It’s nice to have Patrick Moore write “Lets not miss the nuclear renaissance” in the Globe and Mail 25/05/06, but he should have someone with real experience of nuclear power check the statements (in italics ) which he has made such as:
§ Chernobyl had no containment structure unlike all reactors in the West. Presumably this refers to the steel and concrete reactor containment dome provide on water cooled reactors, including the vacuum buildings of the multiple CANDUs.
However such containment structures are not provided on MAGNOX reactors. There are major differences between the design of Chernobyl – an RMBK reactor cooled by steam with the graphite core at very high temperature – and the UK MAGNOX reactor cooled by carbon dioxide with the graphite core at a lower temperature. However the primary containment is somewhat similar and none of the 24 MAGNOX reactors in the UK have secondary containment structures for the reasons quoted by Loftness in his 1964 book, “Since a major break in the MAGNOX reactor vessel is considered very unlikely, secondary containment is not generally provided.”
I worked at the Hunterston A in Scotland where the MAGNOX reactor was enclosed in a beautiful glass building through which the steam generators and reactor pile cap could be seen through the glass from a hill outside. This enclosure was typical of the other MAGNOX reactors in the UK.
However, the operators at the Windscale, UK. plutonium producing reactor may have wished that a secondary containment had been provided when in 1957, the uranium fuel cladding and graphite core was on fire for 42 hours causing a considerable discharge of radioactive material to the surrounding countryside.
§ The Chernoby accident was due to bad design with shoddy construction and unprofessional operating procedures.
There was some criticism that the construction in other areas of the plant deviated from the design, but this is not given as a contributing to the accident. I conclude that even high quality construction would not have alleviated the accident.
§ The Three Mile Accident was the only serious nuclear accident in North America.
What about the nuclear explosion of the SL-1 reactor in Idaho in 1960, when three operators working on top the reactor were killed ? This 3 MW thermal reactor was intended to become a portable supply of heat. Again Loftness informs that although the reactor building was not a containment shell ( it was a mild steel, cylindrical structure), the radioactivity of 1000 r per hour was almost entirely retained within the reactor building, where the three operators were working because the reactor was supposed to be shutdown.
We should ensure that statements made in support of nuclear renaissance are technically and historically accurate, to enhance the credibility of the Canadian Nuclear Industry. Comments submitted by Neil Craik, Charter Member of the CNS.