Lecturers of the Department of Nuclear Engineering, Chulalongkorn University have found no contamination or spreading of Caesium-137 to the environment in the area of Prachin Buri Province as reported in the news. The Department aims to provide academic services and radiation measurements by a team of experts with in-depth measurement equipment.
Following the disappearance of Caesium-137 radioactive materials from the area of Si Maha Pho District, Prachin Buri Province in early March this year leading to a large number of social media posts on the grave dangers of Caesium which caused great panic and concern from the public on the impacts on health and environment. Prices of agricultural produce plunged and farmers had to plead that assurance be given that their products were edible and free from radiation.
Equipped with their expertise and readiness in terms of equipment, faculty members of the Department of Nuclear Engineering, Faculty of Engineering, Chulalongkorn University, have shared their knowledge via various social media channels. They also assembled a team of experts comprising professors, scientists and students to visit the area in question to analyze Caesium-137 samples found in the environment such as earth, water, food, and plants in the Prachin Buri area.
The analysis found “no contamination of Caesium-137 detected” and “no spreading of Caesium 137 in the air” which means that people can carry on with their daily lives as usual.
“Radiation” has been widely used in both the industrial and medical circles such as the x-ray we all know well while in industries there is considerable use of radioactive substances as well. Most people do not know this and therefore, are filled with fear for it rather than appreciation for their numerous benefits. Having the right information is therefore very important,” said Associate Professor Nares Chankow of the Nuclear Engineering Department, Faculty of Engineering.
For these professors, this provides the opportunity for members of the public to get to know what Caesium-137 is and if there are still doubts about the possibility of contamination then the Nuclear Engineering Department can provide academic services and high-speed measurement and analysis free of charge.
What is Caesium-137?
A lecturer of the Nuclear Engineering Department, Faculty of Engineering, Chulalongkorn University, Rawiwan Kritsananuwat, Ph.D. explained that Caesium-137 is a human-made radioactive isotope with the qualities of a soft, flexible silvery-white metal that has a half-life of about 30.17 years. When it decomposes it will release beta particles and gamma rays and turn into Barium-137.
Caesium-137 is commonly used as a gamma-emitter in industrial applications for example food sterilization, measurement of materials, humidity and density, metal thickness gauge and geoprobe in the drilling industry as well as the use of radiation for cancer treatment.
Do we know that Caesium might also be found in soil?
Dr. Rawiwan tells us that Caesium-137 can be found in the environment like soil or water. What has been found are the fallouts from the nuclear weapon experiments as well as the nuclear accident at the Chornobyl Nuclear Power Plant in Ukraine.
The Caesium-137 from these fallouts have already disintegrated throughout more than one half-life which means that the number has reduced to about half of when the incidents took place. “It is possible to find Caesium in the areas where samples have been collected but in very small quantities and they aren’t harmful,” Dr. Rawiwan assures us.
Caesium-137 isn’t as scary as we think
According to Associate Professor Nares Chankow of the Nuclear Engineering Department, the disappearance of the Caesium-137 should not cause us too much worry since the lost items are covered by steel and lead that serve to shield the rays causing some people to think they are steel bars that can be sold for scrap and have sent them to smelting plants so that the steel could be recycled.
“Normally the smelting plants have furnaces which use closed systems and have a system for treatment of dust and pollution generated by the furnaces. The dust from the smelted steel would be contained in a Big Bag container. Ever since the incident was featured in the news there have been already been orders to halt any movement out of the plant.”
Associate Professor Nares offers further clarification that the melting point for Caesium is 28.5 degrees Celsius while its boiling point is 671 degrees Celsius which is less than steel which has a boiling point of around 1538 degrees Celsius. In the process of melting steel Caesium vaporizes and can attach itself to the particles of their dust which are effectively controlled in the closed system aforementioned.
“The severity of the Caesium rays that might be contaminated in that dust comes in a very small quantity and if some of it spreads into the atmosphere it would be diluted by the air. There is no harm caused to people who may have been exposed to the Caesium that might be found in the environment as a result of the melting of the cylinder in the furnace at Pracchin Buri Province. Moreover, since Caesium easily dissolves in liquids any residuals will only remain in the body for a short period as they would be excreted in the urine.”
Measuring Caesium-137 levels with high sensitivity radiation measurement machine
Phongyut Sriploy, Scientific Services Officer of the Nuclear Engineering Department, has been working on the ground measuring Caesium-137 levels. He finds that the measurement of Caesium-137 is quite simple since Caesium emits Gamma rays which enables us to use basic survey equipment to detect the Gamma emissions to see whether they are higher than the natural background radiation.
“The equipment used for measuring gamma radiation is quite basic and can be used for radiation measurement at close range by placing the machine close to the object. If the object has gamma rays the machine will let out a warning sound and a number shows the level of radiation though it also cannot determine the type of radiation.” Mr. Phongyut related how the Gamma dose rate meter was used.
Aside from the basic measurement equipment, the Nuclear Engineering Department’s team of specialists also used a high sensitivity Gamma-ray spectrometer for in-depth analysis.
“The equipment can cover an area of around 30 – 50 meters. What we do is place it in the area where we suspect there is radiation. If the screen shows a spectrum it can indicate the element found. We use both types of equipment so as that the people in the area can be more confident.” The result of the measurement is that the radiation has an average value of around 0.041 μSv/hr which is considered to be in the range of a “normal” rate for radiation levels in nature.
“A radiation level of higher than 100 μSv/hr is considered to be a high risk that can be harmful to our health.”
Phonyut assured us that the results of the radiation measurement in the area which includes the soil, drinking water, tap water, fruits, and vegetables did not show contamination of radiation and neither was there a spread of Caesium-137 in the air.
“People were very concerned over what had happened. The nearby plants were also fearful that some contamination could spread over to them. Our team’s measurement of Caesium levels has helped everyone involved to be able to live their normal lives without worry or fear” Phongyut concluded.
Chula’s Department of Nuclear Engineering is ready to offer its academic and radiation measurement services to the people so that they regain confidence
The recent incident has spurred interest from people in many sectors to show an interest in Caesium-137 and the possible contamination of various radioactive materials in the environment. Several factories and companies have contacted the Department of Nuclear Engineering to analyze possible radiation contamination and it is willing to offer those services free of charge as part of its CSR contribution to the public.
