wo emergency diesel generators were available for each of units 1–5 and three for unit 6.[65]
In the late 1990s, three additional backup generators for Units 2 and 4 were placed in new buildings located higher on the hillside, to comply with new regulatory requirements. All six units were given access to these generators, but the switching stations that sent power from these backup generators to the reactors' cooling systems for Units 1 through 5 were still in the poorly protected turbine buildings. All three of the generators added in the late 1990s were operational after the tsunami. If the switching stations had been moved to inside the reactor buildings or to other flood-proof locations, power would have been provided by these generators to the reactors' cooling systems. Because the generators had to work at full power, when the wave hit, the crankshafts shattered and the system collapsed. These brittle crankshafts are also used in British reactors.[66]
The reactor's emergency diesel generators and DC batteries, crucial components in powering cooling systems after a power loss, were located in the basements of the reactor turbine buildings, in accordance with GE's specifications. Mid-level engineers expressed concerns that this left them vulnerable to flooding.[67]
Fukushima I was not designed for such a large tsunami,[68][69] nor had the reactors been modified when concerns were raised in Japan and by the IAEA.[70]
Fukushima II was also struck by the tsunami. However, it had incorporated design changes that improved its resistance to flooding, reducing flood damage. Generators and related electrical distribution equipment were located in the watertight reactor building, so that power from the electricity grid was being used by midnight.[71] Seawater pumps for cooling were protected from flooding, and although 3 of 4 initially failed, they were restored to operation.[72]
https://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disa...
wo emergency diesel generators were available for each of units 1–5 and three for unit 6.[65]
In the late 1990s, three additional backup generators for Units 2 and 4 were placed in new buildings located higher on the hillside, to comply with new regulatory requirements. All six units were given access to these generators, but the switching stations that sent power from these backup generators to the reactors' cooling systems for Units 1 through 5 were still in the poorly protected turbine buildings. All three of the generators added in the late 1990s were operational after the tsunami. If the switching stations had been moved to inside the reactor buildings or to other flood-proof locations, power would have been provided by these generators to the reactors' cooling systems. Because the generators had to work at full power, when the wave hit, the crankshafts shattered and the system collapsed. These brittle crankshafts are also used in British reactors.[66]
The reactor's emergency diesel generators and DC batteries, crucial components in powering cooling systems after a power loss, were located in the basements of the reactor turbine buildings, in accordance with GE's specifications. Mid-level engineers expressed concerns that this left them vulnerable to flooding.[67]
Fukushima I was not designed for such a large tsunami,[68][69] nor had the reactors been modified when concerns were raised in Japan and by the IAEA.[70]
Fukushima II was also struck by the tsunami. However, it had incorporated design changes that improved its resistance to flooding, reducing flood damage. Generators and related electrical distribution equipment were located in the watertight reactor building, so that power from the electricity grid was being used by midnight.[71] Seawater pumps for cooling were protected from flooding, and although 3 of 4 initially failed, they were restored to operation.[72]