Where can I find papers analyzing the meltdowns at the Fukushima Daiichi Plant meldown?

I have been doing research about fission plants and would really like to add material on what occurred at the Fukushima plants, in particular the fatal flaws that caused the hydrogen explosion. Was it the reactor , the on site storage facility, or the primary containment that failed first? I am required to have sources be from credible institutions or scientists, but might have some flexibility considering how little time has transpired since the incident.