Fusion power — Commercial power generation from a thermonuclear fusion reactor is not yet realized mainly because:
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Ait is difficult to control fusion reaction (confinement and stability challenges).
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Bthe fuel required (deuterium and tritium) is scarce.
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Cit is difficult to initiate fusion reaction.
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Dthe quantity of fuel required to initiate fusion is prohibitively high.
Answer
Correct Answer: it is difficult to control fusion reaction (confinement and stability challenges).
Explanation
Introduction:Fusion promises abundant, low-carbon energy, but commercial plants remain elusive. The central challenge is maintaining a stable, high-temperature plasma long enough (adequate confinement time and density) to achieve net energy gain.
Given Data / Assumptions:
- Fusion fuels (D and T) are available via seawater and breeding (T from lithium).
- Reactor concepts include magnetic confinement (tokamak, stellarator) and inertial confinement.
- Question asks for the main reason commercialization is not yet achieved.
Concept / Approach:Net-positive fusion requires satisfying the Lawson criterion (sufficient product of density, temperature, and confinement time). Achieving and controlling these conditions without excessive losses or instabilities is the core obstacle.
Step-by-Step Solution:Evaluate scarcity claim: Deuterium is abundant; tritium can be bred from lithium. Fuel scarcity is not primary.Evaluate initiation difficulty: Ignition is challenging, but the sustained control and confinement for net gain is the deeper issue.Evaluate fuel quantity: Required quantities are tiny; quantity is not the limiting factor.Therefore, the main barrier is control and confinement stability, making (a) the best answer.
Verification / Alternative check:Research highlights include turbulence suppression, disruption avoidance, and materials able to withstand neutron fluxes, aligning with the control/confinement challenge.
Why Other Options Are Wrong:
- (b) Fuel scarcity is not the issue; D is abundant; T can be bred.
- (c) Initiation alone is not the key barrier; sustaining and controlling the plasma is.
- (d) Fuel quantity needed is very small, not prohibitively high.
Common Pitfalls:Equating ignition with commercialization; ignoring engineering challenges in confinement, materials, and tritium breeding.
Final Answer:it is difficult to control fusion reaction (confinement and stability challenges).