中法核工程与技术学院核声论坛（总第154期）
Corrosion products in secondary circuits of nuclear Pressurized Water Reactors – Decreasing the source term and evaluating their behavior and their consequences
报告人简介About the speaker：
Grégory LEFEVRE is the director researcher in CNRS, Senior researcher. He received PhD in Physical and Analytical Chemistry, Univ. Nancy I (France), 1999. His thesis title is Study of sorption mechanisms of iodine; application to environment.
Positions held:
1999-2000 : Researcher in French Air Force
2000-2004 : Researcher in Center for Metallurgical Chemistry Researches (Vitry/Seine - France)
2004 : Researcher in Electricité de France company, Research department of chemistry (Moret/Loing - France)
2005- : Researcher in Chimie Paris Tech Engineer School
2019- : Associated Professor at Paris Sciences et Lettres University
报告摘要Abstract:
This talk will deal with chemistry in the secondary circuit of PWRs. Corrosion of black steel leads to the release of iron corrosion products, present as colloidal iron oxide particles or dissolved ferrous ions. The consequences of the presence of these species are problematic, such as fouling, clogging and formation of hard sludge in steam generators (SG). In collaboration with EDF R&D, we have performed several studies to tackle some critical points. (1) The objective of the first work was to evaluate the use of film forming amines to protect the secondary circuit of PWR from corrosion during shutdown. (2) Once corrosion products have been formed in the reducing conditions characterizing the secondary circuit solution, magnetite particles are mainly found. However, some ferric oxides have been identified in industrial circuits, and they could increase the risk of stress corrosion cracking of SG tubes, in comparison to magnetite. Thus, the oxidation kinetics and mechanism of magnetite has been thoroughly investigated in a second work. (3) Another impact of the presence of dissolved iron is the precipitation of sludges at the bottom of SG tubes, with the risk of degrading them. In this phenomenon, impurities from the solution such as aluminium and silicium precipitate along with magnetite, leading to deposits hard to remove by chemical ways. This phenomenon has been reproduced in a laboratory setup to characterize the deposit formed. (4) Another consequence of the corrosion products is an impact on the roughness, and so on the friction pressure drop in the circuits. A study in collaboration with the University of Pisa has just begun, and some preliminary reflections will be presented.
中法核工程与技术学院
中法核工程与技术学院