Shimane 1, Japan's first domestically built nuclear unit (460 MWe BWR, 1974), was retired in April 2015 and is being decommissioned by Chugoku Electric in four stages. The plan targets completion by March 2046; Unit 2 on the same site restarted in 2025.

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Current state

Status	Active dismantling
Country	Japan
Location	Matsue, Shimane Prefecture
Site	Shimane
Units	Unit 1
Unit count	1
Reactor types	BWR
Net capacity (MWe)	429
Owner / licensee	Chugoku Electric Power
Strategy	Immediate dismantling
Final shutdown	2015-04
Target completion	2046
Spent fuel	Fuel to be removed during Stage 1 (~6 years).

Notes

Net capacity 429 MWe per WNA (460 MWe gross per WNN).

Timeline

1974-03 — Shimane 1 began commercial operation. (source)
2015-03-18 — Chugoku decided to decommission Shimane 1. (source)
2016-05-06 — Chugoku submitted its four-stage decommissioning plan to the NRA. (source)

The timeline is append-only: corrections are added as new entries. Stated targets appear in the current-state table, never as milestones.

Related sites

Biblis Nuclear Power Plant (Units A and B) Active dismantling · Germany
Brokdorf Nuclear Power Plant (KBR) Active dismantling · Germany
Brunsbüttel Nuclear Power Plant (KKB) Active dismantling · Germany
Chinshan Nuclear Power Plant Fuel removal · Taiwan
Chooz A Active dismantling · France
Crystal River Unit 3 Site restoration · United States
Doel Nuclear Power Plant (Units 1-3) Shut down · Belgium
Dounreay (DFR and PFR fast reactors) Active dismantling · United Kingdom

See all 72 sites in the Nuclear Decommissioning Tracker →

Sources

Decommissioning plan submitted for Shimane 1 — World Nuclear News, checked 2026-10-11
Nuclear Power in Japan — World Nuclear Association, checked 2026-10-11
Status of decommissioning of Unit 1 at Shimane Nuclear Power Station — IAEA INIS, checked 2026-10-11
FIELD REPORT Chugoku Electric Power's Shimane Nuclear Power Station — Hitachi, checked 2026-10-11