This is some information that I am in the process of analyzing in order to draw a more detailed picture of the man made and natural causes of the nuclear meltdown. I would like to share it, since this information has been mentioned but not frequently examined in the media.
1967: Changing the layout of the emergency-cooling system, without reporting it
On 27 February 2012 NISA ordered TEPCO to report by 12 March 2012 about the reasoning to change the layout for the piping for an emergency cooling system from the plans originally registered in 1966 before the reactor was taken in operation.
After the plant was hit by the tsunami, the isolation condenser should have taken over the function of the ordinary cooling pumps, by condensing the steam from the pressure vessel into water to to be used for cooling the reactor. But the condenser did not function properly, and TEPCO could not confirm whether a valve was opened.
In the original papers submitted – in July 1966 – for government approval of the plans to set up the reactor, the piping systems for two units in the isolation condenser were separated from each other. But in the application for the construction plan of the reactor – submitted in October 1967 – the piping layout was changed by TEPCO, and the two piping systems were connected outside the reactor. The changes were not reported in violation of all legal regulations. [44]
1976: Falsification of safety records by TEPCO
The Fukushima Daiichi nuclear power complex was central to a falsified-records scandal that led to the departure of a number of senior executives of TEPCO. It also led to disclosures of previously unreported problems at the plant,[45] although testimony by Dale Bridenbaugh, a lead GE designer, purports that General Electric was warned of major design flaws in 1976, resulting in the resignations of several designers who protested GE’s negligence.[46][47][48]
In 2002, TEPCO admitted it had falsified safety records at the No. 1 reactor at Fukushima Daiichi. As a result of the scandal and a fuel leak at Fukushima, the company had to shut down all of its 17 nuclear reactors to take responsibility.[49] A power board distributing electricity to a reactor’s temperature control valves was not examined for 11 years. Inspections did not cover devices related to cooling systems, such as water pump motors and diesel generators.[50]
1991: Back-up generator of reactor nr. 1 flooded
On 30 October 1991 one of two backup generators of reactor nr. 1 did fail, after it was flooded in the basement of the reactor buildings. Seawater used for the cooling of the reactor was leaking into the turbine-building from a corroded pipe at a rate of 20 cubic meters per hour. This was told by former TEPCO employees to the Japan Broadcasting Corporation news-service in December 2011. An engineer told, that he informed his superiors about this accident, and that he mentioned the possibility that a tsunami could inflict damage to the generators in the turbine-buildings near the sea. After this TEPCO did not move the generators to higher grounds, but instead TEPCO installed doors to prevent water leaking into the generator rooms. The Japanese Nuclear Safety Commission commented that it would revise the safety guidelines for designing nuclear plants and would enforce the installation of additional power sources. On 29 December 2011 TEPCO admitted all these facts: its report mentioned, that the emergency power system room was flooded through a door and some holes for cables, but the power supply to the reactor was not cut off by the flooding, and the reactor was stopped for one day. One of the two power sources was completely submerged, but its drive mechanism had remained unaffected.[51][52][53]
2006: The Japanese government opposes a court-order
In March 2006 the Japanese government opposed a court order to close a nuclear plant in the west part of the country over doubts about its ability to withstand an earthquake. Japan’s Nuclear and Industrial Safety Agency believed it was “safe” and that “all safety analyses were appropriately conducted”.[54]
2007: Tsunami-study ignored
In 2007 TEPCO did set up a department to supervise all its nuclear facilities, and until June 2011 its chairman was Masao Yoshida, the chief of the Fukushima Daiichi power plant. An in-house study in 2008 pointed out that there was an immediate need to improve the protection of the power station from flooding by seawater. This study mentioned the possibility of tsunami-waves up to 10.2 meters. Officials of the department at the company’s headquarters insisted however that such a risk was unrealistic and did not take the prediction seriously.[55]
2008: Seismic-concerns
In addition to concerns from within Japan, the International Atomic Energy Agency (IAEA) has also expressed concern about the ability of Japan’s nuclear plants to withstand seismic activity. At a meeting of the G8′s Nuclear Safety and Security Group, held in Tokyo in 2008, an IAEA expert warned that a strong earthquake with a magnitude above 7.0 could pose a “serious problem” for Japan’s nuclear power stations.[56]
2011: Results of Governmental Investigations
On request of the Japan Broadcasting Corporation, on 2 October 2011 the Japanese Government released a report of TEPCO to NISA. These papers proved that TEPCO was well aware of the possibility that the plant could be hit by a tsunami with waves far higher than the 5.7 meters which the plant was designed to withstand. Simulations done in 2008, based on the destruction caused by the 1896-earthquake in this area, made it clear that waves between 8.4 and 10.2 meters could overflow the plant. Three years later the report was sent to NISA, where it arrived on the 7 March 2011, just 4 days before the plant was hit by the tsunami. Further studies by scientists and an examination of the plant’s tsunami resistance measures were not planned by TEPCO before April 2011, and no further actions were planned to deal with this subject before October 2012. TEPCO official Junichi Matsumoto said that the company did not feel the need to take prompt action on the estimates, which were still tentative calculations in the research stage. An official of NISA said that these results should have been made public by TEPCO, and that the firm should have taken measures right away.[57][58]
This all was in sharp contrast with the events at the Tōkai Nuclear Power Plant where the dike around the plant was raised to 6.1 meters after evaluations showed the possibility of tsunami-waves higher than previously expected. Although the dike was not completely finished at 11 March 2011, the plant could ride out the tsunami, even though the external power-sources in Tokai were lost too. With two (of three) functioning sea-water-pumps and the emergency diesel-generator the reactor could be kept safely in cold shutdown.[59]
On 26 November a TEPCO spokesman mentioned that TEPCO would have been better prepared to cope with the tsunami in March 2011, if it had taken the 2008-study more seriously. TEPCO was also willing to use the estimates of renewed study done by a national civil engineering society for its facility management.[55]
Nuclear Safety Commission Chairman Haruki Madarame told a parliamentary inquiry in February 2012 that “Japan’s atomic safety rules are inferior to global standards and left the country unprepared for the Fukushima nuclear disaster last March”. There were flaws in, and lax enforcement of, the safety rules governing Japanese nuclear power companies, and this included insufficient protection against tsunamis.[60]