More information has been coming out about the earliest moments of the Fukushima Dai-ichi nuclear incident and the design of the reactors. It turns out that I was incorrect in surmising that the results of the experiment at Chernobyl or perhaps continuing to run the reactors might have ameliorated some of the disaster.
Firstly, the Chernobyl experiment was only supposed to cover the 75 seconds from SCRAM to the point when the generators would have been supplying full power for cooling. Secondly, the 1986 disaster was actually the fourth time the experiment had been attempted – it had failed the previous three times. Which would lead one to conclude that it is not possible to bridge the loss of power by using residual steam pressure to continue to spin the turbines.
Next, the design of the Fukushima Dai-ichi reactors had flaws that would have defeated my suggestions. During the massive quake, the active reactors were SCRAMed. The diesel generators were brought online and were functional until the tsunami hit. The facility had 5.7 metre seawalls and the tsunami was estimated to be 13-15 metres high. This flooded many of the buildings. The older reactor buildings had their generators in the basement of the reactor building. The newer reactors at least provided external generators that were stationed up a hill. But all of the electrical switching components were still in the basement. As were the turbines. Even if steam had been available for the turbines, the turbines would still have been lost when the tsunami hit nearly an hour after the quake.
Finally, my suggestion would not have helped at Reactor 4, which was already shut down and could not supply any energy. The spent fuel pool next to the core contained 1,331 fuel rods. Alternative methods were used to cool the spent fuel in the pool.