Architect of Fukushima Daiichi Reactor 3, Uehara Haruo, the former president of Saga University had an interview on 11/17/2011.
In this interview, he admitted Tepco’s explanation does not make sense, and that the China syndrome is inevitable.
He stated that considering 8 months have passed since 311 without any improvement, it is inevitable that melted fuel went out of the container vessel and sank underground, which is called China syndrome.
He added, if fuel has reaches a underground water vein, it will cause contamination of underground water, soil contamination and sea contamination. Moreover, if the underground water vein keeps being heated for long time, a massive hydrovolcanic explosion will be caused.
He also warned radioactive debris is spreading in Pacific Ocean. Tons of the debris has reached the Marshall Islands as of 11/15/2011.
(Source)