On humanity’s long journey in search of clean energy, nuclear power—thanks to its astonishing energy density and low-carbon characteristics—has become a crucial pillar of the global energy transition. However, the safe and stable operation of nuclear reactors, the effective treatment of nuclear waste, and the commercial application of fusion energy remain formidable challenges, like three great mountains pressing upon the shoulders of scientists.
Remarkably, an unassuming compound—lithium chloride (LiCl)—is playing an indispensable role in the nuclear energy field by virtue of its unique physicochemical properties. It is hailed as a “hidden hero” that supports nuclear safety and drives technological innovation.
Now, let us step together into the “nuclear domain” of lithium chloride and unveil the mysteries that lie behind it.
I. The Role of Lithium Chloride in Nuclear Energy
► Applications in Nuclear Reactors
In the operation of nuclear reactors, lithium chloride—with its distinctive physicochemical properties—serves as an indispensable “safety barrier.” It can effectively absorb and neutralize neutrons produced during nuclear reactions, thereby reducing radiation risks and ensuring the safe and stable operation of the reactor. In addition, LiCl exhibits excellent thermal stability, enabling it to maintain its performance under high-temperature conditions and provide continuous protection for the reactor.
► Neutron Absorber and Safety Assurance
As the core component of any nuclear power system, the safe and stable operation of a nuclear reactor is vital to both human and environmental safety. Lithium chloride plays a crucial role in this regard. It not only helps control the rate of the nuclear reaction but also prevents potential hazards caused by overheating of the reactor core. In this sense, LiCl acts as a robust safeguard that reinforces reactor safety.
► Moderator and Emergency Coolant
In thermal neutron reactors, fast neutrons must be slowed down to thermal neutron energies (about 0.025 eV) by a moderator in order to effectively trigger the fission of uranium-235. Owing to its lightweight lithium component, lithium chloride can be used as a moderator or in combination with other moderating materials. This enhances neutron-slowing efficiency, boosts reactor power output, and reduces radiation damage to structural materials, thereby extending equipment lifespan. Moreover, LiCl solutions can reduce coolant vaporization, lowering the risk of steam explosions.
► Nuclear Waste Treatment
Nuclear waste treatment has long been a major technical challenge in the nuclear energy field. LiCl demonstrates unique value in this area as well. It can react with certain radioactive elements in nuclear waste to form compounds with lower or even negligible radioactivity, thereby achieving a form of “purification.” This characteristic gives lithium chloride a significant advantage in nuclear waste management.
► Fixation and Adsorption of Radioactive Substances
Lithium chloride can react with radioactive ions—such as cesium ions (Cs⁺) and strontium ions (Sr²⁺)—to form poorly soluble precipitates, significantly reducing the mobility of nuclear waste. Specifically, when lithium chloride combines with phosphates, it forms cesium lithium phosphate (CsLiPO₄), a compound with extremely low solubility that can stably immobilize cesium over long periods. Likewise, its reaction with sulfates produces lithium strontium sulfate (SrLi₂(SO₄)₂), effectively preventing strontium from entering groundwater and further ensuring environmental safety.
► Role in Nuclear Fusion
In the field of nuclear fusion, LiCl also plays an indispensable role. Its unique physical and chemical properties make it a potential “fuel of the future.” Although nuclear fusion technology still faces major challenges, the applications of lithium chloride undoubtedly bring new hope and momentum to this promising field.
► Tritium Breeding and Neutron Shielding
In nuclear fusion—the technology often hailed as the “ultimate energy source”—the production of its key fuels, deuterium (D) and tritium (T), relies on reactions between lithium isotopes (⁶Li) and neutrons. In this process, lithium chloride serves as an effective carrier of lithium resources, making it an indispensable component of the fusion fuel cycle.
In fusion reactors, lithium chloride is carefully incorporated into the inner blanket structures, where it plays a crucial role in tritium breeding through a series of nuclear reactions. In addition, LiCl can be used as a neutron shielding material, effectively reducing radiation damage and helping lower construction costs.
II. Challenges and Future Prospects
With the continuous advancement of nuclear energy technologies, the advantages of lithium chloride as a neutron-shielding material have become increasingly prominent. However, as nuclear applications grow more demanding, lithium chloride is also confronted with new challenges. How to further enhance its performance while ensuring safety has become an urgent issue to address.
At the same time, as nuclear technologies continue to evolve, the application scope of LiCl is steadily expanding, and its future potential is virtually limitless.
III. Conclusion: Lithium Chloride — The “Hidden Champion” of the Nuclear Era
In the nuclear energy sector, LiCl plays an essential and multifaceted role. It not only contributes to the core aspects of reactor safety and control—ensuring the stable operation of nuclear facilities—but also demonstrates remarkable effectiveness in the safe treatment of nuclear waste, protecting the environment from radioactive contamination.
Moreover, lithium chloride is indispensable in tritium breeding for fusion fuels and in innovative neutron-shielding applications, providing strong technical support for the development and utilization of fusion energy. As scientific and technological progress continues, the potential of LiCl will be further unlocked, enabling it to contribute even more to the creation of a low-carbon, safe, and sustainable energy system for humanity.