TOKYO (Reuters) - A lack of preparation and poor communication at top levels after disaster struck were among the failures that turned a nuclear accident at Japan's Fukushima plant into the worst atomic crisis in 25 years, a panel probing the disaster said on Monday.
The panel -- headed by an expert in why big mistakes are made -- said Tokyo Electric Power, the utility operating Fukushima's tsunami-wrecked Daiichi nuclear power plant, as well as regulators failed to sufficiently anticipate a massive tsunami and the devastating impact likely to result.
The Daiichi plant, 240 km (150 miles) northeast of Tokyo, was hit on March 11 by a tsunami that exceeded 15 meters in some areas. The tsunami knocked out the plant's cooling systems, resulting in meltdowns of nuclear fuel.
"The government's nuclear regulatory body did not require Tepco to take specific measures, such as additional construction, after they received simulation results from Tepco in 2008 and early in 2011 regarding the impact of tsunamis on their facilities," the panel said in the interim report.
In 2008 Tepco simulated a tsunami exceeding 15 meters reaching Daiichi but did not take action, dismissing the likelihood of such a wave, the panel added.
The report also noted that Tepco did not have enough expertise on the ground after the disaster struck, saying it made mistakes like misunderstanding the functioning status of the No.1 reactor's cooling system and mishandling the No. 3 reactor's cooling system.
The panel also said poor communication between the government's crisis management centre and top officials, despite both being housed in the same building, delayed the use of a system that predicts the spread of radioactivity, holding up and preventing more accurate evacuation orders.
The 12-member panel, set up in May on the initiative of then prime minister Naoto Kan and headed by Yotaro Hatamura, an engineering professor at Tokyo University who specializes in the study of failures, will release a final report next summer. The panel includes seismologists, former diplomats and judges.
The government announced on December 16 that reactors at the plant had reached a state of cold shutdown, a milestone in cleanup efforts and a pre-condition for allowing about 80,000 residents evacuated from a 20-km (12 miles) radius of the Daiichi plant.
But a public poll by the Nikkei newspaper on Monday showed that 78 percent of those surveyed did not agree with the government's decision to declare a cold shutdown.
Critics say the cold shutdown declaration was premature since the aftermath of the Fukushima accident is far from over.
"We can't agree with the prime minister's assertion that matters have been settled at Daiichi. The crops in Fukushima are still contaminated. No progress has been made in reducing the uncertainty felt by the residents," said Michio Furukawa, the mayor of Fukushima's Kawamata town and a member of the panel.
The government said last week it may take another seven years before the inside of the reactors can be checked due to high levels of radiation and technological constraints.
The report did not provide a detailed assessment on the damage to the Daiichi plant caused directly by the earthquake that triggered the tsunami, a key question that could affect whether other reactors that are now off-line for checks, can restart operations to avoid a power crunch.
Tepco has so far said the tsunami that followed the quake caused most of the damage.
Separately, the government said on Monday it would draw up new evacuation zones by the end of April, and areas where annual radiation levels are currently higher than 50 millisieverts would not be deemed suitable for living for at least five years.
The drawing up of new evacuation zones could in theory make it easier for Tepco's other Fukushima plant, the Daini plant to resume operations but Tepco has not begun applying to authorities for a restart and the Fukushima governor has said he wants all reactors in the prefecture to be decommissioned.
Editing by Edwina Gibbs