Small modular nuclear reactors gain widespread adoption

Small modular reactors (SMRs) are a new class of smaller, cheaper, safer and more adaptable nuclear power plants that gain widespread adoption from the mid-2020s to the mid-2030s.* They are defined by the International Atomic Energy Agency as generating an electric output of less than 300 MW, reaching as low as 10 MW for some of the smallest versions. This is compared to larger, conventional reactors, which typically produce 1 to 2 GW.
Electricity was first generated from nuclear energy in 1951, during tests of an experimental reactor in the high desert of Idaho. The original output was estimated at 45 kW. In subsequent decades, reactors grew much larger, with outputs reaching the gigawatt scale. Later, more than half a century after the first commercial use of nuclear energy, reactor designs with lower electrical outputs were starting to be developed again.
In the early decades of the 21st century, the need for small modular reactors was arising due to several different factors. Firstly, they could be built at a much lower cost than traditional reactors, making them less risky from an investment viewpoint. They were especially attractive to developing nations (which lacked the ability to spend tens of billions of dollars on infrastructure), to remote communities without long distance transmission lines, and for areas with limited water and/or space.
SMRs could be designed with flexibility in mind. Unlike the larger power plants (most of which used "light water" designs based on uranium fuel and ordinary water for cooling), they were being developed in a broad range of shapes and sizes, with various fuels and cooling systems. Some could even use existing legacy radioactive waste as an energy source. Among the most promising concepts were those able to be assembled in factories and delivered in sealed containers – meaning the plant would never require decommissioning, but could simply have its power source replaced like a battery, further reducing costs. In a similar vein, some of the other proposed concepts generated far less waste than conventional reactors. SMRs would also allow increments of capacity to be gradually added as power needs increased over time.
There were yet more advantages. The smaller size and safety features of the SMRs would mean both a reduced environmental impact and little or no damage from an accident – easing public concerns – while ensuring a faster and simpler planning process. Being much smaller and easier to construct, the time required from ground breaking to commercial operation could be greatly reduced, compared to larger power plants that often required decades to plan, build and test. Additionally, the threat of nuclear weapons proliferation was eliminated by the design, materials and safety aspects of SMRs.
This variety and flexibility, alongside the demand for lower carbon energy, was leading to a renaissance in nuclear power generation. By the mid-2010s, around 50 experimental prototype SMRs were in development (excluding nuclear submarines and ships). A small number achieved commercial viability in the early 2020s** and these paved the way to greater adoption through the following decade.* By 2035, the SMR industry is generating several tens of gigawatts in energy and is valued at nearly half a trillion dollars worldwide.*

Manned missions to the Moon

During this period, at least two space agencies conduct manned exploration of the Moon. This occurs in parallel with private commercial ventures including lunar tourists. The huge length of time since Apollo had led to a perception among the general public that space travel was making little or no progress. In reality, a number of developments were underway.
Perhaps most notable was the rapid emergence of China. In 2003, its first astronaut had been placed into orbit. This was followed by two additional manned missions in 2005 and 2008. Within a decade, China was building its first space station,* while launching probes to the lunar surface including a sample return mission.* The country had even greater ambitions, however, putting its first astronauts on the Moon by the late 2020s.* This would take place in the southern polar region, with abundant solar energy, relatively stable temperatures and the presence of water-ice.*
Russia was making strides too. After years of stagnation, its space program saw a resurgence in the 2010s with a dramatic increase in funding.* A new spaceport was operational by 2018, while rockets were being developed based on cheaper acetylene and ammonia fuel,* along with huge payloads up to 180 tons. By the early 2030s, this combination of better infrastructure and technology, increased funding and government commitment would lead to a manned Russian presence on the Moon.*

China on the Moon, 2025-2030.

NASA had been developing a new rocket – the Space Launch System (SLS)* – along with a manned spacecraft placed at Earth-Moon Lagrange Point 2.* The agency's longer term goals included sending astronauts to Mars, rather than the Moon's surface.* However, private commercial ventures, such as inflatable modules designed by Bigelow Aerospace, were also getting underway and involved some testing and collaboration with NASA.** Additionally, the SLS had performed lunar orbits during its testing,* along with crewed asteroid missions.*
The European Space Agency (ESA) was less vocal than other agencies when it came to manned lunar missions. Announced in 2001, its Aurora Programme included the goal of sending astronauts to the Moon and Mars during the late 2020s and early 2030s. However, these plans were quietly dropped after being challenged by ESA's main financial contributors (France, Germany and Italy). Lacking direction and leadership, the programme became focused on robotic-only exploration of Mars.*
Other nations had shown an interest in manned lunar exploration and even permanent bases – including Japan, India and Iran. However, despite making significant progress, a lack of technical experience and the sheer financial commitment needed would postpone their goals until somewhat further into the future.