Unit №6 of the Novovoronezh Nuclear Power Plant (NV NPP) has already become a part of the history of Russian nuclear construction thanks to its innovativeness. The seventh unit – a complete copy of the sixth one - is currently undergoing full-scale adjustment and startup procedures. But it is Unit №6 of the NV NPP that will forever remain the first of its kind.
For the most interesting facts about the Novovoronezh power plant unit read the following RIA “Voronezh” article.
1. The first of its generation
Today, 3+ generation power units are being built in the USA, France, and other countries. However, it is Unit №6 of the NV NPP that became the first third-generation nuclear power unit put in operational commission in the world. That happened in February of 2017.
A third-generation unit is primarily innovative technologies and improved technical and economic performance. The power unit corresponds to all post-Fukushima requirements including the combination of active and passive safety systems.
2. The first post-Soviet power unit built from scratch
In the 1990s, the country was going through hard times. It affected the nuclear field as well. Power Unit №6 of the NV NPP became the first one in Russian built from scratch and put into commission after the collapse of the USSR.
According to the criteria of the International Atomic Energy Agency (IAEA), the construction of Unit №6 of the NV NPP officially began on June 24 of 2007 when the first cubic meter of concrete had been poured.
3. The parent water-water energetic reactor
The Voronezh Region has a special role in the development of atoms for peace. It is the Novovoronezh NPP that became the first NPP in the Soviet Union with a water-water energetic reactor (WWER).
In total, the Novovoronezh site was used to build and put into commission six power units with WWERs. All the projects are parents ones. The serial construction of power units with WWERs began in the country only after the implementation of projects in Novovoronezh.
The power capacity of Unit №1 (already taken out of service) launched in 1964 is 210 MW. Each following unit was more powerful than its predecessor: the power capacity of the second one is 365 MW, of the third and the fourth – 440 MW, of the fifth – 1000 MW, of the sixth – 1200 MW.
4. A passive system in case of a blackout
Aside from traditional safety systems, the AES-2006 project used to build the sixth power unit of the NV NPP includes additional ones – passive systems operating without electric power or human interference, exclusively under the influence of natural factors.
Among such passive systems, in particular, is the Emergency Active Zone Cooling System (EAZCS): it consists of 12 gigantic reservoirs filled with aqueous solution of boron hydroxide. Their total volume is 1.2 thousand cubic meters. In case of an emergency, when the pressure in the first (next to the reactor) circuit drops below a certain level, the boron-containing water starts flowing in the reactor – without turning on additional systems or mechanisms. This stops the nuclear reaction.
One of the 12 water reservoirs of the EAZCS
Also, the new power unit has a Passive Afterheat Removal System (PARS) in case of a blackout. Even in case of absence of all power supply sources, the system provides long-lasting afterheat removal from the active zone of the reactor into the atmosphere – entirely due to natural circulation: the air (the cooler) gets drawn into the heat-exchanging units, gets heated and then returns to the atmosphere.
The assemblage of the dome part of the PARS
The PARS is a know-how of Russian design engineers. The Power Unit №6 became the first one in Russia equipped with this passive safety system.
5. A four-storey house trap
The so-called molten core catcher is another protection stage in case of an emergency. This is a structure with a diameter of 8 m and a height of 12 m (approximately 4 floors), located under the reactor and filled with special material. In the event of an emergency situation, the reactor vessel along with all the contents (the core meltdown) falls into this huge “pan”. The “trap” is capable of holding the melt, removing heat from it for an unlimited time and preventing the radioactive substances from entering the environment.
The “trap” is an invention of Russian scientists: it was first used in the construction of nuclear power plants in China and India.
6. The far swim of the heavyweight
Almost all the equipment to the Novovoronezh construction site was delivered by road and rail. A rare exception was the reactor vessel of power unit No. 6. Given the weight (about 330 tons) and the size of the cargo (the diameter is about 5 m, the length is more than 11), the transportation was possible only by water.
The heavyweight reactor covered 3.8 thousand km along the Neva, Ladoga and Onega lakes, the Volga-Baltic Canal, the Volga, and the Don. The reactor vessel for power unit No. 7 of the NV NPP was delivered in the same way.
7. The “top” cooling tower
A cooling tower is a structure intended for cooling water. One cooling tower instead of two per power unit was erected at the Novovoronezh site, as it was at domestic NPPs earlier. Therefore, it is significantly higher – 171.5 m (approximately a 57-storey building). The Novovoronezh cooling tower is the highest in Russia. It is also one of the tallest buildings in the Voronezh Region. For comparison: the height of the Voronezh TV tower is about 200 m, the Chizhov Gallery tower is 100 m, Serdtse Goroda Residential Development is 97.5 m, and the Blagoveshchensk Cathedral is 97 m.
In total, the construction of the cooling tower, which diameter at the base reaches about 130 m, took more than 10 thousand cubic meters of concrete.
The special marking in the form of red “checker patterns” on the cooling tower of power unit No. 6, which was made by industrial climbers, is a signal for aircrafts. According to the Guidelines for the Operation of Civil Airfields of the Russian Federation, the cooling tower as a high obstacle must have air navigation.
8. The largest “windage”
In December 2013, a unique operation took place at the NV NPP construction site: the largest structure of all that was installed on the building of the reactor of power unit No. 6 – the second tier of the outer containment dome – was raised at the 60-meter height. The object is of huge windage. This is a giant-sized metal ring: the height is of a two-story house, the bottom diameter is 46.25 m, the top one is 34.5 m, and the weight is about 180 tons.
The new power units of the NV NPP have a double (inner and outer) reactor containment dome, i.e. a double wall and a double dome, which protect the first contour from external natural and man-made impacts, including earthquakes, hurricanes, plane crashes.
9. The center of foreign attraction
The Novovoronezh NPP was the first among the Russian nuclear power plants where the International Personnel Training Center was established. Thus, the NV NPP today is not just an enterprise producing electricity and heat, but also a full-fledged participant in the international atomic education market.
The center is equipped with laboratories and computer classes, workshops and conference rooms. It has a full-scale simulator, a complex software and hardware complex, equipped with unit control centers of power units No. 6 and No. 7 of the NV NPP and simulating all the NPP operation modes.
Since the opening of the center in 2016, 327 students and 273 specialists from Egypt, Bangladesh, Vietnam, Turkey, and Belarus have been trained here in the “atomic craft”.
10. The first All-Russian Student Construction Project “Peaceful Atom”
In the summer of 2014, the All-Russian student construction project took place in the Voronezh Region, the first in the Central Federal District. It also became the first All-Russian sectoral student construction project “Peaceful Atom”. 350 students from seven regions of Russia: the Voronezh Region, Moscow, St. Petersburg, Udmurtia, the Perm and Altai territories, the Sverdlovsk, the Rostov and the Kaluga regions helped the professional builders and assemblers to erects the unit. The guys worked as painters, plasterers, assemblers, helped to lay pipes and ventilation, to equip the territory.It should be noted that the construction teams worked on the construction of the new units of the NV NPP both before and after the All-Russian Construction Project – from 2011 to 2018.