Experience in application and efficiency assesment of protective measures used after the Chernobyl accident

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Experience in application and efficiency
assesment of protective measures used after the
Chernobyl accident

• academician, prof. Prister B,
• bprister_at_mail.ru

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A basic parameter for a decision-making about
conducting counter-measures is a dose of
irradiation of population. The doses of
external and internal irradiation are
proportional the density of radio-active
contamination of territory and its ecological
properties
Therefore, the priorities are carrying out
monitoring of soil contamination and prediction
intake of radionuclides in plants
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Values of agrochemical characteristics of the
main soil types Ukrainian Polesie and
Forest-Steppe were vary in a wide range
Each soil type consisted of 3 to 15 soil differs
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Likhtarev,2006
The spatial distribution of internal radiation
dose is determined more by ecological factors
than by Cs-137 fallout density that is why in
settlements located at 300 km from ChNPP the
dose is higher than in settlements around
epicenter of the accident.
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The spatial distribution of internal dose the
population of Rivne region due to the consumption
of milk (cow pasture, a 137Cs contamination of
the Ci/km2), calculated using the model
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Monitoring of contaminated territories (Soils)

• In the first days after the Chernobyl accident
  were identified spots with significantly higher
  density of contamination of Cs-137. There is a
  need in the shortest possible time to identify
  critical areas in order to clarify their
  radiation environment and the countermeasures.
• In June 1986 we have developed a technique and
  with agronomic and agrochemical services
  Gosagroprom USSR and sanitary-epidemiological
  service of the monitored soil farmland. Sampling
  was carried out by taking the average
  representative sample for each of the 445
  administrative districts of Ukraine. Individual
  samples were collected on five fields of each of
  the 25 - 28 farms area in each district.
• The samples were combined and mixed in the back
  of dump truck and an aliquot was used for
  measurements. Gamma-spectrometric analysis of
  Cs-137 and Sr-90 determination of radiochemical
  were assigned to 11 research teams and regional
  zonal agrochemical laboratories of Ukraine under
  centralized metrological support.
• For 10 days the average levels of pollution map
  of the territory of the 445 regions of Ukraine
  long-lived radionuclides, which revealed all the
  spots with elevated density of fallout.
• We proposed to provide such monitoring in
  Fukusima region.

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The scheme of radiation monitoring of agrosphere
after the accident in 1986
Belorussia
?
For control and prediction agricultural
contamination was formed the monitoring network
agrosphere
Each year, sampling was performed at 9 fields at
each from 33 farms
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In order to predict contamination of crop
production is very importance that for Cs-137
confirmed a linear relationship between specific
activity in plants (kBg kg-1) and soil
contamination density (kBq m-2), proved for
Sr-90 in the track of the Kyshtym accident
The value of  TF of radionuclides does not depend
on the density of soil contamination for all
types of crops on all soil types
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Dynamic of transfer factors TF of radionuclide
in plant from soil
Cs-137, Hay of sown grass on soil ---
peat-bog --- soddy-podzol --- chernozem.
Sr-90 Bulb of potatoe on soil ---
soddy-podzol --- gray-forest --- chernozem.
Cs-137, Soddy-podzol soil --- hay of natural
grass --- hay of sown grass --- grain of wheat.
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• Analysis for dynamics of radionuclides TF from
  soil to plants showed that the values of Cs-137
  TF decreased with time after deposition. In the
  first 3 - 5 years the decrease is rapid, and in
  the following - is slow.
• The value of Sr-90 TF decreases monotonically
  during the post-accident period.
• Analysis showed that the half-decrease periods of
  TF are similar for different plants species on
  the soil of the same type. This means that the
  biological characteristics of the plants did not
  affect the processes of transformation of
  radionuclides forms in the soil.
• Comparison of these parameters for different soil
  types with the characteristic of time of sorption
  equilibrium establishment in the soil allowed us
  to describe the scheme of radionuclides forms
  transformation.

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Average for groups of crops values of transfer
factors TF(0) 137Cs extrapolated to the time of
fallout, (kg-1??2 )10-3 (? ? 25)
10 30 times
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15-30 times
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The range of average values TF Cs-137 in
different types of grassland herbage in 1987
(n240, s 50)
Type of soil Type grassland Range for TF, (Bq/kg)/(kBq/m2)
Soddy-podzolic loamy terrestrial normal 1.0 - 4.1
Soddy-podzolic loamy floodplain wet 2.1 - 6.0
Meadow sandy terrestrial normal terrestrial normal 2.1 - 5.0
Meadow sandy terrestrial normal floodplain wet 8.8 - 12.8
Soddy-podzolic sandy terrestrial absolute 3.5 - 8.0
Soddy-podzolic sandy terrestrial normal 5.2 - 13.1
Soddy-podzolic sandy Terrestrial excess humidified 16 - 32
Soddy-podzolic sandy floodplain wet 29 - 49
Peat-bog Terrestrial drained 35 - 55
Peat-bog Floodplain wet 67 - 92
Peat-bog Lowland wetlands 165 - 221
Critical product on contaminated territory is
the milk. Forage grasses are critical fodder,
especially in the growing organic wetlands and
sandy acidic soils.
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Week
10 years
20 years
Day
Month
Year
Iodine blocking
Dynamics of conducting of counter-measures after
an accident
Evacuation
Limit on the pastering of animals
Limits on a consumption of the fresh
plant-grower and stock-raising products
Decontamination (dezactivation)
Agromeliorativnye measures
Veterinary and zootechnics counter-measures
Processing of products of plant-grower and
stock-raising
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The three basic principles the concept of
agriculture in the affected areas

• To avoid individual dose exceeding the content of
  Cs-137 in the product must not exceed permissible
  levels.
• It is implemented by carrying out countermeasures
  (budget).
• If action is not advisable to conduct activities
  on the territory ceases.
• 2. Minimization of the collective dose is
  achieved by reducing the flows of Cs-137 into the
  body through measures that are selected to
  conduct optimization procedures and are
  implemented if a significant effect on the
  radiation situation.
• 3. Countermeasures - always intervention. When
  choosing them consider not only radiological, but
  also social, medical and other factors.

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Change in time of the area of agricultural
land, where lime (A) and fertilizers be applied
(B) as countermeasures in the former Soviet
Union contaminated by the Chernobyl accident,
ha.
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The dynamic of the applying of the fundamental
improvement of the grassland contaminated after
the Chernobyl accident, ha.
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The main goal of countermeasures to decrease
individual radiation dose of population up to
normative levels.
Decrease of radioactive contamination of plant
products after countermeasures application, times
Countermeasures Countermeasures 137Cs 137Cs 90Sr 90Sr
Countermeasures Countermeasures Soil Soil Soil Soil
Countermeasures Countermeasures mineral organic mineral organic
Liming, 4-6 t/h? Liming, 4-6 t/h? 1.5-3.0 1.5-2.0 1.5-2.6 -
NPK in optimal ratio NPK in optimal ratio 1.5-2.0 1.5-3.0 0.8-1.2 -
Manure, 50 t/h? Manure, 50 t/h? 1.5-3.0 - 1.2-1.5 -
Liming NPK Liming NPK 1.8-2.7 2.5-4.0 - -
Ceolite, sapropel Ceolite, sapropel 1.5-2.5 - 1.5-1.8 -
Ploughing , 35-40 sm Ploughing , 35-40 sm 8.0-12 10-16 2.0-3.0 -
Improvement of meadow and pasture Fundamental 1.5-9.0 4.0-16 1.5-3.5 3.0-5.3
Improvement of meadow and pasture Light 2.0-3.0 2.0-14 2.0-2.5 3.0-5.0
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The map of contamination territory of Ukraine
Cs-137
The river Pripyat
The irrigation of fodder crops
The irrigation of rice
Requirements for the content of radionuclides in
the water for irrigation were more stringent
than for drinking water.
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• In Ukraine during the Chernobyl accident a large
  proportion of products, including rice, produced
  on irrigated lands, areas which accounted for 2.4
  million hectares.
• Although the irrigated lands are located more
  them 600 km from the Chernobyl zone, migration of
  Sr-90 with waters of the river Dnepr resulted in
  increase the density of soil contamination in the
  checks and, consequently, the grains of rice a
  few times.
• This made it necessary to create a system for
  monitoring agricultural areas on irrigated lands
  and reduce the irrigation of rice and fodder
  crops.

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Dynamics of accumulation of Cs-137 (1) and Sr-90
(2) in the soil rice paddies
kBq/m2
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Dynamics of radionuclides accumulation in a
grain of rice in irrigated paddies after
Chernobyl accident
Years Bq/kg (n9, s 30) Bq/kg (n9, s 30)
Years
Years 90Sr 137Cs
1972 0.33 2.4
1982 0.30 0.7
1985 0.11 0.6
1986 0.07 1.0
1987 0.15 1.6
1988 0.19 1.5
1989 0.37 1.2
1990 0.56 0.9
1991 0.69 1.1
1992 0.81 1.0
1993 1.12 0.9
1994 0.70 2.0
1995 1.27 1.1
1996 1.30 0.8
20 times
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Action plan for clean milk production
Spatial Distribution analysis of milk
contamination levels
Soil and fodder analysis on the territories with
high milk contamination
Development of the countermeasures
Development of supply chain and differentiation
of milk processing according to the contamination
levels
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Ways to reduce the radionuclide contamination of
animal products

• Developed three radically different and
  effective ways to reduce the content of
  radionuclides in milk and muscle tissue (meat)
  animals
• first - to reduce radionuclide intake and
  concentration of radionuclides in milk and meat
  in
• 3 - 5 times by adjusting the feed with a
  low content of Cs 137
• second - by shifting the radionuclides in
  the rumen of the ionic state to a bound before it
  enters the small intestine to prevent its
  absorption into the blood
• Ferrocine reduced Cs-137 transfer meat
  and milk by 3-10 times.
• third - to pre-slaughter fattening "clean"
  feed. Proved that for fattening animals clean
  feed for 40-60 days a large proportion of Cs-137
  excreted from the body, and the content of
  radionuclides in the muscles is reduced by 6-10
  times.
• Application of zeolite in the feeding
  period prior to slaughter can have a 2.0-2.4
  times decrease the accumulation of Cs-137 in
  muscle tissue of animals.

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(No Transcript)
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Radiological efficiency of the ferrocine and
feed additives on the basis zeolites
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Countermeasures ensured decrease of Cs-137
content in milk and meat in 4-12 times and
allowed to prevent of the collective dose above
1000 man-Sv in each country.
Decrease of radioactive contamination of milk
processing production, times
Product 137Cs 90Sr
Sour cream 1.2-1.3 1.3
Cottage cheese 1.1-1.4 increase in 5-6
Hard natural cheeses 2.4 increase in 8
Butter 3.6-5.6 1.9-9.1
Dried milk increase in 8 increase in 8
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Distribution of settlements by rating doses
based on overall dosimetrical pasportization
(Ukraine).
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• The dose, calculated by the content of Cs-137
  in milk and potatoes, and their of the daily
  consumption several times higher than values
  calculating dose according to the WBC -
  monitoring.
• This demonstrates the high conservatism of
  methods for assessing exposure to the population
  used in the first period, people's ability to
  limit the consumption of "dirty" products, as
  well as a significant decrease in the consumption
  of milk and milk products by the population over
  the last decade. Poor diet can induce health is
  much more significant damage than irradiation at
  low doses.
• The question deserves a detailed study and
  monitoring. Need to develop more adequate models
  to reduce the conservatism of dose estimates in
  the long run.

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Our proposal on 2012-2013 Topic 1.
"Reconstruction of spatial distribution of
radiation dose of the thyroid gland (thyroid)
population. Rate ratio of I-131 to Cs-137 and
its stability in the region of influence of the
accident at Fukushima. Based on the distribution
of Cs-137 prediction using the developed
mathematical model of ISP NPP and validation
reconstruct data on the density of fallout
I-131. Make a prediction of the spatial
distribution of radiation dose thyroid population.

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Topic 2. "The organization of land use in the
contaminated area after accident." To monitoring
agricultural sphere Analyze, and if necessary
create a database for monitoring soil and
agricultural products. Conduct comprehensive
mapping - levels of pollution and agrochemical
properties of soils. Develop a forecast of
contamination of the products in time with the
use of models and databases Institute for safety
problems NPP. According to the results highlight
the control zone with a different probability of
production of specified levels of contamination
of products - milk, vegetables and others.
Identify the most critical landscapes, soils,
crops that provide the greatest accumulation of
radionuclides on the territory with equal density
of contamination. Optimize system of pollution
control products. Compare data prediction and
control of standards and identify areas where
intervention is necessary - a change of land use,
the countermeasures.

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• Theme 3. Optimize supply scheme and the sale of
  products and its technological processing.
• Conducting analyze the pattern of supply,
  processing and use of products from contaminated
  areas.
• Develop a scheme of the targeted supply of
  products subject to the differencial appointment.
• Identify the need for processing of products.

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Theme 4. To assess the radiation situation on
irrigated lands. Consider the structure of
irrigated land (if any) flood irrigation rice
receipts, irrigation , and to evaluate sources of
water for irrigation. According to monitoring
data and model calculations to predict the
dynamics of water pollution from each
source. Organize control of water sources by
chemical composition. In order to predict
contamination of crop production for the type of
product and method of irrigation. Assess the
need for countermeasures.

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• Thank you for the attention!