Thanks to Jim Muckerheide for the June 29, 2004 article from the Guardian "World's Oldest Nuclear Power Plant Closes", which was of personal interest because I made business visits to both Chapel Cross and Calder Hall in the early 60's. Also when I was a graduate apprentice with Met Vick in Trafford Park Manchester, I used read the Manachester Guardian. So I was disappointed in the following obvious inaccuracies in the article.
"Opened in the 1950s, the power stations at Chapelcross, Calder Hall, and Galloway in southwest Scotland ..."
Galloway is the district in Scotland where Chapelcross is located. There is no power sation of that name.
"Calder Hall has also been earmarked for closure." But the BNFL website says Calder Hall ceased generation in March 31, 2003, which now allowed Calder Hall to claim being the world's currently longest-serving nuclear power station, because the Calder Hall units went into service a few years before Chapelcross.
The Guardian article also did not explain why these old small Magnox units continued to operate, whereas the newer larger units at Berkley, Bradwell, Hunterston "A", Hinkley and Trawsfyydd where all shutdown years ago. Was it something technical about Chapel Cross and Callder Hall, like lower gas temperatures, or was it because they also produced another valuable product ?