UPSC Mains 2025 GS3 Q5: model answer

Fusion joins light nuclei, such as deuterium and tritium, releasing huge energy with no carbon and little long-lived waste. India's work is led by the Institute for Plasma Research (IPR), Gandhinagar.

Indian programme

• ADITYA, India's first indigenous tokamak (1989), upgraded later.
• SST-1, a steady-state superconducting tokamak.
• India joined ITER in 2005 as one of seven members.

Contributions to ITER (in kind, about 9% of cost)

• The cryostat, the largest stainless-steel vacuum vessel of its kind, built by L&T and assembled at the site in France.
• In-wall shielding, cooling water and cryogenic lines.
• Ion cyclotron and electron cyclotron heating systems and diagnostics.
• Indian scientists and engineers in the project team.

If ITER succeeds (target: 500 MW output from 50 MW input)

• Proof that fusion can give net energy, opening the way to demonstration plants (DEMO).
• Near-limitless clean baseload power to meet net-zero goals.
• Less dependence on oil and gas geopolitics.
• Indian industry gains high-tech skills.

Fusion is a long-term bet, likely after mid-century, but India's role ensures it will share the technology when it comes.