1

2

1. Introduction 2. Materials and Methods 3. Results and Discussion 4. Conclusions

• Determining the background radiation level due to natural radioactivity sources of terrestrial and cosmic origin.

• It provides a baseline for comparison with environmental data during the operational phase and after decommissioning the facility.

• In line with the internationally agreed principles of radioactive waste management, and the national Regulations on Radioactive Waste Management prepared by INRA-AEOI, the safety of this facility needs to be ensured during all stages of its lifetime. In this direction, the radiological environmental monitoring and Preliminary Post Closure Safety Assessment are done during preoperational period of the Anarak site.

3

4

Anarak Near Surface Repository

Anarak This area is located in Isfahan province, at a

distance of 32km North-West of Anarak. Anarak is located at a distance of 70

km North-East of Naein and 210 km East of Isfahan.

5

Objectives: • To assess the environmental radioactivity level of the

Anarak site and surrounding region prior to operation phase.

• Preliminary Post Closure Safety Assessment is done in various scenarios to estimate doses of radionuclides in comparison with dose constrain established by INRA.

• The results from this study are expected to serve as baseline data of natural radioactivity level and will be useful in assessing public doses.

• These studies are required for the licensing process for near surface disposal repository.

6

• The Preliminary post closure safety assessment has been performed based on ISAM methodology recommended by IAEA and AMBER Code is used for simulation of each scenario.

• Three scenarios have been selected:

1. Water erosion,

2. Bath-tubbing and

3. Human intrusion

7

Design scenario

Preoperational radiomonitoring • using grid and judgmental sampling patterns • 200 samples: foodstuff, feeding material, surface and

ground water, soil and sediment, airborne particulate, radon and external radiation were collected and analysed.

• The nearest population centre to this facility is Anarak city with about 1500 population.

• The monitoring area spans an area of 5000 km2. • All samples were taken from various points, including:

Anarak site, Anarak city, Chah-Gorbe, Ashin, Esmailan and Piyouk villages and agricultural field-Dagh-e-Sorkh

8

9

Radiation Sources

Cosmic Naturally-Occurring

Radioactive Material Global Fallout

Radionuclides 3H, 7B, 14C 238U, 232Th, 40K, 222Rn 137Cs, 90Sr, 3H, 14C

Key Radionuclides in Pre-disposal Radiomonitoring Program

10

Sampling Media Sampling

Device

Sampling

Type

Analysis

Device

Sampling

Frequency

Air Particulates

High Volume

Sampler Judgmental

Low Level

Counter Quarterly

Radon RAD7 RAD7

Direct Radiation

TLDs Grid and

Judgment

TLD

Reader Quarterly

RS-230

GR-135

RS-230

GR-135 Annually

Soil - Grid and

Judgmental

HPGe

LSC Annually

Sediment - Judgmental HPGe

LSC Annually

Water

Resources

Groundwater - Judgmental HPGe

LSC

Low Level

Counter

RAD7

Semi-

annually

Surface Water - Judgmental Seasonally

Biota Samples

Foodstuff

Animal

- Judgmental HPGe

Low Level

Counter

Annually Vegetabl

e

Feeding Material - Judgmental Annually

Preliminary Post Closure Safety Assessment: Results for Design Scenario

• Assuming the representative person who is living near the repository, 1100 years after closure and in case of water erosion scenario the maximum total dose is less than 0.2 mSv y-1.

11

Preoperational Radiomonitoring: Results for Representative Environmental Samples

• Soil and sediment samples:

Mean activity concentrations of 238U, 226Ra, 232Th, 40K and 137Cs in the soil and sediment samples were about 34.12±1.39, 34.03±0.69, 35.14±3.46, 527.09±17.72 and 5.944±1.2 Bq Kg-1, respectively.

• External background dose rate:

By using TLDs in 25 points, the maximum average dose equivalent value measured was approximately 100 µSv month-1.

The measured gamma absorbed dose rate in the air at 1 m above the ground ranged from 0.043 to 0.075 nGy h-1 with an overall arithmetic mean of 0.068 nGy h-1.

• The ambient radon concentration in the air:

vary from 5.55 to 18.4±0.2 Bq m-3.

12

• Preoperational Radiomonitoring: Results for Representative Environmental Samples

13

Sample Milk Chicken Meat Feeding Material Grain Vegetable

Gross α Activity

(Bq/L or Bq/Kg) 7.5 <MDA 8.9 22.3 1.51 6.71

Gross β Activity

(Bq/L or Bq/Kg) 255.3 146.9 92 570.7 229.7 264.4

Activity level in common food commodities

• Preoperational Radiomonitoring: Results for Representative Environmental Samples

Drinking water, surface and groundwater samples:

• Tritium activity in all samples was below the MDA,

• The geometric mean for alpha and beta radioactivity was 0.37 and 0.42 Bq/L, respectively.

• Activity level of 238U, 226Ra, 232Th, 40K and 137Cs was below the MDA.

14

• The results of design scenario demonstrate that the effect of surface water erosion scenario is acceptable. The results suggest that doses would still be well below the typical acceptance criteria, even with cautious assumptions likely to result in over-estimates of dose in surface water erosion scenario.

• (Assuming the representative person who is living near the repository, 1100 years after closure and in case of water erosion scenario the maximum total dose is less than 0.2 mSv y-1. Furthermore, the maximum dose is caused by 241Am that is equal to 0.15 mSv y-1).

15

The activity concentration levels of the natural and artificial radionuclides were determined in the all samples collected from Anarak site and surrounding area using active and passive device. All results showed the background level of the natural and artificial radionuclides before any operation in Anarak Near Surface Disposal Facility.

16

17

Saeed Momenzadeh Amirmasood Taherian

Mehdi Boroumandi Asghar Mohammadi

Saber Hassanlou Hamidreza Pakouyan

Nasrin Gourani Fariba Hadian

and Amir Bagheri

18

19

20

21

22

23

24

25

Water source name

coordination Usage

latitude longitude

Ghorban abad spring

730799 3691316 Waterhole

Ashin Qanat 730751 3708923 Cultivation, Farming, Drinking water

Chah-Gorbeh Qanat

752887 3702907 Cultivation, Farming, Drinking water

Poiyk farm Spring 755492 3692154 Cultivation, Farming, Drinking water

Anarak dam (Spring)

747753 3691328 Drinking water

Anarak Well (Brine Water)

749512 3685161 Enter the municipal tap water (hygienic and irrigation)

Ismaeilian Qanat 751153 3681448 Cultivation, Farming

Well No.10 698167 3690650 Cultivation, Farming

Anarak Well 749463 3687742 Drinking Water

26

27

Detection limit:

0.37 Bq/L

(MCL): 11.1 Bq/L

28

Position Samples for Inside and Outside the Site

Direct Radiation Dosimetry

GR-135 Device

- D.R(5 & 100 cm)

- Total count (5 & 100cm)

RS-230 Device

- Absorb D.R(5 cm)

- Investigate of uranium, thorium and

potassium concentration (ppm)

Direct Radiation Dosimetry

Dose rate at 5 cm from ground surface (nSv/h)

Direct Radiation Dosimetry

The total count rate at 5 cm above ground surface (cps)

Direct Radiation Dosimetry

Dose rate at 100 cm from ground surface (nSv/h)

Direct Radiation Dosimetry

The total count rate at 100 cm above ground surface(cps)

Direct Radiation Dosimetry

Dose rate at 100 cm from ground surface (nGy/h)

Direct Radiation Dosimetry

Uranium concentration with RS-230 (ppm)

Direct Radiation Dosimetry

Thorium concentration with RS-230 (ppm)

Direct Radiation Dosimetry

Potassium concentration with RS-230 (percent)

Direct Radiation Dosimetry

The proposed location for the installation TLD inside and outside

site of Talmesi

Direct Radiation Dosimetry

The Average Dose Rate in Passive Method

Direct Radiation Dosimetry

TLD Dosimetry results of the second quarter

Direct Radiation Dosimetry

42

Sampling points

Milk Feeding Material

Milk Grain Meat

Vegetable

Vegetable

Meat & Chicken

Nothing!

How “Zygophyllum atriplicoides” drying plant (a plant native to the region)

43

44

Sampling of wheat

How drying vegetables

45