Still working under the looming shadow of a complete meltdown, officials at Japan's tsunami-stricken Fukushima Daiichi nuclear plant saw recent encouraging news buffered Friday by another troubling development: radioactive water seeping out of reactors and directly into the Pacific, Japan's critical protein lifeline.
Tests done 330 meters from one of the plant's coolant water outlets showed radioactive iodine levels at 1,250 times normal, raising new concerns that one of the three hardest-struck reactors may be allowing radioactive materials to leak directly into the environment. Officials fought back against that assessment Friday. "There is no data suggesting a crack," said Nuclear and Industrial Safety Agency spokesman Hidehiko Nishiyama.
Nevertheless, "the situation today at the Fukushima Daiichi power plant is still very grave and serious. We must remain vigilant," Prime Minister Naoto Kan said.
Entering the third week since the powerful earthquake and ensuing tsunami that killed at least 10,000 and left another 17,000 Japanese missing, the world has anxiously watched as officials try to regain control over several damaged Fukushima reactors, all of which lost power after the earthquake, causing several explosions and emissions of radioactive steam and smoke.
Though Japanese officials expanded the evacuation zone around the plant from 12 to 18 miles, air-borne radiation levels have decreased in recent days. On Saturday morning, radiation at the plant's main gate hovered at .219 millisieverts per hour, down from the 400 millisieverts per hour measured near Units 3 and 4 on March 15.
What's more, Tokyo downgraded concerns about radiation getting into the city's drinking water after levels had risen to those believed harmful to babies. Those levels are now under the 100 becquerel level, meaning it's likely safe for babies to drink.
Two plant workers were seriously hurt on March 24 when radioactive water inside Unit 3 sloshed over their boots, burning their feet. Workers are stepping up efforts to bail out water from inside the reactors into special on-site vessels so the water doesn't escape into the ground.
The 50 becquerels of radioactive iodine per cubic centimeter of seawater found in the ocean on Friday is a "relatively high level," Mr. Nishiyama said.
But officials said the radioactive iodine found in the seawater only has a half-life of eight days, meaning it's not likely to have long-term health repercussions, though environmentalists are warning that dangerously high levels could impact sea life and potentially Japan's fishing fleet.
A more critical question is where the radioactive water is coming from.
Tokyo Electric Power officials said Friday they don't believe water is actually leaking out of the reactors. Officials said the high concentrations found in the seawater could be caused by airborne radiation in the area or water that came close enough to the reactors to absorb radiation.
Radioactive water around the plant, however, is to be expected in light of the pumping and spraying efforts as workers have attempted to cool the cores and prevent a meltdown.
Those assessments, however, have not eased concerns of a leaky reactor raised this week. One potential culprit is Unit 3, which was rocked by a high-impact hydrogen explosion on March 14. A breach in Unit 3 could be a crack or a hole in the reactor core's stainless steel chamber or in the spent fuel pool that's contained by a massive concrete container.
If any of the unit's containments walls are cracked, it could hobble efforts to seal up the plant to contain its potentially deadly radiation. Tepco, the power plant's operator, said on Friday that the operation to stabilize Fukushima could take another month or more.
"We are still in the process of assessing the damage at the plant, so we can't put a deadline on when the cooling operations will work again," a spokesman from TEPCO, the plant's operator, told Agence France-Presse.