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Published August 1, 2023

The world’s increasing demand for energy, combined with global warming concerns, has intensified the push towards renewable clean sources of energy like wind, solar, geothermal, hydropower, and other viable alternatives to existing fossil fuels. In the face of growing demand, the world is shutting down nuclear power plants. Nuclear energy has been around for decades, and apart from a handful of bad accidents, nuclear energy has provided clean and carbon-free unlimited power to the grid.

There is an argument to be made that even a handful of catastrophic events involving nuclear energy is enough to simply shy away from that source of unlimited power. On the other hand, a lot of time and resources have been spent trying to find clean sources of alternative energy like those previously mentioned and we have yet to find one capable of delivering the energy that fossil fuels deliver. And although investment in clean energy technologies is significantly outpacing spending on fossil fuels, according to the IEA World Energy Investment 2023 report, the fact remains that fossil fuels in the form of oil, coal, and natural gas have been powering the economies of the world for the past 150 years. Today, these energy sources continue to supply approximately 80 percent of the world’s total energy needs (Figure 1).

There are some that would say these renewable sources of power are simply just not enough for the world’s demands and that perhaps humanity would be wise to take another look at nuclear power.

Figure 1: World total energy supply by source, 1971-2019. (Source: IEA, https://www.iea.org/data-and-statistics/charts/world-total-energy-supply-by-source-1971-2019, License: CC BY 4.0)

Statista¹ states that as of May 2023, there were 436 nuclear reactors in operation in 32 countries around the world. Operable nuclear reactors are those connected to the grid. Of these, the United States has the largest number of nuclear power reactors in operation with 93 units.

In March of 2023, it was announced that for the first time in almost seven years, a new nuclear reactor had been constructed in the United States. Georgia Power announced that the Vogtle nuclear reactor Unit 3² had reached “initial criticality,” meaning that it had started the nuclear fission process of splitting atoms inside the reactor to generate heat, with the expectation that it would be fully online in three to four months. The Vogtle nuclear reactor Unit 4 is expected to follow suit. The last nuclear reactor to come online, according to the Nuclear Regulatory Commission, was the Watts Bar Unit 2 reactor in Tennessee in 2016.

The nuclear power process is a complicated one, but it starts with uranium, a heavy metal that is mined from the earth. The uranium is processed and refined into a form that can be used as fuel—typically uranium-235 or uranium-238—in a nuclear power plant. These forms of uranium are isotopes, which means they have the same number of protons, but a different number of neutrons. The process of nuclear fission starts by introducing a neutron, an uncharged particle, to the uranium atom. When the neutron collides with the uranium atom, it is absorbed into the nucleus of the atom, making it unstable. This causes the uranium atom to split, releasing a large amount of energy in the form of heat. The process also releases two or three additional neutrons, which in turn, collide with other uranium atoms creating a chain reaction where each fission process leads to more fission processes.

This is the basic process by which a nuclear reactor generates heat, which is then used to heat water and produce steam, which drives steam turbines and generates electricity. Carefully controlling this process is crucial to safely operating a nuclear reactor and generating a steady supply of clean, unlimited power.

Nuclear waste comes from many sources associated with the operation of a nuclear power plant. The spent uranium fuel rods, for instance, are a highly radioactive byproduct of the fission process and a significant source of nuclear waste. In addition to spent fuel rods, things like reactor coolant water and used protective clothing and equipment, which are generally less radioactive than spent fuel, must still be handled carefully to protect human health and the environment.

Nuclear waste disposal poses a significant challenge. It involves encapsulating the waste in solid materials and then storing it in a safe location. For high-level waste, like spent fuel rods, this often means deep geological repositories, where waste is buried deep underground in stable rock formations. These sites must be carefully managed to ensure the waste remains safely contained for the many thousands of years it will take for the radioactivity to decay to safe levels. New research is being conducted on how best to find alternatives to potentially recycling nuclear waste.

Imagine if you did not have to recharge your wearable devices, or your cell phone or laptop. What if all Internet of Things (IoT) devices did not require recharging? While that might be a tall order for us to accomplish today, perhaps not for long. Diamond batteries are an emerging technology that uses radioactive diamond crystals to generate small amounts of electricity with the added benefit of potentially offering an alternative to recycling nuclear waste.

Diamond batteries are a concept for a new type of battery that would use the radioactive decay of nuclear waste to generate electricity. Diamond batteries would use radioactive isotopes like Carbon-14 (C-14), obtained from nuclear waste as their energy source, potentially helping to reduce the amount of waste that needs to be stored. The C-14 would be encased in the diamond, which is an excellent conductor of heat and can be used to carry away heat energy generated by radioactive decay. This heat energy can then be converted into electrical energy. Subsequently, the diamond would be encased in a non-radioactive diamond layer to absorb radiation and make the battery safe.  

Diamond batteries can generate electricity for a very long time, potentially up to thousands of years, because of the long half-life of C-14—some 5,000-plus years. Because of their long lifespan, they have been proposed for applications like powering spacecraft, pacemakers, and devices in remote/hazardous areas. At present, diamond batteries are relatively low-power devices, generating up to around 1 milliwatt of electricity. This limits their applications to devices with very low power consumption. However, research is ongoing to improve their efficiency and power output.

Some of the major companies and organizations working on diamond battery technology included NDB Inc., a U.S.-based startup that originated much of the early research on diamond batteries. They have developed prototypes and aim to commercialize the technology. Researchers at the University of Bristol have published influential studies on using nuclear waste as a radiation source for diamond batteries. Others currently engaged in diamond battery research include Australia’s Macquarie University, who have partnered with NDB on developing diamond battery prototypes. The German research organization Fraunhofer Institute for Ceramic Technologies and Systems is also working on enhancing the efficiency of diamond batteries, and the Lawrence Livermore National Laboratory, a U.S. national lab, has conducted research on radioactive diamonds for batteries.

So, while still largely in the research and development phase, these companies, startups, and research institutions are pushing diamond battery technology forward through materials science, manufacturing, and engineering innovations, but commercial viability still appears to be some years away.

A new battery power management solution from Texas Instruments and one from Analog Devices Inc. are featured in this week's New Tech Tuesday. Power management designs will benefit from these reliable, robust products with precise measurement capabilities and ultra-low power consumption.

The Texas Instruments bq21080 Linear Battery Charger IC is a compact, single-cell, linear battery charger offering power path and ship mode, designed to maximize battery life with four ultra-low quiescent current modes. It efficiently supports loads up to 2.5A. Its input voltage operating range is from 3.0V to 5.9V, making it optimal for battery-to-battery charging. The battery regulation voltage can be configured with a precision of 0.5 percent in 10mV increments ranging from 3.6V to 4.65V. Fast charge currents are also configurable between 5mA and 800mA. Additionally, the bq21080 incorporates one push-button wake-up/reset input and integrated fault protection for safety. This charger is ideal for various wearable devices such as smart AR/VR glasses, TWS headsets, and smartwatches.

The Analog Devices Inc. ADBMS1818 Battery Monitor efficiently measures up to 18 series-connected battery cells with a maximum total measurement error of under 3mV. With a cell measurement range of 0V to 5V, it accommodates most battery chemistries. All 18 cells can be rapidly assessed in 290μs, and lower data acquisition rates can be selected for significant noise reduction. Multiple ADBMS1818 units can be series-connected for real-time monitoring of extended, high-voltage battery strings. It features an isoSPI interface, enabling high-speed, RF-immune, long-distance communications. Power can be sourced directly from the battery stack or an isolated supply. Each cell incorporates passive balancing with individual PWM duty cycle control. This battery monitor also boasts an integrated 5V regulator, nine general-purpose I/O lines, and a power-efficient sleep mode that curtails current consumption to a mere 6μA. Packaged in a 64-lead Low Profile Quad Flat Package with an exposed pad (LQFP_EP), the ADBMS1818 promises enhanced thermal performance.

As the economies of the world continue to seek clean energy sources to combat global warming, renewable sources like solar and wind have proven insufficient to meet current demands. Meanwhile, nuclear power remains controversial despite providing consistent, carbon-free energy for decades. Most pressingly though, nuclear waste accumulation requires disposal. New research into diamond batteries offers a potential solution for recycling this nuclear waste while at the same time offering limitless low power. These tiny nuclear units harness radioactive isotopes inside lab-grown diamonds to produce small electrical currents. While their power output is currently limited, their exceptional lifespan, lasting potentially thousands of years, makes diamond batteries ideal for niche, remote, or low-power applications. While promising, the commercial viability of diamond batteries likely remains years away. Though risks persist, advanced nuclear technologies like diamond batteries warrant continued research alongside renewables to meet the world's growing energy demands.

Sources:

1. “Number of operable nuclear power reactors worldwide as of May 2023, by country,” Statista, June 13, 2023, https://www.statista.com/statistics/267158/number-of-nuclear-reactors-in-operation-by-country/.
2. “Building carbon-free nuclear energy,” Southern Company, accessed July 28, 2023, https://www.southerncompany.com/innovation/vogtle-3-and-4.html.