Four Power Priority: Mass production of modular N-reactors - I
by Ramtanu Maitra on 07 Dec 2018 4 Comments

There are many apparent reasons why the United States has virtually abandoned its nuclear power generation growth. One is that the US attitude to industrial development has undergone a sea-change over the last three to four decades. In the 1950s, electricity consumption grew at an annual rate of almost 12 percent. Throughout the 1960s through 1970s, that growth rate hovered between 5 to 8 percent before it collapsed to zero and below zero, resulting in the cancellation of new power generation plants with the approach of this millennium. All this happened because the powers-that-be in the United States chose to move the nation’s focus away from maintaining the country as an industrial powerhouse through modernization and innovation, to instead become increasingly a financial hub - pursuing the British model.


Adopting such an active de-industrialization policy - and allowing basic heavy industries to ebb and wither - coupled with a steady infiltration of anti-nuclear activists at various policy-making levels into the US government during the same period, took a heavy toll on the growth of the nuclear power sector. The stagnation of the industrial sector in this country that dragged down the nation’s overall productivity, as well as the interrelated decline of the power sector - nuclear, in particular - was perhaps an important reason why the nuclear industry did not diversify to usher in other, and equally important, ingredients.


One of the key areas of nuclear development that has been largely ignored in recent decades has been the development of small modular nuclear reactors (SMRs), a technology which would rejuvenate the nuclear sector and establish a future for the nuclear power sector worldwide. One may argue that the United States does not need small reactors since it has the basic transportation and industrial infrastructure and strong electrical grid needed to support large, “economy of scale” reactors. That is a valid argument. However, there are important reasons why small modular reactors should have been made commercial decades ago.


Need for Modular Reactors


Looking back, it becomes apparent why nuclear power was born in the more advanced, developed nations. The development of such front-line technology required prime resources, including very skilled manpower in the form of scientists, experimentalists, engineers - and accompanying scientific and technological institutional infrastructure. It also needed a significant level of physical infrastructure, including power and transport, an industrial base, and an economy that generates surplus wealth. The initial development of peaceful nuclear energy took place exclusively in countries that already had a developed electrical power system. The attraction of nuclear power for these countries was the potential to accelerate the process of development, while not having to depend on such finite resources as coal and gas.


In other words, nuclear power did not help any country to develop an electrical power infrastructure from scratch. In recent years, China, and to a certain extent India - both now among today’s nuclear power generating nations - have succeeded in developing their electrical power capacity significantly, but neither did so using nuclear power. Nuclear power’s contribution to these countries came later, mostly for supplementing power growth, or replacing any number of less-productive or polluting power sources. According to a recent report of the International Energy Agency, nuclear power production will grow by about 46 percent by 2040 - and more than 90 percent of the net increase will come from China and India.


Since development of nuclear power was initially the concern entirely of the industrialized West, where bulk power was the need of the hour, this provided little incentive to develop smaller reactors where the production of electricity is more expensive than with the larger reactors.


In the United States, the manufacturing of nuclear reactors, generators, etc., is the responsibility of private entrepreneurs. The installation and daily operation of these reactors also belongs to the private sector. The US government only comes in as the regulator. For the private utility, the prime objective is to make nuclear power economically competitive with coal, gas or hydro. Under the circumstances, the only objective of the private sector is how to optimize profit by building these reactors to fit the economy of scale. Even today, six decades later, this remains the primary concern for those who are building nuclear power plants and supplying power to consumers in the United States.


Unfortunately, such a market-driven approach obscures the true, far-reaching importance of nuclear power. It is not simply a reliable source of continuous electricity. Rather, understood from the standpoint of energy flux-density, it becomes a revolutionary ingredient in developing the basic infrastructure and productive power of the nation. Here lies the importance, and future, of small modular reactors.


Economy of Scale for Reactors


Since nuclear power generation began in the 1950s, the size of reactor units has grown from 60 megawatts (MW) to more than 1600 MW, with corresponding economies of scale as the driving force. At the same time, many hundreds of smaller power reactors have been built for naval use and as neutron sources, yielding enormous expertise in the engineering of small power units. These small reactors did not seek the economy of scale, but catered to a vital need where cost was a secondary factor.


In their paper, “Nuclear Reactors: Generation to Generation,” authors Stephen M. Goldberg and Robert Rosner pointed out that “Generation I” refers to the prototype and power reactors that launched civil nuclear power. This generation consisted of early prototype reactors from the 1950s and 1960s, such as Shippingport (1957-1982) in Pennsylvania, Dresden-1 (1960-1978) in Illinois, and Calder Hall-1 (1956-2003) in the United Kingdom.


The Second Generation, or “Gen II,” includes pressurized water reactors (PWRs), which began operation in the late 1960s and comprise the bulk of the world’s 400+ commercial PWRs and boiling water reactors (BWRs) that are in operation today. These have an expected life-span of about 40 years, although many have exceeded that life-span and will remain in operation for at least 20 more years.


There are other types of reactors, such as Canada’s heavy water reactors (CANDU) that are also recognized as Gen II reactors. Gen II designs require relatively large electrical grids and have a safety envelope based on Western safety standards. The economics of existing Gen II plants and of those under construction or in the planning stage are generally favorable, particularly in some parts of Asia. Gen III nuclear reactors are essentially improved Gen II reactors. These improvements in Gen III reactor technology are aimed to extend the operational life to 60 years, potentially to greatly exceed 60 years, prior to complete overhaul and reactor pressure vessel replacement.(1)


While these developments enhanced the economy of scale, they also pushed aside the development of small reactors, because of the latter’s much higher megawatt-to-megawatt cost when compared to these Gen II or Gen III reactors. But the story has a downside.


Now that the United States has not built a nuclear power plant for decades, and in the context of the de-industrialization of the nation, the ability to manufacture ultra-heavy forgings - each of which weighs greater than 400,000 pounds - a necessity for the Gen III reactors, no longer exists in the United States. At this point, the United States is today simply incapable of producing a Gen II or Gen III nuclear reactor.


US can’t make Gen III Reactors


Peter Alpern wrote in 2009: Four of the most complex parts of a nuclear power plant - the containment vessel, the reactor vessel components, the turbine rotors and steam generators - are made from over 4,000 tons of steel forgings, and almost none of those components are manufactured in the United States. The reactor vessel functions like the outer shell of an egg, protecting all the vital internal pieces, including the components in which the nuclear reaction takes place. The outer vessel alone weighs over 500 tons and is made up of seven very large forgings, including several that make up the nozzle.


The newest nuclear plant design on the market, the Generation III Evolutionary Power Reactor (EPR), from the French nuclear engineering group Areva, uses four steam generators - each of which weighs up to 500 tons. A generator rotor weighs in excess of 200 tons, according to Craig Hanson, vice president and product line manager for nuclear plant builder Babcock & Wilcox. And, for each nuclear plant, there are three to four turbine rotors. (2)


The Gen III reactors require steel ingots weighing between 500 to 600 tons each. No steel producers in the US can handle that size or weight, says Chris Levesque, Areva’s president and general manager at its Newport News, VA, facility for fabricating heavy reactor components: Forgers are limited because while [a forger] can make his press bigger and he can make his machine tools bigger, he needs a larger ingot. He’s limited by the steel mill and the ability of not just a mill that can make that big of an ingot, but [can] also transport it to him by rail. You’re talking about a piece of metal that’s huge and needs to stay hot and get from the mill to the forge. One of those mills can’t exist just to supply the forge.


The largest US ingot manufacturer, the now defunct Bethlehem Steel, could produce an ingot of about 380 tons - good enough for the Gen II reactors, but not so for the Gen III reactors. And that Bethlehem Steel capability no longer exists.


While America dismantled its capabilities vis-à-vis heavy forging, new heavy forgers have emerged - not many, but a few. According to Alpern’s article, Japan Steel Works (JSW) is by far the largest, providing 80 percent of the large forged components for all nuclear power plants being built in the world today outside Russia, including the steam generator, reactor pressure vessels and turbine shafts.


Several other countries are also involved in Gen III, or similar, reactors, and heavy forging capacity is emerging in those nations, including China (China First Heavy Industries) and Russia (OMX Izhora), along with new capacity emerging in South Korea (Doosan) and France (Le Creusot). It is also being planned in the U.K. (Sheffield Forgemasters) and India.



1. “Nuclear Reactors: Generation to Generation,” by Stephen M. Goldberg and Robert Rosner. American Academy of Arts & Sciences, 2011.

2. “U.S. Cedes Capability for Largest Nuclear Forgings,” by Peter B. Alpern. Forging, June 16, 2009.


(To be concluded…) 

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