Hungarian Uranium Legacy Sites

Monitoring after closure

László JuhászNational Research Institute for Radiobiology and Radiohygiene

2

Brief history In the south part of Hungary, near Pécs city the

uranium was produced from a low grade underground sandstone ore (about 0.1 % U).

Besides mining activities, both the acid leaching process and the alkaline heap leaching technology were applied in the mill operation.

After 40 years operation the uranium mining and milling facilities were finally shut down in 1997.

Planning, surveying and making appropriate strategy for restoration tasks were launched in 1990’s.

There was no foundation, government has given budget for the remediation started in 1998.

The remediation was terminated in 2008

3

Uranium mining and milling area

4

Employees and uranium production

Employees And Uranium Output Between 1956-1997.

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

19

56

.

19

58

.

19

60

.

19

62

.

19

64

.

19

66

.

19

68

.

19

70

.

19

72

.

19

74

.

19

76

.

19

78

.

19

80

.

19

82

.

19

84

.

19

86

.

19

88

.

19

90

.

19

92

.

19

94

.

19

97

.

Year

Em

plo

yees

0

100

200

300

400

500

600

700

800

Meta

ll i

n T

on

ne

Employees

Uranium in tons

5

The most important radiation sources of uranium

mining and milling activity

Transportation roads and pipelines

Milling facility area

400 000 m2

Waste rock piles

900 000 m2 25 million tons

Leaching heaps

470 000 m2 7.2 million tons

Tailings ponds

1 630 000 m2 20.4 million tons

Total affected area 62 ha

6

Main authorities

- competent Inspectorate for Mining is responsible for aspectsrelating to mining activities, mining technology, mining safetyand geology, as well as remediation.

- competent Inspectorate for Environment, Nature and Waterenforces aspects relating to environment protection, natureconservation, protection of water quality, water utilisation andprotection of water bases

- competent Health Authorithy (Radiological Center) isresponsible for the radiation protection of workers and thepublic

7

Licensing of uranium mining and

milling

•Lack of national legislation in 1990’s: negotiations between

authorities and operator on licensing conditions

•First licence in 1998 (amended in 2002, 2004, 2007, 2009, 2011

and 2012) granted by the competent regional environmental

authority including radiation protection prescriptions

• No foundation: Governmental Resolution Budget

• Modified governmental budget and deadlines:

2193/2004: 18,5 → 19,1 billion HUF new deadline: 31. 12. 2006

2122/2006: 19,1 → 20,7 billion HUF new deadline: 31. 12. 2008

8

The most important radiation sources of uranium

mining and milling activity

Transportation roads and pipelines

Milling facility area

400 000 m2

Waste rock piles

900 000 m2 25 million tons

Leaching heaps

470 000 m2 7.2 million tons

Tailings ponds

1 630 000 m2 20.4 million tons

Total affected area 62 ha

Radionuclide inventory at Pécs

uranium mining and milling site

Radionuclide

Activity in Bq

Waste

rock

Tailings

pond

Heap

leaching

U-238 1,26 E13 1,69 E13 4,61 E12

U-235 5,9 E11 7,94 E11 2,26 E11

Ra-226 1,26 E13 2,34 E14 1,14 E13

Pb-210 1,26 E13 2,32 E14 1,15 E13

Total activity 1,8 E14 2,4 E15 1,4 E14

10

Ranges of main radiological parameters

Parameter W-Mecsek

areas

Waste

rock

piles

Heap

leaching

areas

Tailing

ponds

Unit

Ambient

gamma dose

rate

150-250 200-1000 1100-1500 200-3000 nGy/h

Rn-222

act. conc.

8-12 10-50 10-50 40-1100 Bq/m3

Rn-222

exhalation

rate

0.02-0.06 0.1-0.5 0.5-1 2-10 Bq/m2s

Ueq

concentration

of rock

3-5 50-100 50-200 50-150 g/t

Usage of restored area Release of a given area without any restriction is only possible

if the radiation levels have been decreased to the original

background conditions.

Release of an area for restricted use is possible if the

radioactive levels were decreased until that the radiation dose

of public/workers falls below 1 mSv/year effective dose limit.

Restricted use means the exclusion of food production and

building human residences, schools, hospitals, etc. Industrial

and marketing activity can be performed, using the still

existing/reconstructed infrastructure.

The restoration was planned to reach to this situation.

12

Landscape before and after remediation

Shaft

13

Landscape before and after remediation

Milling site

Dose rate before and after remediation

14

2 540 000 compact m3 + 44 300 m3

1 070 000 compact m3 + 34 732 m3

Relocation and remediation

of heap leaching sites

15

1994. NOV.12 melléklet

1995. SZEPT.12 melléklet

(nGy/ h)

After remediation of

waste rock pile 3

Dose rate before and after remediation

of waste rock pile 3

16

After remediation

of tailings pond 1

After remediation of

tailings pond 2

17

Reference background levels

Radioactive

parameter

In all areas

222Rn

concentration

outdoors

12 Bq/m3

222Rn

concentration

indoors

128 Bq/m3

Ambient gamma

dose rate

250 nGy/h

Activity

concentration of

soil*

180 Bq/kg

Remarks: *Expressed in 226Ra equivalent

Radiation protection criteria after closure 1a

Requirements for restored places:

Parameters Values

Rn flux < 0.74 Bq/m2/s

Gamma dose rate* ≤ 250 nGy/h

Remarks: * average value, it should not exceed above 450 nGy/h

Radiation protection criteria after closure 1b

soil disturbance is prohibited

grass, pasture field are permitted

production of foodstuff for people prohibited

human residences; recreation, sport, social

facilities; schools, hospitals not permitted

Radiation protection criteria after closure 2a

Reuse of facilities (buildings), operational area, roads,

neighbour area (not belong to mining area):

Parameter Value

Gamma dose rate* ≤ 250 nGy/h

Remarks: * average value, it should not exceed above 450 nGy/h

Radiation protection criteria after closure 2b

Before any usage of operational area

radiological expert opinion is needed

During soil disturbance radiological control

and monitoring should be performed

After any disturbance activity background

levels should be set back

Radiation protection criteria after closure 3

Limit for contamination of groundwater:

Radionuclides Limit

Nat U 0.4 mg/m3

Ra-226 0.63 mg/m3

Radionuclide Liquid discharge Airborne discharge

Ra-226 7.4 E9 -

U-234 1.1 E11 9.1 E8

U-235 1.1 E11 9.6 E8

U-238 1.1 E11 2.4 E6

Annual discharge limits from restored area (Bq)

Radiation protection criteria after closure 4

Dose constraint for the restored area: 300 µSv/a

Radiation protection criteria after closure 5

Metalic waste*

general use without restriction < 0.05 Bq/cm² (3 alpha particles/cm²/m)

metallurgical or mining re-use 0.05-0.5 Bq/cm²

emplacemet in waste rock pile 3 >0.5 Bq/cm² (30 alpha particles/cm²/m)

Other waste materials (debris, sludge, wood, rubber,…):

handling as normal waste ≤ 200 Bq/kg

emplacemet in waste rock pile 3 > 200 Bq/kg

Release of materials:

Remark: * only for fix contamination

Chromium 50

Cobalt 20

Nickel 20

Copper 200

Zinc 200

Arsenic 10

Molybdenium 20

Selenium 10

Cadmium 5

Tin 10

Barium 700

Mercury 1

Lead 10

Boron 500

Silver 10

Limit for metal and semimetal contamination in groundwater (µg/l)

Fluoride mg/l 1500

Sulfate mg/l 250

Phosphate (PO43-) mg/l 500

Nitrate mg/l 50

Ammonium mg/l 500

Limits for inorganic compound contamination in

groundwater (µg/l or mg/l)

Chromium 75

Cobalt 30

Nickel 40

Copper 75

Zinc 200

Arsenic 15

Selenium 1

Molybdenium 7

Cadmium 1

Tin 30

Barium 250

Mercury 0,5

Lead 100

Silver 2

Limits for metal and semimetal contamination in soil (mg/kg)

Long-term tasks

removal of uranium from surface and groundwater (the

capacity of the water treatment station is 1.5 million m3

annually);

groundwater desalination (treatment of an average water

volume of 2000 m3/day);

maintenance of water treatment stations, decontamination

and water discharging systems;

operation of the unified water discharge system;

maintenance and after-care of areas of limited utilisation;

operation of environmental monitoring system

Monitoring after closure

Environmental monitoring system consits of:

• Hydrogeological

• Radiological

• Rock, soil movement survey

Each monitoring is to be performed on the

basis of annual plan.

Environmental monitoring program after

closure was prescribed in environmental

licence decision

Radiological monitoring

In situ measurements

Sampling on site

Measurements in laboratory

Continuous monitoring stations

In situ measurements

Gamma dose rate: in mesh points of 20mx20m, 50mx50m

above 1m of surface, detection 10 nSv/h-

Air 222Rn concentration: detection 1 Bq/m³ -

Air short lived radioactivity: determination of radon

progenies, detection 1 Bq/m³ - from 1 m³ air

Integral air 222Rn concentration: SSNTD, exposure time 3

months, detection ~Bq/m³ -

Fallout: collection of precipitation during 3 months

Aerosol, flying dust: detection <0.1 mg/ m³- from ~10 m³ air

Soil radioactivity in depth by 20 cm: gamma probe,

detection ~50Bq/kg

Soil surface 222Rn exhalation: radon accummulated in semi

cylinder, detection ~mBq/m² s -

Sampling

Soil sampling: taking representative soil

sample (~ 1kg) from 1m² in depth of 10 cm

Plant sampling: taking ~1kg plant sample

Water sampling: taking water sample from

flooded mines, streams, groundwaters

(monitoring wells) and surface waters

Measurements in laboratory 1

Air long lived alpha radioactivity: determination from

aerosol filter sample, detection ~ mBq/m³

Soil Ra-226 equivalent activity concentration: high

sensitivity scintillation detector, detection from 40 keV

Soil gamma spectrometry: semi conductor detector

(HPGe), measure time 10000-50000 s, detection 1 Bq/kg

Plant ash beta activity concentration: high sensitivity

alpha/beta detector, measure time 1000-3600 s

Plant ash gamma spectrometry: semi conductor detector

(HPGe), measure time 50000-100000 s, detection 1 Bq/kg

Measurements in laboratory 2

Water natural U content: determinated with ICP-MS ,

detection 0.05 µg/l

Water Ra-226 activity concentration: determined with liquid

scintillation, detection 0.1 Bq/l

Evaporated water beta activity concentration: low

background and high sensitivity alpha/beta detector,

detection 0.1 Bq

Water alpha spectrometry: determination of U-234, U-235,

U-238, Po-210 activity concentration: detection 1 mBq/l

Continuous monitoring stations 1

Complex radiation montoring station comprises: Ambient gamma dose rate: measurements by 1 hour, from 50

nSv/h

Istantaneous air Rn-222 activity-concentration: measurements

by 10 minutes, from 2 Bq/m³

Istantaneous air short lived radioactivity: determination of

radon progenies by 10 minutes, from 1 Bq/m³

Cotinuous air sampling by 1 m³/h

Temperature, pressure, relative humudity mesurements

Aerosol, flying dust concentration: filter measurements by 1

week, from 0.01 mg/ m³

Continuous monitoring stations 2

Air Rn-222 activity-concentration monitoring: Determination with PIPS detector by hour (together with climate

parameters)

Range: 0,1 kBq/m3 – 5 MBq/m3

Air release monitoring Cotinuous air sampling

Aerosol, flying dust concentration: filter measurements by 1

week, from 0.01 mg/ m³

Natural U content determination: filter measurements by 1 week,

low background and high sensitivity alpha/beta detector

Long term plan of restored tailings ponds and

waste rock piles

surveying gamma dose rate in mesh points in each 3 year

Cotrolling radon barriers: complex radon examination (act.

conc., exhalation, radon progenies) yearly, later 3-5 years

Radioniclide migration: vertical, horizontal by 3-5 years

38

Special requirements for radiation monitoring 1

Restored and operational area:

• at main outlet points continuous measurement of

radon must be performed

• integral radon measurements should be agreed with

radiological authority

• measurements of gamma dose rate in mesh points

should be carried out in each 5 year

Special requirements for radiation monitoring 2

Other area:

• all radiological parameter should be on background level,

monitoring is not needed

• activity concentration and uranium content of mud of

streams by 200 m should be determined

• measurements of gamma dose rate at banks of streams

by 10m must be performed in each 2 year

• gamma dose rate measurements of roads and curbs must

be surveyed, and at later works on roads radiological

control is needed

Surveyed remediatied

area

Rn

sesonal

Year Gamma

dose rate

Complex

radon

Soil

Plant Profile

No. of

sample

Waste rock pile 1.1/4 y

4 x 3 pcs

2014

(2017)

20x20 m

300 pcs

100x100 m

12 pcs

3 migr.vert.

2 migr.horiz.

(2015)

15 pcs

6 pcs9 pcs

Waste rock pile 2. 1/4 y

4x3 pcs

2014

(2017)

20x20 m

430 pcs

100x100 m

17 pcs

3 migr.vert.

2 migr.horiz.

(2015)

15 pcs

6 pcs9 pcs

Waste rock pile 3. 1/4 y

4x5 pcs

2014

(2017)

50x50 m

200 pcs

200x200 m

12 pcs

5 migr.vert.

2 migr.horiz.

(2016)

25 pcs

6 pcs11 pcs

Tailings pond 1.

1/4 y

4x5 pcs

2013

(2016)

50x50 m

420 pcs

200x200 m

26 pcs

5 migr.vert.

2 migr.horiz.

2013

35 pcs

6 pcs

11 pcs

Tailings pond 2.1/4 y

4x 5 pcs

2013

(2016)

50x50 m

240 pcs

200x200 m

15 pcs

5 migr. vert.

2 migr.horiz.

2014

35 pcs

6 pcs11 pcs

Waste rock pile 3A. 1/4 y

4x3 pcs

2013

(2016)

20x20 m

220 pcs

100x100 m

9 pcs

3 migr. vert.

1 migr.horiz,

2013

25 pcs

6 pcs11 pcs

Waste rock pile Frici

shaft

1/4y

4x 3 pcss

2013

(2016)

20x20 m

50 pcs

100x100 m

5 pcs

2 migr.vert.

l migr.horiz.

2013

15 pcs

6 pcs11 pcs

Surveyed operational area Year Soil Plant Air Complex

radon Gamma dose rate

Mine operational yard 2. 2013 (2016) 2 2 2 50x50 m 10x10 m 180 pcs

Mine operational yard 3. 2013 (2016) 2 2 2 50x50 m 10x10 m 240 pcs

Mine operational yard 1. 2013 (2016) 4 4 4 50x50 m 10x10 m 270 pcs

Surveyed outlet of mine

shaftRn monitoring

Complex air

measurements

SSNTD SSNTD

indoor outdoor

Mine transport shaft 1. continuous 6 pcs/y 6x4 pcs/y 6x4 pcs/y

Mine North shaftcontinuous

6 pcs/y 6x4 pcs/y 6x4 pcs/y

Surveyed water flow Frequency Activity concentration

of bed sediment

Gamma

dose ratePlant

Year No. of sample Mesh points Sample

Stream Zsid 2013

(2015) 5 pcs by 200 m

2x10m

170 pcs2 pcs

Stream Kajdács 2013

(2015) 18 pcs by 200 m

2x10m

700 pcs2 pcs

Canal Milling Facility 2013

(2015) 12 pcs by 200 m

2x10 m

440 pcs2 pcs

Canal Zóki 2013

(2015) 32 pcs by 200 m

2x10 m

1240 pcs2 pcs

Surveyed

dwellingsYear

Complex

air

Complex

radon Soil Plant

SSNTD SSNTD

indoor outdoor

Kővágószőlős 2013 (2015) 1 pc 1 pc 1 pc 1 pc .. 1x4 pcs/y 1x4 pcs/y

Pellérd 2013 (2015) 1 pc 1 pc 1 pc 1 pc 1x4 pcs/y 1x4 pcs/y

Surveyed area

Continuous

/Automatic

monitorlng

Fall-out

SSNTD SSNTD

indoor outdoor

Tailings ponds 1.

and 2.

1 pc radiation

monitoring3x4 pcs/y -- 6x4 pcs/y

Mine water treatment

facility

1 pc radiation

monitoring 1x4 pcs/y 8x4 pc/sy 4x4 pcs/y

Chemical water

treatment facility1 pc Rn monitoring

--2x4 pcs/y 2x4 pcs/y

Disposal of inert

waste -- 1x4 pcs/y -- 1x4 pcs/y

Loess mine -- 1x4 pcs/y -- --

Release point Release way Monitoring method Frequency

Mine water treatment

facility

2 pcs stack

air

Unat

continuous

sampling,

weekly

gross alpha activity

dust and aerosol

Discharge from Frici

shaft to sidestream of

stream Bicsérd

water Complex water

examinationhalf year

Discharge to stream

Pécsi-VÍz (one point)water

Complex water

examination quaterly

Surveyed groundwater area Object

(pcs)

Measure-

ment of

water

level

Water

samplnig

Radio-

logical

meas-

urement

Full scale

water

exami-

nation

Partial

scale

water

exami-

nation

Trace

element

exami-

nation

North mine facilities 91 91 91 91 91 0 0

Waste rock pile 1. and 3.

(drills) 27 108 65 65 34 17 5

Heap leaching field 2, waste rock

pile 2. 57 164 164 89 75 5

Waste rock pile 3., inert waste

disposal31 101 101 49 52 10

Migration barrier at waste rock

pile 3.33 78 78 25 31 34

Tailings ponds (1., 2.) 159 545 62 154 394 19

Wells of water supplying area at

Pellérd and Tortyogó44 79 79 57 20 58

Digged wells at Cserkút 3 4 4 1 2 4 1

Digged wells at Kővágószőlős 7 7 7 7 3 7 3

Surveyed spring (outlet) and surface

water

Object

(pcs)

Water

samplnig

Radio-

logical

meas-

urement

Full

scale

water

exami-

nation

Partial

scale

water

exami-

nation

Trace

element

exami-

nation

WRP 2., Frici shaft, stream Bicsérdi 29 92 92 24 40 7

Waste rock pile of air-shaft 4, 1 4 4 2 2 1

Waste rock pile 4. of shaft 4. 1 1 1 1 1

Air-shaft Tótvár 1 1 1 1 1

Waste rock pile of air-shaft 5. 1 1 1 1 1

Waste rock pile of shaft 5. 1 1 1 1 1

Heap leaching field 2, WRP 1. (ditch) 5 9 9 4 4 2

Tailings pond 1. 4 16 16 4 12 4

Tailings pond 2. 4 16 16 4 12 4

Seepage water of tailings ponds 8 32 32 8 24 8

Mine water release (monitoring point) 6 32 32 14 18 7

Stream Rékás 3 6 6 6

Stream Kaidács 2 4 4 4

Stream Zsid 2 4 4 4

Stream Névtelen 2 4 4 4

Periphery site 2 2 2 2

Canal Zóki 3 6 6 6

Stream Pécsi-víz 6 20 20 8 12

Stream Sás 3 6 6 3 3

Stream and spring Nyáras 2 6 6 3 3 1

Stream Körtvélyes 2 4 4 2 2

577000 577500 578000 578500 579000 579500 580000 580500 581000 581500 582000

74500

75000

75500

76000

76500

77000

77500

78000

Zagytér kelet

Zagytér vízkezelő

Pellérd lakossági

Pellérd

I.

II.

A zagytározók és környékük radiológiai monitoring állomásai

Á: Monitoring állomás Hullópor gyûjtõ állomás

Löszbánya

Geotechnika konténer

Location of monitoring stations at tailings ponds

Á: automatic minitoring station Fall-out collection station

Gamma dose rate

Soil Water Air Biosphere

Radiology(U, Ra, Th, g-

dose)

Chemical

Pollution,(CH, acid,

trace elements)

Erosion

Movement

Environmental Monitoring System

Radiology(U, Ra)

Chemical

Pollution,(anorganic, CH,

trace elements)

Water level

Water quantity

Radiologyaerosol

fallout

radon

Vegetation(radiologic

elements)

Humandosimetry

(labour

hygiene)

Location of monitoring

sampling points

IAEA per review 1

IAEA peer review in December 2010, main findings:

• Risk of pollution of surface waters has been decreased,

• Facilities for water treatment are in a good function,

• For protection of aquifers, water treatment shall be

performed for few decades,

• Monitoring program is in line with the expectations of

IAEA.

IAEA per review 2

Main recommendations:

- Long-term (30 years) strategic plan should be elaborated,

It’s accomplished

- Review of modeling should be performed for rank of layers of

tailings ponds,

It’s close to accomplished

- Erosion damages should be repaired,

The repairs are being continually performed

- Infiltration parameters for waste rock piles should be reviewed,

- On tailings ponds 2 new lysimeter were installed, but on rock

piles not yet

- Gas migration from mine cavities should be thoroughly examined,

- The examination of gas migration is being continually

performed under monitoring programme

IAEA per review 3

- Groundwater and polluted water transport model should be set

up,

It’s completed

- Passive methods for water treatment should be preferred,

Passive methods are preferred at present and in the future

- New equipment for monitoring and new damage averting plan

are needed,

It’s continually set up

- Uniformity of emission limits based on risk analysis should be

set off,

Authorities have accepted limitation on risk analysis in

many cases

Conclusions

Exact and updated radiation data: essential

basis after closure

Radiation protection criteria system should be

based on comprehensive background database

Modelling, studies and other R&D works are

needed for selection of suitable monitoring

program after closure