screening assessment of radionuclide · pdf filetailings “d”carried out by use of...

State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkraineInstitute of geological sciences, National Institute of geological sciences, National

Academy of Sciences of UkraineAcademy of Sciences of Ukraine

SCREENING ASSESSMENT OF RADIONUCLIDE MIGRATION IN GROUNDWATER FROM THE “DNEPROVSKOE” TAILINGS IMPOUNDMENT

(DNEPRODZERZHYNSK CITY) AND EVALUATION OF REMEDIAL OPTIONS

V. Riazantsev: SNRCUV. Riazantsev: SNRCUA.SkalskyA.Skalsky, , D.D.BugaiBugai:: Inst.Inst. of Geol. ScienceGeol. Science

International Symposium on Uranium Raw Material for the Nuclear Fuel Cycle: Exploration, Mining, Production, Supply and Demand, Economics and

Environmental Issues (URAM 2009)Vienna, Austria, 22–26 June 2009

IAEA, URAM-2009, AUSTRIA, VIENNA, 22-26 June, 2009

State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of Ukraine

CONTENTSCONTENTS• Location of Prydneprovsky Chemical Plant (PCh.P) and general characteristic of its tailings.

• Hydrogeological conditions and monitoring system.• Screening assessment of radionuclide migration from “Dneprovskoe” tailings:- radionuclide transport modeling software,- parameters of the radionuclide transport model,- modeling predictions of groundwater transport of uranium from tailings “Dneprovskoe” to Dnepr River under different remediation scenarios.

• Conclusions



Chernobyl contaminated area

Dneprodzerzhinsk site

Uranium Miningand Milling area



44

1

2 3

4

5

6

7

8

9

10

Uranium tailings in Dneprodzerzhinsk site

RELEASES from tailing sites :

“Dnierovske” ( 4 – water )“Lazo” ( 10 - water)“Central Yar” ( 3 – water)“South-Eastern” ( 2 – water)“Sukhachevske” ( 8, 9 air and water)“Industrial Site” ( 1 – water)“Base “C” (6, 7)


State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkraineBasic objects subject to the control and rehabilitation

Residential area

Industrial site

Treetuzny pit

Konopl yanka ri v.

Dniper riv.By-product cokeplant slime pit

Ash-disposal areaof metallurgical works

“Dneprovskoe” tailings


State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of Ukraine““DneprovskoeDneprovskoe”” tailingstailings



General characteristics of the General characteristics of the PCh.PPCh.P tailingstailings

1300.00330.00660.061965-88„Lantan fraction“14005.912.0731954-68„Dneprovskoe“4400.150.3251960-91„Base C“

2704.49.6701983-92“Sukhachevskoe”2nd section

7108.619.0901968-83“Sukhachevskoe”1st section

670.150.333.61956-80„South-Eastern“1040.100.222.41951-54„Central yar“1800.350.776.01949-54„Western“

Gross activity,TBq

Volume,x106 m3

Amount ofthe waste,x106 t

Area, hectares

Period ofoperation

Tailing names



The monitoring well network at PChP site

The system of the hydrogeological monitoring consists of 57 wells. The 49 of these wells are setted at the tailings “Dneprovskoe”. The tailings “Western” is equipped by 4 wells, a the tailings “Central Yar” is equipped by 3 wells. There are no monitoring wells at the tailings “South-East”.



The monitoring well network at PChP site

The 4-D control well


State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkraineTable 3. Radiation characteristics of groundwater of “D” site in selected wells for years 2005/2006 (Voitsekhovitch et al., 2006)

1,002,0±0,6< 0,20,8±0,04

0,09±0,030,43±0,06

0,09±0,030,40±0,06

5,848-D

0,98-5,8±1,45,8±1,2

2,41±0,355,4±1,2

2,36±0,352,316-D

1,071,6

7,9±2,315,1±3,016,0±3,2

6,8±1,35,69±0,31

7,3±1,39,38±2,40

19,318,4

19-D

1,181,04

10±30,84±0,245,0±1,0

0,22±0,052,4±0,5

0,26±0,052,5±0,5

6,411,1

4-D

0,810,42

4,6±1,42,62±0,780,23±0,04

0,90±0,180,20±0,02

0,73±0,16<0,03

7,37,2

2-D

234U/238UΣβBq/L

ΣαBq/L

U-238Bq/L

U-234Bq/L

Salinityg/L

Well#


State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkraineGeological crossGeological cross--section of tailing section of tailing ““DD”” alongalong

KonopliankaKonoplianka -- Dnepr lineDnepr line


State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkraineContents of water Contents of water -- soluble salts in tailing materialssoluble salts in tailing materials

149,8/0,150Ca(HCO3)21274,2/1,3186,6/0,19CaSO4

29,4/0,030CaCl2946,9/0,90Ca(NO3)21270,7/1,324,1/0,02MgSO4

43,8/0,040MgCl2923,8/0,90Mg(NO3)2776,7/0,80Na2SO4

1971,5/20NaCl895,1/0,987,9/0,09NaNO3

7,5/0,0070KCl117,3/0,128,1/0,008KNO3

tofrom

CONTENTml g in 100 g dry material / % in dry materialSalt type



Specific activity of main radionuclides in tailing Specific activity of main radionuclides in tailing materialsmaterials

7141090650416991065612238max

18445242071392717723576average

210Ро210Pb230Th226RaUSpecificactivity,Bq/kg



Average contents of uranium in underground waters within Average contents of uranium in underground waters within zone of tailing pond zone of tailing pond ““DD””, control and observation zone , control and observation zone

((20002000--20062006))

0.1

1

10

100

2000 2001 2002 2003 2004 2005 2006 2007рік

U, Б

к/л

Техногенний г-т ("Д")Аллюв.г-т ("Д")Аллюв.г-т (СЗЗ-ЗС)



Filtration model of tailings Filtration model of tailings ““DD”” sitesite

Visual Modflow 3.0 PRO is integrated soft for 3-D modeling of underground water flow and pollution (radionuclide) migration. It included design module MODFLOW, MODPATH, ZoneBudget, MT3Dxx/RT3D, and WINPEST



Filtration zone Filtration zone and boundary and boundary condition for condition for

modelingmodeling


State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkraineCross section of filtration model along 21 columnCross section of filtration model along 21 column



Dispersion of filtration property of rocks in zone of 2-nd calculation layer of filtration model

Color scale of filtration coefficients



Dispersion of Dispersion of filtration feed filtration feed

(input) in filtration (input) in filtration zone of tailings zone of tailings ““DD””



Dispersion of underground water layers on calibration stage.(real conditions for Treetuzny pit)



1

10

100

1000

10000

100000

1000000

W.6593 W.6594 W.1ZP W.2 ZP W.3 ZP W. 2D W. 4D W.19D W. 16D W. 48D

Total alpha-activity238+234U238U226Ra

Tailing Tailing “Zapadnoe” Tailing ”Dniprovske”“Centralny Yar”

234,238234,238U U ии 226226Ra in porous water of tailingsRa in porous water of tailings 20062006--20072007

Bq/m3



• Prediction calculation for radionuclide migration from tailings “D” carried out by use of the “Ecolego” soft, developed by SSK.



АB C

“Ecolego” interaction matrix for radionuclide migration model from “D” tailings: (А) – general matrix, (B) – tailing sub system matrix; (C) aquifer sub system matrix



Block scheme of radionuclide migration Block scheme of radionuclide migration from from ““DD”” tailingstailings



Result of modeling: Base predictionResult of modeling: Base prediction. . U concentration in U concentration in alluvial aquifer on 750 m distance from alluvial aquifer on 750 m distance from ““DD”” tailingstailings

0.1

1

10

100

1000

1 10 100 1000 10000Час, роки

Конц

ентр

ація

уран

у, Бк

/л


State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkraineResult of modeling: Conservative prediction. Radionuclide Result of modeling: Conservative prediction. Radionuclide

concentration in alluvial aquifer on 750 m distance from concentration in alluvial aquifer on 750 m distance from ““DD”” tailingstailings

0.1

1

10

100

1000

1 10 100 1000 10000Час, роки

Конц

ентр

ація,

Бк/л

URa-226Po-210Pb-210


State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkraineU flux from U flux from ““DD”” to Dnepr river for different scenarioto Dnepr river for different scenario

U f l u x f r o m " D " t a i l i n g s t o D n i e p e r R i v e rf o r d i f f e r e n t s c e n a r i o s

0

5 E + 1 2

1 E + 1 3

1 , 5 E + 1 3

2 E + 1 3

2 , 5 E + 1 3

0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0 3 0 0 0 3 5 0 0 4 0 0 0 4 5 0 0 5 0 0 0t i m e , y

U flu

x, Bq

/y

b a s e c a s ec o n s e r v a t i v es o i l c o v e rw a s te r e m o v a l


State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkrainePreliminary estimations of effect of tail material deleting or Preliminary estimations of effect of tail material deleting or

coverage of tailing surface (population dose exposure due to coverage of tailing surface (population dose exposure due to water use on 750 m distance from water use on 750 m distance from ““DD”” tailings)tailings)

0

1

2

3

4

5

6

0 1000 2000 3000 4000 5000years

Expo

sure

doze

, mSv

/ybase caseconsrvative casesoil coversourse removal


State Nuclear Regulatory Committee of UkraineState Nuclear Regulatory Committee of UkraineВозможныеВозможные стратегиистратегии реабилитацииреабилитации промплощадкипромплощадки ПХЗПХЗ ии прилегающихприлегающих территорийтерриторий

LAZO

Suhachovkatailing

Sediment box

Coverage and waterproofing

residential area

Konoplyanka riv.

Treetuzny pit

Industrial site

Dniper riv.Possible strategy of rehabilitation of Possible strategy of rehabilitation of PridneprovskyPridneprovsky sitesite



ProblemsProblems• Verification of dates.• Uncertainty and inconsistency of dates.



SUMMARYSUMMARY• Main source of contaminations – formation of

thehnogenic aquifers. Max predicted value of U-concentrations in groundwater on control zone (rehabilitation case) has twice decrease in comparison with base case. Isolation or removing of tailings in the first 1500 years gives the same effect for groundwater contamination. Main sources of contamination is initial radioactive contamination of alluvial aquifer under tailing which exist in both scenarios.



SUMMARYSUMMARY• For base scenario U-flux to Dneper start in 500

y, max flux (8,7×10E+12 Bq/y) rich in 2000 y.• For conservative scenario U-migration process

occur more fast. Visible U-flux has started in 50 y., max flux (21×10E+12 Bq/y) rich in ≈300 y.

• Covering or removing of tailing result in decreasing of U-flux in twice in comparison of base scenario and have the same effect in first predicted 2000-2500 y.



SUMMARYSUMMARY• Perspective and effective economical approach

could be tailing conservation in-situ by creation of soil cover, which minimize infiltration of atmospheric precipitation into tailing body and minimize of radioactive contamination of ground water.



Result of successful rehabilitation Result of successful rehabilitation



THANK YOU!THANK YOU!

screening assessment of radionuclide · pdf filetailings “d”carried out by use of...

Documents