Here's what I've harvested from NIRS:

"UPDATE, Noon, Thursday, April 21, 2011. As expected, the Japanese government has now turned the 20 kilometer "evacuation" zone into an exclusion zone. People entering the zone can be fined up to $1200 or jailed up to 30 days for entering the zone. Streams of people entered the zone earlier today before the new law went into effect to gather their possessions and check on their homes. The government will now allow a single visit per household, lasting no more than two hours, for people to gather their possessions. People returning from these visits will have to be screened for radiation. It is not clear what will happen to possessions found to be radioactive.

It is highly unlikely people will be allowed to return to the area, although the Japanese government appears to be willing to accept higher annual radiation levels for the public than other nations. For example, the government has allowed schools in Fukushima Prefecture outside the evacuation zone to open in April, despite radiation readings at 75% of the schools monitored showing radiation levels above the legal standard for a "radiation controlled area" – defined as an area where unnecessary human entry and radioactive exposure are to be prevented and avoided.

NHK TV reports that radioactive groundwater has been seeping into Units 5 and 6 at Fukushima Daiichi. These units are set some distance apart from the crippled Units 1-4, which means the overall contamination of the area, and migration of radioactive water, is significant.

Several media outlets reported that a Tepco official said Wednesday that Unit 1 is "melting down," although no clarification was included in these reports. Today, Tepco says that while there has been fuel damage at Units 1-4, it denies that there is ongoing melting of fuel."

It is of great concern that there is ground water migration of radioactive contaminated water from Units 1-4 to Units 5 and 6. But it's certainly not to be unexpected.

Charley Noble