Haiyang-4

Background: The AP1000 reactor, explained

Current state

Notes

On schedule for 2027 commercial operation (56-month plan from April 2023 first concrete). Trajectory mirrors Haiyang-3 with ~10 months lag: external containment dome Feb 2026 vs Mar 2025 for unit 3; final CB-20 module Jun 2026 vs Aug 2025. Milestones are SPIC/CNNC announcements corroborated by World Nuclear News and NucNet.

Milestone log

• 2025-06-24 — Reactor internals (260 t) hoisted into reactor building (RPV installed November 2024) (source)
• 2025-09-06 — Inner steel containment vessel top head (658 t, ~40 m diameter) installed; nuclear island shifted from civil works to installation (source)
• 2026-02-09 — External containment steel dome hoisted into position (source)
• 2026-06-16 — Listed as under construction in the WNA world table, grid connection estimated 2027 (source)
• 2026-06-29 — CB-20 containment water tank module (419 t) installed — last large module; Haiyang Phase II entered installation and commissioning phase (source)

The milestone log is append-only: corrections are recorded as new entries, never rewrites. Full history via /api/v1/changes.

NNN coverage

Sources

1. https://world-nuclear.org/information-library/current-and-future-generation/plans-for-new-reactors-worldwide
2. https://pris.iaea.org/pris/
3. https://www.world-nuclear-news.org/articles/final-module-installed-at-haiyang-4
4. https://www.nucnet.org/news/china-announces-progress-at-three-nuclear-construction-sites-2-1-2026
5. https://www.world-nuclear-news.org/articles/inner-containment-dome-in-place-at-haiyang-4
6. https://www.world-nuclear-news.org/articles/reactor-internals-installed-at-haiyang-4