Evaluation of radioactive contamination at al tuwaitha nuclear site using gis

Dissertant

al-Shar, Hisham Muhammad Jawad

Thesis advisor

Zabun, Abd al-Razzaq Tarish
al-Ubaydi, Abd al-Hamid Muhammad Jawad

University

University of Technology

Faculty

Building and Construction Department

University Country

Iraq

Degree

Master

Degree Date

2012

English Abstract

One of the potential problems in Iraq is radioactive contamination and nuclear waste disposal.

Recent efforts have been paid towards the decommissioning of the past nuclear program.

Ministry of Science and Technology start the decommissioning program which includes the capacity building capabilities, establishing decommissioning plan and waste management.

The goal of this study is to evaluate the existing radiological hotspots and find out the radioactive elements (234, 235,238) U, 137Cs, 60Co, 90Sr and 40 K contribution in the surface soil and the exposure dose levels at Al Tuwaitha nuclear site .

In addition, the risk assessment of the identified hotspots has carried out using risk assessment software and ArcGIS package.

The sensitive radioactive elements in each hotspot and the correlation between the risk and each element were identified.

It’s found that Cesium 137 and Cobalt 60 were the most sensitive radionuclides in two of the hotspots.

The contaminated hotspots were determined by using the integration of Geographic Information Systems (GIS) and risk assessment analysis.

For this purpose, total of 201 soil samples were analyzed, four hotspots identified and assessed their risks.

The output digital map layers includes contours for each radioactive element concentrations, while the exposures dose radioactive maps were created by additive interpolation method of the geographical information system.

The results shows that the average exposure dose rate level is exceed the permitted level by (9500) times higher than environmental levels of the UNSCEAR (2000).

The Russian 5MW reactor is the highest hotspot in Al Tuwaitha nuclear research center with exposure dose about 140 mrad/hr, it also noted that 238,235,234 U concentration level exceed the permitted level by (75) times over the UNSCEAR (2000) regulation in spot near Ishtar village and many other uranium contamination inside Al Tuwaitha Nuclear Research Center (NRC) and location C.

The 60Co, 137Cs and 90Sr, are present with very high contamination activity in spent fuel waste storage area.

The equivalent doses in the hotspots achieved from the radionuclide’s concentration and characterized into equivalent dose exposure for 40K, U sum, 60Co, 137Cs and 90Sr.

Most areas contaminated with equivalent dose have value around (0.01) mrad/hr or less are not appearing as effective level.

The results show that 35% from contaminated area (7 km2) has value from (0.01-0.1) mrem/hr, and 30% in the range between (0.1-0.5) mrem/hr, and 33% found in the range between (0.5-40) mrem/hr and only 2% found in the range between (40-105) mrem/hr.

It’s also shown that the total risk came from hotspots 2 which located near the fuel cycle storage of the IRT 5000 reactor with level of 469 mSv/y .

The correlation plots show that the hotspot 1 best fit found the uranium with correlation 0.98 (98%), while the hotspot 2 best fit found for 60Co with correlation factor of 0.998 (99.8%), and the hotspot 3 best fit found for 137Cs with correlation of 0.997 (99.7 %) and for hotspot 4 the best fit found with the 40K with correlation factor of 0.92 (92%).The total scatter chart shows correlation of 0.99 (99%) with 60Co.

Main Subjects

Engineering & Technology Sciences (Multidisciplinary)

Topics

• Iraq
• Economic aspects

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-420061