WASHINGTON (AP) – The government has calculated a new total cost to open and operate the nation’s first nuclear waste dump – over $90 billion.

It’s the first official estimate since 2001, when the figure stood at $58 billion.

Ward Sproat, the Energy Department official in charge of managing the controversial Yucca Mountain repository project in Nevada, disclosed the new number to reporters after a congressional hearing Tuesday.

It includes $9 billion already spent and covers about 100 years of operation until the dump, 90 miles northwest of Las Vegas, is sealed up forever.

Some of the increase is due to inflation, Sproat said. Also Energy Department officials now expect the dump will hold more radioactive waste than the 77,000 tons initially approved by Congress.