After 11 years and more than $2.2 billion, a proposed burial site for nuclear waste in Nevada will pass a key milestone when projects scientists issue a report giving the green light for the continuation of the project.

The interim report will acknowledge that scientific uncertainties remain but will say nothing has been found that would suggest the Yucca Mountain site should be abandoned. A final decision about the use of the site is unlikely to be made before 2001.

The proposed site, northwest of Las Vegas, is the only location in the USA being considered for the disposal of more than 73 000 t of highly radioactive reactor waste. However critics have lobbied the US Department of Energy to abandon the scheme, claiming it may be vulnerable to the ingress of groundwater.

The proposed plan envisages a services of tunnels 250 m underground which will house the waste. If the project proceeds, it will not be completed, at the earliest, until 2010.

The US government has spent approximately $6 billion over three decades searching for a suitable site for high level radioactive waste. In 1987, the US Congress limited the search to Yucca Mountain.