Experts on explosion at Japan nuclear plant

Experts on explosion at Japan nuclear plant

“It looks as if the coolant pumps had initially stopped working. They shut down automatically when the reactor shuts down, but there is a backup system running off a diesel generator — it looks as though that’s the bit that failed.

“As a result there is no way of pumping heat out of the reactor, so it has to cool naturally. If the reactor gets too hot, in principle this means the fuel rods can melt — but it looks unlikely this has happened to any great extent in this case.

Paddy Regan
Professor of Nuclear Physics at the University
of Surrey

“By sampling the air around the station, you'd be able to tell how much radioactivity has been released. The thing they will be looking for more than anything is whether there’s any evidence of the fuel actually degrading,” he said.

“If the fuel is substantially intact, then there will be a much, much lower release of radioactivity and the explosion that’s happened might be just due to a build-up of steam in the reactor circuit.

“The most probable (cause of the explosion) is the coolant, particularly if it’s water, can overheat and turn to steam more rapidly than it was designed to
cope with.”

Timothy Abram,
Professor of Nuclear Fuel Technology at Britain’s Manchester University

“The explosion at No 1 generating set of the Fukushima nuclear plant in Japan will not be a repetition of the Chernobyl nuclear disaster,” Interfax quoted the
Ukrainian expert as saying.

He said the Japanese nuclear power plants use  reactors of a totally different design to Chernobyl’s. “Japan has modern-type reactors. All fission products should be isolated by the confinement (the reactor’s protection shell).

Only gas emission is possible.” Hlyhalo said Japanese nuclear power plants are earthquake resistant.

Valeriy Hlyhalo,
Deputy director-general of the Chernobyl Nuclear
Safety Centre

“It does seem as if the back-up generators although they started initially to work, then failed,” Grimes, an expert in radiation damage said. “So it means slowly the heat and the pressure built up in this reactor. One of the things that might just have happened is a large release of that pressure. If it’s that then we are not in such bad circumstances.

“Despite the damage to the outer structure, as long as that steel inner vessel remains intact, then the vast majority of the radiation will be contained. “At the moment it does seem that they are still contained and it’s a release of significant steam pressure that’s caused this explosion. The key will be the monitoring of those radiation levels.”

Robin Grimes,
Professor of Materials Physics at Imperial College, London

“We don’t have any information from inside the plant. That is the problem in this case. If it melts down the probability that there would be a breach or that radiation would get outside of the plant because of weakness of the structure of the plant ... is much greater.”

Nuclear expert
Mark Hibbs of the Carnegie Endowment for
International Peace