In 2000, the DoE and Bechtel National, Inc. (the contractor retained to build the Vitrification plant at Hanford) began construction of the plant before the design of the critical elements of the plant had been completed - in fact, before the design of many of those elements had even been started. The goal, to save time and money.
Trying to build a house? No problem... our construction team have built a few of those so they know what to do based on early architectural sketches and teamwork. But this is not a house, it is a vitrification plant for 50+ million gallons of the worst nuclear waste in the world with a total radioactive potential of around 170-180 million curies (Cernobyl released about half that). Oh, and that shit is not only hot radioactively, it is hot temperature-wise too.
Today, 60 of 177 storage tanks are leaking with the rest at a high risk of leaking, and if all goes well the complex to house the worst of the waste after vitrification will be built by 2048, with the whole vitrification process completed by 2062. Unless there are delays... after all, this is a government project, they are good at hitting project deadlines, right?
Each tank is layered, with a relatively solid layer at the bottom, a salt cake above that, then sludge followed by liquid and a gas layer. Sounds a bit like my toilet after a bad Chinese meal... only more of it. Most of the radioactivity is in the solids and sludge whereas most of the volume is in the liquids and the salt cake - you need the liquid to transfer the rest through the crappy piping and filters from the storage tanks to the vitrification plant, and it all has to flow fast enough to keep the solids moving without causing any blockages or radioactive buildups.
To top it all off, the glass mixture used in the vitrification process has to be tailoered to the mixture in the tank, and given the diversity of radioactive processes, materials and production methods in use on site, there will be at least 10 compounts required, with no way of knowing what is in what tank short of analysing the contents and getting a representative sample of everything in the tank.
Simple :-S
To my layman's mind, two things come to mind - 1. The whole thing is a complete clusterfuck, and it will be a miracle if the whole lot does not end very badly. 2, Top priority is to contain the leak in the immediate vicinity, but short of digging some massive trenches and excavating a huge foundation then filling the whole lot with some kind of radioactive-resistant concrete, and doing it in such a way that you can inspect the result for leaks, I cannot see how they are going to manage that.
Time to call in Bruce Willis and get him to start drilling, I guess.