A definitive explanation is unknown, though Mizuno suspects that a mixture of hydrogen and oxygen in the headspace of the cell was ignited. Mizuno has performed these experiments hundreds of times, and this apparatus had been well-tested over the last five years.
Before the experiment, Mizuno had checked all of his equipment and had made sure that the exhaust tube was clear.
“The outlet tube leading to the mass spectrometer was definitely not blocked or impeded, so the gas in the headspace was at one atmosphere,” he reported.
A high-pressure build-up of hydrogen and oxygen has been ruled out.
At the time of the explosion, a collector that would normally have aided in the collection and removal of the effluent gasses was removed, though this was not unique.
“The funnel around the cathode was taken off for the analysis of the generation gas during plasma electrolysis,” Mizuno said. “I have performed such measurements 40 times in the past and confirmed the safety of this procedure many times.”
Mizuno turned the experiment on when he arrived in the laboratory that afternoon. It had not been on long enough to develop the plasma, which usually takes about 20 minutes. About 5 seconds later, when he observed that electrolysis started, he increased the voltage to 20 volts and the current to 1.5 amps. About five or six seconds later, Mizuno reported seeing a bright white flash of light from the submerged portion of the cathode, where the plasma normally would develop.
The light “expanded, and at the same instant the cell exploded,” Mizuno said. The safety doors to the incubator were blown open, and glass and electrolyte were blown up to 6 meters from the experiment platform.
Mizuno documented the event in his accident report (New Energy Times Report (PDF)). He listed several possible causes, though he was tentative about any of the prosaic explanations.
Chemist Dieter Britz from the University of Aarhus was curious about how such a small amount (3cc) of hydrogen gas might have caused such a large explosion in the cell.
“It is also hard to imagine that there should have been enough for such a violent explosion,” Britz said. “You have no doubt seen the school experiment, where a lighted taper is inserted into a tube with some hydrogen in it. You get a nice ‘pop.’ In an open cell, [such as this] after a short time of electrolysis, that is what I would expect. So this is very strange, and I have no guesses.”
The explosion was perhaps similar to the one on Jan. 2, 1992, that killed SRI International researcher Andy Riley, though the SRI cell was closed and under high pressure. Mike McKubre, the director of the energy research center at SRI, who was wounded in the 1992 explosion, as well, cautioned that any exposed metal can cause a recombination explosion.
“I found it is impossible to impress on people just how explosive a stoichiometric mix of hydrogen and oxygen is, McKubre said. “Even a few cc’s can be dangerous, even deadly. You don’t need to search for an ignition source. Any metal will do.”
The only other well-known cold fusion explosion was that of Martin Fleischmann and Stanley Pons in 1985, though a source who wishes to remain anonymous states that the Lawrence Livermore National Laboratory had a Fleischmann-Pons-type explosion in 1989, as well.
Mike Carrell, a previous board member for Infinite Energy magazine, postulates a two-stage reaction in the Mizuno explosion.
“First there is a spark or flash, then an expanding glow, then an explosion,” Carrell said. “When the disturbance reaches the surface, the stoichiometric H2-O2 mixture may well have ignited, contributing to the explosion.”
Horace Heffner, a cold fusion enthusiast, offered this analysis. “It appears that the explosion may well have been ignited in the flask, but the main energy from the explosion came from the top interior of the Yamato 1L-6 incubator. It looks like the explosive force was primarily downward, and the overpressure on the conical cap on the flask blew the flask apart in radial directions, leaving the base cracked but in place. It looks like the base of the flask may be stuck (by prior heating) to the polypropylene insulation underneath it.
“Assuming the plastic door was not blown to pieces, the overpressure was clearly enough to blow open the plastic door before the glass shards went through the open door. This indicates the overpressure hit the door before the flask pieces. The source of the blast pressure that opened the plastic door was therefore not inside the flask but rather probably coming from the top of the 1L-6 downward.”
Heffner speculated that hydrogen from the reaction flask is dumped into the interior of the 1L-6 where it can accumulate in various spaces and thus be exploded by an ignition event in the flask.
The big question on everyone’s minds is whether this was a chemical explosion – or a nuclear explosion. A physicist who considered the amount of energy required to convey the 800cc of electrolyte a distance of up to 6 meters, was unconvinced that this was a chemical reaction.
Jed Rothwell, who translated Mizuno’s book Nuclear Transmutation: The Reality of Cold Fusion to English, assisted with this story and reports that Mizuno is back at work starting the experiments again, despite the trauma.
“Mizuno has guts,” Rothwell said. “All cold fusion researchers have guts. They are an ornery bunch, but you have to admire them.”
Photographs taken by Mizuno and others are here: New Energy Times