100% yes, it is safe. Tritium is a very weak beta emitter, so tritium itself cannot emit radiation strong enough to even penetrate your skin. According to the NRC, drinking water for an entire year from a well contaminated with 1600 pCi/ml of tritium (comparable to levels identified in a drinking water well after a significant tritiated water spill at a nuclear facility) results in a radiation dose of 0.3 mrem. That is 12 times lower than the dose you receive from a cross country flight (DC-LA and back). The federal limit (in the US) for radiation workers is 5 rem per year. 0.3 mrem is 0.00003 rem. This release of tritiated liquid by Japan is completely safe, and very far below any regulatory limit.