33 years are separating us from the accident at the Chornobyl Nuclear Power Plant, from which Ukraine cannot recover until now. And if in 1986 people were interested in coping with the consequences of the explosion as quickly as possible and with minimal losses, now it is important to know how safe the Chornobyl NPP is, including nuclear power plants in general, and what are the prospects for the development of nuclear energy in Ukraine. How safe the sarcophagus is, what to do with the nuclear fuel that is concentrated in it, and whether our country can afford to abandon electricity produced at nuclear power plants – Opinion has talked to the director of the Institute for Safety Problems of Nuclear Power Plants of the National Academy of Sciences of Ukraine, Doctor of Technical Sciences Anatolii Nosovsky.

How can you assess the security level of the Chornobyl NPP today, 33 years after that terrible accident?

At that time, power units with HPCR (high-power channel reactors ‒ author’s note) operated at the Chornobyl NPP. Now others are used at Ukrainian NPPs, WWER, that is, water-water energetic reactors. Immediately after the Chornobyl accident, a lot of measures were taken to improve the safety level of channel reactors. And not only at our Ukrainian reactors, but also those that stood at the Ignalina NPP in Lithuania. In Russia ‒ at the Leningrad, Smolensk and Kursk nuclear power plants. Therefore, the problems that led to the Chornobyl accident were excluded. And the reactor plants used at the stations now meet all modern safety requirements. And somebody may say whatever wants, but I assure you that all three Chornobyl NPP units that worked after the accident were completely safe at the time of their closure.

How safe is the sarcophagus, that is, the Shelter object now, because there is still a problem with unstable structures, nuclear fuel, etc.?

The issue of security at the Chornobyl site is constantly in the focus of attention of many specialists. The power units are exempt from nuclear fuel. The fuel has been transferred to a temporary storage facility ‒ TSF-1. A storage facility for Spent Nuclear Fuel of the dry type is currently being built and will soon be commissioned ‒ specifically for the Chornobyl-type reactors. Work is underway to convert the Shelter into an environmentally friendly system. The level of security of the Shelter increased significantly in 2016 when an arch or new safe confinement was erected over the sarcophagus. This construction has a number of systems that allow you to safely carry out the dismantling of the Shelter itself.

But first, it is necessary to carry out all the work related to the commissioning of new safe confinement. We plan to finish by the end of this year. And the tender for the dismantling of unstable structures of the Shelter object has already been announced. The fact is that when these unstable constructions which could collapse at any time were stabilized, the builders gave a guarantee that they would last at least until the end of 2023. This means that by 2023 we must dismantle these unstable structures.

Is there already anyone willing to participate in this tender?

I do not have information yet who will perform this work as a general contractor, but the construction organization, which has relevant experience, must deal with dismantling because the work is very complicated. Scientific support, most likely, will be carried out by projectors. We are talking about the Kyiv Research and Design Institute “Energoproekt”, the State Research Institute of Building Structures, and the Institute for Safety Problems of Nuclear Power Plants of the National Academy of Sciences.

Анатолій Носовський: про Чорнобиль, безпеку атомних електростанцій і майбутнє ядерної енергетики

Are there many such organizations in Ukraine that will entail this work?

“Ukrbudmontazh”, which has already performed work on the Chornobyl site, has relevant experience. There is a number of other domestic construction organizations that can also participate in such works. So, I think, there will be no problems with construction organizations.

You claim that now everything is safe at the Chornobyl NPP, but the human factor can always interfere…

Well, the human factor is such a thing, which is difficult to envisage. No one is immune from this. That is why relevant organizational and technical measures are constantly being developed and implemented to reduce risks and minimize the influence of the human factor during such demanding work. A safety culture program has been actively implemented.

But there are other hazards at the Chornobyl site. And I tell you more, we will be dealing with them for a long time. First of all, we are talking about unstable structures, which I have already mentioned. They need to be dismantled as soon as possible. This will reduce the risks of collapse, including those associated with the destruction of the arch. Secondly, we still have the problem of nuclear fuel concentrated in the Shelter, which is under the control of the IAEA (International Atomic Energy Agency). The Spent Nuclear Fuel cassettes are still in the storage pools ‒ we simply cannot get to them to extract. And it must be done.

In addition, there are several other clusters of molten nuclear materials. On the one hand, scientists have proven that most of them are nuclear safe. On the other hand, there is one cluster, which safety is doubtful.

What kind of clusters are we talking about?

The cluster is in one of the premises of the object “Shelter”. It is under a layer of concrete, and therefore it is very difficult to reach to it, to take samples from there and make sure that it is also nuclear safe. For this, you need to conduct a series of experiments that cost a lot of money. And until they are carried out, scientists believe that this cluster is nuclear-dangerous.

Have they calculated at your institute how much money is needed to carry out this work?

I have not calculated these things, but definitely, it is quite expensive because it is impossible to work there without human participation, and the level of radiation danger is very high. The algorithm works like this: to install the appropriate equipment, a drill rig, to drill the concrete, to take samples of these nuclear materials and make their analysis to show what is there. It will also allow assessing the number of nuclear materials there, their composition and whether it can lead to a chain reaction. The work is very difficult.

The Institute for the Safety of Nuclear Power Plants has been dealing with the problem of the Chornobyl site since 1986. What are you doing now?

Since then, our scientists have been conducting research and creating the necessary databases: the state of the constructions of the destroyed power unit, nuclear materials, accumulations of these nuclear materials, water accumulations in the Shelter. See what happens with the fuel that is destroyed. A lot of dust is concentrated in the Shelter, and therefore there is constant aerosol activity. Scientists determine how this dust will behave under the influence of air currents and the like. How it will influence people, working on the dismantling of the construction. In particular, we constantly monitor the state of groundwater around the Shelter.

And what are the results of this monitoring?

So for now, thank God, we have nothing to worry about. Therefore, a zero result is also a result. I can assure the public that now radioactive materials associated with some leaks in the sarcophagus do not get into the Prypyat River or into any other water object. The arch also plays its role, under which it is now hiding. Therefore, today the radiation situation around the Shelter has indeed improved.

But it cannot be called perfect…

It is impossible. However, the Exclusion Zone can already be reduced. Let’s say, to a radius of 10 km. And let it be too early to transfer this territory for the needs, relatively speaking, of the national economy, the Agency for the Management of the Exclusion Zone is engaged in creating protected areas in these territories. And this is the right approach. It will take some more time, it opens up opportunities for the future use of these territories, not only for the location of industrial enterprises but also for agriculture.

The ecologists doubt that the Shelter can be turned into an absolutely environmentally friendly object. Do you think this is possible?

There is nothing unreal in the world. Of course, it is possible. It’s just a very big expense. Now there are two approaches to solving the problem. The first is to do nothing with it, pour concrete and leave this object, like an Egyptian pyramid, forever. You know, if there was no nuclear fuel there, it could have been done that way. But as long as nuclear materials are there, they need to be removed from there. Only after that, it will be possible to talk about the possibility of object burial on site.

Although more than 30 years have passed since the Chornobyl accident, the society does not want to understand that the Exclusion Zone is for a long time. These are not even dozens ‒ for hundreds of years. It is impossible to clean it to a green lawn, where there will be no risk for a person.

Анатолій Носовський: про Чорнобиль, безпеку атомних електростанцій і майбутнє ядерної енергетики

And what is the other approach?

As for me, it is much better to decommission, remove and bury it. There are radioactive wastes that live for a long time, and they require disposal in deep geological formations. So do in the world. Usually, special mines are made in the rocks, and then these containers with radioactive waste are brought there and buried forever. This requires a special repository, which is not in Ukraine. Therefore, with the help of the European community, we are investigating the possibility of its creation in the exclusion zone. There are granite layers, you can use for this.

Now, besides Chornobyl, we still have 4 operating nuclear power plants. Can you assure that they are completely safe now?

Yes, there are 4 more sites: these are the Rivne, Zaporizhzhya, South-Ukrainian and Khmelnytsky NPPs, which are equipped with water-water energetic reactor (WWER). These nuclear installations are much more reliable than the high power channel reactors (HPCR) that were at the Chornobyl NPP. They have protective containment, serious security systems.

Scientists carry out scientific and technical support for the activities of these reactor installations, control their safety level, and participate in the development of measures to improve the safety of WWER. If earlier all these questions were closed to the public, now they are open to the whole world. Therefore, special reports are developed on the safety analysis of these nuclear installations, including those for the public, and they should know what is happening and where.

In addition, Ukraine is a member of the International Atomic Energy Agency (IAEA); therefore, we have inspections of this organization at all NPP sites. Experts of the IAEA control first the safety of our reactor installations that is an additional guarantee for people. However, incidents at nuclear power plants occur from time to time. After big ones like Chornobyl or Fukushima, you have to revise a lot of positions drastically.

Are we talking about security systems? What exactly will change first of all?

There is a whole range of changes; they are connected with control systems, cooling systems. The Chornobyl NPP completely reconstructed the security systems. After the accident at Fukushima, a thorough analysis of the safety of Ukraine’s nuclear reactors, the so-called stress tests, was carried out again. Such stress tests show weaknesses, and then later technical and organizational measures are developed that are implemented in practice. I do not want to load you with terms, but this is a job that never stops.

Анатолій Носовський: про Чорнобиль, безпеку атомних електростанцій і майбутнє ядерної енергетики

No matter how much the experts talk that modern reactors at our nuclear power plants are safe, people, who live near nuclear power plants constantly oppose such a neighbourhood. So, the public negatively perceives the idea of ​​completing the 3rd and 4th power units at the Khmelnytsky nuclear power plant. And this position can be understood…

Once again I want to assure you that all reactor installations are now truly safe: if scientists doubted this, they would have been stopped it already. Even the smallest events that occur at nuclear power plants are immediately investigated and published very quickly in the media. But all these events, according to the international scale of nuclear events, which is used to assess emergency cases in the field of nuclear energy, are usually below zero. This scale, developed by the IAEA after the Chornobyl accident, has 7 levels. The seventh ‒ the highest ‒ is the Chornobyl disaster. And the fact that from time to time there are some deviations in the operation of nuclear power plants, it is regarded as a zero level. These are minor events that are not related to radiation exposure to humans and the environment.

As a scientist, do you see at least some light at the end of this tunnel?

If our leaders do not turn resolutely towards science, Ukraine will not ever become a normal state that can compete with European markets; it will remain a raw material appendage of Europe. As for our nuclear power plants, it should be borne in mind that the nuclear industry has long been international, and our nuclear power plants are under the control of the international community. The world in no way will allow Ukrainian nuclear installations to be dangerous. But with this approach, as it is now, Ukraine may lose its nuclear energy.

Interview by Larysa Vyshynska

Photo by Yevheniya Kudin from the personal archive of Anatolii Nosovsky

Illustration by Nastasia Petrova

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