エネルギー
安全でコンパクトな核バッテリーがエネルギー貯蔵を革命的に変える可能性
すべてに核エネルギー？
When nuclear power generation became a practical technology, it gave hope that the energy that had so far only been used to create world-ending bombs could also save the same civilization from resource depletion.
As climate change is a growing concern, 核エネルギーは復興の兆しを見せている, as it is an available, scalable, and low-carbon energy source that could bridge the gap until renewables & batteries are ready to replace fossil fuels. And new nuclear power plant designs are coming that can make it cheaper, safer, and more flexible, as we explained in “SMR（小型モジュラー原子炉）に関する最新情報 – 依然として核エネルギーの未来” and “第4世代核エネルギー：より安価、よりクリーン、より安全”.
However these large power plants are not how science-fiction writers initially envisioned nuclear power. Leading thinkers like Isaac Asimov were much more ambitious, and imagined miniaturized nuclear-power generators that could fit into trains, cars, and even smaller devices, making the idea to recharge or refuel them essentially obsolete.
One step in such a direction is being taken with the presentation of nuclear batteries small enough to power small electronic devices. And it would do so safely.
This research work was presented at the spring meeting of the American Chemical Society (ACS) by Su-Il In, a professor at Daegu Gyeongbuk Institute of Science & Technology (South Korea), under the title “Next generation battery: Highly efficient and stable C14 dye-sensitized betavoltaic cell”.
バッテリーの制限
Most electronic devices today are limited in their capacity by their battery, usually using lithium-ion technology. This is true for smartphones, drones, sensors, etc.
As addition, mining for lithium is an environmentally destructive process, and lithium could become a pollutant in the future.
So scientists have long considered the alternative of using radioactive decay, a process taking hundreds or even tens of thousands of years, to be a better alternative, that would require no reloading of devices at all.
However, as such devices would be radioactive, the strictest standards of safety would have to be matched.
ベータ放射能
There are many different forms of radioactivity. Of these, gamma decay is the most dangerous, as it emits very powerful gamma rays, that can cause cancer and other damage.
出典: Compound Chem
Alpha and Beta decays are a lot less dangerous, and the radioactive emissions can be stopped with a thin layer of aluminum or even just paper.
適切な同位体の選択
Which radioactive activity occurs is dependent on the radioactive element and its isotopes, so some power sources are a lot safer than others. For this reason, materials like uranium would not be a good match for small nuclear batteries.
However, carbon-14, a naturally occurring isotope of carbon, often used in establishing the date techniques, would be a good match.
An extra advantage is that carbon-14 is being produced by the existing fleet of nuclear power plants anyway, making it inexpensive, readily available, and easy to recycle. Lastly,
“I decided to use a radioactive isotope of carbon because it generates only beta rays. And because radiocarbon degrades very slowly, a radiocarbon-powered battery could theoretically last for millennia.”
Pr. Su-Il In – Professor at Daegu Gyeongbuk Institute of Science & Technology
ベータボルタイック技術
Leverage beta decay for power generation is not an entirely new concept and is known as betavoltaic, with a beta particle replacing photons used in classic photovoltaic.
In betavoltaic, an electron instead of a photon strikes a semiconductor, which results in the production of electricity.
This semiconductor material is the key part, as how efficient it is will determine the overall energy conversion efficiency rate. So far, betavoltaic semiconductors have been very low in efficiency or too fragile to last as long as nuclear fuel.
二酸化チタン半導体
Prof. In and his team used a material commonly used in solar cells, titanium dioxide, and added a ruthenium-based dye. To make the bond between the dye and the semiconductor solid enough, they used a citric acid treatment.
The ruthenium dye, when hit by a beta particle (a powerful electron), creates a cascade of electron transfer reactions, called an electron avalanche. The titanium dioxide then collects the generated electrons and turns them into usable electricity.
両電極の処理
The researchers discovered that you could radically boost the efficiency of the process by putting the ruthenium dye on both the cathode and anode of the nuclear battery.
Compared to a previous design with radiocarbon on only the cathode, this led to a much higher energy conversion efficiency, going from 0.48% to 2.86%.
応用
Because this system is likely to be for now more expensive than a usual battery, it will find its first applications were not replacing or recharging the power source is the most useful.
For example, pacemakers and other medical implants could be powered for a lifetime with such beta-voltaic batteries.
Sensors in sensitive or hostile environments, like nuclear reactors, factories, the deep sea, or deep space, could also greatly benefit from this concept.
さらなる改良
This technology and impressive increase in efficiency join other research looking to utilize radioactive decay for energy production without a nuclear reactor. For example, 核廃棄物を利用して別種の核バッテリーを製造するというアイデアについて最近議論しました.
Prof. In suggests that further efforts to optimize the shape of the beta-ray emitter and develop more efficient beta-ray absorbers could enhance the battery’s performance and increase power generation.
Overall, this technology is likely to keep improving as our understanding of semiconductors and rare metals progresses.
核エネルギーへの投資
Cameco – Westinghouse Electric Company
(CCJ )
In 2022, Camecoは米国の主要な原子力発電所建設会社であるWestinghouseの49％の支配権取得を決定し、巨大投資会社Brookfield（51％の支配権）と共同で行いました, together with a giant investment firm, Brookfield (51% control).
The company has a massive renewable/low carbon power generation division in the form of $19B Brookfield Renewable Partners (BEP ). Brookfield Corporation as a whole is a massive asset management company with almost a trillion dollars under management.
This means that Westinghouse is now going to be able to access a very deep pool of capital, something that is often an issue for nuclear reactor builders, as new projects require years of investment before bringing in revenues.
While longer to materialize into revenues, once in construction, a new reactor generates revenues for Westinghouse from the 6th year after design and engineering studies and will keep doing so for the entirety of the construction project for a period of more than 10 years.
出典: Cameco
Westinghouse’s work-horse is the tried and tested AP1000 reactor design (6 in operations and 6 in construction), using the company’s CANDU standard, one of the most common in the world.
It is also working on the AP300小型モジュラー原子炉, which is likely to be deployed スロバキアで, フィンランドで, and スウェーデンで, and the マイクロリアクター e-Vinci, illustrating the company’s continuous innovations and how it is keeping up with the industry’s latest trends.
出典: Westinghouse
Westinghouse is instrumental in a large part of the nuclear supply chain. Due to tight regulations, such parts and equipment will be required for any new power plant, traditional or SMR alike.
Overall, even if the supply issue around uranium gets solved and uranium prices crash, the ownership of Westinghouse should allow Cameco to benefit from the ongoing nuclear renaissance for several decades at least.
The rest of the Cameco company is a uranium miner, likely to also benefit from the ongoing renaissance of nuclear energy. Its main mining assets are in Canada and Kazakhstan.
Historically, uranium and nuclear reactor companies have suffered from the fear of nuclear disaster and concerns regarding nuclear waste.
As newer and safer designs mature, and as nuclear wastes become a valuable resource instead of a problem, this should no longer be a problem. This includes carbon-14 production for betavoltaics, which could become an additional production of Westinghouse power plants.
In addition, the push for more low-carbon power sources, while renewables are still to fully solve the problem of intermittent production, especially in winter, should help nuclear energy make a powerful comeback.
(この研究で使用された元素の需要ポテンシャルに興味がある場合は、チタン投資に関するレポートをご参照ください)
最新情報 Cameco-Westinghouse Electric Company
