I tuned into Frontline last night to watch Inside Japan’s Nuclear Meltdown which was quite topical after Martin Fackler’s New York Times front page story harrowing tale of how close the Japanese government had come to abandoning the stricken Fukushima nuclear power plant and evacuating Tokyo. Most of what happened I already knew but the one detail that amazed me was how some smart engineers (they are nuclear scientists after all) used car batteries to avert a nuclear meltdown.
The Frontline documentary tells the story of events as they unfolded after the earthquake. Workers at the plant calmly looked after the reactor which had already gone into automatic shutdown as it is designed to do after any major earthquake. As we all know, the tsunami (40 feet by the time it hit the sea wall outside the reactor) overwhelmed the plant’s defenses and flooded the backup generator cutting off power to the pumps which were vital to keeping the nuclear fuel cooled down.
And this is where it gets scary. Not having power meant there was no light in the reactor control room. There also was no power going to the gauges that measured the temperature in the reactor core, an all important measurement if you’re trying to keep the thing from overheating and melting down.
Someone (that person deserves a medal) had the brilliant idea to have everyone run out to their cars and pull the batteries so they could hook them up via jumper cables to the control room instruments and get enough of a current to power the gauges.
As the operators surveyed the damage, they quickly realized that the diesel generators couldn’t be salvaged and that external power wouldn’t be restored anytime soon. In the plant’s parking lots, workers raised car hoods, grabbed the batteries, and lugged them back to the control rooms. They found cables in storage rooms and studied diagrams. If they could connect the batteries to the instrument panels, they could at least determine the water levels in the pressure vessels.
– ieee spectrum, 24 hours at Fukushima cover story
What they found was that the reactor core was overheating and in danger of exploding which would have sent radioactive debris all over Tohoku. Using this data, they then made the very difficult decision to send personnel in to manually (remember they didn’t have power) turn the valves that would vent off steam to reduce pressure. This was a crucial action that, if not taken, would have made an already severe situation ten times worse.
Further Reading: Letter from Fukushima, The New Yorker