That triggered the emergency diesel generators to startup and provide backup power for plant systems.

由此工厂自备紧急柴油发电机启动为工厂提供电力。

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There are four generating sets in this power plant, three for service and one for emergency. They are all diesel-alternators.

发电机有四台机组，其中三台是工作发电机，一台是应急发电机，它们都是柴油交流发电机组。

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The plant's operator Tokyo Electric Power Co (Tepco) said exposure to radiation levels in the No 3 reactor for four-and-a-half hours would exceed the emergency safety limit for power plant workers.

BBC: Robots record high radiation levels at Japan reactors