Commonwealth Fusion has published five peer-reviewed papers laying out the physics case for ARC, its planned 400 MW fusion power plant, which would follow the company's smaller SPARC tokamak now under construction. The papers suggest ARC could produce more energy than it consumes using high-temperature superconducting magnets, molten-salt heat extraction, and 15-minute fusion pulses. Ars Technica reports:

ARC will be a tokamak that hosts fusion between hydrogen's two heavier isotopes, deuterium and tritium. This reaction results in a helium nucleus and releases a neutron and radiation. The helium transfers heat to the plasma, maintaining the conditions needed for fusion, but it is otherwise a waste product, referred to as "ash" in the fusion context. The neutron and radiation, however, are put to use. Part of that use is simply imparting energy into a blanket of molten salt that surrounds the fusion chamber. That energy, in the form of heat, will be used to drive a turbine that produces the electricity. The molten salt includes lithium ions; when one lithium isotope absorbs a neutron, it decays into more helium, plus tritium that can be used as fuel for the reactor. There are isotopes present that will also release additional neutrons, allowing this process to generate sufficient fuel.

Overall, the present design of ARC is expected to produce about 1.13 GW of fusion power, with 500 MW of that extracted as electricity. Some of that (100 MW) will be needed to power the plant's operations, leaving 400 MW to be sent to the grid. The rest of the energy is either kept in the tokamak to maintain the fusion reactions or lost due to inefficiencies in the heat and energy transfer of the system. There's a lot of uncertainty about these numbers; the 1.13 GW is just the center of a range of potential values running from 900 MW to 1.3 GW, so the 400 MW output may need to be adjusted up or down accordingly.

Some of that 400 MW comes during periods where fusion is not occurring. The nuclear reactions will occur within 15-minute-long periods that will be interspersed with one minute resets. The resets are meant to be kept short enough that nothing has much of a chance to cool down before it gets heated up again -- thermal inertia will let it continue generating power. That will be one of the key differentiators with SPARC, which doesn't have the heat extraction needed to maintain stable fusion for these long time periods, and so can't maintain the near constant temperatures needed for reliable power generation.

It's inevitable that parts of the device will be exposed to radiation and perhaps fusion plasma. The inner walls of the reactor will be shielded by tungsten, which will limit erosion by the conditions. Meanwhile, the vacuum vessel is designed to be replaced every one to two years. The papers note that this flexibility will allow them to make some design changes even after ARC is built. To enable this, the whole tokamak is meant to split in half for maintenance.

Abstract credit: https://slashdot.org/story/455446/

In early March, while attending the Nuclear Energy Summit, Rwandan President Paul Kagame reaffirmed his ambition to develop civilian nuclear reactors in Rwanda. “Nuclear energy is not too complex or risky for developing countries,” he said during the meeting. “It will diversify our energy mix while providing the stability required for industrial growth and long-term transformation.”

Currently, Rwanda’s energy supply is largely dominated by hydropower and thermal energy. In 2020, just half of the population had access to electricity; by 2030 the country aims to reach 100% electricity access. The East African country is banking on nuclear power to supply 60-70% of its electricity mix.

The recent summit took place just one day after the International Atomic Energy Agency (IAEA) concluded a trip to Kigali to assess Rwanda’s readiness for nuclear energy. The IAEA inspected 19 points considered essential for launching a civilian nuclear program, including the legal framework, radioactive waste management and safety.

After a weeklong evaluation, the IAEA concluded that Rwanda is making strong progress toward establishing its nuclear program. “Strong government support and the effective coordination of the preparatory work helped Rwanda make significant progress towards deciding on a nuclear power programme,” Mehmet Ceyhan, technical lead of the IAEA nuclear infrastructure development section and team leader for the mission, said in a press release. “The level of preparation and involvement from all participating organizations and teams during the mission reflected a deep commitment to the programme.”

According to the IAEA, Rwanda is currently identifying candidate sites for its planned small modular reactor (SMR) project. Mongabay contacted the Rwanda Atomic Energy Board, the national agency overseeing the country’s civilian nuclear program, as well as the IAEA for additional information but did not receive a response by the time of publication.

Rwanda expects its first SMR reactor to be operational by the early 2030s. It is expected to be built faster and at lower cost than conventional nuclear power plants.

In 2023, Rwanda signed an agreement with Dual Fluid Energy Inc., a Canadian-German nuclear technology company, to pilot advanced nuclear reactor technology in the country. The government has also partnered with institutions from Russia and the United States to explore the development of SMRs. In 2025, Rwanda was also in discussions with Niger, One of the world’s largest uranium producers, to establish a potential partnership.

Nuclear energy is gaining renewed interest across Africa. Countries such as South Africa and Kenya are also moving toward nuclear power plants. The 28th United Nations Climate Change Conference (COP28) in Dubai in 2023 marked a milestone for the nuclear industry when it was formally recognized as one of the solutions for producing low-carbon energy. Since then, it has increasingly been promoted as a tool to help reduce greenhouse gas emissions and combat climate change.

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After a weeklong IAEA mission assessing 19 points including legal framework and safety, Rwanda was found to be making “strong progress toward establishing its nuclear program,” with President Paul Kagame stating that “nuclear energy is not too complex or risky for developing countries.” Rwanda expects its first small modular reactor to be operational by the early 2030s, aiming for nuclear to supply “60‑70% of its electricity mix” as the country targets 100% electricity access by 2030.

The country has partnered with Canadian‑German firm Dual Fluid Energy and institutions from Russia and the US to develop SMR technology, and has been in discussions with uranium‑producing Niger. Nuclear energy is gaining renewed interest across Africa, with South Africa and Kenya also moving toward nuclear power plants.

Continuing its hostile actions, the American-Zionist enemy launched a projectile that struck the vicinity of the Iranian Bushehr nuclear power plant at 9:08 PM on Tuesday.

The Iranian Tasnim News Agency reported that initial reports indicate that the incident resulted in no material, technical, or human losses, and no damage was inflicted on any of the plant's various sections.

The vicinity of this plant was previously targeted by another projectile on March 16, which also ended without casualties or damage.

The agency emphasized that the attack on peaceful nuclear facilities constitutes a blatant violation of international conventions and obligations related to the inviolability of such facilities from military action. It considered this an act that could have serious and irreversible consequences for the security and safety of the region, particularly the Persian Gulf states.

The UK's science minister is announcing details of a five-year, £2.5 billion investment in nuclear fusion, reports the Times of London, "including building one of the world's first prototype fusion power plants in Nottinghamshire and developing a UK sector projected to employ 10,000 people by 2030."

Despite the potentially transformative impact of fusion, which in theory could provide limitless clean energy and create a £12 trillion global market, no country has managed to use this fledgling technology to generate useable electricity... [T]he UK is backing a spherical tokamak design... investing an initial £1.3 billion into a prototype fusion power plant called Step (Spherical Tokamak for Energy Production) on the site of a decommissioned coal-fired power station at West Burton in Nottinghamshire. Paul Methven, chief executive of the government-owned UK Industrial Fusion Solutions, which is delivering the Step project, said the aim is to get the reactor operating early in the 2040s. "It's quite an aggressive programme," he said. "We need to show that we can achieve genuine 'wall socket' energy — which has not been done before."

On Monday, [science minister] Vallance will also announce £180 million for a facility in Culham, Oxfordshire, to manufacture tritium fuel and £50 million for training 2,000 scientists and engineers in fusion-related disciplines. The government is also buying a £45 million fusion-dedicated AI supercomputer called Sunrise to model plasma physics. Scientists at the UK Atomic Energy Authority last year developed an AI model that can rapidly simulate how the ultra-hot fuel in a fusion power plant will behave, cutting calculations that previously took days down to seconds...

Vallance will also announce new support and collaboration for the many fusion, robotics, engineering and AI start-ups working in Britain, to develop a strong supply chain for a new fusion sector. One of those companies, Tokamak Energy, which spun out from the UK Atomic Energy Authority in 2009, has already built a smaller reactor that has informed the Step design. In March 2022, it became the first private organisation in the world to surpass 100 million degrees Celsius in its reactor.

Abstract credit: https://slashdot.org/story/453340

EU's reliance on fossil fuels seen as strategic disadvantage

Germany began phasing out nuclear power after 2011 Fukushima disaster

France seeks nuclear expansion, uranium supply diversification

Maud Brégeon, an engineer and energy expert, has been appointed France’s Deputy Minister for Energy. She supports nuclear power and the development of EPR reactors to secure energy supply and reduce reliance on fossil fuels.

Will these changes of the environmental regulations have a long term positive or negative impact on the nuclear industry?

https://www.nytimes.com/interactive/2025/10/22/climate/china-us-nuclear-energy-race.html

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