What is the peaceful nuclear energy, and what place does it take in the nuclear industry? What type of the reactor will be sufficient for the floating nuclear power plants in Yakutia? Is there any prospective for the good old pool-type reactors? Answers to these and other questions of AtomInfo.Ru web-edition has given Yuriy Dmitrievich Baranaev, head of the IPPE laboratory of the small nuclear energy.

What is hiding behind this definition?

First of all let us come to an agreement about definitions - what do we understand under small nuclear energy? According IAEA gradation, low-capacity reactors are facilities with the capacity less than 300 MWe.

I should say that this gradation is used in the energetics that is working for the network, but not for the autonomous consumer. Some states, which don't have powerful energy systems, and don't have financial resources or experience, are obliged to start with low-capacity generating units. But nevertheless, their final aim - competitive large-scale energy producing. Use of the low-capacity facilities is the initial stage on the way to this goal.

Small nuclear energy, generally, and small energy in Russia are traditionally close to the notion of autonomous energy sources. In this area there is no need of high-capacity units, because we deal either with autonomous consumers, or with the small net. 300 MWe for such objectives is, strictly speaking, excessive efficiency. That is why I would like to emphasize, that in our dialog the upper limit of small nuclear energy is within the limits 50-100 MWe.

I should specify that there is no any official definition to the small nuclear energy. There is a kind of a compromise between the specialists that I have already mentioned - small nuclear energy in our country is oriented to the power supplying of autonomous isolated consumers in the regions with expensive organic fuel.

There is one exclusion I would like to mention - even in the regions with centralized power supplying existence of small nuclear energy is possible, but in this case its role should come to heating. Heat resources are trivially local, as it is impossible to transfer heat on big distances. So appears one more niche for small nuclear power sources.

Origins of small nuclear energy - TES-3, ARBUS and Bilibinskaya NTPP

Small nuclear energy had started with the American program in fifties-sixties. Americans tried to use reactors of different types to solve the problem of power supplying to the defense objects. Capacity of such facilities was not more than 40 Mwe. Within the frameworks of this program was created a well-known floating NPP "MN-A1 Sturgis" that was based in the Panama channel area.

In our country work over the creation of small nuclear energy objects had been also done. First reactor of this type was TES-3 facility. It was a transportable NPP, based on 4 off-road vehicles. It was build and launched in IPPE in record time. It was a small station producing only 1.5 MWe, with water-water tank reactor. It was planned that TES-3 would be presented during the second Genevese conference to demonstrate the power of our state and achievements of the nuclear industry.

TES-3 first criticality took place at 7 June 1961.
TES-3 start-up occurred at 13 October 1961.
Operation of the transportable station continued till 1965.

Approximately at the same time in Dimitrovgrad appeared "ARBUS" facility (Arctic reactor unit-type facility) with reactor with organic fuel (gas-oil). This direction was developing actively, there were even plans to build an industrial facility, but problems with organic coolant appeared to be so serious, that finally the development of this technology was stopped.

TES-3 and ARBUS - are well-known examples of realized low-capacity nuclear facilities projects. But I would like to stress, that a single operating industrial facility of small nuclear energy in the world is Bilibinskaya NTPP in Chukotka. Four blocks of this nuclear heat and power plant can produce up to 48 MWe for the power supply system and are stable supplying heat to Bilibino. Facility has been working for 30 years already and recently the justification of its exploitation prolonging for the next 10 years has been finished. Bilibinskaya NPP - is an IPPE creation.

The first floating NPP could be different

After TES-3 serious forces were applied to use water-water tank reactors in small nuclear energy. A series of small reactor facility projects for NPPs of different purposes - for the military, for geologists and other potential consumers were designed. There was an interest to this direction, but it didn't go further than a designing stage.

Most advanced appeared to be the projects of low-capacity NPPs (ASMM) with ABV-type reactors (Nuclear Tank Water Reactor). IPPE had a direct relation to ABV reactor and was a research manager of the project. Main ABV peculiarity was an integral construction: there was a core and a steam generator within the vessel of the reactor. It reduces radioactive circuits branching and gives a possibility to refuse from the circulating pump and to provide the work of the reactor at full capacity by the natural coolant circulation within the reactor vessel. Rather attractive alternative from economical and safety points of view.

Work at ASMM with ABV reactors moved rather far at that time. In early sixties under IPPE scientific management Russian-Hungarian NPP project "Sever-2" with two ABV-1.5 reactors was developed. In 1994 a project of the floating NPP "Vonolom-3" with two ABV-6 reactors was finished. Design manager of the reactor facility was one of the strongest designing offices - I.I.Africantov OKBM. Technical project of this facility was elaborated by the shipbuilding office in St.Petersburg "Baltsudproekt".

Being rather simple ABV reactor is an innovative one. It has been spoken a lot about integral design, but nevertheless no integral water-water reactors had been created! Designing work hadn't been stopped till the end of the previous century and is being carried out nowadays in different countries including Russia. International consortium of reactor producing companies with "Westinghouse" participation is trying to create its own integral project - it is a low-capacity facility IRIS. There is a significant progress in this direction in Argentina (CAREM reactor, 25 MWe capacity and in Republic of Korea (SMART reactor, 100 Mwe capacity). Last researches are obviously focused on the market of developing countries.

Fate of the floating NPP "Volnolom-3" appeared to be not so enviable. Baltic factory in St.Petersburg was ready to accept the order, but the customer stopped financing, and construction of the floating NPP had to be postponed. Finally, Rosatom management which realized FNPPs availability for Russia decided to bet by the development of this direction on the loop monoblock reactor KLT-40 which had been widely used in the maritime transport energy. Motivation was simple - there are operating prototypes of these reactors, manufacturing capabilities and cooperation between organizations. It was reasonable to rely on this powerful backlog by creating a floating nuclear facility.

Certainly, transition from the reactor - "propulsor" to the power generating facility always demands changes in the construction of the facility. As a result of KLT-40 modifications a stationary version of KLT-40 and a project of a floating power generating unit (PEB) with this reactor were created.

KLT-40 program is successfully, but not without difficulties moving forward. Nowadays, as you know, the first floating NTPP in Severodvinsk is under construction. Launch of the facility is planned in 2010.

Frankly speaking we were not particularly enthusiastic about the refusal of the idea of creating "Volnolom-3" floating NPP: we have had rather convincible arguments. In due time IPPE was managing elaboration of a state program on a large-scale ASMM introduction in remote isolated regions. This work was led directly by now late Yuriy Anatolievich Sergeev, Honored power engineer of Russia, who had started his career from the post of a deputy scientific manager of TES-3 project.

He initiated analytical researches of low-capacity nuclear generating units market, was an organizer and a participant of several expeditions to the remote Northern and North-Eastern regions. There was elaborated a program specifying about 100 locations for the possible small NPPs stationing. Later on this amount was reduced to 30 and this program was endorsed by Gosplan of USSR in sixties. Several NPPs with different reactor facilities, including ABV were mentioned there.

As a result it was found out, that for the large-scale ASMM introduction it was necessary to promote low-capacity facilities. For ABV-6 reactor with thermal capacity of 38 MWe which provided 6 MWe of electricity and 12 giga-calories per hour of heat there were tens of potential places for constructing. Floating NPP with two KLT-40C reactors that is being built gives up to 70 MWe of electricity and up to 70 giga-calories per hour of heat. It appeared to be not so easy to find places where demands of local electricity consumers were so significant.

Here appears a collision. The lower is the capacity, the more expensive is the energy and heat producing. And on the other side the lower is the capacity the larger is the market. And it is very difficult to find the optimum.

Mainstream production - is one more positive factor for any technology, but as for the floating nuclear facilities one more circumstance should be taken into account. The matter is that the design demands factory maintenance of the facility in 12 years. Delivery of the facility to the shipbuilding enterprise, its servicing and returning of it takes more than a year. Arises a question - what will consumers do during these two years? In a due time the following scheme for the FNPP with KLT-40C was proposed - six locations for the facilities which should be built with a 2 years interval should be defined and the last seventh one should be built as a replacement of the first one. And then the process goes cyclically. But these six locations are not so easy to find.

There are not so many places in Russia were it is possible to send a 70 MWe floating NPP. We have to think about foreign consumers, but it is extremely important to convince them at first, that this nuclear technology is mastered and works reliably in Russia.

The history of the floating NPP with ABV-6 reactors has had a reassuring continuation in 2007. Rosatom leader Sergey Kirienko and President of Sakha (Yakutya) Vyacheslav Shtirov signed an agreement on cooperation with an objective to realize investment projects of building FNPPs for electricity supplying in several northern regions simultaneously. These facilities should be built on the base of ABV-6M reactors, and should be stationed along the river banks.

Correspondent arrangements have been already issued, works on ABV-6 are being resumed, and we hope to take part in this program.

If this program of building 6 generating units is realized, I believe that demand for the floating NPPs will increase immediately. But still nowadays many consumers are considering FNPP as an exotic one, but as soon as it will turn into the reality, consumers not only in Russia, but also abroad will appear.

RUTA - a nuclear stove

I would like to touch upon one more direction in the small nuclear energy - using small nuclear energy sources for heat supplying. This direction as I have already said has its niche even in the regions of central power supplying.

What should a nuclear facility for heating be like? Any nuclear power source anyway is very expensive. If we compete with heat stations and boiler houses on organic fuel, we should propose a nuclear facility, that shouldn't be very expensive, but will stay rather reliable and secure. One of the decisions is a radical decrease of temperature and pressure within the reactor till the minimum level, which will allow maintaining only one consumer characteristics - heat producing with parameters, acceptable for the domestic heating.

IPPE in recent years promotes the idea of using RUTA reactors for heating. These facilities are based on the principals of a common pool-type reactor. Analogs of such reactors are widely used for research purposes and are built in many large cities.

RUTA chief designer is NIKIET, which has a large experience in constructing of pool-type research reactors. Adopting a pool-type constriction we consciously exclude the possibility of high pressure in the first circuit and of increasing outlet coolant temperature higher than 100°C. In most cases it is enough for heating. On the other hand, lack of pressure is the main factor of increasing the safety of the facility. In western countries they use a notion, that I like very much and it suits the reactor RUTA: "Transparent safety" or "transparent, obvious safety". And it is really obvious, that a simple pan looks safer, than a pressure cooker that has a high pressure inside!

In conditions of Russia RUTA-type facility could find a broad application. It was proved by the results of the potential market researches, carried out with the participation of the designing institute SantechNIIproekt of the Rosstroy state agency. And as usual, a demonstration sample is needed for the large-scale introduction. It is necessary to show, that the technology works, that the way from sketches to "hardware" is gone through, and it is possible to use it widely. Housing and communal services that are responsible in Russia for energy supplying are looking at RUTA with interest, but they need an operating sample.

We offer to build such a demonstration facility RUTA in Obninsk. Unfortunately, this idea has not found a financial support. May be time has not come yet. Technicoeconomic report on stationing RUTA in Obninsk on the IPPE site, elaborated in 2004 with the participation of AEP and NIKIET showed competitiveness of this project by existing at that time in Obninsk tariffs for heat. From that time tariffs increased more then twice, having made RUTA recoupment quicker. If we take into consideration that gas-prices are increasing it becomes obvious that RUTA is rather economically attractive. Though, the first demonstration facility is impossible only on commercial terms, and state financing will be of great help here.

RUTA reactor can be used not only within the country, but be supplied abroad. It meets all the demands, including low fuel enrichment. Though there were no any exportation potential research of the facility, foreign buyers will appear. In particular, this facility can be used effectively for the sea water distillatory desalination in water-scarce regions of North Africa, South Africa, South-East Asia. Technical elaborations on the possibility of such an application are available.

By the way, the idea of using pool-type reactors for heating came from Canada - country with a climate like in Russia. In seventies they offered a modification of the SLOWPOKE project that was used for remote regions heating they were even negotiating with potential buyers about the deliveries of such facilities. But by different reasons the deal failed. Main reason was the absence of full-scale reference facility.

SLOWPOKE reactor - is a low-capacity pool-type reactor, its project was elaborated by the royal corporation AECL at the end of sixties. Reflector - beryllium, fuel - uranium of weapon enrichment.There are some SLOWPOKE modifications, and there are foreign clones, including Chinese ones, that were used on different purposes, for example as a neutron source. Model SLOWPOKE - 3 with the capacity from 2 to 10 MWe (heat) was oriented on remote Canadian regions heating, but it didn't enter the market.

Official decoding of the abbreviation SLOWPOKE is Safe LOW - Power Kritical Experiment. Mistake in the word "critical" was made by the authors intentionally.

China has its own researches of pool-type heating reactors. As you can see interest to this direction exists all over the world. It is time for us to stop promoting and start creating a technical project of RUTA. Certain inspiration gives the fact that at the last scientific technical council of Rosatom on regional and small energy RUTA was named among the projects that were to be elaborated.

Interest to the small nuclear energy in the world changes wave-like, growths are replaced by declines. But I have to remind, that Russia has a special situation. We have an enormous territory in remote regions in the zone of decentralized energy supplying. If we want to make these territories comfortable, we should think over the way of providing heat and electricity for them.

We will have to solve these problems may be not today, but tomorrow or the day after tomorrow, anyway we will do have to solve them. Small nuclear energy will surely be called for in this case.

SOURCE: AtomInfo.Ru

DATE: May 04, 2008

Topics: NPP, Russia, Floating NPP