"I am sick and tired of war. Its glory is all moonshine. It is only those who have never fired a shot nor heard the shrieks and groans of the wounded who cry for blood and vengeance, for desolation." - General William Tecumseh Sherman
A friend emailed me recently and asked what I thought about the big radioactive spill at Hanford Building 324. I hadn't even heard about this event, so I had to learn about it before commenting. So I read up, and here is the comment...
The Hanford Site was the primary Plutonium production facility for the US during the latter half of WW2 and throughout the cold war. The Plutonium was necessary for the ongoing nuclear arms race and for weapon testing and improvement. Neither the government nor the contractors were terribly concerned about the environment in that era, and we now are confronted with their legacy.
First off, let's locate this place. Below: The US Pacific Northwest, with the Hanford site marked.
Below: A little closer in, focused on Washington State.
Next we have the location of *this* particular Hanford problem (there are many) marked with an arrow, along with the Tri-Cities area, which encompasses the communities of Richland, Pasco, and Kennewick. The Columbia river runs top to bottom, and is joined by the Snake River at the bottom right.
Below: A closer image of Building 324 (center), showing how near it sits to the Columbia river, a rich ecosystem containing millions of salmon, walleye, and sturgeon - as well as trout, bass and many other species.
I posted about a minor radiological incident at Hanford a few years ago. This event led to a shelter-in-place order for the entire site. Every once in a while something newsworthy happens there.
Hanford Building 324 contains an abandoned Hot Cell. A Hot Cell is a specially designed room where highly radioactive substances can be remotely handled.
Spent reactor fuel is often handled in a Hot Cell, where Post Irradiation Analysis (PIA) is performed. This is done to learn how well fuel or cladding materials are holding up in the harsh environment of a reactor core over time, and to then improve upon them. There were a number of improvements to the fuel slugs at Hanford over the years, very likely as a result of PIA performed in Building 324.
Hot Cells are also frequently used to chemically separate useful radioisotopes from spent fuel for medical (radiotherapy machines) or other uses, such as radioactive sources for industrial radiography - to capture images of defects deep inside steel castings.
Hot Cells are pretty cool. They have thick concrete walls and thick lead-glass windows to protect workers from insane levels of radiation, while also providing a view and manipulation of things inside. Hot Cells have remote manipulator arms, allowing incredibly lethal stuff to be safely handled. Remote cameras, tools, and microscopes are often inside the hot cell, allowing close inspection of metal grain structures. Chemical separations can be remotely performed, if the necessary equipment is placed inside in advance.
The "hot" side of the Hot Cell is kept at a slight negative pressure, so that air will leak in, rather than lethal radioactive particles leaking out. The suction fan has several HEPA (High Efficiency Particluate Absorption) filters in line to remove radioactive particles from the air. After filtration, the discharge of the fan is released from a tall stack, because no filtration process is perfect.
The reason I know a little bit about Hot Cells is that I used to work next door to one. General Atomics had a Hot Cell in the building next to where I worked as a reactor operator.
The Hot Cell at General Atomics had a small manipulator trainer that I sometimes goofed off with during lunch. The trainer sat in a clean area, and it had a yellow piece of plexiglass between you and a bench-top on the far side of the plexiglass, so it looked like you were viewing the other side through leaded glass. The Hot Cell head physicist was a pretty chill dude to let me goof off in there. On the other side of the plexiglass sat one of these kid's toys. I usually knocked the entire thing over before managing to insert a peg in a hole. Using the remote manipulators takes quite a bit of skill, which I obviously never acquired.
Here's another thing to consider: Even a cockroach will die from the radiation levels in a Hot Cell that contains spent reactor fuel - I've witnessed it.
Back to Hanford though... Building 324 once had a similar working Hot Cell, where they at some point performed chemical separation of various radioisotopes from spent nuclear reactor fuel - most likely fuel that came from the nearby Plutonium production stream.
Below is an aerial look at Hanford Building 324. The railroad tracks would have brought freshly irradiated fuel via remote-control train into the building. Photo courtesy of US Department of Energy
Below is a view (from 2017) of a crew preparing to begin a shift of clean-up operations inside Building 324. The decontamination support zone appears to be on the left, and the hot zone is on the right. The hot zone apparently requires forced air-purifying respirators, which are hanging off he back of each worker, and full anti-contamination suits. Photo courtesy of US Department of Energy.
There are a few other things to notice in this image. At the top left is one of the old Hot Cell work stations with manipulator arms hanging down from the wall, with a lead-glass window. Look above the open door at the gray hydraulic ram. That's a huge ram, and it's needed because that door weighs several tons. The door is filled with lead, and impossible to move with human muscle. Also note how the edge of the door is stepped, as is the door frame. This is to provide overlap, preventing radiation from shining directly out along a gap. The stuff inside a Hot Cell is exceedingly dangerous, so these guys still have to worry about skin contamination and inhaling radioactive dust as they clean up - decades later.
On to the legacy problem and current issue with Building 324.
In the 1980's, one of the Hot Cell stations was preparing a concentrated radioactive source made of Strontium-90 and Cesium-137 which was to be shipped to Germany, once prepared. These nuclides were likely extracted from several batches of spent reactor fuel. There was a spill, which was unfortunately not contained by the Hot Cell floor. The Hot Cell floor was made from stainless steel, but perhaps it was damaged when a heavy shielded container fell on it during the spill. In any event, the highly radioactive stuff - apparently in liquid form - leaked into the soil underneath the building.
Strontium-90 has high biological uptake - it is chemically similar to
calcium, and tends to bind up into bone. With a half-life of 29 years,
it will be generations before the hazard of loose Strontium-90 will become
negligible.
The 1980's spill was re-discovered in 2010, as preparations were being made to demolish building 324. The soil was incredibly contaminated - up to 8900 Roentgen/hr. This works out to 2.5 Roentgen/second. Nasty. That would lead to a Lethal Dose in 3 minutes for 50% of those exposed, within 30 days time (LD-50/30).
Upon re-discovering the spill, they halted the plan to demolish the building. Instead, new plans were made. They would leave the building standing, and use the Hot Cell's existing shielding to safely remove the contaminated flooring and excavate the lethal contaminated dirt from a remote location on the other side of the Hot Cell wall. Brilliant and safe! Below is an image of the digging rig they hoped to use inside the Hot Cell, being tested out in a different location.
They also planned to put a "sarcophogus" over the top of the building, so that rainwater would not be able to leach materials further away from the area. Building this "sarcophogus" required digging holes, pouring reinforced concrete pilings, and using these to support the new over-structure. That's when they learned that the soil outside of the Building 324 perimeter was also contaminated. Not good news at all. It is very unlikely that the soil outside the building perimeter is anywhere near as badly contaminated and deadly as the soil directly below the Hot Cell - just that it is contaminated enough that it will have to be carted off.
It currently looks like they will have to demolish the entire building after all, and then haul off a great deal more soil than they ever anticipated into a safe storage facility. It's critical to protect the aquifer, which lies just 47 feet below grade.
Why does it sometimes seem that we will all become contaminated at some point? This is why!
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