The Future of Nuclear Energy in a Carbon-Constrained World

Nuclear Power Industry

A MIT panel concludes that harnessing the power of the atomic nucleus for peaceful purposes was one of the most astonishing scientific and technological achievements of the 20th century. It has benefitted medicine, security, and energy. Yet, after a few decades of rapid growth, investment in nuclear energy has stalled in many developed countries and nuclear energy now constitutes a meager 5% of global primary energy production. In the 21st century the world faces the new challenge of drastically reducing emissions of greenhouse gases while simultaneously expanding energy access and economic opportunity to billions of people.

We examined this challenge in the electricity sector, which has been widely identified as an early candidate for deep decarbonization. In most regions, serving projected load in 2050 while simultaneously reducing emissions will require a mix of electrical generation assets that is different from the current system. While a variety of low- or zero carbon technologies can be employed in various combinations, our analysis shows the potential contribution nuclear can make as a dispatchable low-carbon technology. Without that contribution, the cost of achieving deep decarbonization targets increases significantly (see Figure in report). The least-cost portfolios include an important share for nuclear, the magnitude of which significantly grows as the cost of nuclear drops.

Despite this promise, the prospects for the expansion of nuclear energy remain decidedly dim in many parts of the world. The fundamental problem is cost. Other generation technologies have become cheaper in recent decades, while new nuclear plants have only become costlier. This disturbing trend undermines nuclear energy’s potential contribution and increases the cost of achieving deep decarbonization. In this study, we examine what is needed to arrest and reverse that trend.We have surveyed recent light water reactor (LWR) construction projects around the world and examined recent advances in cross-cutting technologies that can be applied to nuclear plant construction for a wide range of advanced nuclear plant concepts and designs under development. To address cost concerns, we recommend:

1. An increased focus on using proven project/ construction management practices to increase the probability of success in the execution and delivery of new nuclear power plants. The recent experience of nuclear construction projects in the United States and Europe has demonstrated repeated failures of construction management practices in terms of their ability to deliver products on time and within budget. Several corrective actions are urgently needed:
   
   (a) completing greater portions of the detailed design prior to construction;
   (b) using a proven supply chain and skilled workforce;
   (c) incorporating manufacturers and builders into design teams in the early stages of the design process to assure that plant systems, structures, and components are designed for efficient construction and manufacturing to relevant standards;
   (d) appointing a single primary contract manager with proven expertise in managing multiple independent subcontractors;
   (e) establishing a contracting structure that ensures all contractors have a vested interest in the success of the project; and
   (f) enabling a flexible regulatory subcontractor environment that can accommodate small, unanticipated changes in design and
   construction in a timely fashion.
2.  A shift away from primarily field construction of cumbersome, highly site-dependent plants to more serial manufacturing of standardized plants. Opportunities exist to significantly reduce the capital cost and shorten the construction schedule for new nuclear power plants. First, the deployment of multiple, standardized units, especially at a single site, affords considerable learning from the construction of each unit. In the United States and Europe, where productivity at construction sites has been low, we also recommend expanded use of factory production to take advantage of the manufacturing sector’s higher productivity when it comes to turning out complex systems, structures, and components. The use of an array of cross-cutting technologies, including modular construction in factories and shipyards, advanced concrete solutions (e.g., steel-plate composites, high-strength reinforcement steel, ultra-high performance concrete), seismic isolation technology, and advanced plant layouts (e.g., embedment, offshore locations), could have positive impacts on the cost and schedule of new nuclear power plant construction. For less complex systems, structures, and components, or at sites where construction productivity is high (as in Asia), conventional approaches may be the lowest cost option.

It is important to emphasize the broad applicability of these recommendations across all reactor concepts and designs. Cost-cutting opportunities are pertinent to evolutionary Generation-III LWRs, small modular reactors (SMRs), and Generation-IV reactors. Without design standardization and innovations in construction
approaches, we do not believe the inherent technological features of any of the advanced reactors will produce the level of cost reductions needed to make nuclear electricity competitive with other generation options. In addition to its high cost, the growth of nuclear energy has been hindered by public concerns about the consequences of severe accidents (such as occurred at Fukushima, Japan in 2011) in traditional Generation-II nuclear power plants.

3. Reactor designs are frequently classified into four generations. The first commercial nuclear reactors built in the late 1950s and 1960s are classified as Generation-I systems. Generation-II systems include commercial reactors that were built from 1970 to 1990. Generation-III reactors are commercial designs that incorporate evolutionary improvements over Generation-II systems. Generation-IV is the classification used to describe a set of advanced reactor designs that use non-water coolants and are under development today. These concerns have led some countries to renounce nuclear power entirely. To address safety concerns, we recommend:

•  a shift toward reactor designs that incorporate inherent and passive safety features.
• Core materials that have high chemical and physical stability, high heat capacity, negative reactivity feedbacks, and high retention of fission products, together with engineered safety systems that require limited or no emergency AC power and minimal external intervention, will likely make operations simpler and more tolerable to human errors. Such design evolution has already occurred in some Generation-III LWRs and is exhibited in new plants built in China, Russia, and the United States. Passive safety designs can reduce the probability that a severe accident occurs, while also mitigating the offsite consequences in the event an accident does occur.
• Such designs can also ease the licensing of new plants and accelerate their deployment in developed and developing countries.

We conclude that advanced reactors like LWR-based SMRs (e.g., NuScale) and mature Generation-IV reactor concepts (e.g., high-temperature gas reactors and sodium-cooled fast reactors) also possess such features and are now almost ready for commercial deployment. Further, our assessment of the U.S. and international regulatory environments suggests that the current regulatory system is flexible enough to accommodate licensing of these advanced reactor designs. Certain modifications to the current regulatory framework could improve the efficiency and efficacy of licensing reviews.