For over four decades, the Joint European Torus (JET) fusion laboratory in Oxford has been at the forefront of nuclear fusion research, seeking to unlock the potential of clean, near-limitless energy. However, the world’s most successful reactor will soon conclude its final experiment, marking a significant chapter in the pursuit of sustainable energy solutions. This article delves into the history of nuclear fusion, the legacy of JET, and the future of fusion research.
A Quest for Clean Energy
Nuclear fusion, a process that powers the Sun and stars, has long been considered the holy grail of energy production due to its ability to generate abundant energy without emitting greenhouse gases. Unlike nuclear fission, where heavy atoms are split apart, fusion involves forcing pairs of light atoms together.
The Birth of JET
In the late 1950s, the United States declassified its war research on fusion, sparking a global race to harness fusion for energy. The UK and Europe joined forces, leading to the creation of the Joint European Torus (JET) in Oxfordshire, UK. Scientists from across the continent were brought together to collaborate on this groundbreaking project.
The Tokamak Model
JET adopted the tokamak model, which employs magnetic fields to confine a hot, ionized gas called plasma inside a vessel. This configuration allows light elements to fuse and produce energy. JET also made the strategic decision to use a mix of deuterium and tritium, radioactive isotopes of hydrogen, for its experiments, which proved to be a pivotal choice for fusion reactors.
Milestone Achievements
In 1991, JET conducted the world’s first experiment with the deuterium-tritium fuel mix. Subsequent experiments achieved higher energy yields, culminating in JET holding the world record for the most energy produced in a fusion experiment, totaling 59 megajoules in a five-second pulse. Despite these accomplishments, the goal of producing energy to power homes remains distant.
Challenges and Legacy
JET faced challenges and delays, including a decade-long suspension of experiments in the mid-2000s when the internal structure was replaced. The current focus is on enhancing plasma stability, redistributing power loads, and improving reactor materials’ durability. Following the conclusion of experiments, JET’s decommissioning phase will provide valuable insights into how reactor materials have evolved over time, aiding the maintenance of other fusion sites.
The Future of Fusion Research
The Iter reactor in southern France, the world’s largest fusion project, will benefit from JET’s research. It is a multinational consortium that includes the EU, Russia, the US, and China. However, the UK recently opted not to participate in Iter. Instead, the UK government committed £650 million to a domestic fusion programme, including the construction of a prototype fusion energy plant called STEP in Nottinghamshire. The UK aims to begin operations in the early 2040s.