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.

NOVOTNY Radek;  JANIK Premysl;  TOIVONEN Aki;  RUIZ MORENO Ana Maria;  SZARAZ Zoltan;  ZHANG Lefu;  SIEGL J;  HAUSILD P;  PENTTILA Sami; 

2017-01-17

ASME

JRC99235

2332-8983,    2332-8975,   

http://nuclearengineering.asmedigitalcollection.asme.org/article.aspx?articleid=2546687,    https://publications.jrc.ec.europa.eu/repository/handle/JRC99235,   

10.1115/1.4032871,