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As Vietnam resumes its nuclear power projects to meet escalating energy demands, thorium-based nuclear energy emerges as a promising pathway. This presents an opportunity for the nation to leverage advanced, sustainable technologies, shaping the future of its energy landscape.
Thorium – A Promising Nuclear Fuel Resource
Thorium (Th-232) is a naturally occurring radioactive element with global reserves estimated to be 3–4 times more abundant than uranium. According to the International Atomic Energy Agency (IAEA), thorium reserves exceed 6 million tonnes worldwide, with significant deposits in countries such as India (~1.07 million tonnes), Brazil (632,000 tonnes), Australia (595,000 tonnes), and the United States (595,000 tonnes). In Vietnam, thorium is present in rare earth deposits in provinces like Lai Châu and Yên Bái, with estimated reserves in the tens of thousands of tonnes—sufficient to potentially meet the country’s energy needs for decades if effectively utilized.
Unlike uranium-235 (U-235), thorium-232 is not directly fissile. Instead, it functions as a “fertile material.” When irradiated with neutrons in a reactor, Th-232 undergoes a transmutation process: it first transforms into thorium-233, which then decays into protactinium-233 and ultimately into uranium-233 (U-233). U-233 is a potent fissile isotope capable of sustaining a nuclear chain reaction, generating thermal energy that can be converted into electricity.
This fuel cycle offers distinct advantages: the radioactive waste from thorium-based processes has a significantly shorter half-life (~500 years compared to tens of thousands of years for uranium waste), and U-233 is less suitable for weapons proliferation than U-235 or plutonium-239, enhancing nuclear security. Given thorium’s abundance both globally and domestically, Vietnam stands to reduce its reliance on imported uranium, optimizing indigenous resources.
Thorium-Compatible Nuclear Reactor Technologies
Several reactor designs have been developed or are under development to harness thorium efficiently. Key technologies include:
Molten Salt Reactor (MSR)
MSRs utilize thorium dissolved in a molten salt mixture (typically fluorides or chlorides) at high temperatures, serving as both fuel and coolant. Operating at low pressure, this design enhances safety and enables online fuel reprocessing, minimizing waste. The United States demonstrated the feasibility of this technology with a small-scale MSR at Oak Ridge National Laboratory in 1967. Currently, China is advancing MSR development, targeting commercial deployment by 2030.
Heavy Water Reactor (HWR)
Heavy water reactors, such as the CANDU design from Canada, can be adapted to use thorium alongside small amounts of uranium or plutonium as a starter material. Heavy water (D₂O) efficiently moderates neutrons, optimizing the conversion of Th-232 to U-233. This technology leverages existing infrastructure of CANDU.
Fast Breeder Reactor (FBR)
FBRs employ fast neutrons to convert thorium into U-233 while simultaneously breeding additional fissile material. France operated the Superphénix FBR from 1985 to 1997, and Russia’s BN-800, connected to the grid in 2016, demonstrates potential for thorium integration. These projects affirm the viability of FBRs, though they require substantial technical investment.
High-Temperature Gas-Cooled Reactor (HTGR)
HTGRs can use thorium embedded in coated particle fuel (TRISO), cooled by helium gas. This design offers inherent safety through passive temperature regulation and high thermal resilience. China achieved a milestone with the commercial operation of its HTR-PM (Generation IV) reactor in Shandong in December 2023, showcasing thorium’s potential in compact systems suitable for Vietnam.
Prospects in Vietnam
With a national target of net-zero emissions by 2050 and rapidly growing electricity demand, thorium could be a cornerstone of Vietnam’s energy strategy. Technologies such as MSRs, FBRs, and HTGRs can exploit domestic thorium resources, delivering stable, low-carbon power while reducing dependence on imported fuels. This positions Vietnam closer to a sustainable energy ecosystem.
Challenges
Despite its promise, deploying thorium-based reactors in Vietnam faces hurdles. MSR and FBR technologies remain in development and have not yet achieved widespread commercialization, unlike conventional light water reactors using uranium. Vietnam would need to invest in research, infrastructure, and specialized human resources. High initial costs also pose a barrier, necessitating collaboration with leading nations such as China, India, Russia, or lessons from the United States and France.
Nevertheless, these challenges are surmountable. The passive safety features of MSRs and HTGRs can mitigate accident risks, addressing public concerns post-Fukushima. International partnerships could optimize costs and accelerate implementation timelines.
Thorium and advanced nuclear reactor technologies offer a transformative pathway for Vietnam’s energy sector. With its abundant reserves and inherent advantages, thorium represents not only a viable energy solution but also an opportunity for the nation to establish itself in the global nuclear technology arena. While challenges remain, the potential of thorium is undeniable, promising a cleaner, more resilient energy future for Vietnam.
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