Press Releases 2013

On March 29, 2013, we published ‘A summary on the Fukushima Nuclear Accident and the Nuclear Safety Reform Plan,' and we have announced the progress on a regular basis.

On November 1, we published ‘A progress report on Nuclear Safety Reform Plan (FY2013 2nd Quarter)' and set it our target to separately examine and report on the unidentified and unsolved matters of the Fukushima Nuclear Accident.
We made a report on these issues, in response to our examining and the things pointed out in the Nuclear Reform Monitoring Committee held on December 2. Today, we would like to announce the report.

We will continuously try to 1) reveal the whole pictures of the accident such as figuring out the behavior of the reactors at the point of the accident etc., based on a systematic on-site survey and a simulation analyses, and 2) make use of the whole pictures, in order to enhance the safety, which is our duty as a nuclear operator, and develop the decommission of reactors. Also, we will work on the nuclear safety reform, and announce our progress on these approaches on a regular basis.

It was found that the information on the location of the wave gauge at Fukushima Daiichi Nuclear Power Station was incorrect, therefore we corrected the following documents on September 3, 2019. Corrected texts are hilighted in yellow, and corrected images are surrounded by yellow line.
・Summary
・Attachment Earthquake-tsunami-1

 

-'Report on the survey and study results of unconfirmed and unexplained events of the Fukushima nuclear power plant accident First Progress Report' (Summary) (PDF 3.10MB)

-'Evaluation of the situation of cores and containment vessels of Fukushima Daiichi Nuclear Power Station Units-1 to 3 and examination into unsolved issues in the accident progression Progress Report No. 1'

Main body (PDF 589KB)

List of separate volumes
[Separate Volume 1] MAAP analysis results as of March 12th, 2012 (provided by Japanese only) (PDF 829KB)

List of attachments
[Attachment 1] Overview of MAAP (provided by Japanese only) (PDF 581KB)
[Attachment 2] List of issues (provided by Japanese only) (PDF 3.50MB)
[Attachment 3] Latest results of MAAP5 analysis (to be published)
[Attachment 4] Status of investigation on estimating the situation of cores and containment vessels (PDF 2.87MB)
[Attachment Earthquake-tsunami-1] Arrival times of tsunami at the Fukushima Daiichi Nuclear Power Station site (PDF 3.13MB)
[Attachment 1-1] Water injection volume to the reactor Unit-1 set in the MAAP analysis (PDF 69.1KB)
[Attachment 1-2] Estimation of fuel range water level indicator responses of Unit-1 (PDF 220KB)
[Attachment 1-3] Impacts of the earthquake on Unit-1 (PDF 455KB)
[Attachment 1-4] Examination into water injection by fire engines (PDF 605KB)
[Attachment 2-1] Reactor pressure behaviors at Unit-2 (PDF 279KB)
[Attachment 2-2] Containment vessel pressure behaviors at Unit-2 (PDF 306KB)
[Attachment 2-3] Water injection volume to the reactor of Unit-2 set in the MAAP analysis (PDF 99.4KB)
[Attachment 2-4] RCIC flow rates after the loss of power supply at Unit-2 (PDF 106KB)
[Attachment 2-5] RHR system situations after tsunami arrival at Unit-2 (PDF 327KB)
[Attachment 2-6] Behavior of primary containment vessel pressure starting about 12 o’clock on March 14th in Unit-2 (PDF 583KB)
[Attachment 3-1] Reactor pressure behavior during high pressure water injection at Unit-3 (PDF 296KB)
[Attachment 3-2] Water injection volume to the reactor of Unit-3 set in the MAAP analysis (PDF 130KB)
[Attachment 3-3] Reactor pressure decreasing behavior at about 9:00 on March 13th in Unit- 3 (PDF 436KB)
[Attachment 3-4] Reactor pressure behaviors from about 02:00 to about 09:00 on March 13th at Unit-3 (PDF 413KB)

*English translations of the full edition report is now being developed and it takes a while to complete them.
We will post the translations one by one when it is prepared.
(The documents written in Japanese below will be replaced by English translations.)
We apologize for this inconvenience caused.