TEPCO Kashiwazaki-Kariwa Reactor Shutdown 2026: Five Hours After Criticality

A 13-year wait ended in just five hours. Tokyo Electric Power Company (TEPCO) announced on January 22, 2026, that it's shutting down the newly restarted Unit 6 reactor at the Kashiwazaki-Kariwa nuclear power plant. The reactor, which was the first to be reactivated by TEPCO since the 2011 Fukushima disaster, was brought to a halt after an alarm was triggered during critical control rod operations.

TEPCO Kashiwazaki-Kariwa Reactor Shutdown 2026 Context

According to Reuters, the alarm sounded at 12:28 a.m. on Thursday, shortly after the reactor reached criticality—a self-sustaining nuclear chain reaction—at 8:32 p.m. the previous evening. The issue appears to involve the equipment used to maneuver the control rods, which are essential for adjusting nuclear fission. While TEPCO is investigating the root cause, the Nuclear Regulation Authority (NRA) confirmed the reactor remains stable with no immediate safety threats detected.

Public Skepticism and Regulatory Response

The Niigata prefectural government reported no abnormal radioactivity levels around the seven-unit complex. Despite these assurances, the sudden shutdown has reignited public debate. Critics point to the utility's troubled history, including a recent revelation that 88 control rods had been misconfigured for decades. For many, this incident isn't just a technical glitch; it's a reminder of the immense challenges TEPCO faces in regaining public trust after more than a decade of being offline.