ISEC First Place – Nuclear Security and Nanotechnology
Introduction
The 13-day confrontation between the Soviet Union and the United States during October of 1962 was marked by the nuclear stalemate that became known as the closest the world has ever been to a nuclear conflict (1). Since then, international pacts such as the 1970 Non-Proliferation Treaty (NPT) and the 1991 Strategic Arms Reduction Treaty (START) have been passed to prevent a recurrence of the October Crisis. However, as the global use of nuclear technology for generating energy grows increasingly common, incidents such as the Fukushima Dai-ichi nuclear meltdown remind us of the terrors of potential nuclear disasters. The deployment of nuclear plants perpetuates the risk of nuclear accidents and nuclear proliferation (2). But rather than forgo the use of the world’s largest source of emission-free energy and second-largest producer of electricity, the incorporation of nanotechnology into nuclear science offers hope for the future of nuclear energy and security.
The repercussions of nuclear catastrophes stemming from inadequate security measures can reverberate around the world years after the actual incidents. The United Nations’ International Atomic Energy Agency (IAEA) declared that the recent Fukushima crisis has “escalated to its worst level since a massive earthquake and tsunami crippled the plant more than two years earlier” as storage tanks continue to leak radioactive water (3). Although an earthquake provided the ultimate trigger for the incident, the damage could also be attributed to human negligence at multiple levels, according to the Tokyo Electric Power Company (TEPCO). These included the ill-advised decision to release volatile hydrogen gas to vent steam (that later reacted with oxygen in the second containment structure, resulting in structure-damaging explosions and a radioactive leak) and pumping saltwater to cool reactor temperatures (which damaged the reactors) (4). Today, contamination has risen to a level five times the maximum human exposure capacity. Yet this crisis is still far from the worst-case scenario; an accidental release of the remaining radioactive material within the plant could have generated far greater health and environmental hazards (5). Given that the decommissioning of the plant would require an additional 40 years, the possibility of another nuclear mishap seems greater than ever.
At first glance, the problems stemming from the use of nuclear energy seem daunting. Yet they can be divided into three central concerns: future nuclear meltdowns, nuclear proliferation, and international nuclear security. All of these categories involve issues of international relations, environmental sustainability, and health. At the heart of solution lies nanotechnology, the manipulation of matter on the atomic and nuclear scale.
Future Nuclear Meltdowns
At the time of the Fukushima Incident, Japan was ranked as the third leading country in scientific research and technology, suggesting that Japan should have been one of the countries most capable of dealing with a nuclear catastrophe (6). Its failure to do so, however, points to the possibility of additional nuclear meltdowns in the future, especially considering the growing number of countries interested in developing nuclear power plants (7). These nations are eager to claim the economic and environmental benefits associated with nuclear energy but have been a source of concern since many of the countries lack experience in dealing with nuclear technology, making them less reliable at responding efficiently to a nuclear emergency compared to their developed counterparts (7).
Instead of depending solely on emergency procedures, however, pre-emptive measures must also be taken. Researchers at the Los Alamos research institute have made progress in producing self-repairing substances within nuclear reactors utilizing the unique properties of nanocrystalline materials (10). These virus-sized copper particles consist of a series of nanosized particles (called grains) and the interfaces between them (called grain boundaries) and possess the ability to absorb and eliminate any defective particles (10). This characteristic was observed when scientists monitored defects and grain boundaries in a series of computer simulations in which particles were exposed to radiation. Researchers expected to see the standard phenomenon responsible for the failure of nuclear reactors: the formation of wide spaces in between the individual atoms (called vacancies) as a direct result of the radioactive energy displacing the particles out of place, causing brittleness and swelling in the material that eventually causes the nuclear reactors to fail (10). Instead, scientists discovered that particles underwent a process now dubbed the “loading-unloading” process:
“On the shorter timescales, radiation-damaged materials underwent a ‘loading’ process at the grain boundaries, in which interstitial atoms became trapped—or loaded—into the grain boundary. After trapping interstitials, the grain boundary later ‘unloaded’ interstitials back into vacancies near the grain boundary. In so doing, the process annihilates both types of defects—healing the material.”
This finding debunked the belief that nanocrystalline grain boundaries can only accumulate interstitial atoms, encouraging further studies into the functions and capabilities of self-healing regarding nanoengineered material surfaces. Most importantly, the low energy threshold required for this mechanism to take place consolidates this process as a viable addition for future designs of much more radiation-tolerant nuclear structures (10). Should the allure of national development continue to drive interest in erecting nuclear power plants in developing countries, the self-restoring capabilities of nanocrystalline materials could decrease the number of nuclear accidents by proactively enriching nuclear structures before an emergency response is necessary.
Nuclear Contamination
Another problem posed by nuclear energy use is nuclear waste. Environmentalists over the decades have lobbied against nuclear power plants because of the radioactive byproducts of nuclear energy. The chief concerns of nuclear waste have boiled down to the assertions that radioactive uranium lasts for hundreds of thousands of years, allowing its radiation to permeate bodies of water, wildlife, and agriculture. Much of the nuclear waste may take an upward of 240,000 years before it becomes safe to approach. Although institutions such as the Nuclear Security Summit and the IAEA are doing their best to maintain the safety of nuclear plants, the IAEA has acknowledged that it cannot possibly prevent all problems (7).
In spite of this global hurdle, Professor Huai-Yong Zhu from the Queensland University of Technology supports theory that could drastically lower radioactive emissions. A nanofiber comprised of inorganic titanic oxide, he claims, can lock radioactive material from exposure to water and wildlife, surpassing the current methods of using microporous minerals (known as zeolites) and clay to absorb radiation (12). Professor Zhu said that “one gram of the nanofibers can effectively purify at least one [metric ton] of polluted water.” When used conjunctively with silver oxide nanocrystals, these nanofibers were able to capture and incapacitate harmful radioactive ions known to induce cancer (12).
In a similar effort, former Los Alamos National Laboratory engineer Liviu Popa-Simil revealed that harmful radiation could also be translated into usable electricity. When radioactive matter runs through nanotube complexes packed with gold and coated by lithium hydride, a stream of high-energy electrons is produced. This stream can eventually come in contact with electrodes, which allow the electric current to flow (13). This practice allows electricity to be harvested from both high-radiation centers (such a nuclear waste dump) and directly from radiation emitted from a nuclear reactor, potentially easing a major environmental consequence of nuclear energy. Continued development of Popa-Simil’s concept may be instrumental in bridging the gap between nuclear energy and nuclear security. By mitigating the consequences of nuclear waste, nuclear energy can be utilized without the constant fear of environmental destruction.
International Nuclear Security
The Seoul Nuclear Security Summit, comprised of 53 world leaders, meets yearly to discuss national and international issues regarding nuclear security. In spite of having advanced international nuclear security objectives in response to the Fukushima incident, the summit has found it difficult to reach a global consensus due to differing national opinions regarding nuclear proliferation and weaponry. With 473 nuclear power plants and over 17,000 nuclear weapons distributed internationally, the numbers continue to grow, escalating the chances of domestic and international nuclear disasters. In the year 2000 alone, nearly 310 tons of usable, weapons-grade uranium was produced worldwide (to put this into perspective, just 8 kilograms is sufficient to manufacture a Nagasaki-scale bomb) (8). Although the bulk of the 1,600 tons of highly enriched uranium (HEU) and 500 tons of plutonium are separated and securely guarded by the world’s two largest nuclear giants–United States and Russia–the remaining radioactive substances are scattered among thirty-some countries and susceptible to theft (7). Increased proliferation of nuclear weapons pushes the world closer and closer to global nuclear war.
While nanotechnology possesses the capability of restricting many of the environmental implications of nuclear waste, no international organization can guarantee that each sovereign nation will handle its radioactive material responsibly. What nanotechnology can guarantee, however, is a reliable detection system in the event that nuclear warheads are fired. Researchers at Louisiana Tech University have developed a multi-channel nanoparticle device that is capable of alpha, beta, gamma, and neutron detection (11). Taking advantage of the fact that fissionable bombs emit all five of the given types of radiation, scientists can convert each species into electrons through physical mechanisms (including charge conversion, and thermonuclear fusion reactions) to pinpoint the exact radioactive isotope (11). Such information might be crucial for an immediate response in the event of danger. With the use of multiple high-flux regions, particles can be successfully identified as one of four different types of radiation (11). The developed glass microdevice harbors a patterning that discriminates between all types of radioactive waves, a property crucial for determining the exact composition of the nuclear material (11). This detection mechanism proves to be superior to modern technologies because of its additional ability to detect beta and gamma radiation despite lead-shielding. The device produced successful results when tested with a cobalt gamma source and is undergoing continual refinement. The adaptation of this particular nuclear response system worldwide will curb the threat of a nuclear launch and drastically reduce the chance of nuclear turmoil.
Through a multi-faceted approach to enforcing nuclear security centered around nanotechnology, the hopes of a consequence-free nuclear future is becoming a reality. By increasing the synergy between nuclear science and nanotechnology, the world can advance its understanding of nanotechnology and take control over nuclear power.
Contact Tony Pan at ton ypan19@gmail.com
References
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