Prime Minister Naoto Kan categorically denied allegations Monday that he ordered Tokyo Electric Co. to temporarily stop injecting seawater into an overheating reactor at the Fukushima No. 1 nuclear power plant a day after the March 11 devastating earthquake.
According to Tepco, workers began pumping seawater into the No. 1 reactor at 7:04 p.m. on March 12 and stopped the test at 7:25 p.m., resuming the injection after 55 minutes.
But recent media reports have suggested that Kan ordered the utility to stop after being told by Haruki Madarame, chairman of the Nuclear Safety Commission, that there was a danger of restarting a chain reaction in an event known as a “recriticality.”
Madarame later denied making such a statement.
During a special Lower House Diet committee session Monday on restoration efforts related to the Great East Japan Earthquake, Kan said he was not aware that Tepco had begun pouring seawater into the No. 1 reactor in the first place and therefore could not have given orders to stop.
“We were not informed of the injection of the seawater nor the suspension,” Kan said. “Despite some media reports, we did not . . . stop the injection at all.”
The government also scrambled to correct a statement attributed to Madarame, in which the former University of Tokyo professor was quoted as saying that pouring seawater into the reactor could lead to the “risk” of a recriticality.
At the same Diet committee Monday, Madarame said he told Kan that “the possibility of a recriticality was not zero” but that he had been consistent in saying that water should be poured into the reactor vessel to cool it down.
A hydrogen explosion occurred less than an hour after the injection of water into the No. 1 reactor was stopped at 2:53 p.m. on March 12.
Tepco also recently revealed that most of the fuel rods in the reactor melted down, made holes and sank to the bottom of the containment vessel early in the morning of March 12.
The government and Tepco’s initial handling of the ongoing trouble at the Fukushima plant, now the worst nuclear accident since the 1985 Chernobyl disaster, have come under intense domestic and international scrutiny.