Revolusjonerende batteri konverterer nukleært avfall til langvarig kraft

Mange måter å splitte atomer på

Nuclear power is often associated with massive power plants, giant cooling towers, and the fear of nuclear meltdown. This is progressively changing thanks to the emergence of SMR‑er (Små modulære reaktorer) and fjerde generasjon av kjernekraftverk (følg lenkene for detaljerte investeringsrapporter om begge).

Both conventional and newer nuclear power plants rely on the same concept of using nuclear energy to warm up water into steam and use the steam to generate electricity via turbines.

Another way to utilize the heat of nuclear reactions is through radioisotope thermoelectric generators (RTG), usually running on plutonium and used for deep space missions.

There are, however, other ways to harness nuclear energy. En av dem er betavoltiske batterier, which use beta radiation to directly generate a current through separating electrons from atomic nuclei in a semiconductor absorber.

Now, a new concept on how to generate power from nuclear reactions has been created by researchers at the Ohio State University and the University of Toledo (USA). It transforms the radiation into light, which is then converted into power by a solar cell, a process called radiovoltaics.

They published their results¹ in Optical Materials, under the title “Skintillatorbaserte nukleære fotovoltaiske batterier for kraftgenerering på mikrowattnivå”.

Utnyttelse av kjerneenergi

When radioactive atoms are split, a few things occur at once. The original atoms split and emit some of their components, in the form of neutrons and/or alpha & beta particles, with the exact reaction depending on which radioactive element is used.

Kilde: Britannica

This can be used to create a chain reaction in the right conditions, which greatly increases the power output of uranium in nuclear power plants.

Another possibility is for some isotopes of certain elements to break apart spontaneously over time. As the original uranium atoms in nuclear fuel break apart, they transform into new elements, creating a complex mix of new elements, many of which are highly radioactive.

This means that these new elements spontaneously break apart a lot more often and emit a lot of energy per second.

Resirkulering av kjerneavfall

The new elements created in nuclear reactors are commonly referred to as nuclear waste, as they cannot be used to generate more power simply in traditional reactors. Their higher spontaneous radioactivity is also a problem, as it makes them very toxic for centuries or millennia.

One way to deal with the issue is to vitrify (turn into glass) and bury the nuclear waste, hoping this is enough to keep it from harming anyone in the next 10,000 years.

Another option is to reuse some of these wastes in special reactors called fast reactors, breeder, or burner reactors.

Such reactors operated in France in the 1970s-1990s. Modern versions of fast breeder reactors include, for example, the designed but not built PRISM fra GE‑Hitachi.

Another option is to use the natural high-energy production of these elements and turn them into power without needing special reactors.

Omforming av stråling til lys og kraft

Finne riktig scintillator

Gamma radiation emitted by highly radioactive elements is difficult to convert directly into electricity because they are so powerful that it tends to damage the semiconductor material that could be used to generate power.

So, while the concept has been tested since the 1950s, yields have been extremely low, ranging from 0.4% to 4.5%, with additional issues of the durability of the system.

Kilde: Optical Material

What the Ohio researchers changed is to use a scintillator, which emits light when it is exposed to radiation. This required a lot of effort to find the right scintillator material as it required to be in the sweet spot matching all requirements:

• Sterk absorber av stråling, både for å øke avkastning og beskytte solcellen.
• Utsendt lys må ha riktig bølgelengde som matcher solcellens absorpsjon.
• Motstand mot skade over tid, slik at lysproduksjonen forblir konstant.
• Tilstrekkelig tykk for å absorbere stråling, men tynn og transparent nok til ikke å absorbere for mye av det utsendte lyset.

Their choice ultimately fell on Cerium-doped Gadolinium Aluminum Gallium Garnet High Light-Yield (GAGG:Ce-HL – Gd3Al2Ga3O12).

Kilde: Optical Material

Produsere kraft fra stråling

The solar cell chosen was a thin-film polycrystalline CdTe, using gold and indium contacts. The main reason for this choice was its high resistance to radiation compared to silicon-based solar cells, up to 3 MGy (Megagrays).

Kilde: Optical Material

To test the concept, the researchers used irradiation from Cesium 137 and Cobalt 60, produced by benchtop irradiators.

Kilde: Optical Material

A surprising finding of the experimental test was that the shape and size of the crystal used as a scintillator could strongly impact the efficiency of the process.

Overall, a larger volume is a good thing, helping capture more radiation and convert more energy into light.

Kilde: Optical Material

The resulting power was up to 1.5 μW under a radiation dose rate of 10 kRad/h (using cobalt), despite the very small size of the prototype, only 4 cubic centimeters in volume.

“Dette er banebrytende resultater når det gjelder kraftutbytte. Denne to‑trinnsprosessen er fortsatt i sine tidlige faser, men neste steg innebærer å generere høyere watt med skaleringskonstruksjoner.”

Ibrahim Oksuz – forskningsassistent i mekanisk og romfartsingeniør ved Ohio State.

Applikasjoner

Batteries of this type could theoretically keep running forever without any maintenance or intervention. In practice, it would likely last as long as the solar cell, with the rest of the system likely to work for many more decades without requiring any intervention.

Because it is still an experimental system and active isotopes are not produced in massive quantities, this is unlikely to be soon powering our smartphones.

It could however be used to create power sources for sensors and equipment in environments where the minimum of human intervention is preferable, or even impossible. For example, in deep space facilities, under the sea, or in nuclear reactors.

Most likely, it will take at least another 5 years before any real-life usage, and a few more years for more generalized applications of this technology.

“Å skalere opp denne teknologien vil være kostbart med mindre disse batteriene kan produseres pålitelig. Videre forskning er nødvendig for å vurdere batterienes nytte og begrensninger, inkludert hvor lenge de kan vare når de er trygt implementert”

Ibrahim Oksuz – forskningsassistent i mekanisk og romfartsingeniør ved Ohio State.

It would also radically change how nuclear “wastes” are perceived. From an unfortunate byproduct of nuclear reactors, they could become a very valuable power source for advanced sensors and electronics in critical functions.

And, of course, recycling nuclear waste into power sources would solve the problem of dealing with nuclear waste in the first place.

“Kjernebatterikonseptet er svært lovende. Det er fortsatt mye rom for forbedring, men jeg tror at dette i fremtiden vil skape en viktig plass for seg selv både innen energiproduksjon og sensorindustrien.”

Ibrahim Oksuz – forskningsassistent i mekanisk og romfartsingeniør ved Ohio State.

Kjernebedrift

Cameco – Westinghouse Electric Company

In 2022, Cameco tok beslutningen om å kjøpe 49 % kontroll i Westinghouse, den ledende byggeren av kjernekraftverk i USA, 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.UN.TO ) (BEPC )  (BEP ). Brookfield Corporation (BN ) 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 6^th year after design and engineering studies and will keep doing so for the entirety of the construction project for a period more than 10 years long.

Kilde: 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 small modular reactor, which is likely to be deployed in Slovakia, Finland, and Sweden, and the microreactor e-Vinci, illustrating the company’s continuous innovations and how it is keeping up with the industry’s latest trends.

Kilde: 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.

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.

Siste om Cameco

Studierreferanse:

^{1. Ibrahim Oksuz, Sabin Neupane, Yanfa Yan, Lei R. Cao. (2025). Optisk materiale. Volum 25, februar 2025, 100401 https://www.sciencedirect.com/science/article/pii/S2590147825000038#abs0010}