# Fukushima Daiichi decommissioning and water release

> Live situation record from CLSTR: https://clstr.news/situations/fukushima-daiichi-decommissioning-and-water-release
> Updated: 2026-08-29T07:11:25.000Z. Sources: 7. Developments: 3.

The decommissioning and water management operations at the Fukushima Daiichi Nuclear Power Plant continue amid technical challenges and international scrutiny. After three years of discharging treated water into the ocean, Tokyo Electric Power Company (TEPCO) has released approximately 173,000 tonnes across 22 rounds. 

As of late August 2026, the facility has commenced its 23rd release of treated water. This 19-day operation aims to discharge approximately 7,800 tons of water diluted with seawater, with an estimated total tritium content of 1.2 trillion becquerels. These releases are intended to reduce the number of on-site storage tanks to facilitate decommissioning activities, such as constructing facilities for fuel debris retrieval.

Despite these efforts, the total volume of stored water has decreased by only 7% to 7.6% because new contaminated water is continuously generated by groundwater and rain contacting melted fuel debris. While the International Atomic Energy Agency (IAEA) reports no unusual radioactivity in the marine environment, international tensions persist. China, Hong Kong, South Korea, and Russia maintain import restrictions on Japanese seafood due to safety concerns.

Technical assessments have revealed structural damage within the facility, including a 3-meter hole at the bottom of the Unit 3 reactor pressure vessel. TEPCO intends to begin large-scale removal of debris as early as fiscal year 2037. Additionally, repairs have been completed on an expanded solid waste incineration facility that had been offline since February 2024; it is expected to resume operations in August. The long-term decommissioning plan is targeted for completion by 2051.

## Timeline

### 2026-08-29: Fukushima Daiichi begins 23rd treated water release

Fukushima Daiichi has begun its 23rd treated water release, aiming to discharge 7,800 tons over 19 days to facilitate decommissioning and waste management.

2 sources. https://clstr.news/cluster/fukushima-daiichi-begins-23rd-treated-water-release

### 2026-08-29: Fukushima Daiichi Unit 3 reactor vessel found with 3-meter hole

TEPCO discovered a 3-meter hole in the Unit 3 reactor pressure vessel at Fukushima Daiichi, containing potential nuclear debris. Cooling and water treatment operations remain ongoing.

2 sources. https://clstr.news/cluster/fukushima-daiichi-unit-3-reactor-vessel-found-with-3-meter-hole

### 2026-08-24: Fukushima Daiichi treated water release reaches three-year mark

Three years into the treated water release at Fukushima Daiichi, TEPCO has discharged 172,700 tonnes, though stored water levels have only decreased by about 7% due to ongoing contamination.

5 sources. https://clstr.news/cluster/fukushima-daiichi-treated-water-discharge-reaches-three-year-mark

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Cite as: Fukushima Daiichi decommissioning and water release. CLSTR, https://clstr.news/situations/fukushima-daiichi-decommissioning-and-water-release