[Kim Byung-min's Science Village] Will 'Tritium' with a 12-Year Half-Life Not Accumulate if Continuously Released?

Determining Toxicity Depends on Dosage

Byungmin Kim, Science Writer

Any adult male in the Republic of Korea who has fulfilled their national defense duty would have handled a personal firearm, specifically a rifle. Rifles have devices called the front sight and rear sight to adjust the aiming point. Aligning the front and rear sights is necessary for accurate shooting. The rear sight is often coated with a substance commonly referred to as 'phosphorescent paint.' This fluorescent or phosphorescent material is applied to allow precise identification of the rear sight position even at night. Unfortunately, I once received a rifle with the coating peeled off, which made night shooting training quite challenging.

Fluorescent or phosphorescent materials do not emit light by themselves. They need to absorb energy from an external source to emit light. However, rifles do not have any device to supply energy. The demand for light in places where energy supply is difficult is not limited to rifles. Compasses, watches, emergency exit signs, and others also require such materials. Humanity has used radioactive substances for this purpose. Radioactivity refers to the intensity of radiation emitted as the atomic nuclei of certain unstable elements spontaneously decay. This radiation carries high energy.

Hydrogen is the simplest element among all elements. Typically, its nucleus contains one proton without any neutrons. This form of hydrogen accounts for 99.958% of naturally occurring hydrogen and is called 'protium.' However, hydrogen has other isotopes. Hydrogen with one neutron added to the nucleus of protium is called 'deuterium.' There is also an isotope with two neutrons, known as 'tritium.' Tritium is unstable; its neutrons convert into protons, releasing electrons in the process, and it transforms into helium. This is a type of nuclear decay called beta decay, during which radiation is emitted. In the past, the rear sights of rifles were coated with fluorescent materials mixed with tritium.

Conceptual diagram of tritium purification.

Japan's Decision to Discharge Fukushima Nuclear Plant Contaminated Water into the Ocean
Natural Purification and Scientific Feasibility Claimed,
But Radioactive Nuclides Are Only Diluted, Not Eliminated

Japan has decided to discharge contaminated water from the Fukushima nuclear power plant into the ocean. Tritium is at the center of this issue. Some refer to this as creating a 'sea of death,' while others claim the radiation levels are safe. What is the truth?

Since science is also the language of mathematics, let's look at the numbers. Japan plans to dilute 1.25 million tons of contaminated water 400 times to 500 million tons, lowering the concentration to 1,500 becquerels per liter, which is below the permissible discharge standard, and release it over 30 years. Is this level safe?

Soybeans are a healthy food rich in protein and potassium. However, a tiny fraction (0.012%) of natural potassium is the radioactive isotope potassium-40. Moreover, potassium-40's radioactivity is 340 times stronger than that of tritium. Since coffee beans are a type of bean, those of us living in the 'coffee republic' have been drinking beverages containing radioactive substances without much thought.

Using coffee as an example, radioactive substances are commonly encountered around us. The World Health Organization (WHO) sets the drinking water standard for tritium at 10,000 becquerels per liter. Additionally, tritium has a half-life of 12.3 years, meaning its radiation level halves approximately every 12 years. The radioactive material on the rear sight of the rifle I was issued seemed to noticeably dim over time.

There is the second law of thermodynamics in natural phenomena. In an isolated system, entropy increases, so once the contaminated water diluted 400 times disperses into the Pacific Ocean, it will never reconcentrate. Dilution reduces concentration. It is a method to reduce the amount of harmful substances to levels that do not harm humans or the environment. This is already a common technique used in pollution control. Therefore, the statement that diluted treated water is safe is a scientific conclusion based on numbers.

Of course, this is an irrefutable fact theoretically. However, there is a significant flaw here. Japan's exclusive focus on 'tritium' to explain and persuade the public about the contaminated water discharge is that flaw. Moreover, the contaminated water issue is not the end of the problem.

Press conference regarding contaminated water from the Fukushima nuclear power plant.

European Pristine Mountain Range Named 'Alps'
Only the ALPS (Advanced Liquid Processing System) Name Is Clean

You may be familiar with the Alps, a mountain range representing Europe's pristine regions. The name of Japan's nuclear contaminated water treatment system is also ALPS (Advanced Liquid Processing System). Whether intentional or not, it likely symbolizes the cleanliness of the treated water. The purification of contaminated water involves filtering out radioactive nuclides. For example, 62 types of positively charged ionic nuclides dissolved in water, such as strontium-90 and cesium-137, can be filtered using their electrical properties. This allows compliance with international discharge standards. However, 12 radioactive nuclides, including tritium, lack electrical polarity and cannot be filtered; they are only diluted. Tritium is indistinguishable from normal water. This is likely why tritium has become the focal point of controversy.

The Fukushima nuclear accident is classified as a level 7 event, the same as the Chernobyl accident in the former Soviet Union. A blackout disabled the cooling system, causing the nuclear fuel rods to melt. High-dose radioactive materials lethal to humans met groundwater. Fukushima's location in an area rich in groundwater was unfortunate for nature and humanity. The 12-year half-life applies only to tritium; the other 11 nuclides have half-lives ranging from hundreds to thousands of years.

Japan plans to complete decommissioning within 40 years, but 880 tons of nuclear fuel debris remain inaccessible to humans and even robots after 10 years, making decommissioning seem distant. Therefore, the core issue with contaminated water is that the melted nuclear fuel continues to generate contaminated water until decommissioning is complete. The contaminated water is not a past or present issue but an ongoing one.

The annual exposure limit is set at 1 millisievert or less, but this standard is a product of social consensus. It is a government responsibility standard. There has been no scientific statistical basis, nor is it considered a medically safe level. The radioactive nuclides in treated water are diluted substances, not eliminated. As they circulate through the vast ocean, the ecological impact cannot be guaranteed. Honestly, the outcome is uncertain.

Humans do not eat cockroaches due to the perception of uncleanliness. Would they eat them if they were organically and hygienically raised? Humans rely on experience. No matter how science changes perceptions, disgust based on experience prevents consumption. Although numbers claim diluted treated water is safe, it is difficult to consume seafood with peace of mind. This is due to past experiences with radiation exposure-related diseases and ecological destruction.

So, is there no alternative to ocean discharge? One method is to solidify the treated water at ultra-low temperatures and bury it underground. Another is to convert it into steam and evaporate it at the atomic level, sending it into space. Of course, these methods cost tens to hundreds of billions of yen. In comparison, ocean discharge costs 3.4 billion yen.

'Olympic Rings Sculpture Ahead of "100 Days to Opening" of Tokyo Olympics'
[Image Source=Yonhap News]

Why, despite knowing everything, is this being concealed and rushed? The reason is that contaminated water treatment is being weighed against economic feasibility. The Olympics were held on shaky ground weakened by the collapsed nuclear plant and COVID-19. For Japan, hosting the Olympics symbolizes escaping the nuclear accident.

However, it is not appropriate to revive old anti-Japanese sentiments. The Japanese government is not trusted even within its own country. They may be trying to use anti-Japanese sentiment as a political tool to gain domestic support. Recently, as domestic and international public opinion worsened, the Japanese government promised to expand contaminated water storage tanks by 23 units. Still, this only adds 30,000 tons of storage and delays the discharge schedule by five months.

These are all just their plans. The contaminated water treatment and discharge plans, as well as their execution, remain uncertain. All possibilities must be kept open, and appropriate responses prepared in advance. The media should not shake the public by focusing solely on tritium to cover the government's diplomatic shortcomings. The core issue is neither understanding tritium nor exposure levels. The simple question is whether the public will be safe. Scientific evidence is needed to support this.

The amount of contaminated water will undoubtedly increase. In nature, large quantities always perform significant functions. The famous alchemist Paracelsus (1493?1541) comes to mind: 'All things are poison, and nothing is without poison; only the dose makes a thing not a poison.'

Byungmin Kim, Adjunct Professor, Nano Convergence School, Hallym University

This content was produced with the assistance of AI translation services.