N.Chimedtsogzol, Ts.Erkhembayar, Ts.Otgontuya, M.Baatarkhuu School of Material’s Science, Mongolian University of Science and Technology, Mongolia Ash Radioactivity of the Fourth Thermal Power Plant in Ulaanbaatar City of Mongolia

Outlines Purpose of the study Method of the study Sampling points Results Conclusion

Introduction Thermal plants, which use coal, cause air pollution, desertification and soil erosion. Also they are producing tons of ashes per one day. TPP4 was built with assistance from the former Soviet Union and commenced operation in 1983.

View of the Fourth Thermal Power Plant ash reservoir in Ulaanbaatar City of Mongolia.

A high-resolution gamma spectrometer “Canberra” with 4096 channels and German detector Experimental method

Methodology

The following formula has been used to determine the specific activity of radioactive isotope within ash by using the total absorption peak Where: N(E i ) – area under of total absorption peak -rays with the energy E i t – measurement time, sec - detector efficiency, k - geometry factor of the detector m - sample mass, kg A- specific radioactivity, Bq/kg - gamma ray emission factor

№Sample name Isotope activity, Bq/kgElement content 226 Ra 232 Th 40 KU, г/тн Th, г/тн K, % 1 Ash from the stove №4 of the fourth power plant Ash from the stove №1 of the fourth power plant Ash from the stove №5 of the fourth power plant Ash from the ger (national house) stove Coal from Alagtolgoi Mine494< <0.1 Acceptable level[1] (for 0.7liter volume of Marineli vessel, one hour measurement ) EXPERIMENTAL RESULTS

Results Radioactivity of ash samples

Equivalent activity of Radium Ra=A Ra A Th A K, (Bq/kg) Where: A Ra, A Th, A K, are specific radioactivities of isotopes 226 Ra, 232 Th, 40 K respectively

№Sample name Ra Bq/kg 1 Ash from the stove №4 of the fourth power plant Ash from the stove №1 of the fourth power plant Ash from the stove №5 of the fourth power plant Ash from the ger (national house) stove Coal from Alagtolgoi Mine 48.8 Equivalent activity of Radium

№ Equivalent activity of radium, Bq/kg Gamma ray dose rate, µR/h Dedication 1≤370≤20Furniture, civil construction 2≤740≤40Only for industry, road material 3≤2220≤120 Only for construction, located far away from population and underground construction 4≤3700≤200 Only for construction, located far away from population and underground construction 5>3700>200 It’s not possible to use for any kind of construction. Mongolian standard of ash volume in construction materials

Equivalent activity of Radium

CONCLUSION 1. Ash radioactivity depends on coal content and burning temperature. 2. Equivalent activity of radium from the stove №5 was higher than acceptable level of furniture and civil construction. But It’s possible to use for industry and road material. 3. It needs more control of ash samples usage for building materials.

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