Dysprosium titanate as an absorber material for control rods

Disprosium titanate is an attractive control rod material for the thermal neutron reactors. Its main advantages are: insignificant swelling. no out-gassing under neutron irradiation, rather high neutron efficiency, a high melting point (similar to 1870 degrees C), non-interaction with the cladding at temperatures above 1000 degrees C, simple fabrication and easily reprocessed non-radioactive waste. It can be used in control rods as pellets and powder. The disprosium titanate control rods have worked off in the MIR reactor for 17 years, in VVER-1000 - for 4 years without any operating problems. After postirradiation examinations this type of control rod having high lifetime was recommended for the VVER and RBMK. The paper presents the examination results of absorber element dummies containing dysprosium titanate, irradiated in the SM reactor to the neutron fluence of 3.4 x 10(22) cm(-1) (E > 0.1 MeV) and, also, the data on structure, thermal-physical properties of dysprosium titanate. efficiency of dysprosium titanate control rods. (C) 2000 Elsevier Science B.V. AII rights reserved.