Victor Sergeevich Severianinov - the 5th director of the First NPP, he was holding this position from 1970 to 1990. Veteran of work, war veteran, Guards-lieutenant-mortar man. He has battle and labour awards - order "Order of The Great Patriotic War" of the second degree, order "Sign of Honor", medal "For the capture of Kenigsberg" and "For the Victory over Germany". In January 2008 Victor Sergeevich is 83 years old.
Not closer than Urals and not further than Baikal
I am a Muscovite, I joined the Moscow Engineering Physics Institute after the front and graduated from this university in 1954. Two years before that, I had visited Obninsk to undergo practical trainings as a forth-year student. I had been in the Laboratory "B" for a month. Finally, I and my fellow students - the whole group, about ten students - were sent to Obninsk.
We didn't object to such a turn in our destinies, and at that time it was impossible to object. Frankly speaking, we all were really very glad. Our teachers on the question about the place of our future work usually were giving the following answer: "Not closer than Urals and not further than Baikal". And we found ourselves on the object that was only 100 km from Moscow. Of course we were glad, frankly speaking.
First I was working in the laboratory of Boris Grigorievich Dubovsky and was making critical facilities there. But within a matter of a month I was proposed to work on the First NPP as an engineer-physicist. I had been working for a year at this post and then came to my chief Nikolay Andreevich Nikolaev and told him: "I'm going to marry, and I would like to have a flat or a room at least". He asked: "Who is your wife?" I answered that we had been the students of the same group.
Nikolay Andreevich Nikolaev - the first director of the First NPP. He came to Obninsk from the post of the Chelyabinsk-40 military reactor director.
Everything happened this way. We have been given a room, Ninel arrived (Ninel Andreevna - Victor Sergeevich's wife). I turned over my duties of an engineer-physicist to my wife and began working at the reactor control desk.
Being still an engineer-physicist I was taking account of the First NPP's operation. Nikolaev had to phone to the ministry and report what is the reactor power, what are the parameters, how many isotopes have been produced, how much heat and electricity have been generated, what was the burn-up, heat generation and other parameters. I had been accumulating all these data. That is why Nikolaev demanded that I should assist at all the operational meetings where I had seen several times Kurchatov, Slavsky and other fathers of the nuclear industry. I was sitting with my register-book near Nikolaev and giving him a precise data when it was necessary.
Then I had been working on different posts till the post of the First NPP director. I have been proposed to work in Moscow on the administrative post, to go on a business trip to Libya - but I didn't want to leave the facility, that had already become native to me. Though working on it was very difficult…
First problems of the First NPP
The First NPP had to be closed right after the first launch according to the Kurchatov's decision, which was rather reasonable.
According to the design, reactor vessel should be filled with helium. But when we started filling it, it turned out that it was impossible to increase the pressure even on some millimeters of the mercury column. We started searching for the leaks. When we brought a leak detector to the upper plate of the reactor, detector went off the scale. It was understandable. According to the design, on the upper plate were located 156 copper gaskets under the risers and 156 same gaskets under the channels and they were tightened underneath by 4 bolts. It turned out to be impossible to check the sealings.
Finally we realized that it was impossible to fill the reactor with helium. That meant, that NPP wouldn't work at its designed parameters, because graphite temperature would exceed set-up parameters and the danger of graphite burn out would appear.
We had to use the mixture of helium and nitrogen, but leaks remained. Finally, we chose a technical nitrogen, that allowed 0.5% oxygen content. All the same we didn't manage to maintain set-up parameters, and it was decided to operate the reactor at decreased capacity levels.
On helium we managed to reach a 50% level, then 75%, after that a nominal level, that we managed to maintain only for 2 hours. I would like to remind you, that nominal level for the First NPP was 5 MWe at the turbogenerator, and thermal capacity was 29 MWe. Though, we managed to work at these parameters, reported and met a governmental delegation. Frankly speaking, we were working at 50% capacity when the delegation arrived.
That day another event occurred, which now can be recalled with a smile, but at that time it was not funny. When the delegation arrived, the SCRAM happens. Let alone regulations! Chief engineer was crying to the operator at the control desk: "Increase the capacity immediately!" And we managed to increase it while the delegation was changing their clothes and going to us. So we reported about the successful launch of the reactor.
And then, hard days of operation problems started. The reactor vessel cracked. It was welded on the lower plate - it was impossible to weld up the crack as well as to explore the damage. We had to guess by the indirect signs - when we had been filling the layer with water, it leaked to the facing of the concrete footing, and it signified that rupture existed. We began to gasket "Leonids" that they should withstand the gas-leaks.
"Leonids" - were the water defense tanks. For security reasons coded identifications for materials and equipment were used on the First NPP.
We worked on the nitrogen with the constant replenishment, because without it, it was impossible to increase and maintain the pressure. We used up to three tanks with nitrogen during a shift. We were easing it to the facility and it immediately came out of it. Let us calculate - we were working in three shifts and it means that we could spend up to 10 tanks of nitrogen with the pressure of 150 atmospheres.
Then problems with safety channels followed. They were implemented from the thin stainless steal (0.25 mm, if I am not mistaken), and safety rods were with the pellets made of boron carbide. The pellets began to swell and thin-walled rods began cracking because of irradiation. The channels were replaced; we have mounted 0.5 mm thick rods.
On the next stage we began thinking of boron carbide cooling. Rods were hung up on the rope from the stainless steal. It turned out to be completely impossible to strengthen the rope maintaining the freedom of movement. Frankly speaking, even the design of the reactor foresaw flow-overs from the safety channels. Finally we had to use the boride steel without cooling.
Cooling system consisted of 24 riser pipes, located around of the reactors active zone. A special circuit was mounted for them. The inlet and outlet headers were mounted under the lower plate of the reactor. It was extremely difficult for the personnel to approach to this construction - neither to examine them nor to repair. At the same place, under the plate, u-bend connections of 24 riser pipes were situated. There were situations when the screws were simply cracking, as they were tightened manually, as strong as it was possible, because we didn't have dynamometers. Imagine the situation: screw cracks, pressure decreases, reflector is uncooled, graphite temperature in the reflector rises, temperature of the shell grows - how should we approach to that screw? After such an occurrence the weld seam on the vessel may have cracked, we have already discussed it.
The First NPP reactor had, probably, 200 different devices. All devices were lamp, amplifier construction contained paper capacitors produced in Armenia. Regularly they came out of work. The capacitor was disabled and it meant that the safety system was activated. And we had 128 of such channels. As a result we had 2-3 SCRAMs during a shift and up to 30 SCRAMs in a month.
Can you imagine one more thing for the better understanding? If operators couldn't define at once, that the alarm was false and dragged out with the analysis of the reasons of the safety system activation, we had to return to the power from zero. In other words, blindly, as galvanometers began perceiving a neutron flow not at once. For such situations we had a special procedure - lift the rod a little and wait, lift the rod a little bit more and wait again.
It didn't go without caprices of the first circuit system. The CN-6 gland pumps were mounted there first. The pressure was 100 atmospheres; graphite stuffing box was on the axle. How could we keep radioactive water inside in such circumstances? According to the project the system of a stuffing box tightening from outside was provided, from the outer side where were given 100.5 atmospheres and pure water was delivered to the circuit by the axle.
But this system appeared to be unreliable. It was implemented automatic, devices that maintain 0.5 atmosphere difference were mounted. We had a case when temperature drop was not maintained and hot water under pressure of 100 atmospheres and with the temperature of 190°C went out through the axle, the axle warmed up and choked. As a result the pump was blocked. And do you imagine what does the block of the pump, which pumps the water through the reactor means?
And again we managed to cope with this situation and changed the pumps on the naval ones. We had to cut the circuit for that. There we faced another problem - how to get out the old pumps from the boxes? We had to hollow the reinforced concrete wall that was half a meter thick. Soldiers were driven there and they hollowed the holes of the due size.
Everything seemed to be done. But not! Now we had to change the whole power supply system, because old pumps were using a direct current. It was done to use an accumulator in case of "Mosenergo" shutdown. But naval pumps, that we had received, were using alternating current. So we had to remake the whole "Leonardo system", including such things as accumulators recharging system.
And then our channels began to leak, "wet" incidents came, "dry" incidents, incidents when a rod was blocked in the channel. We have accumulated an enormous experience. Operators from other stations were coming and telling us that they hadn't managed to achieve a due capacity during a year. We were only smiling and offering them to train at our facility.
After 15 years of exploitation, to 1970 reactor was in such a bad state that we had to stop it or to make a complete overhaul.
A significant part of graphite in a graphite layer burned out. By the extraction of fuel channels graphite was crumbling, we had to clean the cells and broach them with the broach tool.
There were permanent leaks of fuel channels and safety channels in the reactor. Gas-filled atmosphere was explosive because of the possible formation of detonating mixture. There was no any constant control over hydrogen. There were a lot of leaks on the upper plate of the reactor on the outlet paths of the fuel channels in the places inaccessible for repair. Leaking standard paths were replaced by the bridges, that made the extraction of fuel channels by reactor overloads difficult, and it led to the personnel irradiating.
Wishing to prolong lifetime of the reactor we (me and a chief engineer V.B.Tregubov) decided to make a complete overhaul. Feasibility study was written and activity network was made. Ministry allowed to stop the reactor for 9 months and make these and other necessary activities, such as steam-generator and graphite layer repair to prolong a lifetime of the reactor on 10 years more.
Reactor was totally unloaded; it meant that all the 156 channels, including fuel, experimental and safety ones were extracted. All the risers and paths were also demounted. Graphite layer was partially repaired; outlet and inlet paths were changed. "Sphere-cone" connections in inaccessible for repair places were replaced by welding. All the extracted channels were examined in the hot cell, divided and moved to the special storage.
After this and other work, reactor was loaded with the new channels and launched. Everything we had done prolonged the lifetime of the reactor not on 10, but on 30 years. Complete overhaul was made in 1971 and was completed by the First NPP personnel without outside help.
One learns from one's mistakes?
At the time of constructing of the First NPP we had the following politics - most important was to be the first, and nobody was thinking about the future. Most important thing was to "crow" and after us a deluge!
The fate of the First NPP was defined this way. Facility has been launched, let it work for a campaign and that's all. Some people were speaking about two campaigns. These were hesitations- whether the NPP will last out three or six months with the help of the staff? So we were the first, reported about it, and then the facility was useless.
But Slavsky interfered in this case and said - we don't need the facility, but we need the reactor, as we can make researches and testings for the new generations of reactors on it.
So we have decided that there won't be a NPP in Obninsk, and its reactor would be turned into experimental one. Energy production hasn't been planed any more and we came into the disposal of science.
All next years we have been working for the Beloyarskaya NPP, for the Bilibinskaya NPP, for the navy, for space, for medicine, and helped to heat Obninsk - but we were not producing electricity. To 1970 turbine was demounted and utilized by the order of IPPE chief engineer.I have already mentioned that the First NPP gave us unique experience. But, unfortunately, I must confess, that our comrades managed to learn by our mistakes not at once. How were the people acting at that time? We had been having one problem after another on our NPP, but reports were: "The First NPP is safe, reliable and is working like Swiss watch."
As a result big brass had a false impression that the development of nuclear energy would be an easy task. And as you remember, it was decided to build the first stage development of Beloyarskaya NPP with AMB reactors. I am completely sure, that if constructors had a full information about the results of our work, they would refuse from AMB projecting and would start searching for another alternatives - and may be they wouldn't even build RBMK.
AMB reactors were like our one - also graphite, also channel-type. But our active zone was one meter seventy centimeters long and the active zone of Beloyarskaya NPP was six meters long, and the total length of the channel of Beloyarskaya NPP was twelfth meters. Only imagine such a "tunnel"! Graphite is swelling, fuel elements are cracking, serious exploitation problems appear.
At the first unit of Beloyarskaya NPP fuel assembly damages were occurring repeatedly. In the second block in 1977 nearly a half of fuel assemblies of the active zone melted. Blocks with AMB reactors were finally shutdown in 1983 and in 1990.
Frankly speaking, I was shocked when I saw the sizes of AMB channels for the first time. If an assembly was blocked in the channel, on the First NPP we extracted the blocked assembly applying a load of a ton. We knew, that by the load that is more than a ton an assembly rupture may occur, and the place of rupture was unpredictable. And it was not the case. Only imagine that we are extracting an active part from the reactor, and at that moment rupture occurs. What should we do, if it is impossible even to enter the hall? That is why when the fuel channel was blocked, extraction was stopped and it was extracted by piecemeal.
And now multiply our problems on the difference of scale between our and Beloyarsky reactors. They say that when on Beloyarskaya NPP channel was blocked they used drilling machines to extract swelled fuel elements! Everything turned into the mass, which was pumped out lately. To cut a long story shot, people had a hard time there.
And that idea about a steam nuclear overheating in a direct-flow scheme, when a channel was filled with water and an overheated steam was coming out? No matter how clean the water was, a solid residue of 3 mgr/l was allowed. So, in boiling and steam drying zone accumulation of salts begins. There were experiments with experimental channels - thermal couples were placed there and temperature was observed. Received results were very pessimistic. Temperature in fuel elements was slow and sure growing because of salts accumulating and heat exchange disorder. And it was a setting for the safety system activation!
Finally first two blocks on Beloyarskaya NPP were to be closed. And what was next? There were no any ideas, any offers or projects how to take them out of service. Now all the designers have to provide this closure stage in the project. There are even ideas of transferring some percents during the exploitation of the facility to the fund of its closure. At that time, on Beloyarskaya NPP we faced this situation for the first time, and simply didn't know what to do.
Personal opinion
My personal opinion about nuclear energy came through three stages during my life.At first I was a real patriot of nuclear industry. I was proud of participating in the creation process of the First NPP, of taking part in searching for the ways of peaceful application of nuclear energy. Were had been working without reckoning anything - neither hardships nor dangers.
We were working, we were proud and never grumbled. But then, when we were fed up with problems I began to realize that nuclear energy was not a gift. We had to decide what to do, at least, with uranium-graphite water-cooled reactors. The third period came after Chernobyl…
Our country is rich with natural resources - oil, gas, coal. There are technologies for heat stations harmful emissions reducing. More and more I am thinking over the question - do we have to build reckless in Russia new and new nuclear blocks? Especially, when we have neither projects, nor experience of reactors decommissioning, this operation will demand significant wastes.
I don't have a definite answer.
Thank you, Victor Sergeevich, for the interview for our AtomInfo.Ru web-edition.
SOURCE: AtomInfo.Ru
DATE: March 24, 2008
