Atom Expo 2107: Nuclear conference and exhibition

August 10th, 2017, Published in Articles: Energize

 

The Atom Expo 2107 exhibition and conference was held in Moscow from 19 to 22 June 2017. Covering mainly the nuclear power plant (NPP) industry, the function was attended by 6000 delegates from over 60 countries. The conference consisted of some 20 main sessions covering a variety of topics, spread over three days. The conference was accompanied by an extensive exhibition by suppliers of NPP and associated industries. This article summarises the main topics presented, events and impressions gained at the event.

In addition to the formal conference, there were numerous technical presentations given in the exhibition area as well as press briefings. The conference session speakers used Russian mainly, and simultaneous translation was adequate but sometimes difficult to follow.  Although international in nature, attendance seemed to be mainly from central European, Middle Eastern, Far Eastern and African countries.

Fig. 1: The conference centre at Gostiny Dvor, Moscow.

 

Main theme: Is nuclear energy a thing of the past?

Nuclear energy: the energy of the future or a relic of the past” was a question posed during the conference. If one considers the pressure placed on the nuclear power industry in terms of cost, stringent safety regulations, competition from other technologies, public resistance and other factors, one could be justified in believing that nuclear energy is a dinosaur that belongs in the past, and that the hoped-for nuclear renaissance of the recent era has fizzled out, the industry is in its death throes, and will soon disappear into history.

However, the information provided by speakers at the various sessions of the congress, as well as the numerous exhibitors of nuclear power systems, components manufacturers and other services, painted a different picture, and served to nudge the answer in the direction of the former rather than the latter part of the question. Although nuclear may be going through what seems to be the doldrums at the moment, it is far from being a relic. If one takes developments into account, existing systems may well be considered relics of the past in years to come, but future systems offer many advantages and have the ability to meet most of the requirements for new energy sources, giving the industry a positive outlook.

The nuclear power industry seems to be caught in a state of transition. The next generation of NPPs, high temperature generation 4 reactors, is at least a decade away from large scale commercialisation, small modular reactors show more promise but are still several years away. Upgraded versions of the Gen 3 NPPs, Gen 3+, although offering improved performance and safety, are experiencing delays in construction due to technical problems, changing safety rules, costs, legislation and other issues. Plans for re-use of spent fuel are all dependant on development of next generation plant, and dealing with spent fuel remains an issue.

In spite of this there are ambitious nuclear build programs in several countries, with China and India leading the field. Unlikely countries such as those in the middle east, which have adequate solar and fossil fuel resources, are also considering NPP for thermal based applications. In fact there appears to be far more interest in nuclear power in central Europe, the middle and Far East and Africa, than in Western countries.

Nuclear power is seen as a promising solution to the problems of climate change as it is a non weather- dependant non-carbon source. NPPs do not occupy huge tracts of land and are not harmful to the local flora and fauna. The long life of NPPs also ensures minimal ongoing disruption of the landscape. NPPs offer a viable stable and reliable alternative to fossil fuelled plant, are independent of variations in fossil fuel prices, and for these reasons are being seriously considered as a component of a carbon free generation portfolio by many countries.

Fig. 2: The plenary session.

 

Current hurdles faced by nuclear power plant

Cost of nuclear new build

The build cost of nuclear is often quoted as an impediment to the use of NPP in the energy mix. Current build cost is affected by a number of factors :

  • Increased safety regulations- the Fukushima incident sparked a flurry of new safety regulations designed to improve the safety of NPP. Incorporation of these safety issues has increased costs of the first built NPP, but should reduce with volumes. The adoption of extreme safety requirements has made the cost of NPPs uncompetitive in some countries.
  • Development costs-one speaker claimed that 50% of the cost of a new NPP is development costs. Production of standard versions should reduce the contribution of development costs to unit costs.

Construction times.

Delays experienced with first of a kind Gen3+ reactors are often quoted as problem areas typical of NPP construction. Once issues are overcome standard plant should take less time to construct.

Waste and spent fuel management

This is an ongoing issue which should be resolved in future with the closed fuel cycle

Public acceptance

Nuclear energy is under a constant barrage of negative publicity from anti-nuclear organisations and professional activists. The industry needs to take steps to aggressively counter this.

legislation and licensing

Current legislation differs from country to country. The licensing process can be lengthy and complicated in some countries.

Developments in NPP

Increased lifetime

The current generation of NPPs has an expected lifetime of 30-40 years. This is determined by the core containment vessel lifetime, as this is seen as a component which cannot be replaced. The lifetime of the unit is limited by embrittlement caused by thermal and neutron irradiation. Research has solved the problem of embrittlement and life times of 60 years with a possible extension to 100 years are now being quoted.

Closed fuel cycle

The closed nuclear fuel cycle (CNFC) involves recycling spent fuel from reactor to form new useable fuel. The process is expensive and difficult with conventional slow breeder reactors, and is not used very much. The picture changes with fast neutron reactors, which are able to use spent fuel in repetitive cycles, consuming a large amount of the fuel, and producing a much lower level of actinides in the process.

An innovative approach is the two component system, which makes use of thermal (PWR) and fast neutron reactors (FBRs) in an interactive manner. The thermal plant would run on mixed oxide (MOX)fuel and produce spent fuel which would be processed and used as fuel for the FBR. Spent fuel from the FBR would be reprocessed into MOX for the PWR. In addition, fast reactors “burn” minor actinides which are the major contributors to an overburdened radioactive wastes handling system in a long-term perspective.

An advantage of this system is that existing stocks of spent nuclear fuel could be used up, reducing the need for new uranium mining, and the final waste product, containing short life fission products, would be considerably reduced .

Gen 4 reactors

Gen 4 reactors are intended to replace the existing Gen 3 models in future, and offer higher efficiency, less waste production and more flexible operation. Most proposed Gen 4 reactors are of the fast neutron type, or fast breeder reactors. All are high temperature types and are at different stages of development .

Rosatom has operated a series of high temperature fast breeder reactors since the 1980, the latest of which is the BN 800 and the BN 1200. The BN 800 is delivering power to the grid, while the BN1200 is still in design stage. The reactors uses liquid sodium as a coolant, and fuel is a mixture of uranium and plutonium, and is designed to be used with a “closed fuel cycle.”

The atomic battery

At the μW scale of the market was the nuclear battery demonstrated at one of the stands. This small device uses a combination of radioactive material and photovoltaic cells (radiation PV ?) to produce a very low power electrical source. The battery has a lifetime of 20 years and is expected to find application in such areas as pacemakers and other medical implant devices.

Fig. 3: The nuclear battery.

 

Nuclear waste and spent fuel disposal

Many countries adopting a wait and see attitude as regards spent fuel, and SNF is stored on site rather than being buried. The future holds the possibility of re-use of spent fuel, possibly in a two component system.

Safety of nuclear power plant

Although the Fukushima incident was a unique occurrence, it has resulted in more stringent safety requirements for all NPPs. The current political situation and climatic and geological instability demand that safety systems must be designed to guard against both human abuse and natural disaster. The latest approach is based on mitigating what are known as “beyond design basis events” or BDBE. BDBE are accident sequences that are possible but were not fully considered in the design process because they were judged to be too unlikely. In that sense, they are considered beyond the scope of design-basis accidents that a nuclear facility must be designed and built to withstand. As the regulatory process strives to be as thorough as possible, “beyond design-basis” accident sequences are analysed to fully understand the capability of a design.

It may not be possible to incorporate BDBE prevention in the design of the NPP, but it may well be possible to formulate mitigation actions for such events. Referring to Fukushima, the use of mobile power generators may have enabled the plant to be kept in a stable state. NPPs such as the Beloyarsk  BN 600 have provided both mobile power units and mobile pumping units on site to handle DBBEs.

All of the known major nuclear incidents were related to core meltdown due to overheating, and most of the NPP safety focus today is related to the reactor core. Modern designs are aimed at preventing core overheating and meltdown, or containment of core material after meltdown in the case of disastrous failure. Many new designs incorporate passive as well as active safety systems. This is not to say that safety of other plant is neglected, but such systems are well developed and proven.

Environmental safety in the nuclear industry

Legacy issues remain a problem

Some nuclear plant and fuel production sites from many years ago remain a problem as waste disposal was not handled properly and contamination of water and soil resulted. Particular reference was made to Mayak, a nuclear fuel processing site from the cold war era, where nuclear waste was dumped directly in the rivers and lakes. The community had to be moved from one site, because of high radiation levels. Other sites in the Antarctic are also problematic.  A clean-up operation of legacy sites is being undertaken, but serious radiation levels still remain.

Current concerns are focused on accidental discharge of radioactive material during fuel processing, refuelling, transport of fuel and storage of spent fuel. Radioactive waste disposal is a well developed and well controlled process, with most sites consisting of deep geological repositories. The process adopted with radioactive waste management is ALARA or “as low as reasonably achievable.” It means making every reasonable effort to maintain exposures to ionizing radiation as far below the dose limits as practical, consistent with the purpose for which the licensed activity is undertaken. Another approach is that of radiation equivalence which means that the level of radiation of the waste would eventually fall to that consistent with the natural level of the material when in the ground.

3-D printing impact on NPPs

3-D printing has advanced from a laboratory novelty to a system that can produce high precision components from virtually any manufacturing material. The use of this technology for producing components of nuclear grade required in NPPs is being considered. While the kind of 3D printers available on the high street print using plastics or resins, in industry the techniques are far more advanced, using lasers to melt powdered metal and ceramics into ultra-thin layers which are built up to create finished products. 3D printing is good at producing complex shapes and allows designs that cannot be accomplished using conventional manufacturing techniques. Although not used in the NPP industry at the moment, several manufacturers such as Rosatom, who are using 3D printing in their non-nuclear business, are developing the process of 3-D printing of NPP components. Siemens Germany have 3D printed a replacement part for Krško nuclear power plant in Slovenia. This is a metallic, 108mm diameter impeller for a fire protection pump that is in constant rotating operation. 3D printing could allow the manufacture of standard components at any location, including on-site at the NPP.

Digital IT and nuclear

The power generation sector is moving from analogue controls to digital control and monitoring systems, and several major companies have purpose designed digital control and monitoring systems available. Most though are designed for thermal power coal fired stations. There is a development towards digital controls for NPP and the newer stations coming on line and in construction are using digital systems. The challenge is in converting older nuclear plant to digital, which must sometimes be done on an add-hoc basis for each station, as some older analogue sensors cannot be simply replaced and must be interfaced via a/d converters.

Conversion of non-safety related I&C systems to digital operation is taking place on older NPP, but the critical systems remain analogue in nature. In general, use of digital communication systems in NPPs lags considerably behind that in non-nuclear systems due to the stringent requirements these systems have to comply with to be acceptable for NPP applications. Gen III and III+ plants are expected to bridge this gap somewhat with their extensive application of digital I&C.

I&C architectures in new plants will make extensive use of digital communication, both between safety systems and between non-safety- and safety-related systems. One of the more significant regulatory implications here is maintaining not only physical and electrical independence but also data independence between safety and non-safety systems, thereby guaranteeing that a transmission error in one channel or division will not cause the failure of another channel or division.

The most serious problem facing digital I&C is that if cyber-security. The possibility of hacking into a NPP control systems and disrupting operation or causing a nuclear incident must be a tempting vision to extremists and terror groups, and making the systems invader proof are perhaps restricting the use of digital or public communication networks .

South African NPP developments

There are two projects running in South Africa with the aim of developing HTGC reactors based on the pebble bed design abandoned in 2010.

The Eskom/NWU pebble bed NPP

This unit is under development by a team at NWU and other universities, funded by Eskom. According to Dr. Anthonie Cilliers, who was a delegate at the conference, the design process is well underway and licensing process could begin as early as 2018. Licensing is expected to be complete within three years, after which construction of a demonstration unit will be undertaken at Pelindaba outside Pretoria. “Although the licensing will be for a demonstration unit, it could cover commercial production as well”, said Cilliers. The NPP will be a helium gas cooled pebble bed design, with a single pass through cycle. The helium gas drives a turbine directly, and the unit also makes use of a post turbine heat exchanger based on molten salt, which will allow storage of heat and use of heat for non-power generating processes. Heat storage instead of direct use will also allow generator load-following to be implemented outside of the reactor.

 

Fig. 4: Dr. Antonie Celliers speaking at the conference.

 

The Steenkampskraal thorium limited ( STL) pebble bed reactor

When the pebble-bed reactor program was shut down, development of the principle, based on thorium as a fuel, was continued by a company financed by a consortium of private investors. According to a representative of the company, they have designs for several sized plants up to 300 MWth capacity, and are preparing to begin the licencing process. The company has acquired a thorium mine in South Africa, and thorium based fuel pebbles have been successfully tested in a full operational cycle at Thor energy in Norway.

Social upliftment and NPP

As with most other new electricity generating plant, social upliftment of the community in the vicinity of the NPP is part of the program. Novovoreneska was quoted as an example. Because of the high tech nature of NPP compared with other generators, higher levels of training and education are required from staff, and this generally results in an increased level of education in the area.

Exhibition

The exhibition featured both major companies involved in the construction of NPP such as Rosatom ,AREVA, Korea, and many others, but also the numerous suppliers of parts and ancillary equipment for NPP. In keeping with the location, companies featured enormous stands,  and included actual components such as the fuel rod assemblies ( minus the fuel) , models of NPPs, numerous video presentations, and the usual load of pamphlets, many of which were only in Russian

Fig. 5: The exhibition.

 

It is a pity that an exhibition with the same features could not be mounted in South Africa. There are nuclear conferences in SA but the amount of equipment on display is limited. Having access to actually see what an NPP consists of and watching the numerous videos and virtual webcasts at many of the stalls would dispel a lot of the misunderstanding and mistrust that exists about nuclear power in this country.

Signing of agreements with African countries. (Nuclear renaissance in Africa?)

During the conference, agreements were signed between the Russian state nuclear company and four African countries. The agreements ranged from co-operation on the development of nuclear science to planning or investigation of the possibilities of constructing nuclear power. The interest shown by Africa in nuclear is interesting, as many of these countries such as Uganda and Ethiopia, have adequate hydro resources. This reinforces the need in developing countries for a reliable life source of power which is not weather dependant. Agreements signed between the countries concerned and various government departments and enterprises were as follows:

  • Uganda: Co-operation in the sphere of uses of atomic power for peaceful purposes
  • Ethiopia: Co-operation in the sphere of uses of atomic power for peaceful purposes; co-operation in the sphere of training of specialists in atomic energy.
  • Sudan: Co-operation in the sphere of uses of atomic power for peaceful purposes.
  • Zambia: Contract for assessment and development of nuclear infrastructure for  Zambia; contract for the preliminary site survey for the centre of nuclear science and technology in Zambia; agreement for construction of the centre of nuclear science and technology; pre-feasibility studies and feasibility studies for a nuclear power plant in Zambia.

It would appear that Zambia is seriously considering the construction of a nuclear power plant .

Kenya was not included in the signings but a presentation by Thuo Njoroge Daniel, resident analyst for GBS Africa, indicated that Kenya was a leader amongst the east African countries as far as preparedness for nuclear was concerned. Nuclear policy and legislation is in place. Nuclear power is seen as a strong option for the provision of reliable cheap energy to east Africa.

Fig. 6: Thuo Njoroge Daniel (GBS) speaking at the conference.

 

East Africa has made had made discoveries of several resources recently, and the official policy is that beneficiation of these resources should take precedence over simple export. According to Daniell, additional cheap reliable electrical power will be required for the development of a beneficiation industry, and nuclear energy is being considered as a way of achieving thus. Other east African countries, such as Uganda, Tanzania and Rwanda, are implementing legislation which will make the use of nuclear power possible. The establishment of an East African energy research centre which could deal with nuclear as well as other issues, is considered essential for the growth of the area.

Send your comments to energize@ee.co.za

 

 

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