Corrosion behaviour of bare and nicraly coated alloy 214 in supercritical water at 700 C

Concerns with greenhouse gas emissions and the uncertainty of long-term supply of fossil fuels have resulted in renewed interest in nuclear energy as an essential part of the energy mix for the future. Many countries worldwide including Canada, China, and EU are currently undertaking the design of generation IV supercritical water-cooled reactor (SCWR) with higher thermodynamic efficiency and considerable plant simplification. The identification of appropriate materials for in-core and out-of-core components to contain the supercritical water (SCW) coolant is one of the major challenges for the design of SCWR. This study is carried out to evaluate the oxidation/corrosion behaviors of bare alloy 214 and NiCrAlY coated 214 under SCW at a temperature of 700 C/25 MPa for 1000 h. The results show that chromium and nickel based oxide forms on the bare surface after exposure in SCW for 1000 h. A dense and adhered oxide layer, consisting of Cr2O3 with spinel (Ni(Cr, Al)2O4), was observed on NiCrAlY surface after 1000 h in SCW

Materials and Water Chemistry for Supercritical Water-cooled Reactors

Materials and Water Chemistry for Supercritical Water-cooled Reactors is unique in that it brings together materials and water chemistry, their interrelationship, the historical perspective and their application to SCWR conceptual design. Written by world’s leading experts, all active in the area of materials and chemistry R&D in support of GEN IV SCWR, this book presents for the first time a comprehensive reference on these topics, and in particular, how these data relate to the SCWR design itself. This book is an essential text for researchers in the areas of supercritical water-cooled reactor materials and chemistry, working in industry or academia. It will also give newcomers to the field a survey of all of the available literature and a clear understanding of how these studies relate to the design of the SCWR concept. The material presented is at a specialist’s level in materials or corrosion science, or in water chemistry of power plants.JRC.G.I.4-Nuclear Reactor Safety and Emergency Preparednes

European Project “Supercritical Water Reactor – Fuel Qualification Test”: Summary of general corrosion tests

The main target of the EUROATOM FP7 project “Fuel Qualification test for SCWR” is to make significant progress towards the design, analysis and licensing of a fuel assembly cooled with supercritical water in a research reactor. The program of dedicated WP4 - Pre-qualification was focused on evaluation of general corrosion resistance of three pre-selected austenitic stainless steels 08Cr18Ni10Ti, AISI 347H and AISI 316L, which should be pre-qualified for application as a cladding material for fuel qualification tests in supercritical water. Therefore, the experiments in support of WP4 concentrated on 2000 h corrosion exposures in 25 MPa SCW at two different temperatures 550 and 500oC dosed with both 150 and 2000 ppb of dissolved oxygen content. Moreover, water chemistry effect was investigated by conducting tests in 550oC SCW with 1.5 ppm of dissolved hydrogen content. At first, corrosion coupons were exposed for 600, 1400 and 2000 h in JRC IET, VTT and SJTU autoclaves connected to recirculation loop allowing continual water chemistry control during the test. Following examination of the exposed specimens consisted of weight change calculations and detailed macro and microscopic investigation of oxide layers using SEM and EDX. With respect to general corrosion results, all tested steels showed sufficient corrosion resistance in SCW conditions taking into account the conditions foreseen for future fuel qualification test in the research reactor in CVR Rez. When the results of weight change calculations were compared for all three materials, it was found out, that the corrosion resistance increased in the following order: 316L<347H<08Cr18Ni10Ti. Results obtained in hydrogen water chemistry did not indicate any significant beneficial effect compared to tests in SCW with 150 or 2000 ppb dissolved oxygen content. Additional tests were dedicated to investigation of surface finish effect. In these exposures polished, sandblasted and plane-milled surface finish technique were investigated. Beneficial effect of surface cold work in particular of sand-blasting was clearly demonstrated.JRC.G.I.4-Nuclear Reactor Safety and Emergency Preparednes