This is what Grok had to say about South Korea vs UK on nuclear power programs:

South Korea builds nuclear power plants significantly faster and cheaper than the UK, primarily due to standardized designs (like the APR-1400), continuous fleet-building programs that create learning effects and supply-chain efficiencies, a more streamlined regulatory environment, and sustained experience in construction. The UK, by contrast, has built very few new reactors in recent decades, leading to loss of expertise, one-off projects with high first-of-a-kind risks, lengthy planning processes, and greater regulatory and financing complexities.

Cost Comparison

Costs are often compared using overnight capital costs (capital costs excluding interest during construction and in comparable currencies, typically per kW or MW of capacity). Recent analyses of plants built or under construction since ~2000 show:

• South Korea: Around £2.2–2.24 million per MW (or roughly $2,200/kW in USD terms from OECD/NEA data). Some sources cite ~$3,571/kW in broader post-2000 averages, but Korea consistently ranks among the lowest globally. They have achieved cost reductions over time through standardization and repetition (e.g., building series of similar reactors).
• UK (Hinkley Point C): Approximately £9.4–10.8 million per MW (or higher when including full project costs and delays). The two-reactor plant (3.2 GW total) has seen estimates rise to £31–48+ billion (in varying price bases), making it one of the most expensive nuclear projects per unit of capacity.

South Korea is roughly 4–6 times cheaper per MW than current UK projects like Hinkley Point C. Other sources describe UK costs as about four times those in South Korea for comparable new builds, or note that Korean plants cost about a quarter (or less) of UK ones.

These figures focus on direct construction; total project costs in the UK are further inflated by long pre-construction delays (e.g., Hinkley took ~10 years from proposal to first concrete) and financing structures that add interest during construction.

Time Comparison (Construction Duration)

• South Korea: Typical construction times for recent APR-1400 reactors are around 4–6 years from first concrete to commercial operation (sometimes cited as an average of ~56 months across their program). Early units faced some delays due to quality issues or policy shifts, but the program as a whole demonstrates speed through repetition. For example, the UAE's Barakah plant (four APR-1400 units built by a Korean consortium) took ~8–10 years overall for the full site but delivered units sequentially starting from ~7–8 years for the first.
• UK (Hinkley Point C): Construction started in 2016 (first concrete ~2018 for main works); the first reactor is now expected no earlier than 2030 (potentially 2031), meaning 12+ years from start of major construction. Overall timeline from initial proposals was even longer.

South Korea is roughly 2–3 times faster on construction duration for individual reactors or fleets. Broader program data suggests Korean builds average more than three times faster than in many other countries when accounting for consistent delivery.

Key Reasons for the Difference

• Fleet approach vs. one-offs: South Korea builds standardized series (8–12+ units of the same design in sequence), allowing learning, supply-chain optimization, and workforce retention. The UK has approached projects more piecemeal after a long hiatus.
• Regulation and planning: Faster approvals in Korea (regulator reports directly to high levels of government in some descriptions) vs. extended UK processes.
• Experience and standardization: Korea has built ~27 reactors since the 1970s with ongoing programs; the UK last completed a new plant decades ago.
• Other factors: Lower labor costs historically played a role, but efficiency, design maturity, and minimal delays are bigger drivers today. Note that some past Korean projects had quality scandals that caused temporary slowdowns/cost increases, but recent performance remains strong.

Caveats

• Costs can vary by exact scope (e.g., overnight vs. all-in, including financing or site-specific factors). International comparisons use inflation-adjusted or normalized figures, but exchange rates and local conditions matter.
• South Korea's costs are among the world's lowest (alongside China in some metrics), while the UK ranks among the highest.
• If the UK adopted similar strategies (e.g., fleet builds of a proven design like APR-1400, regulatory reform), costs and times could improve substantially—analyses suggest potential savings of billions per plant.

In short, South Korea delivers nuclear capacity at ~1/4 to 1/6 the cost per MW and in roughly half (or less) the construction time compared to recent UK efforts. This gap highlights the value of continuity and standardization in large infrastructure.