Development of Alternative Method for Manufacturing Structural Zirconium Elements for Nuclear Engineering

Zirconium is used as a structural material for use in aggressive environments, including the core of nuclear reactors. The traditional technology of manufacturing the structural elements of zirconium nuclear reactors is characterized by a long technological process and a significant amount of waste in the form of metal shavings. The paper presents the results of an alternative technology, spark plasma sintering, for manufacturing zirconium products. A complex of microstructural and mechanical studies of the obtained samples was carried out according to the ASTMB-351 standard. The sintering of zirconium powder and options for subsequent processing by various methods, including non-standard ones such as radial shear rolling, are justified.

Preparation and Properties of NZP Family Ceramics

The matrix of NZP family ceramics is natrium phosphate zirconium (for short, NZP) . NZP family ceramics have the designabolity of thermal expansion coefficient, and the average thermal expansion coefficient can be changed from negative value to positive value by means of composition adjustment, thus obtaining zero thermal expansion ceramics with good thermal shock resistance. With NZP family ceramics the thermal stress can be effectively reduced and the thermal properties of materials can be enhanced.Therefore, NZP family ceramics have become a hot topic in materials science community in recent years.The calcium phosphate zirconium powder was prepared by coprecipitation method, and NZP family ceramics were prepared after pressing molding and pressureless sintering. The results show that the compressive strength of the prepared NZP family ceramics is 199 MPa and the thermal expansion coefficient is-0.5×10-6/°C at sintering temperature of 1100°C.