Corrosion techniques and strategies for used fuel containers with copper corrosion barriers under deep geological disposal conditions:A review

Safe emplacement of high-level nuclear waste(HLNW)arising from the utilization of nuclear power is a frequently en-countered and considerably challenging issue.The widely accepted and feasible approach for the permanent disposal of HLNW involves housing it in a corrosion-resistant container and subsequently burying it deep in a geologic repository.The focus lies on ensuring the dur-ability and integrity of the container in this process.This review introduces various techniques and strategies employed in controlling the corrosion of used fuel containers(UFCs)using copper(Cu)as corrosion barrier in the context of deep geological disposal.Overall,these corrosion prevention techniques and methods have been effectively implemented and employed to successfully mitigate the corrosion challenges encountered during the permanent disposal of Cu containers(e.g.,corrosion mechanisms and corrosion parameters)in deep geologic repositories.The primary objective of this review is to provide an extensive examination of the alteration in the corrosion envir-onment encountered by the UFCs when subjected to deep geologic repository conditions and focusing on addressing the potential corro-sion scenarios.

Corrosion inhibition of stainless steel by a sulfate-reducing bacteria biofilm in seawater

Corrosion inhibition of stainless steel due to a sulfate-reducing bacteria （SRB） biofilm in seawater was studied. By atomic force microscopy, a layer of fish-scale-like biofilm was found to form as stainless steel coupons were exposed to the culture media with SRB, and this biofilm grew more and more compact. As a result, coupons＇ surface under the biofilm turned irregular less slowly than that exposed to the sterilized culture media. Then, physicoelectric characteristics of the electrode/biofilrn/solution interface were investigated by electro- chemical impedance spectroscopy （EIS）, and the coverage of the biofilm as well as the relative irregularity of coupons＇ surface was also re- corded by EIS spectra.. Finally, anodic cyclic polarization results further demonstrated the protective property of the biofilm. Therefore, in es- timation of SRB-implicated corrosion of stainless steel, not only the detrimental SRB metabolites but also the protective SRB biofilm as well should be taken into account.

Polydopamine wrapped polyaniline nanosheets:Synthesis and anticorrosion application for waterborne epoxy coatings

Two-dimensional materials have been proved to be effective in improving the performance of anticorrosive coatings.However,most of the reported two-dimensional materials only have the ability to passively block corrosive media and cannot effectively inhibit localized corrosion reactions at the metal/coating interface.Herein,we first synthesized a novel polyaniline(PANI)nanosheet with both barrier and passivation functions for metals.In addition,polydopamine(PDA)wrapped PANI nanosheets(PANI@PDA)were obtained by in situ self-polymerization reaction of dopamine on the PANI surface,which enhance its interfacial interaction with polymeric resin.The chemical structure,morphology and corrosion inhibition properties of the nanosheets were systematically analyzed.The incorporated PANI@PDA nanosheets in composite coating provide a longer penetration path for corrosive mediums.Secondly,the uniformly dispersed two-dimensional nanosheets induce the formation of passivation film on the metal substrate.The protective effect of PANI@PDA nanosheets on coatings was verified by electrochemical impedance spectroscopy(EIS).Results indicated that the prepared composite coating exhibited excellent corrosion resistance throughout the test cycle.This simple and effective modification strategy based on conductive polymers provides a new insight into the development of environmentally adaptive composite coatings with active and passive protection.

Experimental Investigation on Contribution of CFRP Attachment to Durability of Reinforced Concrete Structure Subjected to Chloride Attack

The function of externally-bonded carbon fiber reinforced polymer （CFRP） in preventing chloride from entering into concrete is verified by experiment. The results show that externally-bonded CFRP can be considered as a part of corrosion prevention system of strengthened concrete structures subjected to chloride ingress, and the contribution of CFRP should be considered in evaluation of durability of reinforced concrete structures with externally-bonded CFRP. With the effective shielding function of CFRP considered, an equation for residual lifetime prediction of concrete structures with externally-bonded CFRP is derived from Fick＇s dispersion law. CFRP has two functions for coastal concrete structures, including strengthening and increasing durability as part of corrosion prevention system.

Laser multi-layer cladding on ZM6 magnesium base alloy

A pulsed Nd: YAG laser is used in multi-layer cladding on ZM6 Mg base alloys. The microstructure is studied with an optical microscope and a scanning electron microscope (SEM). The composition within the layer was determined by electron probe microanalysis (EPMA). X-ray diffraction (XRD) was also used to investigate the phase of constitutes of the cladding zone. The results show that microstructure in solidified cladding layer changes much when treated by high energy laser beam. The microstructure of the ZM6 alloy consists of a-Mg and Mg9Nd, while the L-ZM6 of a-Mg, MggNd and a-Zr. The depth of the cladding is over 1 mm. Many fine particles were found to be distributed homogeneously throughout the matrix and the columnar grain grows along substrate.