This blog is dedicaded to the text that comes from academician V.Legasov audio tapes which he recorded after the Chernobyl accident and not long before his death.
All of this had such an irregular, sudden quality. On the one hand, it could
be explained by the young age of this branch of technology, and to some
extent it is; but on the other hand, it was a reflection of an overall
incorrect manner of working in general. When Nikolai Ivanovich spoke his
words, and they, like a light, retrospectively illuminated all the previous
events, I realised that these were the right words. But I also realised that
this was not specific to the nuclear energy industry, but rather the
consequence of the way work was organized in general, to create, very
quickly create, a new branch of technology that the national economy
needs.
Here’s a way to organize work on construction sites: inconsistency in
different types of production, say, the production of fuel elements; the
machine-building equipment, the unpreparedness of builders to accept this
equipment on time; garbage on construction sites; constant, incomprehensible
changes in the number of construction staff (by construction I mean at
nuclear power plants), at times too many, at others too few. Work, so to
say, is progressing on the station, then abruptly stops because one or the
other equipment is not there.
All this taken together was very unpleasant, and at the same time, hardly
unique or specific to the nuclear energy industry alone. That is why the
words of Nikolai Ivanovich Ryzhkov should be understood in a much wider
context. And when I visited the Chernobyl station after the accident and saw
what was happening there, I myself drew a precise and unequivocal
conclusion, that the Chernobyl disaster is an apotheosis, the pinnacle of
all the mismanagement that has been carried out for decades in our
country.
Of course, what happened at Chernobyl has real, not abstract, culprits to
blame. We already know now that the reactor’s Protection Control System
(PCS) had a defect in it, and many scientists knew this, and they proposed
ways to fix this defect. The Chief Designer, not wanting to do, so to say,
quick, additional work, was in no hurry to change the Protection Control
System.
Also, there are, of course, specific culprits. What went on at the Chernobyl
station itself for many years: conducting, so to say, experiments the plans
for which were made very carelessly and sloppily. Before conducting the
experiments, there were no simulations of possible situations, that is the
situations were not walked through—what will happen if there is a protection
malfunction; what will happen if the process does not execute as planned;
how should the staff react in one situation or the other; can the reactor be
left running when the steam supply to the turbine is stopped; and if this is
done, what could happen; what will happen if the main circulation pumps are
switched on.
Common sense would suggest that all these cases had to be simulated before
the experiment, be it this particular one or any other. But nothing of the
kind, of course, was done. There was an absolute disregard of the viewpoint
of the Chief Designer or the Science Supervisor. It needed a fight to…
[TAPE ERASED]
Speaking of the conversations with Mikhail Sergeyevich Gorbachev. While in
Chernobyl, I spoke with him thrice on the phone. This was rather odd. He, of
course, would call the Second Deputy of the Government Commission, comrade
Silayev Ivan Stepanovich,
or maybe he would call Shcherbina and talk to him, but this was not in my
presence. But sometimes when we were at Silayev’s, then Gorbachev would
call. Ivan Stepanovich would tell him his point of view and then, when more
detailed, specific, technical information was needed, he would ask, “To whom
should I give the phone, Velikhov or Legasov?” And in the first call, he
said, “Give the phone to Legasov.”
So I started talking to him. He, Mikhail Sergeyevich, spoke for two or three
minutes. “What is going on there? I am very concerned about this problem.
Already the name of Gorbachev is being tarnished all over the world because
of this accident. Mass hysteria has begun. What is the real situation
there?” In response to this, I outlined the situation for him; that
basically—as it was after the 2nd of May; the call was around the 4th or 5th
of May—the radiation emissions from the destroyed block have ceased, and the
situation is currently under control. The scale of contamination in the
areas adjacent to the Chernobyl station, as well as the scale of
contamination around the world, is more or less known to us. It was already
clear to us that people injured by radiation, except for those who worked at
the Chernobyl station at the time of the accident, are expected to be
unlikely; that the control of the population is thorough; that if the
countries that came under the nuclear fallout from the accident took proper
informational and sanitary measures, then there will be no real consequences
to the health of the people.
This is what I said to Mikhail Sergeyevich on the 6th of May, not knowing
that on the same day a session of the World Health Organization, specially
assembled about this issue, had come to the same conclusion. That the
accident did not pose any threat to the people in Western Europe and other
countries. I also talked about the specific situation, where the heavily
contaminated areas were, where the situation was more or less favourable,
and how the work was progressing. He was satisfied with this conversation.
The next day, when we were at Ivan Stepanovich Silayev’s office again, the
phone rang once more, and this time he asked for the phone to be given to
Evgeny Pavlovich Velikhov. He began to ask him about the reasons for the
accident, but Evgeny Pavlovich started giving very confusing explanations,
and then quickly said that Valery Alekseyevich [Legasov] will explain this
better, and handed the phone over to me. Perhaps I was too generous with the
details, but I did explain why this accident had occurred. And at that
moment, Mikhail Sergeyevich asked me to write a personal letter to him. And
what surprised me was that I, specifically, had to send a letter about what
had happened and what had to be reported. So I immediately sat down to write
this letter, and after a few edits by Ivan Stepanovich Silayev, it was sent
to Gorbachev that same night, signed by Silayev, Velikhov and me.
The construction of the sarcophagus. Notice the amount of concrete pumps and the volume of the structure itself. Source unknown.
Ivan Stepanovich Silayev, during his term, paid the most attention to the
construction work— arranging the concrete factories, arranging the shipment
of concrete—because it was clear to him that the area around the 4th block
had to be concreted as much as possible. He was very angry with, say,
Makuhin, the First Deputy Minister of Energy and Electrification, who, it
seemed to him, was working slowly; and he even made a quick decision to fire
him. This decision was never implemented, but such words were said. It was
Ivan Silayev who introduced the system of monetary rewards for doing the
most dangerous tasks. And the most dangerous tasks during his term were to
determine whether or not there was water inside the upper and lower
bubblers, and in the rooms beneath the reactor hall because this was
crucial. We were worried that some of the molten fuel would get there, and
possibly lead to powerful vaporization which will carry out additional
radioactivity. And we had to know whether those bubblers were empty or not.
After that, we had to decide whether to leave them empty or to fill them
with special concrete. So Ivan Stepanovich Silayev had to tackle all these
issues.
The concrete factory. Several such were organized to satisfy the enormous requirements of the construction project.
Another view on the concrete loading section.
It was quite hard to get to these bubblers because the adjacent corridors
were flooded with water from the time when they were trying to cool down the
reactor with water. The levels of radioactivity in that water were quite
high, up to a curie per litre in some places and at certain points in time.
The pumping devices were turned on and this water was pumped out. And yet,
the gate valve that needed to be opened to determine if there was water
inside the bubblers, was opened by one of the station workers in very
difficult conditions. So in the evening, Ivan Stepanovich solemnly thanked
him and gave him a package with a thousand roubles. He had obtained the
necessary permission for it. And I saw the face of that man who, on the one
hand, was very proud that he had managed to do this difficult task in such
difficult conditions. However, on the other hand, it was plain to see how he
crumpled that package of money, not like a prize. Basically, it was
uncomfortable for him to refuse this money, but at the same time, the cash
form of the prize itself did not really please him. Probably because indeed,
especially during that period, people who fought with this accident sought
to do their best, to do everything they could, without thinking about any
kind of encouragement, be it material or moral. Everyone worked as a single
collective, attempting to find the best solution.
During this time, it was frightening to look at comrade Konviz—he was from
Hydroproject and
the chief engineer of the station—because he, I think, never slept, not for
a minute. And naturally, to find out how to access various rooms, everyone
turned to him, either to his drawings or simply to his memory, to his
experience.
Here I recall many such annoying episodes. You would look at the drawings
and see an open corridor. You would start moving along this corridor and
suddenly run into a wall. The wall was obviously built there because of some
engineering considerations after the project was completed. It was not in
the design, but it was there and not shown in any of the drawings. There
were reverse cases as well, when, say, where should have been a wall
according to the drawings, in reality, was a doorway. We encountered such
cases as well.
Floor plan of 4th floor of the ChNPP.
Source: reddit (r/chernobyl)
It was particularly hard for the miners because, beneath the station
territory, a large number of pipes and plates were buried in the ground. And
so when they worked using their
or something similar, their way would appear to be clear when looking at the
underground utility drawings. But when they began their work, they
constantly ran into obstacles that were not shown in the drawings.
There were a lot of inconsistencies between the part of the documentation
that was at the station and the reality in various places of the station and
underground facilities. All this certainly gave an impression of gross
neglect, of gross sloppiness towards maintaining documentation, which should
be accurate and describe the state of building structures, and walkways, and
electrical communications at every moment in time. Unfortunately, we came
across this sloppiness quite often. At the same time, I want to highlight
the fact that although these things are irritating when faced day after day,
at that moment the people were so determined, they so wanted to complete
their work, that all these past cases of sloppiness did not cause any fuss
or outcry. All this receded into the background in front of the will to
tackle the situation as quickly as possible.
The number of people staying at the site was increasing day by day because
each group required new assistants, who came either with devices, or with
documents, or with work tools that were needed to perform a task. This
increase in the number of people required new ways of organizing work
because it was no longer possible to personally give specific instructions
and be done with it. That is why after the main problems had been solved (by
main I mean protecting people from immediate danger and localizing the
disaster itself), came the question of managing all these numerous groups of
people who had gathered there at the suggestion of the Government
Commission, according to the decisions of the Operative Group of the
Politburo of the Central Committee, and stayed in ever-increasing numbers,
along with their equipment, on the territory of the Chernobyl nuclear power
plant.
It was necessary to simultaneously organize a number of tasks that were of
completely different types. First of all, start the design of the covering
that would later come to be called the ‘sarcophagus’. This design had to be
done concurrently at the site and in the different design organizations
located in cities across the Soviet Union, mainly in Moscow and Leningrad.
It was necessary to immediately work on zone-wise decontamination, following
the guideline of going from the most contaminated areas to the less
contaminated ones. It was necessary to carry out a survey of the territory,
to continue this reconnaissance, and to check how radioactivity was being
spread by the wind, by the vehicles. It was necessary to tackle the issue of
checking the equipment in the 1st and 2nd blocks, of checking the remaining
structure and equipment in the 3rd block. It was necessary to assess the
condition of all the rooms and areas on the entire Chernobyl station, its
surrounding areas and roads. It was necessary to accommodate the army
divisions as well as the various construction organizations that had arrived
to help solve this situation. A proper management system had to be
established for scientific research, design and execution of projects across
all these very diverse areas of work. The management system for this complex
mechanism was established gradually.
Sarcophagus construction in process. Source unknown, notify us if you know
who owns this picture.
The first two groups, led by Boris Yevdokimovich Shcherbina and Ivan
Stepanovich Silayev, were occupied exclusively with the most important and
urgent tasks. Thanks to the arrival of comrade Voronin, the overall scheme
of work management had started to form. A procedure for ordering materials
was established already; a procedure for work fulfilment. It became clear
that one group of researchers had to work solely on the tasks related to the
4th block, while another would tackle its surrounding area. The third
group—implementers, not researchers; these were mostly the army divisions—
began decontaminating the rooms in the 1st and 2nd block, and also prepared
for the construction of the sarcophagus, because the design was already in
progress in Moscow.
Comrade Voronin was replaced by Yury Nikitich Maslyukov, and during his time
a lot of work was done to build new premises, new villages for the evacuees.
The treatment of roads had begun, and the initial preparations started in
front of the 4th block for the construction of the sarcophagus. The
sarcophagus itself had not yet been begun but the approaches to it had
already been concreted. The most contaminated areas had either been cleared
or concreted for the builders to begin their work on the sarcophagus
construction.
When comrade Gusev came to the site with his team, the main design elements
were being sketched out. It had already been decided to assign the
construction of the sarcophagus to SU 605, a department in the Ministry of
Medium Machine Building; and that a thorough assessment of the internal
condition of the 4th block had to be carried out, of the structural
soundness of its remaining building, so that the project could rely on some
analysis, on some verified data.
And when comrade Vedernikov and his team replaced Gusev, the construction of
the sarcophagus had already begun. Moreover, particularly under Vedernikov,
with the participation of the group leader from the Institute of Nuclear
Energy, comrade Tutnov, a decision was taken that made the construction of
the sarcophagus easier and quicker. Because originally the plan was to build
a dome made entirely of concrete over the wreckage. However, calculations
showed that the time needed for the construction of the sarcophagus could be
significantly reduced if the concrete dome—the reliability of which was
being questioned, whether the design would hold its weight— is replaced by,
so to speak, a pipe run. The pipe system of roof support would protect the
sarcophagus against the possibility of radioactive dust being carried out.
However, more radiation would escape through this top cover but it would be
comparable to or even less than the total radiation on the site. The correct
decision was made during the time of comrade Vedernikov.
And gradually, the following framework of work organization emerged. It came
down to this that the research group from the Institute of Nuclear Energy
together with experts (this group was successively led by experts such as
Yury Vasilievich Svincev, Anatoly Mihailovich Polevoi, Tutnov as I have
already said; next this group was led by comrade Kuharkin Nikolai
Evgenievich. A lot of work was done when comrade Pologikh Boris Grigorievich
led this group. Also, research groups under which particularly a lot of work
was done were led by Kulakov, Borovoi, for example) had to—and this was
their primary objective—thoroughly investigate the premises of the 4th
block. Firstly, find the fuel; determine how was it distributed. Secondly,
install the maximum number of sensors that would ascertain the condition of
the 4th block.
Here I need to pay tribute to comrade Schekalov, the expert from the
Institute of Nuclear Energy, and also to the experts from the Ukrainian
(Kiev) Institute of Nuclear Research, who made great efforts to find the
appropriate paths, put in the necessary sensors, and stretch cables to them.
As for neutron sensors, they were the responsibility of CNIIP [Central
Science Research and Project Institute] of the Ministry of Medium Machine
Building. The experts from this institute were led by comrade Zhernov.
Generally, one of their tasks was to put various sensors in the 4th block
for measuring gamma fields, neutron fields, measuring temperature, measuring
airflow, measuring the hydrogen concentration sensors should it suddenly
appear in the system, etc. These sensors were placed in various spots. This
was dangerous and hard work because they had to go inside the block every
time and search for the most suitable spots that would reliably diagnose the
condition of the 4th block. This was one set of tasks.
At the same time, videos and photos of the rooms of the 4th block were taken
continuously which allowed the engineers to select the proper solutions for
the construction of the sarcophagus itself. During this, the project team
from NIPIET - Leningrad Design Institute of the Ministry of Medium Machine
Building, was working on-site in Chernobyl, and an array of design
decisions, though the general design had been developed at the Institute, an
array of design decisions were made there on the spot. An absolutely
enormous amount of work was done by comrade Kurnosov, the chief engineer of
this project and the chief engineer of the institute itself. He regularly
found proper solutions when one or the other difficult situation arose.
And there were difficult situations. An attempt to pour concrete in an area
was unsuccessful because there were rather large gaps through which the
concrete flowed to the levels below. Methods to hold the concrete in place
had to be thought of. Some supports were not strong enough and reinforcement
was necessary. This harmonious work of the researchers and the designers, in
the end, led to a reliable construction. That was one group of tasks.
Another set of tasks was performed by the construction experts from the
Ministry of Energy who were building a temporary village called
Green Cape
(Zelyoniy Mis). Many prefabricated houses were ordered, made both in Finland
and in the Soviet Union. And for the shift workers that had to work in the
1st and 2nd blocks, a very nice village was constructed with all the needed
amenities: with houses, with shops, with cultural facilities. This village
had been constructed literally in a few months. Boris Yevdokimovich
Shcherbina was personally following the construction of this village, paying
attention not only to the places to sleep after work, but also that there
should be flowers, that the canteen worked as well as in any other part of
the Soviet Union, and that the people felt comfortable there. These
divisions of the Ministry of Energy had taken part in the construction of
the village at Green Cape, and also in the construction of many stations for
the decontamination of vehicles, quite a lot of which had gathered on the
site by then.
The Government Commission itself had already been relocated by this time.
The work was, as before, done in Chernobyl in the former regional Party
Committee building, but the living accommodations were moved approximately
50 kilometres away from Chernobyl. The leaders of the Government Commission,
as well as the various experts that were arriving to perform certain tasks,
lived there.
A large group of researchers from various organizations of the Soviet Union,
from the Academy of Sciences , from the Kurchatov Institute of Nuclear
Energy(when I say Academy of Sciences , for example, I mean of course the
GeoChem [ГЕОХИ] and the entire Ukrainian Academy of Sciences), this whole
group of researchers was working on a detailed assessment of the radioactive
contamination of the area. For this, they used both statistically reliable
samples that were gathered on the site—followed by analysis in the
radiochemical laboratories that had been deployed in Chernobyl, and some
samples were sent to the institutes, the Radio Institute or the Institute of
Nuclear Energy—and measurements of gamma fields made using helicopters.
These surveys were done for both the total amount of gamma radiation and the
isotope spectrum of gamma radiation. And
were found between the contents of individual isotopes, by using relative
contents of which we could predict the concentration of, say, Plutonium that
was released into the environment. Of course, samples of Plutonium, as well
as other heavy alpha-active elements, were collected continuously to compare
the data gathered by the helicopters and through the direct collection.
The responsibilities were distributed in such a way that everything that was
outside of the 30-kilometre zone was controlled both from the air and from
the ground by the Goskomgidromet [State Committee on Hydrometeorology] led
by
Yury Antonovich Izrael. I cannot exactly tell how much time he spent in Chernobyl, and took the
most thorough part in data collection, their correct estimation, researching
the history of the appearance of contamination spots. An enormous amount of
work had been done and as a result, outside the 30-kilometre zone, we were
receiving more and more precise maps that showed the degree of contamination
of various areas.
And within that 30-kilometre zone, the talk was mostly about Caesium
contamination, because several Caesium spots had appeared (these will be
shown on the maps) and the creation of Caesium maps began in the period from
the date of the accident until the 20th of May, after which the
creation of such maps was stopped.
According to existing sanitary norms, decisions were taken that set the
maximum limits [of radiation exposure] that allowed people to live in areas
contaminated by certain isotopes. The local authorities acted according to
these rules, either relocating people or letting them stay, switching to
imported food, or declaring the area safe enough to live in and to use the
land. At the same time, the
Gosagroprom
[State Agro-Industrial Committee] and the experts from the Ministry of
Medium Machine Building were also carrying out analysis of various
agricultural crops, determining the degree of their contamination, observing
the forests and fields around the Chernobyl station, both within the
30-kilometre zone and around it.
As for the 30-kilometre zone itself, it was under the charge of the experts
from the Ministry of Nuclear Energy, the experts from the Kurchatov
Institute, experts from the Radium Institute and the experts from the
Ukrainian Academy of Sciences.
In September, the work of the substitute Government Commission had ended.
All the work was transferred to the revised composition of the first
Government Commission (the one led by Boris Yevdokimovich Shcherbina) that
had been approved. And subsequently, from September onwards, all the work on
the site of the Chernobyl station and within the contaminated zone was the
responsibility of the Government Commission. It made all the decisions,
reviewed all the projects, all the comments, and led all the work.
The order of operations was approximately as follows. Around the beginning
of September, the evacuation efforts had been generally completed and the
evacuees were placed in the newly-constructed villages. Some of the station
personnel got
in Kiev city and some in Chernigov. All in all, the accommodation issues had
been solved. A decision was made to build the city of
Slavutych because it
was clear from the beginning that the shift work method could only be used
temporarily at the nuclear power plant. And so the design of the new city of
Slavutych began; the city that would replace Pripyat as the permanent
residence for the power engineers.
The period of August and September was a period of active preparation to
launch the 1st and 2nd blocks of ChNPP. This launch was carried out
successfully. Moreover, before launching these blocks, an entire complex of
measures, developed by experts to further increase the safety of such type
of stations, was implemented and tested; partially on the 1st block and
fully on the 2nd block. This was sort of the main task in that period.
Concurrently with the preparation for the launch of the 1st and 2nd blocks,
and with performing the launch operations, work was underway on the
construction of the sarcophagus. The original deadline for this construction
was at the end of September, but various issues that naturally come up
prevented this work from being completed in time. But, I will repeat, this
was because unforeseen circumstances cropped up constantly. There were very
large gaps that could not hold the concrete, preventing it from hardening,
and making it impossible to set up the base for the subsequent construction
elements. There were problems with selecting the appropriate material (this,
by the way, was the task given to the experts from Kiev, they were also
employed at the end) that would close the gaps between the components of the
pipe cover. It was necessary to design a forced ventilation system for the
sarcophagus so that if there was not enough natural ventilation, it would be
possible to remove heat by switching on the forced one.
All these issues were gradually solved during the design phase and were
refined during the construction of the sarcophagus of the 4th block. This
construction was a separate saga in itself.
Robot nicknamed "Moon walker" for resemblance with soviet moon rover.
I will repeat that the project teams were working on the spot. The work was
done with the help of two cranes made in the German Federal Republic by the
firm Demag. The primary work was being done using these cranes, but still
many finishing tasks, that would increase the reliability of the
sarcophagus, had to be done by hand or by using various robotic devices.
However, as I have already said, the robotic devices we had, be it our own
or acquired from abroad, turned out to be practically useless in those
conditions. Say, even if a robot had sufficiently reliable electronics, it
could not overcome obstacles, that were the result of a large amount of
wreckage of the 4th block, and stopped. This was the reason they were
unusable. If, however, the researchers received robots that had good
all-terrain travel capability in the most difficult conditions, then their
electronics would fail because of the high gamma radiation and they also
stopped.
The MF-3 robot, ordered from Germany.
So there we were, trying to use robots to clean the contaminated roofs of
buildings where the 3rd and 4th blocks were, and also the roof of the
reactor, of the radioactive contamination. We tried to use robots but this
generally was not very successful. The best technical devices were created
by experts from
NIKIMT. Yurchenko Yury Fedorovich was the director of this organization. He
himself spent a lot of time on the site and under his leadership, the robots
were created, tested and used. But, well, what kind of robots? Ordinary.
Ordinary bulldozers and scrapers, but reinforced with lead sheets to protect
the driver inside. And such vehicles were used to do the majority of
decontamination work in the most difficult places. The army divisions were
primarily used to decontaminate large areas of the station territory and the
insides of the station buildings. They worked very diligently, with great
speed and efficiency.
MF-2 robot being adjusted.
Of course, many things changed as time passed, our views and ways of
working. I remember an episode well when we, with General Kuncevich, arrived
at Pripyat. It seemed that it would be impossible to decontaminate this city
because everywhere one went, there were very high levels of radiation, say,
700-800 milliroentgens per hour. This was the magnitude of doses that we
measured with our devices. But then we did one thing. We broke off pieces of
facing from one of the buildings and took them from Pripyat to Chernobyl.
And it turned out that this facing was radiating 800 milliroentgens per hour
but here [in Chernobyl], it radiated less than 10 milliroentgens per hour.
So it became clear that the contamination sources were not widely spread,
but rather there were local sources of contamination in Pripyat that created
a general environment that made it seem like that decontamination was not
possible.
After we figured this out, and after the most active isotopes had already
decayed, then mainly around August-September, very active work began,
carried out by the military organizations, to decontaminate Pripyat. And the
city of Pripyat was considerably decontaminated by about the same time when
the sarcophagus construction was ending.
While constructing the sarcophagus (it is still under construction), we
solved the problem of how to close the gaps. The following decisions were
taken. Dip asbestos sacks filled with polyethylene chips into appropriate
solutions—this would produce foam—and then use these sacks to close the gaps
on the roof of the sarcophagus. But even before the work on the sarcophagus
ended, work began on checking the condition of the equipment in the 3rd
block. The question arose about what to do with the 5th and 6th blocks.
These were the questions we had.
Around October 1986, the situation regarding work distribution was very
clear. US 605 of the Ministry of Medium Machine Building was completing the
construction of the sarcophagus, which was later named ‘Shelter’. The
builders from the Ministry of Energy were occupied with the construction of
the shift village at Green Cape and some tasks related to the creation
of a decontamination station inside the 30-kilometre zone and some
work on the territory of the station itself. Minatomenergo led the work on
the preparations to launch the 1st and 2nd blocks and had already started to
gradually make their way into the 3rd block to assess its condition. The
army divisions, together with the organizations of Ministry of Medium
Machine Building, were cleaning the roofs of the building where the 3rd and
4th blocks of the Chernobyl NPP were. The military divisions were also
continuing with the decontamination of the villages that were within the
30-kilometre zone. The research group, as I have already said, had divided
its tasks as follows: researching the wreckage of the 4th block; finding the
fuel; and surrounding it with the maximum number of diagnostic devices.
A manned tractor cleans the roof of ChNPP. This was one of few manned vehicles on the roof. It has cleaned 3 zones and was very effective. This is the iconic
T-25 tractor model.
The diagnostic devices were inserted from under the 4th block. For the
bubbler rooms, the diagnostic elements were inserted through holes drilled
into the sidewalls that led to the reactor hall. And the bulk of the
diagnostic devices were inserted from above, hung on special ropes inside
the reactor hall.
At the same time, another group of researchers was occupied with another
task, specifically, studying the migration of radionuclides inside the
30-kilometre zone and around it. We were concerned by the question: how deep
do the radionuclides penetrate after they are deposited on the surface; how
are they absorbed. Different techniques for the artificial absorption of
radionuclides on surfaces were tested. The problems of preventing the
radionuclides from getting into the Pripyat river were solved. Measures were
taken to prevent the radionuclides from getting into the groundwater.
Within the last field, the actions were quite simple. Around 150 wells were
constructed, both diagnostic and service wells. The diagnostic wells worked
continuously and measured the radioactivity of the groundwater, and if
required, the service wells could be turned on to pump out the contaminated
water. But fortunately, during the entire period of work, and to this day,
all the diagnostic wells have shown that the groundwater has always been
clean, and the service wells have never been used.
Complex research was done in the cooling pond near the Chernobyl NPP, where
the radioactivity of the water, as well as silt, was measured. and a lot of
attention was paid to the condition of the Pripyat river itself, the
Kiev reservoir.
But it was very quickly discovered that the water itself did not have much
contamination, but the silt was affected. And the concentration of
radioactive elements in the silt under the cooling pond was up to 10-5
curie, [END OF TAPE 3] while the concentration of radioactivity in the water
was no more than 10-8 or 10-9 curie per litre.
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