KING 5 News has learned there’s been a series of unexpected hydrogen gas releases from a tank holding radioactive waste at Hanford Nuclear Reservation.
Confidential sources say it began on March 16 and lasted for several days, much longer than usual, and they worry a single spark could have set off an explosive release of radioactivity.
This comes two days after a report by a government panel expressing concerns about the release of flammable gasses at Hanford and the government's inability to respond to them.
Our confidential sources and government representatives are giving dramatically different versions of what has happened. Both agre a million-gallon tank holding nuclear waste at Hanford had a build-up of hydrogen gas.
Our confidential sources say it was of a magnitude larger than anything teams there have seen in at least two years and "burped" days longer than normal.
Workers who toil above the buried Hanford tank farms constantly monitor the tanks for gas build-ups and will conduct controlled releases to reduce pressure. We're told this was a spontaenous release, not controlled.
Hydrogen gas is constantly being produced in some tanks by the extremely high temperatures of nuclear waste. They are like dozens of underground crock pots just simmering away. Sometimes, they can boil over.
The Department of Energy released this response:
In mid-March one of Hanford’s double-shell tanks (DST) had a gas release which is an expected periodic event. Of the 28 DST’s at the Hanford Tank Farms, there are five that periodically release hydrogen gas in a spontaneous manner. These releases typically occur every one to two years in these five tanks and can last for a couple of days. Releases in the DST’s have been occurring for decades and are decreasing in hydrogen levels. DOE has specific ignition source controls on these five tanks to minimize the potential for ignition of flammable gas. In addition, all DSTs are actively ventilated to exhaust flammable gas from the tank head space.
In the case of AN-105, on March 16 during a 36 hour release, ORP monitored the level of hydrogen in the tank head space and it was well below the concentration required for a flammable environment (at approximately 37% of the lowest possible flammability limit).
ORP is committed to ensuring the safety of Hanford’s underground tanks.
Public Affairs Specialist
U.S. Department of Energy