Maybe the spent fuel problem is responsible for the heavy emissions visible with the webcams:
Enenews reports from NHK: Another fuel pool loses cooling system at Fukushima Daiichi — CBC: May take days to repair http://enenews.com/nhk-another-fuel-pool-loses-cooling-system-at-fukushima-plant-cbc-solution-may-take-days/comment-page-1#comment-338269
Links provided by Enenews:
Blackout halts cooling system at Fukushima plant NHK March 18 2013 http://www3.nhk.or.jp/daily/english/20130319_01.html
[Excerpted] TEPCO officials say a power blackout has suspended a cooling system for used nuclear fuel at the struggling Fukushima Daiichi power plant.
...The affected system is intended to cool 3 pools containing about 2,100 spent rods from the plant's number 1, 3, and 4 reactors.
...The officials said it will take about 4 days for the pools to exceed 65 degrees -- the firm's limit.
They added the blackout has interrupted the cooling system for another pool containing about 6,300 rods. It has also affected part of a system that disposes of contaminated water... [end]
Crucial system fails at Japan's quake-damaged nuclear plan:Workers at Fukushima Daiichi nuclear plant scrambling to fix broken cooling system in 3 reactors CBC News Posted: Mar 18, 2013 http://www.cbc.ca/news/world/story/2013/03/18/japan-daiichi-nuclear-plant-failure.html?cmp=rss
[Excerpted] Workers at the tsunami-damaged Fukushima Daiichi nuclear plant in Japan are trying to fix a crucial part of the plant that stopped working today.
The system that cools hundreds of spent fuel rods that are stored at the facility has stopped working, which could have dangerous consequences, CBC News producer Craig Dale has learned...Currently the cooling systems in reactors one, three and four are not operational and representatives from TEPCO are unsure how to fix them..
Yesterday looked hot also, but not as hot as today
The TBS webcam was not working yesterday morning.