The WIPP exhaust filter readings have been published. The pre-filter readings for the exhaust shaft were:
1,365 Bq/m3 of Americium
672 Bq/m3 of Plutonium (239+240Pu)
This is a total combined reading of 2037 Bq/m3
These are the levels inside the exhaust shaft before the HEPA filter. This monitoring filter was pulled for testing 24 hours after the incident. Readings inside the mine continued to fall over the next week.
After the HEPA filter the readings were:
1.81 Bq/m3 of 241Am
0.224 Bq/m3 of 239+240Pu
This monitoring filter was in place for 5 days before it was removed for testing.
What these readings show is the level of the HEPA filter’s ability to trap contamination to prevent it from reaching outside. What is still unknown is the total of the release itself. Readings detected contamination at the post HEPA filter, on site at WIPP and about 1/2 mile offsite. DOE claims that the brief release of plutonium to the environment ...