(Note from RC: While tritium has several different experimentally determined values of its half-life, the National Institute of Standards and Technology lists 4,500±8 days (approximately 12.32 years. The only thing that can SHIELD from tritium is SOLID GOLD. Tritiated water is actually 3 molecules of hydrogen vs 2 as in normal water, or H2O. This is why you can't "filter" tritiated or tritium-water)
On 9/12/2013, NRA (Nuclear Regulation Authority) reported there is no technology to remove Tritium from the significant volume of the contaminated water.
They held the working group meeting for the contaminated water in Fukushima nuclear plant on 9/12/2013. In this meeting, they stated Tepco is expecting the multiple nuclides removing system (ALPS) to purify the contaminated water clean enough to discharge.
However, even after the treatment by ALPS, radioactive water Tritium remains in the water. The density is approx. 100,000,000,000 Bq/m3. <----------gasp!
The working group concluded it is impossible to remove Tritium with the existing technology, they decided to appeal the world for the new technology.
Full article here
Well that's reassuring....