Fukushima Daiichi Unit 1
E799461
Fukushima Daiichi Unit 1 is the first reactor unit at Japan’s Fukushima Daiichi Nuclear Power Plant and one of the units that suffered a major meltdown in the 2011 nuclear disaster.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Fukushima Daiichi Unit 1 canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T9446838 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Fukushima Daiichi Unit 1 Context triple: [Fukushima Daiichi Unit 2, sisterUnit, Fukushima Daiichi Unit 1]
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A.
Fukushima Daiichi Unit 4
Fukushima Daiichi Unit 4 is one of the reactors at Japan’s Fukushima Daiichi Nuclear Power Plant that suffered severe damage and a spent fuel pool crisis following the 2011 earthquake and tsunami.
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B.
Fukushima Daiichi Unit 2
Fukushima Daiichi Unit 2 is one of the damaged reactors at Japan’s Fukushima Daiichi Nuclear Power Plant that suffered a core meltdown and severe structural failures following the 2011 earthquake and tsunami.
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C.
Fukushima Daiichi Unit 3
Fukushima Daiichi Unit 3 is one of the damaged reactors at Japan’s Fukushima Daiichi Nuclear Power Plant, known for suffering a hydrogen explosion and core meltdown during the 2011 nuclear disaster.
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D.
Fukushima Daiichi Nuclear Power Plant
Fukushima Daiichi Nuclear Power Plant is a coastal Japanese nuclear power station in Ōkuma, Fukushima Prefecture, widely known as the site of the 2011 reactor meltdowns following a massive earthquake and tsunami.
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E.
Fukushima Daini Nuclear Power Plant
Fukushima Daini Nuclear Power Plant is a Japanese coastal nuclear power station in Fukushima Prefecture that experienced a significant but more contained impact from the 2011 Tōhoku earthquake and tsunami than its neighboring Daiichi plant.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Fukushima Daiichi Unit 1 Target entity description: Fukushima Daiichi Unit 1 is the first reactor unit at Japan’s Fukushima Daiichi Nuclear Power Plant and one of the units that suffered a major meltdown in the 2011 nuclear disaster.
-
A.
Fukushima Daiichi Unit 4
Fukushima Daiichi Unit 4 is one of the reactors at Japan’s Fukushima Daiichi Nuclear Power Plant that suffered severe damage and a spent fuel pool crisis following the 2011 earthquake and tsunami.
-
B.
Fukushima Daiichi Unit 2
Fukushima Daiichi Unit 2 is one of the damaged reactors at Japan’s Fukushima Daiichi Nuclear Power Plant that suffered a core meltdown and severe structural failures following the 2011 earthquake and tsunami.
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C.
Fukushima Daiichi Unit 3
Fukushima Daiichi Unit 3 is one of the damaged reactors at Japan’s Fukushima Daiichi Nuclear Power Plant, known for suffering a hydrogen explosion and core meltdown during the 2011 nuclear disaster.
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D.
Fukushima Daiichi Nuclear Power Plant
Fukushima Daiichi Nuclear Power Plant is a coastal Japanese nuclear power station in Ōkuma, Fukushima Prefecture, widely known as the site of the 2011 reactor meltdowns following a massive earthquake and tsunami.
-
E.
Fukushima Daini Nuclear Power Plant
Fukushima Daini Nuclear Power Plant is a Japanese coastal nuclear power station in Fukushima Prefecture that experienced a significant but more contained impact from the 2011 Tōhoku earthquake and tsunami than its neighboring Daiichi plant.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
boiling water reactor
ⓘ
nuclear reactor unit ⓘ |
| commercialOperationStartDate | 1971-03-26 ⓘ |
| constructionCompany | Kajima NERFINISHED ⓘ |
| constructionStartDate | 1967-07-25 ⓘ |
| containmentType | Mark I containment ⓘ |
| coolant | light water ⓘ |
| coolingLossCause | tsunami-induced station blackout ⓘ |
| coreDamageLevel | major core melt ⓘ |
| country | Japan ⓘ |
| decommissioningStatus | under decommissioning ⓘ |
| designBasisTsunamiHeight_m | approximately 5.7 ⓘ |
| designedBy | General Electric NERFINISHED ⓘ |
| electricalCapacity_MWe | 460 ⓘ |
| emergencyPowerSystem | diesel generators flooded and failed ⓘ |
| event |
2011 Tōhoku earthquake and tsunami
NERFINISHED
ⓘ
Fukushima Daiichi nuclear disaster NERFINISHED ⓘ |
| experienced |
core meltdown
ⓘ
hydrogen explosion ⓘ loss of off-site power ⓘ station blackout ⓘ |
| firstCriticalityDate | 1970-11-17 ⓘ |
| fuelRemovalFromSFPCompletionDate | 2021-02 ⓘ |
| fuelRemovalStatus | fuel removed from spent fuel pool ⓘ |
| fuelType | low-enriched uranium ⓘ |
| gridConnectionDate | 1970-11-17 ⓘ |
| gridConnectionStatus | disconnected from grid ⓘ |
| hydrogenExplosionDate | 2011-03-12 ⓘ |
| hydrogenExplosionEffect | severe damage to reactor building superstructure ⓘ |
| IAESeventClassification | part of INES Level 7 accident at Fukushima Daiichi ⓘ |
| locatedIn | Ōkuma, Fukushima Prefecture NERFINISHED ⓘ |
| moderator | light water ⓘ |
| netElectricalCapacity_MWe | 460 ⓘ |
| notableConsequence | large-scale radioactive release to environment ⓘ |
| operator |
TEPCO
NERFINISHED
ⓘ
Tokyo Electric Power Company NERFINISHED ⓘ |
| partOf | Fukushima Daiichi Nuclear Power Plant NERFINISHED ⓘ |
| plannedDecommissioningDuration_years | 30–40 ⓘ |
| primaryContainmentIntegrity | compromised during accident GENERATED ⓘ |
| reactorSupplier | General Electric NERFINISHED ⓘ |
| reactorType | BWR-3 ⓘ |
| regulator |
Nuclear Regulation Authority (post-2012)
NERFINISHED
ⓘ
Nuclear and Industrial Safety Agency of Japan (historical) NERFINISHED ⓘ |
| safetySystemFailure | loss of core cooling ⓘ |
| safetySystemType | emergency core cooling system ⓘ |
| shutdownDate | 2011-03-11 ⓘ |
| status | permanently shut down ⓘ |
| thermalCapacity_MWt | 1380 ⓘ |
| tsunamiHeightAtSite_m | approximately 13–15 ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Fukushima Daiichi Unit 1 Description of subject: Fukushima Daiichi Unit 1 is the first reactor unit at Japan’s Fukushima Daiichi Nuclear Power Plant and one of the units that suffered a major meltdown in the 2011 nuclear disaster.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.