A lot of different numbers are floating round in the media:
From the Japan Times:
http://search.japantimes.co.jp/cgi-bin/nn20110314a1.html"Radiation around the reactor exceeded the legal limit to hit 1,557 microsieverts per hour at 1:52 p.m. This rate then fell to 184 microsieverts about 50 minutes later."
Monsters and Critics:
http://www.monstersandcritics.com/news/asiapacific/news/article_1625759.php/Radiation-levels-rise-again-at-endangered-Fukushima-nuclear-plant"On Sunday, radiation at one of the Fukushima reactors was at 882 microsievert per hour and briefly topped 1,204. Japan allows an hourly exposure of 500 microsievert, which is a measure of the biological effects of radiation."
Nikkei:
http://e.nikkei.com/e/fr/tnks/Nni20110313D13JF571.htm"TOKYO (Kyodo)--Tokyo Electric Power Co. has notified Japan's nuclear safety agency that the radiation level at the Fukushima No. 1 nuclear power plant has exceeded the legal limit, the agency Sunday.
Hourly radiation at the site was measured at 882 micro sievert, in excess of the allowable level of 500."