What exactly happened at Hamaoka 3–4?

Japan’s nuclear regulator suspended the restart review and moved toward on-site inspections after allegations that seismic inputs were underestimated. The issue is tied to potential data falsification. The process may be redone for affected chapters, delaying approvals until analyses are verified and documentation meets stricter evidence requirements.

How could this affect power prices in Japan?

If nuclear output is delayed, utilities may run more thermal plants and buy additional LNG or coal, lifting near-term fuel costs in yen. Tariff adjustments often follow with a lag and require approvals. Outcomes depend on the inspection timeline, procurement strategies, and broader market fuel price levels.

What should investors watch next?

Focus on inspection results, revised seismic models, and an updated regulatory calendar. Track disclosures on fuel hedging, liquidity, and any guidance change. Community engagement steps in Shizuoka and meeting schedules will signal how quickly approvals might resume or whether new conditions will extend the restart path further.

Does this change Japan’s stance on nuclear policy?

Policy still aims to use nuclear for stable, low-emission supply, but oversight tightens when credibility issues arise. Expect deeper documentation checks, more verification, and longer review queues. The balance of safety and supply remains, yet project-specific timelines can stretch if evidence falls short of regulatory expectations.

Law and Government

January 08: Hamaoka Nuclear Restart Halted on Data Falsification Probe

ByHuzaifa Zahoor January 8, 2026January 8, 2026

The Hamaoka nuclear restart faces a pause after Japan’s regulator moved to suspend and potentially redo the safety review for Units 3–4. The move follows a data falsification probe into underestimated seismic inputs at Chubu Electric and includes on-site inspection plans. For investors, regulatory risk rises, timelines extend, and near-term fuel costs could increase. Delays to the Hamaoka nuclear restart may also test Japan energy policy goals and local community trust in Shizuoka. We explain what changed, the likely cost and schedule effects, and signals to watch next.