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In cdn-nucl-l digest, Vol 1 #2664 it was reported
that the Bruce retube manager suggested at the recent CNS Conference in Calgary
that it could be less costly to cut a large whole in the containment building and
replace the entire reactor assembly as a module, instead of re tubing it. Comments by Neil Craik; 1. This is not possible on the CANDU6s because the
containment building prestressed cables are pressure grouted and cannot be
removed/replaced. On some US containment buildings the prestressed cables are pressure
oiled and so can be removed/placed. This may have been done on some US plants to
replace the Steam Generators During
the construction of at least one C6, the pressure grout seeped through cracks
in the ring beam ensuring a solid structure. Pressure oil would worsen such cracking and also needs a steel
liner. 2. The dousing system and support structure would
have to be removed/replaced; a huge task. 3. I know that C6 calandria’s had CT’s installed
before the calandria was moved in horizontally into the reactor building (RB),
but I am not sure if the PTs were also installed outside of the RB. I can
recall discussions about whether this would put a strain on the PT joints. |