Following up this article ..Emergency mail from Tepco
In the evening of 2/1/2012, Tepco admitted that the amount of water leakage was up to 8.5 tones, though they announced it was only 6L.
Because it contains 35,500 Bq/L, it means at least 301750000Bq of radiation has leaked.
At first they mentioned it in L, which is a unit for volume, and they changed it to tone, which is a unit for weight. Japanese people are confused by this random report of Tepco.
It leaked from a pipe (9mm diameter.) connected to a facility to measure the amount of water in reactor jet pomp. The pipe was completely taken off from the plug but the reason is not known yet. Tepco suspects it might be from frozen water inside of the pipes.
The leaked water didn’t flow out of the buildings but went into the basement floor of reactor 4.
漏えい水は8．5トン＝4号機建屋配管、地下に流入―福島第1
時事通信 2月1日(水)20時54分配信
東京電力福島第1原発4号機の原子炉建屋1階の配管から炉内のものとみられる水が漏れた問題で、東電は1日夜、漏えい量は推定8．5トンに上ると発表した。配管付近の床に漏れていた水量は約6リットルだった。
東電によると、配管は原子炉ジェットポンプの流量を調べる機器のもので直径は約9ミリ。配管はもともと差し込まれていた部位からすっぽり外れていたという。凍結による損傷の可能性もあるが、原因は不明。漏えい水は4号機建屋の地下1階に流れ込み、建屋外への流出はないとしている。