关键词：
High temperature oxidation;Cr-coated Zr-4;Al-coated Zr-4;Diffusion layer;Accident tolerant fuel
摘要：
Y Cr and Al coating were respectively deposited on Zr-4 alloy by magnetron sputtering and high temperature oxidation (HTO) tests were conducted in air environment at 1200 degrees C for 3 h for Cr-coated and Al-coated specimens. The morphology and phase composition of the specimens were detected by SEM, EDS and XRD. The adhesion properties were characterized by scratch test. The XRD results revealed that the two coatings were crystalline with preferred orientation. The results of scratch testing showed that critical load of Cr coating was higher than that of Al coating. After HTO test, the Cr-coated specimen was intact without cracking and spalling off, only the outermost layer of Cr coating was oxidized to a Cr2O3 layer of about 4 mu m thick with a residual Cr layer of about 4 mu m thick, and the internal zirconium alloy was not oxidized. For Al-coated specimen, besides the complete oxidation of the Al coating, there were also about 500 mu m Zr-4 alloy oxidized on each side, and there were a lot of voids and cracks in the specimen. The EDS results indicated that a thickness of about 5 mu m Cr-Zr diffusion layer developed at the interface between Cr coating and Zr-4 alloy for the Cr-coated Zr-4 specimen. While, for the Al-coated Zr-4 specimen, Al diffused into the specimen to a depth of about 100 mu m, and Zr diffused almost to the outermost layer. Moreover, Sn in the Zr-4 alloy is concentrated at the interface between the residual Zr-4 alloy and ZrO2 layer. The obtained results manifested that Cr coating shows better oxidation resistance than Al coating.
摘要：
The process of changing the attachment of a demolition robot is a complex operation and requires a high docking accuracy, so it is hard for operators to control this process remotely through the camera’s perspective. To solve this problem, this paper studies trajectory planning for changing a demolition robot attachment. This paper establishes a link parameter model of the demolition robot; the position and attitude of the attachment are obtained through a camera, the optimal docking point is calculated to minimize the distance error during angle alignment for attachment change, the inverse kinemics of the demolition robot are solved, the trajectory planning algorithm and visualization program are programmed, and then the trajectory planning for the demolition robot attachment changing method is proposed. The results of calculations and experiments show that the method in this paper can meet the accuracy, efficiency, and safety requirements of demolition robot attachment changing, and it has promising application prospects in the decommissioning and dismantling of nuclear facilities and other radioactive environments.
作者机构：
[徐守龙; 邹树梁; 余修武] School of Resource Environment and Safety Engineering, University of South China, Hengyang;421001, China;[吴其反] Department of Engineering Physics, Tsinghua University, Beijing;100084, China;[林奎成] Instituted of Materials, China Academy of Engineering Physics, Mianyang
通讯机构：
[Xu, S.; Zou, S.] S;[Han, Y.] C;School of Resource Environment and Safety Engineering, China;CNNC New Energy Company LimitedChina
摘要：
Attachment changing in demolition robots has a high docking accuracy requirement, so it is hard for operators to control this process remotely through the perspective of a camera. To solve this problem, this study investigated positioning error and proposed a method of error compensation to achieve a highly precise attachment changing process. This study established a link parameter model for the demolition robot, measured the error in the attachment changing, introduced a reference coordinate system to solve the coordinate transformation from the dock spot of the robot's quick-hitch equipment to the dock spot of the attachment, and realized error compensation. Through calculation and experimentation, it was shown that the error compensation method proposed in this study reduced the level of error in attachment changing from the centimeter to millimeter scale, thereby meeting the accuracy requirements for attachment changing. This method can be applied to the remote-controlled attachment changing process of demolition robots, which provides the basis for the subsequent automatic changing of attachments. This has the potential to be applied in nuclear facility decommissioning and dismantling, as well as other radioactive environments.
作者机构：
南华大学资源环境与安全工程学院,湖南衡阳421001;核设施应急安全技术与装备湖南省重点实验室,湖南衡阳421001;[黄斌海; 邹树梁; 李书帆] School of Resource Environment and Safety Engineering, University of South China, Hunan, Hengyang, 421001, China, Hunan Provincial Key Laboratory of Emergency Safety Technology and Equipment for Nuclear Facilities, Hunan, Hengyang, 421001, China
