By Yuka Obayashi and Kentaro Hamada
TOKYO, Sept 5 (Reuters) - Tokyo Electric Power Co (Tepco) , the operator of the stricken Fukushima nuclear plant, is still putting out questionable data on radiation leaks, causing confusion and a heightened sense of crisis, Japan's nuclear regulator said.
The stakes have been raised as Japan makes a final pitch for Tokyo to host the 2020 Olympic Games, while a steady stream of bad news from Fukushima, the site of the worst atomic disaster in a quarter of a century, leaves officials frustrated by Tepco's missteps and miscalculations.
"As I've said before, Tokyo Electric has not been properly disclosing the situation about the contamination and the levels of contamination," Shunichi Tanaka, chairman of the Nuclear Regulation Authority (NRA), told reporters on Thursday.
"This has caused confusion domestically and internationally. Because of that, the Japanese government has a sense of crisis and I, personally, feel a little angry about it," he said.
"I wouldn't go as far as to say Japan's reputation has been made worse, but releasing incorrect information about the radiated water problem has created trouble around the world," Tanaka said.
Japan this week pledged nearly half a billion dollars to contain leaks and decontaminate radioactive water stored at Fukushima that threaten the clean-up from the March 2011 earthquake and tsunami that crippled the plant and brought Japan's nuclear power industry to a virtual halt.
Officials have been keen to assure the world that Tokyo will be safe during the Olympics in seven years, if chosen. Prime Minister Shinzo Abe flies to Buenos Aires later on Thursday from a Group of 20 meeting in St. Petersburg to lead Tokyo's final pitch before the Olympic committee. Madrid and Istanbul are the other contenders.
"We would like to host the 2020 Olympic and Paralympic Games here in Tokyo and welcome athletes, people affiliated with the events and visitors from all over the world," said Chief Cabinet Secretary Yoshihide Suga, adding that food and water in Japan is safe.
Tepco has been criticised for its failure to prepare for the kind of disaster that struck two and a half years ago, and has been accused of covering up the extent of the problems since.
The plant has been beset with power outages and other problems that have prompted experts to question whether Tepco can handle what is an unprecedented clean-up due to the amount of radioactive material on the site and its coastal location.
The company's disclosure of problems at the site and the quality of its data have been a source of constant criticism.
"I have a certain expert knowledge of Tepco's data and their data is not reliable," Kayoko Nakamura, one of five NRA commissioners, said at Thursday's briefing.
After repeated denials, Tepco has admitted that contaminated water has flowed into the Pacific Ocean, and it has discovered leaks from above-ground tanks used to store irradiated water after it has been washed over melted uranium fuel rods to keep them from overheating.
Earlier this week, Tanaka said concerns about contamination in the Pacific were "misplaced."
Tepco said on Thursday there is a possibility that some of the water that leaked from one storage tank has reached groundwater at the site.
Measurable radiation from water leaking from the facility is mostly confined to the harbour around the plant, officials have said, and is not an environmental threat to other countries as the radiation will be diluted by the sea.
Tepco also said on Thursday that the arm of a crane snapped while removing debris from the building housing the damaged No.3 reactor at the Fukushima plant. There were no injuries or damage to the building. (Additional reporting by James Topham and Kiyoshi Takenaka; Writing by Aaron Sheldrick; Editing by Ian Geoghegan)