Crews at the Fukushima Daiichi plant are fighting a two-front war -- forced at times to limit the flows of cooling water on still-dangerous nuclear reactors in order to manage leakage of radioactive waters at the complex that threaten workers trying to restore vital cooling of the reactors to prevent core meltdowns.

The Asahi Shimbun news service said that plant operators had to improvise means of shifting thousands of tons of radioactive water to storage tanks on the complex in order to protect workers trying to restore equipment and controls at blast damaged reactors at units 1,2 and 3. Contaminated water has drained into trenches connected to turbine buildings alongside the three reactors, most seriously in Unit 2, where an explosion damaged a steam suppression pool at the bottom of the reactor's primary containment structure.

"The work will involve seeking a balance between two contradictory considerations," an official with the Nuclear and Industrial Safety Agency told the news service.

Water from trenches is believed to have leaked from reactors into basements of the turbine units that workers are trying to access to manage reactor cooling operations. "Dealing effectively with the contaminated water is vital to containing the spread of radiation. It has to be removed to allow the operation to cool the fuel rods in the reactor cores to move forward," Asahi Shimbun said.

The trenches have a capacity of about 13,300 tons, but as much as 10,000 tons of contaminated water may already have poured into them, the news organization reported. The trenches house electrical cables and pipes providing seawater to cooling pumps and are normally kept dry, allowing workers to inspect the equipment, it said.

"It's obviously very important that they keep the reactor cool, so they need to have a method to do that," Bill Borchardt, executive director of operations at the Nuclear Regulatory Commission told reporters after a Senate hearing yesterday.

"They're having to swing equipment around the turbine buildings" rather than use controls in the buildings, he said. "They're proceeding on parallel paths. It's forcing them to go deeper into Plan C, Plan D, Plan E, but they continue to make progress.

"If they can process the water that's accumulating in the turbine buildings, that would be a good thing, but the top priority has to be to keep the reactor cool so that the situation doesn't worsen. If the higher priority is to keep the reactor cool, you'll do what you need to in order to deal with the accumulating water in the turbine buildings in some of the units," he said.

NRC chairman Gregory Jaczko was scheduled to brief Senate energy appropriations subcommittee members today on his weekend trip to Japan after returning midday yesterday. He met with U.S. embassy officials, NRC staff in Toyko and Japanese utility and regulatory officials.

Plant becomes a 'permanent grave'?

The temperature in the Unit 1 reactor core began rising again today when emergency water flows were scaled back, to deal with the water leaks that are believed to be coming from the reactor containment shell. At 2 a.m. today local time it reached 329 degrees Celsius, higher than the normal operating temperature of 285 degrees, reflecting the dire tradeoff between controlling the reactor temperature to prevent a full core meltdown, and limiting the spread of radioactive water that restricts workers' operations. Water flow to the reactor was raised to bring down the temperature. Pressure in the reactor was stable, Asahi Shimbun said.

Chief Cabinet Secretary Yukio Edano told reporters yesterday that the highly contaminated water and the presence of plutonium on the Fukushima plant grounds "showed there had been a partial melting of fuel rods," news services reported.

"The earthquake, tsunami and the ensuing nuclear accident may be Japan's largest-ever crisis," the Japanese prime minister, Naoto Kan, told Parliament on Tuesday, in his most sober assessment thus far. "We find ourselves in a situation where we can't let down our guard. We will continue to handle it in a state of maximum alert," The New York Times reported.

"The worst-case scenario is that a meltdown makes the plant's site a permanent grave," Tetsuo Iguchi, a professor in the department of quantum engineering at Nagoya University told The New York Times. "In a small island nation like Japan, that's just not an option. That is why the government is trying to prevent a meltdown at any cost."

Banri Kaieda, Japan's industry minister has urged power companies across the country to secure emergency power generators for their nuclear plants, NHK World reported. He said utilities should confirm these actions and conduct drills with equipment within a month, or shut their units down. But Japan is already suffering rolling blackouts from the loss of power generators following the March 11 earthquake and 45-foot tsunami. Nuclear reactors provide about 30 percent of the nation's electric power supply.

Japanese authorities said today the confirmed death toll from the quake and tsunami has risen to 11,232, but another 16,361 people are still missing and that the number of dead and unaccounted for stands at around 28,000, NHK reported.

Tokyo Electric Power Co. chairman Tsunehisa Katsumata apologized to the nation Wednesday for the impact of the nuclear reactor crisis on the nation. He spoke to reporters in Tokyo for the first time since the crisis began. TEPCO's president, Masataka Shimizu, was hospitalized for hypertension and dizziness on Tuesday night, NHK reported.