Update 3: Images of the hole in the roof of the tunnel have been released…
Update 2: An aerial survey midmorning Tuesday showed an opening about 20 feet by 20 feet into the tunnel, which had been covered with about eight feet of soil. As Tri-CityHerald.com reports , the breach could expose the highly radioactive material disposed of in the tunnel to the atmosphere.
No airborne radiation had been detected as of about 10:30 a.m. Radiological surveys were continuing.
Instructions for people to shelter in place were expanded from central Hanford to all of Hanford, including LIGO and the reactor areas along the Columbia River, after the aerial survey. No one is being allowed to enter the site beyond the security barricades.
Earlier in the morning workers near Purex had noticed a 4-foot-by-4-foot depression that was 2 to 4 feet deep over the tunnel.
Workers in Purex were evacuated when the depression was noticed.
About 3,000 workers in central Hanford initially were told to take shelter indoors, including about 1,000 workers at the vitrification plant construction site. Ventilation systems at the vit plant have been turned off as part of the emergency procedure and equipment that could generate heat have powered down.
The DOE announced that secretary Perry is aware of the incident and that there is no initial indication of any worker exposure or an airborne radiological release.
Meanwhile, Private pilots in the area have been told to avoid flying over Hanford. The Hanford Patrol is working with the Federal Aviation Administration to put a formal air restriction in place until the FAA can confirm there is no danger.
Update 1: A robot is being used to sample the contaminated air and soil in the area around the collapse…
And here is a chart of current windflows…