Dynamics of radioactive contamination at Plant during 31 years after the accident

Mark Zheleznyak Project Professor, Institute of Environmental Radioactivity (IER), Fukushima University

1986-2013, Head, Department of Environmental Modelling, Institute of Mathematical Machines and Systems , Cybernetics Center, National Academy of Sciences of , Kiev 1

Chernobyl NPP site before accident

31 years ago - 26 April 1986 – the explosion on Unit ( Reactor) 4 , and following at 10 days atmospheric releases due to the fire Surface contamination with 137Cs in Europe after the Chernobyl nuclear accident. De Cort et al. (1998) Cs-137 fallout density after Chernobyl and Fukushima Daiichi accidents at 80 km zones (Brumfiel G, 2011) Map of Cs-137 of Chernobyl fallout at Ukraine, and Russian Federation within river basin and the regional nuclear facilities and other radioactive contaminated sites ( IAEA- TECDOC-1230, 2006) Personal involvement into studies on the environmental consequences of the accidents- water systems contamination : Chernobyl ( since 5.05.1986 )

Chernobyl-1997

Chernobyl-04. 1986 Personal involvement into studies on the environmental consequences of the accidents: Fukushima ( since 18.11.2013 )

Atmospheric releases Chernobyl NPP(1) and Fukushima Daichi NPP (2) PBq

Radionuclide Fukushima Daiichi Chernobyl NPP NPP Iodine: I – 131 120 1760

Cesium:Cs-134 9 47

Cs-137 8.8 85.0 Strontium: Sr-90 No data on significant release 10

Plutonium: Pu-239 No data on significant release 0.013

(1) – 2005, (2) –UNSCEAR, 2014 EVACUATION and the . : On 2 May 1986, the Soviet Government Commission made a decision to evacuate the population from the area within a 30-km radius of the ChNPP. Soon afterwards, the Government Commission established the Exclusion Zone, from which the population was evacuated and never to return, located inside the dose rate line of 0.2 mSv/hr. In 1992-1993, some additional evacuations from several areas were performed on criteria of annual doses exceeding 5 mSv/year.

100 km city location at Chernobyl Power Plant

Pripyat City ChNPP

Evacuation of Prypiat City started after at 36 hours after the accident (at 14:00 April, 27. 51 000 persons)

1985

2016: View from the evacuated City of Pripyat to New Safe Confinement of the Chernobyl NPP

2016 2016

Crossection SHELTER above reactor 4

2016 : New Safe Confinement at the final stage of the construction

Final stage of New Safe Confinement –NSC move

November, 2016

December, 2016 NSC : Length -150 m Height -104 Contamination of the territory of Ukraine by cesium-137

May 10, 1986 May 10, 2006

Contamination of the territory of Ukraine by strontium-90 (as of May 10, 1986) Total effective doses for external and internal (caused by radioisotopes cesium, strontium and transuranium elements) irradiation, calculated for 1986-2055 (70 years after the accident)

The area of Ukraine’s territory ( “Oblast”- prefecture ) contamination by 137Cs in 1986 and in 2011, thousands square km Pathways of the propagation of radioactivity from the Chernobyl Exclusion zone

10 kmゾーン

30 kmゾーン

水系を介した放射性物質 Forest fires 100 km Kiev- の移行 ChNPP Pu-238 ChNPP Cs-137

Pripyat River Floodplain at ChNPP Inundated by the floods higher than 25% probabilty of exceeding

Sr-90 Sr-90

“ “ Pripyat River Floodplain around Chernobyl NPP was severe contaminated after the accident Pripyat river floodplain was the most significant source of 90Sr secondary contamination in Dnieper system. No significant impact of 137Cs, Sr-90 Contamination Flood protective dyke construction

1993

1999 The most efficient water protection was to prevent the flooding f the most contaminated floodplains by the flood protection sandy dikes constructed at left and right banks of the Pripyat river 21 21 2D modeling predicted the efficiency of special dikes for the reducing of radionuclide wash-off from the heavy contaminated floodplain of the Pripyat River at the city of Pripyat,

1993

1999

Prediction – without dikes - concentration of Sr-90 in water after foooding 10 KBq/m3 After 2 dikes construction at 1.5 KBq/m3 . The forecast on “no dikes“ scenario was confirmed by the measurements during 1991 flooding 22 22 Annual flux Cs-137 and Sr-90 from the Pripyat River 1986- 2015 ( TBq) ( Kanivets at al 2016) Q, m3/s ТБк 50 Cs-137 Sr-90 800 середньорічніWater average витрати discharge води цезій-137 стронцій-90 45 700 40 Cs-137 600 35 500 30

25 400

20 300 Water discharge in 15 Sr-90 Priyat river 200 10 100 5

0 0 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Water systems of Chernobyl and Fukushima regions:

In IER Fukushima University the models tested in Chernobyl are modified for the modeling of Fukushima water bodies

24 The model of radionuclide transport in watershed – river system is applied for Niida river watershed 137Cs density

Example of model implementation for Niida river – simulated decontamination of 3 kinds of land use ( green color) Paddy soils + Farmlands + Bare lands 160000 after "decontamination" 3

m before "decontamination" / q B

, 120000 S S

-

7 Notegamiktia 3 80000 1 -

s Modeled result of C

f o

decontamination

y 40000 t i v i t

c for this scenario - A 0 at Haramachi at 9/21/11 9/21/11 9/21/11 9/22/11 20 % dimishing of maximum Cs 137 oncentration in river water

after "decontamination" 2000000 before "decontamination" after "decontamination" 3 m

400000 /

before "decontamination" q 3

B 1600000

m , / q S B S

, 300000 - 1200000 S 7 S 3

- 1

- 7 s

3 800000 C

200000 1 f s - o

C y

t i f 400000 Haramachi v o i t y

100000 c t

Warabidaira A v i i 0 c t A 0 9/21/11 9/21/11 9/21/11 279/22/11

9/21/11 9/21/11 9/21/11 9/22/11 New Japanies Ukrainian Chernobyk Project 04.2017-03.2022 Project of SATREPS program (JICA-JST): Strengthening of the environmental radiation control and legislative basis in Ukraine for the environmental remediation of radioactively contaminated sites チェルノブイリ災害後の環境修復支援技術の確立

Japanese participants : - Institute Environmental Radioactivity at Fukushima University - Centre for Research in Isotopes and Environmental Dynamics at University of Tsukuba - Fukushima Medical University

Project goals : To use new “Chernobyl zone” research as “time machine” to analyze Cs-137 behavior in environment 31-36 years after the fallout To improve the Ukrainian monitoring system for radioactive substances by the installation of newest equipment To improve the management of Chernobyl zone on the basis of the experience of Fukushima –Daiichi zone Project 2: Detailed study of the radionuclide migration in “water- Project 1: management sediment” systems and assessment of the relevant risks of the Project 1: Analyses of radionuclide dynamics in the ecosystems radionuclide transport from Chernobyl zone surrounding the Chernobyl Cooling Pond , drawdowning in 2015-2018

Google Earth: 12.2014

Google Earth: 12.2016

11.2016 Project 3 : Study of short -range and long-range athmospheric transport of radionuclides from ChEZ with emphasizing on forest fires

Project 4: Implementation of the results of the projects 1-3 and comparative study of Fukushima- Chernobyl experience for the preparation of the joint recommendations for Chernobyl exclusion zone rezoning

Distribution of Сs 137 density

Total effective doses for external and internal irradiation Cancer cases per region of Ukraine