2026年3月托福机经套卷(第8套) - Read an Academic Passage Q1

Magnetic Confinement Fusion Magnetic confinement fusion is a promising approach for generating clean electricity. This technology fuses deuterium and tritium, heavy forms of hydrogen, to release energy while producing minimal radioactive waste when compared to current technologies to produce nuclear power. The basic principle was first demonstrated in 1957: powerful magnetic fields contain extremely hot plasma at temperatures reaching 150 million degrees Celsius—ten times hotter than the sun's core. Without magnetic containment, the plasma would instantly cool upon touching reactor walls, halting the fusion process. Since those early breakthroughs, researchers have built increasingly sophisticated magnetic confinement reactors called tokamaks. The International Thermonuclear Experimental Reactor (ITER), currently under construction, represents the culmination of decades of magnetic confinement research. ITER aims to demonstrate sustained fusion reactions that produce more energy than they consume—a critical milestone called net energy gain. However, significant challenges remain before magnetic fusion can generate commercial electricity. Current experiments require enormous energy inputs to maintain plasma conditions, and the intense neutron radiation gradually damages reactor materials. Additionally, converting fusion energy into usable electricity requires developing efficient heat-to-power conversion systems. Despite these obstacles, successful demonstration of net energy gain could pave the way for fusion power plants by the 2040s.