A Chernobyl-like radiation leak at Gori 1 nuclear reactor, the country’s oldest in operation, could lead to nearly 900,000 deaths and economic losses of 628 trillion won ($537 billion), anti-nuclear activists claimed in a report Monday.

The report, released by a partnership including the Korean Federation for Environmental Movement and a Busan-based anti-nuclear group, analyzed the consequences of a simulated accident at the nuclear power plant using a damage assessment method developed in Japan. It is the first study conducted in Korea that looks into the potential impact of a nuclear disaster, the groups said.

In an accident of a similar scale as the 1986 Chernobyl disaster in the former Soviet Union and if there are no proper evacuation measures, the immediate death toll could reach 47,580, it warned. The long-term cancer death toll is projected to reach a maximum of 850,000.

“Since the Gori 1 reactor is located near Busan, a populous city, an accident could lead to many casualties,” the groups said in a joint statement.

Despite the catastrophic loss projected, Korea Hydro & Nuclear Power Co.’s insurance policy covers just 50 billion won, it pointed out.

The Gori 1, located in Busan, the country’s second-largest city, is the main target of the anti-nuke movement in Korea, after the government in 2008 decided to use it for another 10 years after completing its designed life span of 30 years.

In February, the reactor lost power for about 12 minutes, which affected the operation of key facilities such as those that store spent fuel and cooling water. Some 3.42 million people live within 30 kilometers of the reactor.

The state-run operator of the nuclear power plants played down the report, insisting it was based on a scenario that has a zero percent probability.

“The Korean reactors are of a different design from those used in the Chernobyl plant or in the Fukushima plant (in Japan) and have far stronger reactor containment vessels,” it said in a press statement.

By Lee Sun-young (milaya@heraldcorp.com)