Here is the latest update on Fukushima at BraveNewClimate. Although I am no expert in such matters, I have tried to read along to try and understand what is happening without the hype that one finds from AP and other sources. One issue that was raised this week was a description of reactor 1, which in early reports was described as stable. However, a recent report had claimed that the core had melted into molten lava. From what I am gleaning that is still not a correct description of the situation.
The critical comment from the blog is the following:
1. Reports indicate that some fuel melted and fell to the lower containment sections of units 1-3, where it dispersed in a fairly uniform residue — but this does not seem to have breached containment in any of the reactor pressure vessels. Re-criticality of this ‘corium’ seems very unlikely, but no details can of course be confirmed until the reactor cores are finally dismantled — which may be years away.
What this seems to be saying is that there was some degradation of the core due to the circumstances that resulted from the damage done by the tsunami. What it does not say is that the core has melted into molten lava. I think it was a bit of exaggeration by those who reported it that way.
Also, Barry mentions the robots that Sue has mentioned, the ones sent from Boston to help in the crisis. This is great news that these robots are being used in such a critical fashion.
Information on the partial melting of the core in nr 1 plant can be found at this site. It needs to be understood that there is a difference between a full melt-down and a partial meltdown as explain in the article. It states that the core has partially melted and settled in a granular form. The damage is to be expected, but it has to be understood in terms of “let’s not panic” about meltdowns, because there is nothing in the report to suggest that there has been a “full melt down” with molten lava. Rather it is in “granular form”.
Please check the links that I have provided for further information. Please keep in mind that some people report these situations in a way that is meant to get a certain anti-nuclear reaction.
The accident itself gives us cause for concern about the viability of nuclear power in the future. It is a reminder of the need for plants to be upgraded for the latest technology so that such accidents will not happen in the future. There are many lessons to be learned from what has gone wrong. In the meantime we have to remember the workmen and women who are risking their lives in dealing with this particular situation.