ¹³⁷Cs to grass was usually higher on permanent pasture than on temporary grassland. For both types of grassland, however, there was a considerable but different change of transfer with years. The transfer to grass in the year of the fallout, 1986, depended to a large extent on the thickness and interception capacity of the grass sward. In the following years, it also depended on the caesium-fixing capacity to clay minerals, on K-fertilization and the reverse process of K removal by plant uptake. Ploughing down the contaminated surface layer and the mixing of caesium with mineral soil were effective in reducing the transfer. During the period 1986–1994, the transfer was reduced considerably, showing a range of (0.1–177.3 m²/kg d.w.) × 10⁻³. The calculated annual reduction halftime, T_ar, increased with years after fallout. It is clearly shown that both countermeasures, ploughing and K-fertilization, are of potential value to decrease grass contamination. Where both measures were employed a reduction in the range of 78%–95% was recorded in the year after ploughing.

URL: http://www.sciencedirect.com/science/article/pii/0048969795050590

Transfer of radiocaesium in sensitive agricultural environments after the Chernobyl fallout in Sweden. I. County of Gävleborg

Title: Transfer of radiocaesium in sensitive agricultural environments after the Chernobyl fallout in Sweden. I. County of Gävleborg

Author: Klas Rosén, Åke Eriksson, Enok Haak

Reference: Science of The Total Environment, Volume 182, Issues 1–3, 5 April 1996, Pages 117-133

DOI: http://dx.doi.org/10.1016/0048-9697(95)05056-6

Keywords: Radiocaesium; Chernobyl; Nuclear fallout; Cereals; Grass

Abstract: In 1986, 15 farms in the Chernobyl-affected area of the county of Gävleborg were investigated for radiocaesium transfer to grass and cereal grain. The soil surface layer (0–5 cm) in 1986 and the crop products in 1986–1994 were analysed. The aim was to study the impact of site and soil characteristics on sensitivity of ¹³⁷Cs transfer in a long-term perspective. The transfer was much higher to grass than to cereal grain. For both crop products, however, there was a considerable annual reduction. For grass, and especially in the fallout year 1986, the transfer depended on interception capacity of the stubble and grass sward, on soil fertility and K-fertilization as well as on dilution by crop growth. In the following years, the annual reduction in transfer to grass was reduced by a factor of 2 to 100. Both ploughing through the surface layer and the mixing of radiocaesium with soil contributed to a decreased transfer of radiocaesium to crops. Thick stubble and grass sward on the grassland sites was the main reason for a lag period of high persistent transfer. The annual reduction was less on organic than on mineral soils. Measures to decrease the transfer to crops are discussed in relation to a new concept to evaluate the long-term behaviour of ¹³⁷Cs in agricultural environments

URL: http://www.sciencedirect.com/science/article/pii/0048969795050566

A prognostic estimation of the area contaminated with alpha-emitting transuranium isotopes in Belarus following the Chernobyl accident

Title: A prognostic estimation of the area contaminated with alpha-emitting transuranium isotopes in Belarus following the Chernobyl accident

Author: V.A. Knatko, V.D. Asimova, A.E. Yanush, Yu.N. Golikov, I.I. Ivashkevich, L.A. Kouzmina, Yu.I. Bondar

Reference: Journal of Environmental Radioactivity, Volume 83, Issue 1, 2005, Pages 49-59

DOI: http://dx.doi.org/10.1016/j.jenvrad.2004.07.005

Keywords:Chernobyl accident;^238,239,240Pu and ²⁴¹Am;Belarus

Abstract: As a result of the Chernobyl accident, some regions of Belarus have been contaminated with the plutonium isotopes ^{238,239,240,241}Pu. Considering the importance of the environmental impact of the alpha-emitting radionuclides we have carried out a prognostic estimation of the area contaminated with ^238,239,240Pu and ²⁴¹Am (the latter being a decay product of ²⁴¹Pu) in Belarus. The calculations were made using measurements of ^238,239,240Pu activity concentrations in soil samples from about 600 settlements in the affected region, together with the estimated activity ratio A(²⁴¹Am)/A(^238,239,240Pu). The area contaminated with alpha-emitting transuranium isotopes predicted for the year 2006 has been compared with that estimated for 1986.The results show that by 2006, the area of inhabited districts where contamination with ^238,239,240Pu and ²⁴¹Am exceeds the threshold level of 740 Bq/m², will be 3.7 times larger, reaching approximately 3.5 × 10³ km². Of this, almost 20% will have a contamination level of 1850–3700 Bq/m².

URL: http://www.sciencedirect.com/science/article/pii/S0265931X05000640

Soil contamination with 90Sr in the near zone of the Chernobyl accident

Title: Soil contamination with 90Sr in the near zone of the Chernobyl accident

Author: V.A Kashparov, S.M Lundin, Yu.V Khomutinin, S.P Kaminsky, S.E Levchuk, V.P Protsak, A.M Kadygrib, S.I Zvarich, V.I Yoschenko, J Tschiersch

Reference: Journal of Environmental Radioactivity, Volume 56, Issue 3, 2001, Pages 285-298

DOI: http://dx.doi.org/10.1016/S0265-931X(00)00207-1

Keywords: Soil contamination; ⁹⁰Sr; Chernobyl; 30 km exclusion zone; Map

Abstract: Representative large-scale soil sampling on a regular grid of step width about 1 km was carried out for the first time in the near zone of the Chernobyl accident (radius 36 km). An integrated map of terrestrial ⁹⁰Sr contamination density in the 30 km exclusion zone (scale 1 : 200,000) has been created from the analysed samples. Maps of the main agrochemical characteristics of the soils, which determine the fuel particle dissolution rates and the contamination of vegetation, were produced. The total contents of ⁹⁰Sr on the ground surface of the 30 km zone in Ukraine (without the reactor site and the radioactive waste storages) was about 810 TBq (8.1×10⁺¹⁴ Bq) in 1997, which corresponds to 0.4–0.5% of the Chernobyl reactor inventory at the time of the accident. This assessment is 3–4 times lower than previous estimates.

URL: http://www.sciencedirect.com/science/article/pii/S0265931X00002071

An assessment of cumulative external doses from Chernobyl fallout for a forested area in Russia using the optically stimulated luminescence from quartz inclusions in bricks

Title: An assessment of cumulative external doses from Chernobyl fallout for a forested area in Russia using the optically stimulated luminescence from quartz inclusions in bricks

Author: V. Ramzaev, L. Bøtter-Jensen, K.J. Thomsen, K.G. Andersson, A.S. Murray

Reference: Journal of Environmental Radioactivity, Volume 99, Issue 7, July 2008, Pages 1154-1164

DOI: http://dx.doi.org/10.1016/j.jenvrad.2008.01.014

Keywords: Chernobyl fallout; Forest; Cumulative dose; Fired quartz; Red clay brick; Optically stimulated luminescence

Abstract: Optically stimulated luminescence (OSL) has been used for estimation of the accumulated doses in quartz inclusions obtained from two fired bricks, extracted in July 2004 from a building located in the forested surroundings of the recreational area Novie Bobovichi, the Bryansk Region, Russia. The area was significantly contaminated by Chernobyl fallout with initial ¹³⁷Cs ground deposition level of ∼1.1 MBq m⁻². The accumulated OSL doses in sections of the bricks varied from 141 to 207 mGy, of which between 76 and 146 mGy are attributable to Chernobyl fallout. Using the OSL depth-dose profiles obtained from the exposed bricks and the results from a γ-ray-survey of the area, the Chernobyl-related cumulative γ-ray dose for a point detector located in free air at a height of 1 m above the ground in the study area was estimated to be ca. 240 mGy for the time period starting on 27 April 1986 and ending on 31 July 2004. This result is in good agreement with the result of deterministic modelling of the cumulative γ-ray dose in free air above undisturbed ground from the Chernobyl source in the Bryansk Region. Over the same time period, the external Chernobyl-related dose via forest pathway for the most exposed individuals (e.g., forest workers) is estimated to be ∼39 mSv. Prognosis for the external exposure from 1986 to 2056 is presented and compared with the predictions given by other investigators of the region.

URL: http://www.sciencedirect.com/science/article/pii/S0265931X08000179