On the questions of AtomInfo.Ru web-edition answers the adviser of the IPPE General Director, Chief research worker, doctor of science, professor Georgy Ilyich Toshinsky. By the IPPE order Georgy Ilyich was appointed a research manager of the SVBR-100 facility project.
Georgy Ilyich, please, tell us briefly about the current state of the SVBR-100 technology.
First of all it is important to stress that lead-bismuth technology was initially created and applied at the Soviet naval reactors - it is the project 705 (or the "Alfa" seria).
At first we didn't have necessary knowledge and experience. Naturally we faced a series of difficulties and failures at that stage. They were overcome thanks to the persistent work of a lot of organizations, first of all IPPE and OKB "Gidropress". At serial submarines reactors were working successfully, though, certainly, experience of work with the naval reactors was not so huge as that of the NPPs operation.
At the same time "Rosatom" scientific-technical counsel has recognized this technology as prepared for the demonstration and included into the federal program for its realization at the pilot unit with SVBR-100 reactor.
Please, name the main advantages of SVBR-100.
The main advantage of this technology is modularity, that allows creating of power generating units of different capacity divisible by 100 MWe (el.) on the base of a uniformed reactor module that is implemented on the machine-building plant and completely finished is delivered by railway or other transport to the NPP site. It allows using of progressive methods of mass line building and reduces significantly the investment cycle of NPP constructing.
Certain advantages of this technology is given by the natural qualities of the lead-bismuth coolant, thanks to those coolant is in the reactor under low, completely atmospheric, pressure above its free level (reduction note: water coolant is within the reactor under the pressure of 160 atmospheres).
So there are big advantages from the point of view of the safety. Construction of the reactor excludes the heaviest incidents, connected with the coolant loss.
Besides, this coolant is chemically inert. He reacts weak with water and air, that is why there is no threat of fire and explosions. As an exploiting experience has shown lead-bismuth reactor can work even by the insignificant leaks in steam-generators, that is impossible at the units of the reactors of the other types.
And from the point of view of economy?
Price of the coolant in the total price of the NPP with the SVBR reactor has a small share and practically doesn't influence it. It is not spent. A single loading of the reactor with the coolant is for the whole lifetime of the reactor - 50-60 years.
Are there enough bismuth stores in Russia for the possible commercial program of SVBR construction?
Before "Rosatom" gave an approval to examine these proposals, specialized organizations such as "Atomredmetzoloto" and VNIPI "Promtechnologii", that are engaged in bowels exploring have made necessary researches and determined that Russian Federation is one of the richest on bismuth countries in the world. Only explored deposits in Chita region are enough to launch 70 GWe (el.) of lead-bismuth reactors.
It is impossible to avoid a question of polonium. It is a well known fact, that by the lead neutron irradiation 210Po isotope with the half-life cycle of 138.4 days is formed. Would it be dangerous for the NPP personnel?
Polonium is not the main factor of radiation danger. Its share in the total radioactivity, contained within the reactor, is not big. Alfa-flow of polonium is not penetrative and can be stopped by the very thin layers of material. Though as any other radioactive element, it is certainly dangerous and demands a proper treatment, knowledge, following the precautions that prevent polonium penetrating within the body. All these was elaborated and applied at naval reactors and at prototype stands.
All the civil and military personnel that was working with lead-bismuth technologies was tested on the inner polonium irradiation. This activity showed, that no one - including those, who took part in coolant leaks eliminating - didn't receive a dose of the inner irradiation, exceeding the allowable. It proves the correctness and reliability of the system of precautions.
Completely there is no any leak possibility at SVBR, as this facility will contain only one unit and there won't be tubes with the coolant. By the way, a lead-bismuth feature to harden by the temperature lower than 125°C in certain situations appeared to be rather useful. Leaked coolant was hardening and didn't leak on a large area as water.
What role can SVBR reactors play in the Russian nuclear industry?
Peculiarity of SVBR-100 reactor is its low capacity. It is 100 MWe (el.) that satisfies the electricity demands of the city with the population about hundred thousand people. Many regions of the world and Russia need the energy sources of the low and middle capacity. If we look at the common structure of the whole energy sector - not only small - we will see, that about 70% of energy is produced by the stations with the capacity less than 400 MWe. This part of the nuclear energy market is not closed for today.
One more important question appears in the situation when it is necessary to produce not only electricity, but also heat energy. In this case energy sources should be placed near the towns that will cause increasing of safety demands. In this sector (nuclear heat-electric generating plants) SVBR has good chances for the success. So I would say that the first task of SVBR is a regional and a small energy.
And historically first explored possibility of SVBR using was a renovation of VVER-440 reactor units. Renovation means here placing within the power generating unit building, whose lifetime is over, a necessary amount of SVBR reactor facilities in the room where earlier pumps and steam generators were placed. As a Moscow "Atomenergoproyect" has states, such renovation was technically possible where all the technical-economical researches were implemented. All the other NPP infrastructure will be used without any significant changes. By this approach we have a great economizing.
I will also specify, that for VVER-440 renovation was created a project SVBR-75.
Thank you for the interview for the AtomInfo.Ru web-edition.
DATE: August 02, 2008
Topics: NPP, Fast breeders, Lead-Bismuth, Russia