May 7 (Reuters) - Toshiba Corp said on Wednesday it wrote down by more than $300 million the value of its stake in a company planning to extend a nuclear power plant in Texas, amid uncertainty over the award of licenses for reactors in the U.S.
Toshiba had only last month scored a victory in a dispute with the U.S. Nuclear Regulatory Commission over foreign ownership rules, when the watchdog's judicial arm ruled in the Japanese company's favour.
But the NRC also said it will not make any final reactor license decisions anywhere in the U.S. until late 2014 at the earliest due to issues surrounding the long-term storage of spent nuclear fuel.
Japan's Fukushima nuclear disaster in 2011 has forced a reassessment of atomic power, and cheap shale gas and coal has led to the closure of several older plants in the U.S.
Nuclear Innovation North America, which is 90 percent owned by New Jersey-based NRG Energy Inc and 10 percent owned by Toshiba, wants to build two new reactors at the South Texas nuclear power plant.
"Toshiba has undertaken a conservative reassessment of asset value of Nuclear Innovation North America ... and recognised an operating loss of 31 billion yen ($305 million)," the Japanese company said in a statement.
The South Texas plant has two 1,280-megawatt reactors. In 2007, the plant's owners applied to the NRC to add two Toshiba 1,350 MW Advanced Boiling Water Reactors at a cost of at least $17 billion.
$1 = 101.5550 Japanese Yen Reporting by Aaron Sheldrick