Cleaning Up Sites Contaminated with Radioactive Materials: International Workshop Proceedings (2009)

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24 Areas of the Russian Federation Affected by Radiation Contamination Due to the Chernobyl Nuclear Power Plant Accident* S. M. Vakulovsky, T. S. Borodina, A. A. Volokitin, V. M. Kim, G. I. Petrenko, E. G. Tertyshnik, A. D. Uvarov, and V. N. Yakhryushin, Typhoon Research and Production Association—State Institution, Obninsk As a result of the accident at the Chernobyl Nuclear Power Plant on April 26, 1986, 19 Russian Federation subjects (oblasts and autonomous republics) suffered cesium-137 contamination at levels of more than 1 Ci/km2 (37 kBq/m2). The total land area with this level of contamination in all the affected regions in 1986 was 65,050 km2. Table 24-1 presents a 1998 forecast of expected changes in the contamination level over time due to radioactive decay. As the table indi- cates, by 2006 the contaminated land area totaled 31,120 km2—that is, it had been reduced in size by one-half during the 20 years since the accident. All population centers located in areas with cesium-137 contamination levels of more than 1 Ci/km2 (37 kBq/m2) were studied to determine their level of ra- diation contamination. The results of this research are presented in Table 24-2. From this table, it is clear that based on conditions in early 2006, there were 3,234 population centers in 15 Russian regions with cesium-137 contamination levels of more than 1 Ci/km2 (37 kBq/m2). For all these population centers, calcula-   *Translated from the Russian by Kelly Robbins.   Izrael, Yu. A., et al. 1998. Long-term forecast of changes in the levels of Cs-137 radioactive contamination in areas of Russia after the Chernobyl Nuclear Power Plant accident. Meteorology and Hydrology 4:5-17.  The term population center encompasses urbanized areas of various sizes ranging from large cities to towns, villages, and small rural settlements. 191 

192 CLEANING UP SITES CONTAMINATED WITH RADIOACTIVE MATERIALS TABLE 24-1  Forecast of Expected Changes in Total Land Area in Russia with Varying Levels of Cesium-137 Radioactive Contamination Due to the Chernobyl Accident Area (in km2) with Varying Levels of Local Cs-137 Contamination Year >40 Ci/km2 15-20 Ci/km2 5-15 Ci/km2 1-5 Ci/km2 1986 580 2,070 5,780 56,260 1996 310 1,900 5,330 48,980 2006 40 1,280 3,540 26,260 2016 850 2,780 18,920 2026 625 2,700 15,040 2036 190 2,340 12,500 2046 100 1,500 10,930 tions were made to determine how long it would take for each to move to the next lowest contamination category as a result of radioactive decay. The results of these calculations are presented in Table 24-3, which indicates that there will be no population centers with contamination levels greater than 40 Ci/km2 (1,480 kBq/m2) by 2020, greater than 15 Ci/km2 (555 kBq/m2) by 2063, greater than 5 Ci/km2 (185 kBq/m2) by 2110, and greater than 1 Ci/Km2 (37 kBq/m2) by 2180. Bryansk Oblast suffered the most contamination from the Chernobyl accident of any Russian region. Therefore, information was compiled on the contamination status of the near-earth atmosphere (up to approximately 5 km from the earth’s surface) and bodies of water in this particular oblast. Figure 24-1 provides infor- mation on the change in the average annual cesium-137 activity by volume in the near-earth atmosphere over the city of Bryansk. From this figure, it is clear that the activity by volume decreased by an order of magnitude from 1987 to 1995. During the next 10 years, it changed insignificantly, fluctuating within the range of 1-3 × 10–6 Bq/m3. This amount is seven orders of magnitude lower than the activity by volume allowable for the population, as established by the Radiation Safety Norms (RSN-99). Levels of cesium-137 atmospheric fallout are cited for the population center of Krasnaya Gora (Figure 24-2), where the level of cesium- 137 contamination is close to 5 Ci/km2 (185 kBq/m2), while near this town there is an area with substantially higher levels of soil contamination. Figure 24-2 shows that the level of atmospheric fallout declined by two orders of magnitude in the 5 years following 1986, changed insignificantly from 1991 through 2001, and subsequently fell to five times less by 2005. Figure 24-3 indicates that cesium- 137 concentrations in the soil due to atmospheric fallout over 19 years totaled 11.5 kBq/m2, which is 6.2 percent of initial contamination.   Ministry of Health of the Russian Federation. 1999. Radiation security norms (RSN-99). 

TABLE 24-2  Numbers of Population Centers in the Russian Federation by Level of Cesium-137 Contamination on an Oblast or Autonomous Republic Basis (Conditions as of January 2006) <1 Ci/km2 1-5 Ci/km2 5-15 Ci/km2 15-40 Ci/km2 >40 Ci/km2 Oblast or Total Autonomous Population Total Population Population Population Population Population Republic Centers Samples Centers Sample Centers Sample Centers Sample Centers Sample Centers Sample Bashkortostan 16 65 16 65 Belgorod 550 3,597 419 3,007 131 590 Bryansk 2,007 25,419 1,313 11,589 428 4,676 212 6,764 51 2,301 3 747 Volgograd 5 24 4 17 1 5 Voronezh 1,208 9,636 1,136 8,901 72 735 Kaluga 591 5,952 325 2,250 242 3,220 24 400 Kursk 1,111 6,719 984 5,616 127 1,103 Leningrad 159 1,732 122 1,335 37 430 Lipetsk 214 1,607 170 1,281 44 375 Mary El 25 72 25 72 Mordovia 390 1,459 373 1,358 17 98 Moscow 9 49 9 49 Nizhny 148 742 148 742 Novgorod Novgorod 85 492 85 492 Oryol 1,596 11,850 1,001 7,201 594 4,640 1 9 Penza 202 1,483 180 1,335 22 119 Rostov 2 10 2 10 Ryazan 579 7,365 405 5,871 174 2,493 Saratov 11 41 11 41 Smolensk 89 513 89 513 Tambov 123 961 121 935 2 26 Tula 2,391 19,005 1,340 7,943 995 9,855 56 1,207 Ulyanovsk 131 559 130 552 1 4 Chuvashia 34 89 34 33 TOTAL 11,676 105,904 8,442 61,208 2,887 28,369 293 8,380 51 2,301 3 747 193 

194 CLEANING UP SITES CONTAMINATED WITH RADIOACTIVE MATERIALS TABLE 24-3  Year When Last Population Center in Each Area Listed in Table 24-2 Will Shift from One Cesium-137 Contamination Category to the Next Lower Oblast or Autonomous Republic 1-5 Ci/km2 5-15 Ci/km2 15-40 Ci/km2 >40 Ci/km2 Belgorod 2048 Bryansk 2180 2110 2063 2020 Volgograd 2020 Voronezh 2044 Kaluga 2100 2030 Kursk 2050 Leningrad 2044 Lipetsk 2039 Mordovia 2040 Oryol 2077 2007 Penza 2050 Ryazan 2054 Tambov 2007 Tula 2109 2039 Ulyanovsk 2011 TOTAL 2180 2110 2063 2020 10.0 1.0 10 -5 Bq/m 3 0.1 0.0 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 Years FIGURE 24-1  Changes in average annual cesium-137 activity by volume in the air over Figure 24-1.eps the city of Bryansk since the Chernobyl accident. 

AREAS AFFECTED BY RADIATION CONTAMINATION 195 10000 Measured fallout, Bq/m 2 1000 100 10 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 Year FIGURE 24-2  Annual cesium-137 fallout at Krasnaya Gora settlement. Figure 24-2.eps 12000 Measured concentration, Bq/m2 11000 10000 9000 8000 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 Year FIGURE 24-3  Cesium-137 concentrations in the soil in Krasnaya Gora settlement. Figure 24-3.eps 

196 CLEANING UP SITES CONTAMINATED WITH RADIOACTIVE MATERIALS TABLE 24-4  Concentrations of Cesium-137, Strontium-90, and Tritium in Surface Water and Well Water, 1998-1999 Concentration, Bq/L Body of Water Cs-137 Sr-90 Tritium Lake Svyatoye na Besedi 11.1-11.4 0.40-0.42 1.6-2.1 Lake Kozhanovskoye 5.1-7.1 1.1-1.5 1.4-3.0 Outflow canal from Lake Kozhanovskoye 4.4-5.9 Nagorny Canal 0.5-1.4 Karyer Reservoir 0.30-0.34 0.57-0.86 2.1-3.1 Ponds in rural settlements Yalovka and Nikolaevka 0.6-5.4 0.37-0.91 1.8-2.8 Other small bodies of water 0.07-3.54 0.17-0.71 1.2-4.2 Rivers Iput, Besed, Snov, Korna, Vaga, Tsata 0.01-0.23 0.021-0.095 1.9-2.7 Wells in rural settlement Nikolaevka 0.05-0.4 Well in rural settlement Zaborye 0.08 Well in center of rural settlement Kozhany 0.03 1.5 Borehole in urbanized settlement Mirny, school, water pipeline 0.2 RSN-99 levels of intervention, Bq/L 11 5 7,700 The levels of radioactive contamination in bodies of water in Bryansk Oblast were also studied in detail. Some results of this research are presented in Ta- ble 24-4 and Figure 24-4. The table and figure show that levels of contamination in the water in rivers flowing through the contaminated areas of Bryansk Oblast and in wells located in the most contaminated population centers (Kozhany, Nikolaevka, and Zaborye) are two to three orders of magnitude below the level of intervention established by RSN-99. However, contamination levels in water in closed reservoirs located near those population centers (Lake Kozhanovskoye and Lake Svyatoye na Besedi) are close to or exceed the level of intervention. High levels of cesium-137 contamination in fish have also been identified in these lakes. Table 24-5 presents data on contamination levels in fish from these lakes. As shown in the table, the contamination levels in fish exceeded the maximum allowable level by one to two orders of magnitude.   Vakulovsky, S. M., et al. 2000. Radioecological monitoring of the environment in Bryansk Oblast in 1998-1999. Pp. 19-23 in Proceedings of the International Conference on Radioactivity Associated with Nuclear Explosions and Accidents, April 24-26, 2000, Moscow, vol. 2. 

AREAS AFFECTED BY RADIATION CONTAMINATION 197 Lake Svyatoye Lake Kozhanovskoye Cs, Bq/L 37 Date FIGURE 24-4  Cesium-137 concentration in lakes Svyatoye and Kozhanovskoye. Figure 24-4.eps Partial bitmap image - Low resolution TABLE 24-5  Specific Cesium-137 Activity Levels in Fish, 1998-1999 Specific Activity, Cs-137 Bioconcentration Fish Length, cm Body of Water kBq/kg dry weight Factor in Fish, L/kg Perch 5 Zalomenye 0.6 1,600 Carp 10 Yalovka 0.3 400 Carp 21-23 Vereshchaki 0.3 400 Carp 21-26 Karyer 0.1-0.3 300-900 Carp 25-30 Kozhanovskoye 5.2-9.5 1,100-2,100 Carp 20-36 Kozhanovskoye 6.1-10.0 1,300-2,200 Ruffe 10 Karyer 0.13 400 Northern pike 66 Karyer 0.7 2,200 Northern pike 17-43 Kozhanovskoye 5.5-12.4 1,200-2,700 Roach 10-15 Kozhanovskoye 2-5.8 400-1,300 Roach 22 Kozhanovskoye 6 1,300