22 Reactors in the US are of the same design as the failed reactors in Fukushima

22 aging nuclear reactors in the US that are of the same age and flawed design as the reactors at Fukushima Daiichi (some locations have more than one reactor)

Arnie Gundersen, a former member of the US Nuclear Regulatory Commission, now does consulting work for citizens groups advocating on nuclear issues. Since the Fukushima accident, he has become a leading figure in helping the public understand the issues at stake. Followers in Japan like him so much that they have voluntarily begun translating everything published on his website over the last six months.
In his recent post, Arnie spoke on an issue that should be of high concern for everyone in Canada and the US. The reactors that exploded in Fukushima are exactly the same as 22 Boiling Water Mark 1 General Electric Reactors still in operation in the US. They are getting old, and their failings have been known for a long time, as this NRC memo shows:

NRC Memo dated September 25, 1972
Note to John F. O'Leary
... the acceptance of pressure suppression containment concepts by all elements of the nuclear field, including Regulatory and ACRS, is firmly embedded in the conventional wisdom. Reversal of this hallowed policy, particularly at this time, could well be the end of nuclear power. It would throw into question the continued operation of licensed plants, and would make unlicensable the GE and Westinghouse condensor plants now in review, and would generally create more turmoil that I can stand thinking about.
      - Joseph M. Hendrie

In other words, they knew the design was flawed, but it's too late to go back and change everything now. It's too personally bothersome for the author of the memo, so forget about it. Fortunately, the Three Mile Island nuclear plant was not a Mark 1 reactor. Its superior, larger containment structure is what prevented that accident from being much worse. 
After Three Mile Island, the nuclear industry reluctantly recognized that something had to be done, so they installed a venting system which would release hydrogen gas in the event of a loss of station power and a meltdown of fuel. This system was in place in Fukushima, but for reasons not yet fully explained to the public, it didn't work. It could be because opening the valve required a worker to go into a highly radioactive environment, in full protective gear, and turn a valve 200 times. In the midst of the crisis, no one wanted to send a worker in on a suicide mission. The reactor design failed on all three reactors that were in operation at Fukushima Daiichi.
Even someone as pro-nuclear as the former director of the IAEA, Mohamed AlBaradei, has come out in favor of shutting down these aging, flawed reactors, saying "We must not hesitate to close old reactors the safety of which cannot be guaranteed. I suggest starting with the review of the RBMK type (as in Chernobyl), [Still in operation!] which don't have containment structures, and those of the Fukushima design."
This post is a shout-out to friends and relatives in Canada who live across the lake from Oswego, New York, where there are two Mark 1 reactors still in operation. Some Canadians worry about the reactors closer to home, but these heavy water reactors in Canada have a superior design and excellent safety record. (A recent article in the Literary Review of Canada covers the unfortunate decision of the Japanese to pass over CANDU reactors in favor of American technology.) The first priority for nuclear safety in North America should be the decommissioning of the aging General Electric Mark 1 reactors.

Further reading: Marks to Market: America's Nuclear Time Bombs