Four Power Priority: Mass production of modular N-reactors - II
by Ramtanu Maitra on 08 Dec 2018 0 Comment

What SMRs Promise


In May 2018, a Portland, Oregon-based company, NuScale Power, announced that its design of a small modular nuclear reactor (SMR) had completed the Phase 1 review of its design certification application (DCA) by the US Nuclear Regulatory Commission. According to analysts, Phase 1 is the most intensive phase of the six-phase review, taking more hours and effort than the remaining five phases combined.


What NuScale’s SMR is offering is twelve 50 MW reactors combined, a scaled-down version of large, light water reactors that can be put together module-by-module to develop a generating capacity of 600 MW. Recently, NuScale says its SMR will produce 20 percent more power than what it was designed for. (3)  Because the plant has not been constructed and no power has yet been generated, such claims must remain hypothetical until proven.


What is evident from the cost of the 12-50 MW SMR designed by NuScale, or any other small modular reactor, is that when developed, these reactors, megawatt-for-megawatt, will be more expensive than Gen III large nuclear reactors. However, that cost difference can be reduced significantly if the SMRs are mass-produced.


Even with the higher cost, it is clear that SMRs have a large role to play in coming decades, particularly in developing countries. According to a report, “Small Nuclear Power Reactors,” which can be found on the World Nuclear Association’s website: Small modular reactors (SMRs) are defined as nuclear reactors generally 300 MW equivalent or less, designed with modular technology using module factory fabrication, pursuing economies of series production and short construction times.(4)


It is evident that a number of countries, such as China, Russia, Korea, Canada, India, and Argentina, have developed small nuclear reactors, but very little is known about these countries’ efforts to produce them as modular units, which would make their production and deployment far more effective.


According to the Canadian Small Modular Reactor Roadmap, there are over 150 proposed designs for SMRs worldwide. The national nuclear science and technology organization, Canadian Nuclear Laboratories (CNL), has set a goal of building a new SMR on its Chalk River site by 2026. In June 2017, the Canadian company, Terrestrial Energy, began a feasibility study for the siting of the first commercial Integrated Molten Salt Reactor at Chalk River. To say the least, this is still at an embryonic stage.


China is also developing a 100 MW SMR, designed by China National Nuclear Corporation. Called the Linglong One, this ACP100 nuclear reactor has completed its preliminary design stage and is qualified for construction in Hainan province this year. Its first use will be to generate heat for a residential district, replacing coal-fired boilers. (5)


All that the Canadian Small Modular Reactor Roadmap tells us is that the SMRs are under development in many countries, and there is a strong likelihood that some of them might become operative within a decade. Some of these reactors could be High Temperature Gas-Cooled Reactors or even Pebble-Bed reactors. However, little is known of their progress, or the timetable.


What is at hand, though, is the definitive work done by NuScale and its success in completing the Phase 1 review of its design certification application by the US Nuclear Regulatory Commission. The NuScale SMR is an advanced light-water reactor. Each module is a self-contained unit that operates independently within a multi-module configuration. Up to 12 modules are monitored and operated from a single control room. The entire reactor sits within a containment vessel 65 feet tall and 9 feet in diameter. NuScale’s Russell Ray describes the process in this way:


The reactor and containment vessel operate inside a water-filled pool that is built below grade. The reactor operates using the principles of natural circulation; hence, no pumps are needed to circulate water through the reactor; instead, the system uses a convection process.


Water is heated as it passes over the core, and as it heats up, the water rises within the interior of the vessel. Once the heated water reaches the top of the riser, it is drawn downward by water that is cooled passing through the steam generators. The cooler water has a higher density. It is pulled by gravity back down to the bottom of the reactor where it is again drawn over the core.


Water in the reactor [cooling] system is kept separate from the water in the steam generator system to prevent contamination. As the hot water in the reactor system passes over the hundreds of tubes in the steam generator, heat is transferred through the tube walls and the water in the tubes turns to steam. The steam turns turbines which are attached by a single shaft to the electrical generator. After passing through the turbines, the steam loses its energy. It is cooled back into liquid form in the condenser, then pumped back to the steam generator. (6)


SMR Advantages for Developing Nations


In addition to what Russell Ray describes, which emphasizes the safety part of the NuScale SMR, SMRs in general have many advantages that are of particular importance to countries with weak basic infrastructure. To begin with, the major components of SMRs will be small enough to be made on a production line in a factory, rather than being assembled one item at a time. That means it will be fully set up in a controlled environment away from the wind, rain, and sand - typically present at a construction site - that often delay construction and assembly.


Among the other advantages, these SMRs provide easy transportability. Since they are only 65 feet tall, 9 feet in girth, and weigh about 300 tons, they could be transported from the factory to the construction site by boat, truck, or even railway car - a task that many developing countries’ infrastructure can bear. Another advantage is that SMRs have much smaller emergency planning zones (EPZs), which is the area expected to be affected by a nuclear accident that results in the release of radioactive material.


SMRs require fewer materials and resources, bringing down the one-time capital cost. That suggests the country using SMRs can add power in smaller increments. It also means that the countries with a weak electrical grid - which is a serious problem in most of the developing countries and presents major obstacles to setting up a large single power generation unit - will be able to set up SMRs, which, in return, will provide a steady source of power to develop basic infrastructure, including the strengthening of the electrical grid.


There are other smaller advantages. For instance, a large nuclear power plant needs to change fuel once every 18 to 24 months. Outages are scheduled for the spring or fall when electricity demand is lowest. The outage required for a scheduled refueling is usually no more than 40 days, but during that period no power is generated or delivered by that plant. In the case of SMRs, although it could be five to six years before a shut-down of one of the modules would be necessary to carry out the fuel change, such refueling outages can be staggered, allowing a module-by-module fuel change. This would enable a multi-module unit to carry on supplying power at near capacity throughout its life-time.


SMRs, once developed and proliferated, will also be the anchor for desalination of sea water and brackish water. Desalination of water along vast coastal areas is an essential ingredient for economic development in many developing countries and island nations. Recently, Ibrahim Khamis of the International Atomic Energy Agency was cited as emphasizing that this is not a new idea. Its feasibility and reliability have been well proven, and there is the added advantage that the nuclear power plants can supply either thermal or electrical energy, or both, at varying scales. According to Khamis: We can think of nuclear-powered desalination in terms of two main applications. One is to serve make-up water resources for the plant; the other is to produce potable water. Both applications have already been demonstrated. (7)


In addition, perhaps the greatest advantage of proliferating these SMRs is that they can be located in areas where the population is sparse, and the growth potential is vast - a very common phenomenon in Africa, in some parts of Asia, Central America and the Caribbean islands, for instance. These SMRs could jump-start the much-required developmental process - not in one stroke, but at a steady and escalating pace.


A Power-Starved World


Despite the last six decades of commercial power generation, nuclear power, as an electrical power source, has not contributed to the electricity generating capacity of the “developing nations,” where power generation remains a crucial ingredient for building up the basic manpower, industry, and the absolutely necessary infrastructure of those nations. At present, the world can produce about 20 to 25 large, pressurized light water reactors and a few medium-size (about 700 MW) pressurized heavy water reactors per year, adding up to about 25-30,000 MW annually. That production capability is far, far below what the world needs. For instance, in the period between 2000 and 2010, China alone built about 26,000 MW of power generating capacity, mostly using coal and hydro-electric.


How little has nuclear power contributed to the developing nations? Take the case of the BRICS member nations. These are considered nations that are on the way to becoming developed nations. It is true that in Russia, India and China, nuclear power is growing, and these countries have developed the potential to become major nuclear power generating countries, but in Brazil and South Africa, nuclear power remains an insignificant player in their power capabilities. Brazil has only two reactors, producing about 3 percent of its power in a power-starved country. The same goes for South Africa, where two nuclear reactors at the Koeberg nuclear power station account for around 5 percent of South Africa’s electricity production. South Africa is vastly short of power, yet nuclear power is not playing any significant role.


Beyond those examples, one must take a look at South East Asia, for instance. Existing in the vicinity of four nuclear power manufacturers - China, Japan, South Korea and India - none of the ten members of the Association of South East Asian Nations (ASEAN) - Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam - has a single nuclear power plant. Nuclear has not played any role whatsoever. Most of these nations desperately need a much larger electricity generating capacity for their growth.


In the entire continent of Africa, populated by 1.2 billion people, other than those two Koeberg nuclear reactors in South Africa, nuclear power has no presence. And, yet, Africa is crying out for more electrical power to grow and provide a future for today’s, and tomorrow’s, population. Under current circumstances, these countries cannot have a serious nuclear program based on large nuclear reactors. They simply do not have the infrastructure, or the electrical grid system, to support large Gen III reactors.


For instance, in Nigeria, with a population close to 190 million and the potential to become an economic giant, its transmission system does not even cover large parts of the country. Currently, it has the capacity to transmit a maximum of about 6 GW, and the system is technically very weak, thus very sensitive to major disturbances.


For connecting a large nuclear power plant (say, 1,000 MW), the estimated capacity of a smooth-running grid required is at least 10 GW. (In other words, a single power generation source’s capacity is not to exceed 10 per cent of the grid capacity for smooth distribution.) The situation in most of the rest of Africa, in terms of infrastructure and electrical transmission capacity, is far worse than in Nigeria. A similar situation exists in all of the Caribbean and Central American countries, in the vicinity of the United States - the largest producer of nuclear power. One could go on and on about the shortcomings.


SMRs Will Open Up the World


With the advent of the SMRs - not only the NuScale version, but many other versions that can be developed within a short time by other nuclear power plant manufacturing nations - all of these countries can get an opening. What this will require, however, is for the SMRs to be mass produced in assembly-line fashion, and this will need governments - including most emphatically the governments of the nuclear-producing nations - to get involved and ensure the job is done. The intention must be to enable the developing nations to build up their basic infrastructure and industrial capabilities. That should be attractive for even those private sector manufacturers who think in terms of developing markets for larger economic interactions.


How will these SMRs accomplish what the large nuclear power plants cannot? Take for instance, Indonesia. The Indonesian archipelago has 18,000-plus islands. However, almost 60 percent of Indonesia’s 260 million people live on the island of Java. Indonesian authorities’ many efforts in the past to redistribute the population to various islands have fallen flat because of lack of electrical power, which provides the basis for sustainable living. For Indonesia, it is not possible to build a large nuclear power plant and string the wires across the seas to provide power to the islands. Nor is it feasible to have boatloads of coal crisscrossing the seas, carrying millions of tons of coal daily to feed the coal-fired power plants set up on those islands. For Indonesia, SMRs will offer a perfect solution.


The same can be said of so many countries in Africa. Look at Chad, Sudan, Mali or the Democratic Republic of the Congo. Developing the lands distant from major population centers will open up the countries and provide an opportunity for growth all across the continent. These are important factors, and the correct and rapid development of the SMRs will not only put nuclear power at the helm of power generation for centuries, it will enable many of the developing nations to get out of the otherwise insurmountable poverty trap.



3. “Breakthrough for NuScale Power: Increase in Its SMR Output Delivers Customer

4. “Small Nuclear Power Reactors.” World Nuclear Association.

5. “NuScale’s Small Modular Nuclear Reactor—Reliable, Resilient and Flexible,” by James Conca. Forbes, June 22, 2018.

6. “Can SMR Technology Revitalize the Business of Nuclear Power?” by Russell Ray. Power Engineering, June 13, 2018.

7. “Nuclear-Powered Desalination,” by William Steel. Industrial Water World, October 1, 2018.



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