Small Modular Reactors. Prospects for Further Development in Ukraine

More than 50% of electricity is produced at Ukrainian nuclear power plants (NPPs) that are an important component of the national fuel and energy system. The Energy Strategy of Ukraine until 2035 envisages the policy for long-term operation of operating power units. The issue of new builds becomes more relevant considering the fact that long-term operation of 12 power units out of 15 will expire in the period from 2030 to 2040. editorial board talked to Viktor Shenderovych, veteran of nuclear energy in Ukraine, about what types of power units are better for Ukraine, what are SMR technologies and where they are used.

– Viktor, is it feasible to construct small modular reactors instead of 440 and 1000 MW power units?

Indeed, the Energy Strategy envisages considering long-term operation of operating power units as a priority area for the development of nuclear industry. It is also necessary to take into account the replacement of existing power units with new ones after the expired period of long-term operation and the construction of new (additional) energy capacities. First of all, this concerns Khmelnitsky NPP units 3 and 4, the construction of which is stipulated in the Energy Strategy of Ukraine until 2035. The necessary and adequately justified number of new (additional) power units shall be defined in the development of the action plan on Energy Strategy implementation, taking into account the justification of promising nuclear fuel cycle for the long-term perspective. Making decisions on promising nuclear fuel cycle can significantly influence the selection of the most suitable technologies, including designs of new power units, which are supposed to be implemented as replacing or additional ones. It should be noted that the activities related to the construction of replacing and additional power units depend to a large extent on the possibilities and justification of further long-term operation of operating power units.

At present, decisions are being implemented on long-term operation of power units for 10 years (20 years for Rivne NPP units 1 and 2) with the issuance of appropriate permits. According to the Energy Strategy, long-term operation of WWER-1000 power units is planned for 20 years.

In my opinion, given the considerable international experience in long-term operation, including WWER power units, and major experience in the activities on long-term operation in Ukraine, it should be assumed that long-term operation of operating units for 30 years seems quite realistic (60 years of operation in total). Such a process primarily concerns critical (non-replaceable) components of a power unit, including: reactor, steam generator, the most important components of the primary system, building structures of critical structures, etc.  

Making specific decisions on long-term operation of power units does not solve the issue of making strategic decisions on replacing and additional power units, but only influences the necessary timing for making decisions and implementation.

Taking into account technical and organizational difficulties of activities in nuclear energy field, especially with regard to the construction of new facilities requiring long-term period, this task shall not be postponed and shall start in the near future. One of the most important issues is to select the promising technology (or technologies) and the corresponding type (types) of power units, which shall be considered in the implementation of activities within the Energy Strategy and for the future.

Currently, there are a number of modern technologies and relevant designs referred to 3+ type. These are the designs with high degree of reliability and safety, which can be considered for the use in Ukraine.

SMR technologies (small modular reactors) can also be treated as an alternative taking into account their specific nature and specific conditions of national power industry.

– What are the advantages of small modular reactors?     

The use of SMR in nuclear power industry has the following purposes: increased economy of energy production by reducing capital and operating costs; reduction of construction time; possibility of a more optimal return on investment. All this is in comparison with higher capacity units.

Besides, the following shall be considered among the purposes of SMR use: ensure high level of reliability and safety; possibility of approaching the energy sources to consumers, including power supply of specific regions and territories with a complex geographical location; possibility of power unit operation at load follow mode.

However, in certain sense, these are theoretical advantages, which shall be analyzed and confirmed taking into account specific data on SMR designs and energy system conditions of specific countries.

Currently, SMR design activities are carried out in many countries: Argentina, France, Canada, India, China, Japan, South Africa, Great Britain, Russian Federation, USA, Denmark, South Korea and others.

The range of eclectic power is 50-300 MW. Used coolants: water, gas, liquid metal.

According to official data, several facilities are currently under construction: CAREM-25 in Argentina, KLT-40S in Russian Federation, HTR-PM in China.

The following facilities are at the certification stage or at the final design stage:

SMART in South Korea, RITM-200 in Russian Federation, PRISM in USA.

Below, there are some consideration on the possible advantages and risks of implementing nuclear power development activities taking into account SMR technologies.

First, the advantage of SMR is the technology of modular design that provides for the arrangement of serial production, which potentially should reduce the level of capital costs and shorten the construction time. This is an important factor, since the experience in the construction of new power units in the world shows significant difficulties in the implementation of specific activities, including increased costs in the process of construction and significant increase in construction time. This is typical for the most of projects under implementation in China.

However, since there is no experience in SMR implementation on specific sites, one cannot adequately assess the level of specified advantages. According to available data on some projects at the design stage, there are no tangible advantages in terms of construction costs. In case of replacing expired facilities by SMR units, the increased number of replacing SMR will be required. For example, one will need to construct six SMR-160 units to replace one WWER-1000. This factor may significantly worsen the specified indicators of this technology, including the total costs, as well as the duration of the facility construction in general.

Second, better conditions for return on investment. This factor is a significant advantage of SMR, since it allows return of investment, starting with the commissioning of a first power unit of the series. If we speak about 1000 MW unit, return on investment starts with the commissioning of a power unit. For replacing SMR, it starts with the commissioning of a first power unit of the series, that is much earlier.

Third, safety and reliability. Compared to PWR/BWR, SMR has certain potential advantages. SMR has a simpler design, including the design of the primary and secondary systems. It has lower level of pressure in the primary and secondary systems, which has a positive influence on reliability. Wide use of passive devices is typical for it as well.

However, the issue needs additional study, since based on the available data – safety performance indicators of such SMR are not better that those of modern power units of levels 3 and 3+.

When we speak about SMR using other technologies (gas, liquid metal), the issues of comparing safety level with modern power units of higher capacity also shall be studied.

Fourth, the possibility of using SMR for purposes other than electricity production (desalination plants, heat supply), as well as energy supply of regions with specific geographic conditions.

It seems that these factors are not particularly relevant for the conditions of Ukraine. At the same time, one shall take into account that the potential for the approximation of electricity and heat sources to consumers seems unrealistic for a number of reasons for nuclear power plants in the conditions of Ukraine. The first reason is the complexity of environmental justification related to the siting of nuclear installations with regard to the environment. The second reason is a possible negative attitude of the public. However, there is a possibility that SMR technology will not significantly affect these factors.

Fifth, licensing issues. The use of new technology largely deals with the licensing conditions. Currently, it is difficult to predict results and possible risks of these activities, since first we will need more detailed familiarization with specific SMR designs.

Sixth, the possible placement of the equipment production in Ukraine. SMP technology (it works for PWR/BWR) allows the consideration of a higher percentage of equipment production placement in Ukraine in comparison with power units of higher capacity. However, this issue is also subject to detailed consideration taking into account technical solutions of the projects. 

Seventh, the possibility of unit operation at load follow mode. Compared to power units of higher capacity, this may be considered as a potential advantage, taking into account possible shutdown/start of power units during a day. However, the implementation of such a possibility shall be justified in the designs of specific power units considering the factors of nuclear fuel strength and behavior.

In conclusion, I would like to share some general observations on the applicability of SMR technology in Ukraine.

The power industry of Ukraine is characterized by: a high level of power generation at NPPs with the use of high capacity power units; an extensive energy supply network, which covers the entire country; objective and subjective difficulties in the implementation of activities for the siting of new builds. In addition, in case of decommissioning of existing power units, one will need six SMR-160 units to replace one WWER-1000 unit. This will create additional difficulties and problems to implement such a solution.

In order to develop a justified approach to the determining possibility and appropriateness of using SMR technologies in Ukraine, in my opinion, it would be needed to: develop the feasibility study (or another similar document) on the prospects and appropriateness of using SMR technology in the conditions of our country, taking into account all factors that contribute to the decision making process (technical, organizational, social and other). At the same time, the specific type of SMR does not matter. The second thing is to develop the feasibility calculation to observe different SMR technologies to compare them with selected criteria and factors. Based on the analysis, it would be needed to define technologies and designs that should be considered at subsequent stages of activities.

The results of conducted activities shall provide an opportunity to make a justified approach to the consideration of SMR technologies in the implementation of the Energy Strategy.

– Experts say radiation accidents at modular reactors are impossible. Is it true?

– Such a formulation of the issue is fundamentally wrong. We cannot speak about the impossibility of accidents. This can only be for the case, when the occurrence of an emergency is impossible for physical reasons. According to available data, such designs are not used in SMR technologies under development.

Here we can speak about the lowest possible probability of events leading to accidents, as well as the lowest possible probability of radiation consequences taking into account requirements of national and international documents of a specific country.

– Despite a considerable list of possible advantages, small modular reactors are not yet used on a commercial scale. Why?

I have already noted the state of developing different SMR types. The process of creating new technologies and related designs is related to the need to resolve many technical and technological issues, carry out different analyses and justifications, including safety justifications, deal with licensing issues, etc.

Besides, there shall be a commercial interest in the implementation.

All these factors shall be addressed in terms of the conditions of a specific country and specific investors.

The next few years will show how real are the predictions of implementing SMR technology in the world.

– What do you know about the design of SMR-160 unit by the Holtec International?

– Currently, the design activities are in the active phase and the licensing process is launched. The developers provide for the design licensing in the regulatory authority of Canada. According to the available data, licensing is also planned in the U.S. NRC, which is the regulatory authority of the USA. The developers are going to propose the technology for a number of countries, including Ukraine, for the implementation on their territories.

– Recently, Yurii Nedashkovsky, Energoatom President, said that Ukraine is considering the possibility of constructing small modular reactors on RNPP site. Why RNPP was chosen?

– The stated position of Energoatom is quite logical. RNPP-1 and RNPP-2 are the oldest in the nuclear industry of Ukraine and we speak about decommissioning after long-term operation, these power units are the first on the list. In addition, the capacity of each power unit is 440 MW and this is the most favorable with regard to the comparability of power with SMR (for example, SMR-160).

However, in my opinion, before making a decision of the possible replacement of RNPP-1 and RNPP-2, it would be necessary to develop a feasibility study and feasibility calculation (which I mentioned above). In the case of a positive result of the analysis, one shall develop the feasibility calculation on the option of developing replacing capacities on RNPP site with the use of SMR. This may be SMR-160 produced by Holtec International.

– Modern SMR can be stationary and mobile, land and marine. In addition to the sites of national NPP, what other options for SMR siting can be considered?

– Mobile and marine SMRs are hardly necessary in Ukraine. As for SMR siting, several options are possible.

The first option is the placement of SMR on sites of operating NPPs as replacing installations.

The second option is the placement on new sites. In this case, it would be necessary to consider different complicating factors: the number of possible sites in Ukraine is rather limited and one can speak about large number of SMR units on the site at a level of 1000-2000 MW.

The placement of SMR units on sites of operating heat power plants, including the fact of their closure, is doubtful due to the following reasons: these territories are usually environmentally unfavorable from the point of view of the environment; in the construction of a large number of SMR at different sites, we will face technical, social and economic difficulties.

– Is it probable that we ourselves will produce equipment for SMR? Or we will purchase technologies from the Holtec International or other international companies?

– In case of SMR technology implementation in Ukraine, the placement of equipment production is very important taking into account capacities of national enterprises. This issue can be one of the determining in making decisions on the efficient implementation of this or that technology.

Based on preliminary discussions with the Holtec International, one can make a conclusion that the parties are interested in solving this issue taking into account the interests of both sides. The specific volume of possible placement of equipment production shall be discussed in the following meetings.

– What is your opinion, will SMR construction be positively perceived in Ukraine?

– It is very difficult to answer this question, since it is in many respects connected with the general issue of public attitude to the nuclear industry. The most important factors will be as follows: proved acceptable safety level that is not lower than in current NPP designs; high level of feasibility indicators; reduced impact on the environment, including human, compared to existing nuclear power plants; compliance of siting conditions with environmental safety requirements.

– If the construction and operation of SMR will succeed in Ukraine, what kind of power generation will compete with this technology?

– Nuclear generation will compete with thermal generation. In this case, fare conditions for such a competition shall be ensured.

Given the long-term prospects, the nuclear generation is considered as one of the sources of low-carbon energy, which is currently supported around the world. Renewable energy sources will be treated as an alternative. The most suitable for the conditions of Ukraine are wind and solar energy industry, and possible the use of biomass. It should be noted that the competition will increase with time, since renewable energy sources are constantly increasing their efficiency, taking into account the improvement of technologies, equipment and components. This is a trend typical for the world today.

It is also necessary to consider specific difficulties in the implementation of renewable energy sources, in particular wind and solar sources, including: need for allocation of large territories for the installation of facilities, which may be a challenge for Ukraine; unstable nature of power generation and low production efficiency, which significantly affect the quality of energy production with increasing role of renewable sources in the total production of energy. editorial board