It took TEPCO and the national government who owns and regulates TEPCO more than 2 years to come clean.
It was just a few weeks ago that we finally learned that less than half the water being injected into Reactor 3 was reaching the reactor before the reactor building blew up on March 14, 2011, because the pump to the condenser was dead when the power went out. Water was filling up the condenser.
Huge spikes in radiation levels in wide areas in Tohoku and Kanto between March 20 and 23, 2011 (as seen in the chart from Asahi Shinbun, 8/8/2011) have been a mystery. TEPCO has so far said it doesn't know what was causing these spikes. Fumiya Tanabe, former researcher at the Japan Atomic Energy Agency (JAEA) and the current head of the Research Institute on Safety of Technology Systems, has proposed that Reactor 3 had a second meltdown, so to speak, when the water being injected into the Reactor Pressure Vessel dropped significantly starting March 20, 2011, and that the melted core dropped from the RPV to the Containment Vessel, releasing a large amount of radioactive materials from the Containment Vessel breach somewhere.
That may be, and now we are told that only 10% of the water being injected from the fire hydrant was reaching Reactor 1's Pressure Vessel, and the Pressure Vessel was near empty. Where did the remaining 90% of water go? No one knows.
This release of radioactive materials that happened between March 20 to 23, 2011 is what contaminated the wide areas in Tohoku and Kanto, because the release was met with the rain.
One of the local papers in Fukushima picked up the scene from the teleconference videos that TEPCO recently made available which covers the period from March 16 to April 11, 2011. I don't think anyone else did. Another set of videos covers the period from March 11 to 15, 2011.
From Kahoku Shinpo (3/31/2013; emphasis is mine):
福島第１原発 １号機注水９割漏出か 現場、水圧で認識
90% of water injected into Fukushima I Nuke Plant Reactor 1 may have leaked, the plant management knew by water pressure
TEPCO's teleconference video during the Fukushima I Nuclear Power Plant accident has revealed that there is a possibility that after the power was lost, about 90% of the coolant (water) injected into Reactor 1's Pressure Vessel leaked before it reached the reactor. The plant personnel seem to have known about the leak from the discharge pressure of a fire hydrant. As not enough water was entering the reactor, the reactor core was further damaged during the period from March 20 to 22, 2011, resulting in the release of radioactive materials.
Since March 12, 2011, TEPCO had been injecting water into the reactor via the line of the fire extinguishing system (see the diagram).
According to the teleconference video, Masao Yoshida, then-plant manager, reported at about 1:30PM on March 22, 2011 to the TEPCO headquarters [in Tokyo], "We checked the water injection line to Reactor 1, and at a fire hydrant on the line, the discharge pressure is only 0.1 megapascal." He continued, "We are injecting the water at 1 megapascal, and it is 0.1 megapascal on the way to Reactor 1. The water must be leaking."
TEPCO published the amount of water injected into the reactors by calculating the amount based on the water supply pressure from the fire engine [in this case, 1 megapascal]. However, Yoshida's remark means almost all of water from the fire engine leaked before it reached the reactor.
Based on the temperature and pressure data of the reactor, Professor Shigenao Maruyama of Tohoku University Institute of Fluid Science (his specialty in thermal engineering) says, "There was hardly any water entering Reactor 1 from March 20 to March 22, and Reactor 3 from March 21 to 23. The reactors were being heated without water in them. What water that went in evaporated right away." He points out that a large amount of radioactive materials and steam were leaking from the breach in the Containment Vessels.
According to the calculation by the National Institute of Environmental Studies, radioactive materials released on March 20 were carried by the wind and reached northern Miyagi and southern Iwate, where they met the rain that fell on the ground. TEPCO describes the amount of radioactive materials released after March 20, 2011 and the cause of the release as "unexplained".
In the afternoon of March 20, 2011, the temperature around the Reactor 1 Pressure Vessel was found to be high near 400 degrees Celsius. The plant personnel determined that water was not reaching the reactor, and start examining the water injection line. In the morning of March 22, there was a report at the plant that "the core damage of Reactor 1 has been increasing in the past few days. It is highly possible that water is not reaching the reactor and the reactor is dry".
Takafumi Anegawa, TEPCO's manager in charge of nuclear facility management, says, "We are aware that there is an uncertainty in the amount of water injected. We would like to determine the condition of the reactor at that time and
It's TEPCO's responsibility to disclose all videos, keys to understanding how radioactive materials dispersed
A doubt has surfaced that water injection into Reactor 1's Pressure Vessel was not working. It may have been one of the causes for the wide-area dispersion of radioactive materials, and we need to examine very closely.
According to the data made public by TEPCO right after the accident, the amount of water injected dropped dramatically in Reactor 1 and Reactor 3, starting March 20, 2011. In September 2011, TEPCO recalculated the amount of water based on the data from the flowmeter of the fire engine that pumped the water, and announced a large amount of water had been injected.
The remark in the teleconference video by Masao Yoshida, then-plant manager, regarding the water pressure indicates the original amount was closer to the reality. There are also dialogs that indicate TEPCO had known about the damage to the Containment Vessels from early on. The teleconference video is a useful data to analyze the accident in detail.
TEPCO have disclosed only part of the video, citing protection of privacy of its employees. However, isn't it the responsibility of a company who caused this accident to make it widely available so that many people can examine, and to ask for such examination from all angles?
TEPCO lacks in taking initiative in researching and disclosing. "We reflect on the accident, and make a fresh start as an organization with the world-class safety culture", says President Naomi Hirose. I don't believe there will be a fresh start for the company unless it fundamentally changes its character.
(Commentary: Tomohiko Suenaga, News Department)
Well, remember the "Water Entombment" idea that was tried in April 2011? The idea was to fill the Containment Vessel of Reactor 1 with water to cool the RPV inside the Containment Vessel. If they knew early on that the Containment Vessel was broken, what was this farce of "water entombment"?
TEPCO finally came clean on the breach of the Containment Vessels (Reactor 1 and Reactor 2) on May 24, 2011.