Kansai investors press Mihama restart case as Japan nuclear approvals stall
Waste storage gaps and licensing delays are forcing Kansai Electric to account for risks its disclosures have so far glossed over.
Japan's nuclear restart program is grinding on three fronts simultaneously — waste storage, licensing delays and community resistance — and Kansai Electric's Mihama plant sits squarely in that bottleneck. GlobalData power analyst Attaurrahman Ojindaram Saibasan said existing plants from the pre-2011 fleet are being requalified alongside safety upgrades, but community mistrust continues to weigh on the process.5
Every reactor Kansai brings back online displaces LNG and coal burn in its service area, cutting fuel costs that Japanese utilities still pass through to tariffs. With JKM Asian LNG at $23.76/MMBtu on September 3, that equation is not trivial. The gap between political support for nuclear and the physical steps required to restart ageing units has quietly widened.5
Investors watching Kansai's disclosures have seen this pattern before. Company presentations tend to emphasize safety upgrades completed and regulatory milestones reached, while spending less time on the unresolved items — spent fuel disposal foremost among them. Japan still lacks a final repository for high-level waste, leaving utilities holding increasingly full pools at their sites.5
The comparison that shadows Japanese nuclear timelines is Kashiwazaki-Kariwa, the world's largest nuclear plant, which remains offline fifteen years after the Fukushima disaster. The Economist reported in May (2026-05-19) that restarting that facility would not resolve Japan's broader energy dilemma, pointing to structural issues that persist even when regulators clear individual units. Kansai's Mihama story runs along the same trajectory.1
For spent fuel, the Taiwan Power Co case offers an instructive parallel. Taipower chairman Tseng Wen-sheng said in May that the utility pays NT$100 million to NT$200 million a year to store nuclear fuel in the US that it has never burned, while the stranded fuel is worth roughly NT$8 billion according to Taiwan's auditor-general. Nuclear commitments do not end when a reactor is cancelled — or even when it is built.4
The nuclear supply chain tightening outside Japan does not help Kansai's case on timing. US electricity use is forecast by the EIA to reach a record 4,269 billion kilowatt-hours in 2026, rising to 4,399 billion in 2027, a demand surge that is pulling reactor components, fuel fabrication capacity and skilled outage crews toward American projects. Japan's restarts compete for the same supply chain.3
None of this appears in Kansai's risk disclosures as a discrete line item. But the practical effect is measurable: longer lead times for safety equipment and fuel reloads push restart schedules back, and each delay extends the period in which Kansai must source replacement power from LNG and coal markets. The economics of a reactor returning in 2028 differ materially from one slipping to 2030.3,5
If Kansai cannot demonstrate a credible path to move used fuel off-site, local prefectures retain grounds to withhold consent regardless of central government preference. That risk does not appear in standard discounted cash flow models, yet it has repeatedly killed Japanese restart schedules. It is a known unknown that analysts have increasingly started pricing into utility valuations.5
The other pressure point is how Kansai communicates outage and earthquake risk to shareholders. Japanese utilities have historically framed nuclear risk in probabilistic terms — design-basis events, safety margins. Fifteen years of post-Fukushima experience suggests investors now want scenario analysis that includes extended multi-unit outages and the financial consequences of prolonged idling, not only the base case of an on-time restart.1
Competitors are hedging their own exposure to nuclear delays. Hokuriku Electric is building a new 630 MW LNG-fired unit at Toyama Shinko targeting operations in FY2033, using combined-cycle technology expected to achieve 64% generation efficiency. Every new gas plant commissioned by a rival utility is a structural bet that nuclear timelines will slip again.2
Traders and analysts will get their next signal when Kansai issues its next quarterly update. If the utility starts locking in LNG volumes for 2028 and 2029, the market will know the Mihama restart date has moved again. If it holds off on forward fuel procurement, management's language on waste handling and licensing milestones will be tested against the delays accumulating elsewhere in Japan's nuclear fleet.5,2