Tokyo: The embattled operator of Japan's Fukushima Daiichi nuclear plant has released workers' accounts of the desperate moments surrounding the huge earthquake and tsunami that triggered an atomic crisis.

At a hearing into the March disaster, a chief operator in a control room described how indicator lights on the control panels flickered and went off, while the room's main lights also went out, according to an interim report released on Friday by the Tokyo Electric Power Co (TEPCO).

"I came to realise a tsunami had hit the site as one of the workers rushed into the room, shouting 'Sea water is gushing in!'", the unnamed chief operator was quoted as saying.

"I felt totally at a loss after losing power sources," he said. "Other workers appeared anxious. They argued, and one asked: 'Is there any reason for us to be here when there is nothing we can do to control (the reactors)?'"

"I bowed and begged them to stay."

The 9.0-magnitude earthquake and subsequent tsunami on March 11 paralysed electrical and cooling systems at the nuclear power plant, triggering the world's worst nuclear crisis since Chernobyl 25 years ago.

The atomic accident has not directly claimed any lives but has left tens of thousands of people displaced and rendered whole towns uninhabitable because of radioactivity, possibly for decades. The quake and tsunami killed about 20,000 people.

The interim report, the first to detail workers' testimonies, also described attempts to release pressure from a reactor container by manually opening a ventilation valve as they struggled to avert catastrophic meltdown.

"We put on the full protection gear but couldn't possibly let young workers do the task, as we had to go into an area where the radiation levels were high," one worker recalled.
"When I got to the place to open the valve, I heard eerie, deep popping noise from the torus (a donut-shaped structure at the bottom of the reactor)," he said.

"When I put one of my feet on the torus to reach the valve, my black rubber boot melted and slipped (due to the heat)."

The operators also spoke of dismal working conditions as they battled to stabilise the crippled plant.

"We experienced big aftershocks, and many times we had to run up a hill in desperation (fearing a tsunami) with the full-face mask still on," one worker said.

Another worker spoke of the race against time to lay power cables and bring back the supply of electricity to the plant, saying: "We finished the work (in one section) in several hours, although it usually requires one month or two."