To give you some perspective, here is a diagram of the underground instillation showing the approximate location of the airborne radioactivity that was triggered on February 14th. The gray blocks are actually the salt pillars that support the ceiling, while the white lines are the excavated areas.
|Panels 1 through 6 are full. The panel rooms are numbered 1 - 7 from the back wall of the panel (1) |
forward to the central corridor area (7).
|Here is Panel 7 just after it was excavated (from the DOE)|
|This is a picture of Room 7, Panel 7 taken in October 2013, when it was empty of CH-TRU.|
The circle on the left is a RH-TRU emplacement. This room is
the location where airborne radiation was first detected last month. (Source)
Contact-Handled TRU Waste (CH-TRU) is packaged TRU waste with an external surface dose rate not greater than 200 millirem (mrem) per hour. It is placed in standard 208-liter barrels (SWB) that are stacked three-high in the disposal rooms and surrounded by bagged MgO (magnesium oxide).
Remote Handled TRU Waste (RH-TRU) is packaged TRU waste with an external surface dose rate equal to or exceeding 200 mrem per hour. It is put into shielded canisters measuring 0.66 meters in diameter with a maximum length of 3.07m and a maximum weight of 3.63 tons. The canisters are remotely emplaced inside pre-drilled horizontal holes in the walls of the disposal rooms.
You can see examples of both in the picture below:
The idea is that, since salt flows, over time the salt surrounding the disposal rooms will gradually encapsulate the waste within a few hundred years, isolating it in a salt monolith.
WIPP has not released any information about what they have found so far, but they have posted some pictures of the instruments being lowered.
Panel 7, Room 7 is located roughly 2150 feet down and 2200 feet horizontally from the shafts. A reentry team is currently being trained in order to attempt entry into the mine next week.