Saturday, February 23, 2013

USA: six tanks at radioactive waste storage leaking

Salmon at Hanford site
The damaged site is at Hanford (Washington state), which has 177 tanks of radioactive waste. Of the 177, six (and not just one, as was reported initially) are leaking their deadly cargo to the environment.

The leak may pollute the atmosphere and the Columbia River, which runs through the inner area of Washington state and then marks the border between this one and Oregon before reaching the Pacific Ocean.

The tanks are made of regular steel (subject to oxidation and corrosion) surrounded by reinforced concrete layers.

The tanks are leaking due to poor tank integrity – the waste is corroding the carbon steel lining. When the tanks were built during the World War II, a shortage of stainless steel necessitated the use of cheaper, less robust carbon steel – this practice continued long after stainless steel was again available.
Carbon steel corrodes in highly acidic environments like those in Hanford’s tanks, so large amounts of other chemicals were added to neutralize the pH in the tanks, minimizing the corrosion problem but making the waste very difficult to stabilize.

The tanks were built to last 20 years. They were never designed to permanently store high-level radioactive waste. Most of these tanks, 149 of them, are single-shelled and built between 1943 and 1964. These have far exceeded this 20-year projection. It is no surprise that they are failing. The double-shell tanks, 28 of them, are double-shelled, built between 1977 and 1986. The double shell tanks are more robust, but are also made of carbon steel. To date, none of the double-shell tanks have leaked, but a more secure solution is needed to contain this waste and prevent even more waste from leaking into the groundwater.

This is one of the big problems of nuclear industry all around the world: you build stuff to last 20 years, then extend for some other 10, 20 or 30 years because they don't know what else to do that is not extremely expensive and still not efficient enough, then... 

Eventually it all collapses one way or another, naturally.

Sources: Ex-SKF, Energy News.

Update: at least 67 tanks are "suspected leakers"!!!  More details at Sunday Spin (via EneNews)

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