Nuclear Science and Techniques ›› 2019, Vol. 42 ›› Issue (4): 40602-040602.

### The effect of He bubbles on the corrosion properties of nickel-based alloy in molten salt environment

Guanhong LEI1,2,Sida YANG3,Renduo LIU1,Jianjian LI1,Qing HUANG1,Cheng LI1,Hefei HUANG1,Long YAN1()

1. 1. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. Shanghai Spaceflight Precision Machinery Institute, Shanghai 201600, China
• Received:2019-02-25 Revised:2019-03-19 Online:2019-04-10 Published:2019-04-18
• Contact: Long YAN E-mail:yanlong@sinap.ac.cn
• About author:<named-content content-type="corresp-name">LEI Guanhong</named-content>, female, born in 1988, graduated from Northeastern University in 2012, doctoral student, focusing on irradiation effect on structural material of nuclear reactor|<named-content content-type="corresp-name">LEI Guanhong</named-content>, female, born in 1988, graduated from Northeastern University in 2012, doctoral student, focusing on irradiation effect on structural material of nuclear reactor|YAN Long, E-mail: <email>yanlong@sinap.ac.cn</email>
• Supported by:
Supported by National Natural Science Foundation of China(No.11805256, No.11805261)

Abstract: Background

UNS N10003 alloy is considered to be the primary option of metal structural materials for the molten salt reactor (MSR). It will be affected by the extreme environments, i.e. high temperature, high neutron doses and corrosive coolant during the operation of MSR. Considering that the safe operation of MSR will mainly depends on the service performance of structural alloys, it is necessary to evaluate the performance of such kind of alloys in the complicated environments.

Purpose

This study aims at understanding the effect of He bubbles on the corrosion properties of UNS N10003 alloy in molten salt environment.

Methods

First of all, the 1.2 MeV high temperature He ion irradiation was performed on the UNS N10003 alloy at 650 oC. The irradiation fluence was set up to 5×1015 ions?cm-2 and 5×1016 ions?cm-2 respectively. Then, samples were immersed in a dry high-purity graphite crucible filled with 200 g FLiNaK salts and heated to 650 oC for 200 h. Finally, scanning electron microscopy (SEM) and transmission electron microscope (TEM) were employed to investigate the surface morphology, the distribution of elements and the microstructure, respectively. Nano-indentation technique was used to obtain the hardness.

Results

At the dose of 5×1015 ions?cm-2, there was not obvious difference in the surface morphology and distribution of element distribution of the corroded alloy with and without irradiation. While for the corroded alloy pre-irradiated with He ions at the dose of 5×1016 ions?cm-2, large amount of holes were observed on the surface and the loss of Cr element was found from the bulk to the surface, which can be ascribed to the He bubbles formation. The hardness of irradiated alloy, corroded alloy, and corroded alloy pre-irradiated was 4.12 GPa, 2.65 GPa and 3.16 GPa, respectively.

Conclusion

He bubbles formation play an important role on increasing the corrosion of UNS N10003 alloy. The hardness of irradiated and corroded alloy is lower than the irradiated alloy, and higher than of the corroded alloy. It is a combined effect of irradiation and corrosion.

CLC Number:

• TL341