(Part 4 available now)
and says his explanation that there would be no hydrogen explosion is technically correct.
(Continued from Part 1 and Part 2, from Nikkei Shinbun: Testimony of Dr. Madarame, in the third year of the accident: "Worst case scenario was possible for Fukushima" by Junichi Taki, editorial board member)
--When did you realize that the situation was much graver than the initial assessment?
"I knew something was wrong when I was told that the pressure of the Reactor 1 Containment Vessel was rising, past midnight [of March 11, 2011]. Maybe the DC power stopped, I thought. Still, Reactor 1 could be cooled by the isolation condenser (IC) even in the loss of power situation. Later, I heard the cables from the power supply cars couldn't be connected, or that they needed more cables than available; I speculated that the switchboard was under water, and they were trying to supply power to individual pumps. We (at the Prime Minister's Official Residence) were not aware of what was going on at the plant and what they were trying to do. Human psychology goes from extreme to extreme. I started to feel extremely desperate."
"It was a mistake [PM Kan] to feel relieved"
--The vent you suggested the night before wasn't carried out by the next morning.
"The purpose of the vent had vastly changed from the previous night. By that time [morning of March 12, 2011], it could be assumed [I assumed] that the reactor core melted, and the pressure inside the Containment Vessel was rising (because of water vapor and gas). The vent was necessary in order to protect the Containment Vessel (from damage)."
--In the early morning [of March 12, 2011] you expanded the evacuation zone to areas within 10-kilometer radius.
"I thought 3-kilometer radius was not enough if the reactor core melted."
--If your assessment of the situation was that pessimistic, why did you accompany (then) Prime Minister Naoto Kan in the early morning on a helicopter and told him "there would be no hydrogen explosion"?
"Prime Minister asked me what would happen if the reactor core was exposed. I answered hydrogen would be generated. He then asked me if that would lead to an explosion. So I answered there would be no explosion because the Containment Vessel was filled with nitrogen (and there was no oxygen). My explanation is not wrong. Former Prime Minister Kan writes in his book that it was a "big mistake" to feel relieved by my words, but my explanation is not wrong. It was a mistake (for Prime Minister Kan) to feel relieved."
"I think I heard, right before we boarded the helicopter, that they were about to do the vent. So I thought the vent would have been done by the time we arrive at the plant."
--If what you say is true, then you would have landed on the plant right after the vent. But no one on board the helicopter was wearing the protective clothing."
"I didn't even think about the protective clothing."
--It is said that Prime Minister Kan, on getting off the helicopter, shouted at (then) TEPCO Vice President Sakae Muto, "Why aren't you doing the vent?" So the prime minister knew that the vent hadn't been done.
"I didn't hear the conversation between the prime minister and Mr. Muto, but I suppose the prime minister must have been told about (the vent not being done yet). I was told in the conference room of the Anti-Seismic Building [at the plant]. The prime minister may have used strong words about the vent because I emphasized to him the importance of the vent when we were on board.
Dr. Madarame's schedule on March 12, 2011, from Part 2:
0:55AM Pressure inside the Containment Vessel of Reactor 1 rising; power supply cars arrived, but the power couldn't be restored; [Madarame] suspected the damage of the power control panel
3:00AM confirmed operation of Reactor 2 reactor core isolation cooling (RCIC), decided it was Reactor 1 that was in danger
5:00AM asked to accompany Prime Minister on the on-site inspection
5:44AM evacuation instruction to 10-kilometer radius areas
6:14AM leaving PM Official Residence on a helicopter with PM Kan, explaining about hydrogen explosion to Kan on board the helicopter
7:11AM arrived at Fukushima I NPP, learned that vent hadn't been done
8:04AM left Fukushima I NPP
10:47PM arrived back at PM Official Residence, and walked back to the office of Nuclear Safety Commission
12:08PM Nuclear Emergency Response Headquarters meeting (Madarame was asked at 11:35AM to attend)
1:00PM met with Members of the National Diet elected from Fukushima (stayed in the prime minister's reception room from 1:30PM on)
3:18PM news of successful vent of Reactor 1, discussion of issues concerning seawater injection [into the reactors]
3:50PM news of white smoke rising from Reactor 1
The vent, which was made extremely difficult because there was no power at the plant, was further delayed because of Kan's hastily arranged trip in the early morning of March 12, 2011. The hydrogen explosion was not from inside the Containment Vessel as Dr. Madarame had feared but in the building, either on the 4th floor or the 5th floor (operating floor), with the evidence suggesting the 4th floor, when the hydrogen gas was finally vented but came back into the building instead of going to the exhaust stack.
In other words, the vent may have caused the explosion after all (that was the conclusion of none other than NISA in December 2011). If the vent had been successfully carried out by the time Mr. Kan and Dr. Madarame arrived at the plant, they may have been just in time to witness the Reactor 1 explosion firsthand.