Experience gained in the remote dismantling of the highly activated moderator tank andother RPV internals during the complete removal of the Karlsruhe multi-purposeresearch reactor (MZFR)

摘要

After nearly 19 years of operation, the Karlsruhe multi-purpose research reactor (MZFR) wasfinally shut down in May 1984. The objectives defined for the plant that is located on the premises of theForschungszentrum Karlsruhe had been reached, the tasks assigned to the MZFR had been fulfilled.At the moment, the pressurized water reactor that was cooled and moderated with heavy water and reached agross power output of 57 Mwel is being dismantled. Meanwhile, dismantling work has reached an advancedstage and focuses on the reactor pressure vessel and its internals. The dismantling project is aimed at restoringthe original state, the "green field".The present report describes the experience gained in the remote dismantling of the MZFR reactor pressurevessel.Dismantling is aggravated by the limited space in the prototype reactor facility. For this reason, the RPV isdismantled in its installation position, where it is accessible from above only. Consequently, both the dismantlingand the handling equipment face considerable challenges. Depending on the geometry, activation, and materialof the RPV components, mechanical as well as thermal dismantling techniques are applied. These techniques hadto be modified or even newly developed and qualified for remote operation.