Seismic analysis of the CFETR CS Model Coil
Introduction
The China Fusion Engineering Test Reactor (CFETR) is the next tokamak reactor to manufacture in the roadmap for realizing commercial fusion energy in china [1,2]. The CFETR magnet system comprises a Central Solenoid (CS) with eight modules, 16 Toroidal Field (TF) coils [3,4], 6 Poloidal Field (PF) and a Divertor Coil (DC). The CS plays an important role in plasma current drive and plasma shaping [5].
To develop the coil technologies of large-scale Nb3Sn Cable-In-Conduit Conductor (CICC) for the CFETR and set up a large superconducting magnet test facility in China, the Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) is building the CFETR Central Solenoid Model Coil, which will validate the physical parameters and manufacturing technologies of the future CFETR CS [[6], [7], [8]].
The CFETR CS Model Coil project has been granted in 2014 [9], and up to now, all components for magnet assembly and test facility have been manufactured. Winding of all the 5 (2 Nb3Sn and 3 NbTi) winding packs (WPs) of the Model Coil is finished. The cryostat has been installed and tested. The Nb3Sn inner and outer WPs have been heat treated in an Ar atmosphere, with a maximum temperature difference of 6 K. The vacuum-pressure-impregnating (VPI) process of coil WPs is planned to accomplish in February 2020. The final assembly and cryogenic test of the CS Model Coil are scheduled to be completed in August 2020 and February 2021, respectively.
Although some mechanical analyses under the thermal and electromagnetic loads have been conducted for the Model Coil [10,11], severe dynamic seismic loads may also threat its structural integrity. This paper aims to show the design validation of the CS Model Coil against seismic loads and the analyses described here were based on the ANSYS software. The paper is organized as follows. First, the structure of the CS Model Coil and the generation of the Finite Element Model (FEM) are introduced. Then, the seismic-response-spectrum analysis and the time-history analysis are described. Finally, the results of the analyses and the conclusions are given.
Section snippets
Structure of the CS Model Coil
The inner diameter, outer diameter and height of the CS Model Coil are 1.5 m, 4.5 m and 3.9 m, respectively [11]. As shown in Fig. 1(a), the CS Model Coil is mainly composed of five coil WPs, 30 sets of tension rods and load beams, pressure plates, support plate and support rods. The pressure plates, which are located between the load beams and the buffer zones, are applied to distribute the compression load over the top and bottom of the coil WPs. The coil WPs consist of a Nb3Sn inner WP, a Nb3
Seismic analyses of the CS Model Coil
The seismic RS analysis and the time history analysis have been performed for the CS Model Coil [17,18].
Conclusions
For the CFETR CS Model Coil, the RS analysis under excitation of the Hefei design spectrum has been conducted. The maximum von-Mises stress is 30.9 MPa, which occurs at the lower load beam.
In order to evaluate a more accurate seismic response of the CS Model Coil, a time history analysis under excitation of the artificial Hefei wave has been performed. When the acceleration goes to a peak of 4.3 m/s2 at 22.54 s, the von-Mises stress reaches a maximum of 34.0 MPa, which occurs at the support rod.
CRediT authorship contribution statement
Fan Wu: Methodology, Formal analysis, Software, Writing - original draft. Xiaogang Liu: Conceptualization, Methodology, Writing - review & editing, Supervision. Zhaoliang Wang: Investigation, Resources, Data curation. Yong Ren: Investigation, Resources. Junjun Li: Investigation, Resources. Jie Zhang: Resources. Yu Wu: Funding acquisition. Xiang Gao: Project administration.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
This work is supported by the National Key R&D Program of China (Grant No. 2017YFE0300504, 2017YFE0300500), the Anhui Provincial Natural Science Foundation (Grant No. 1908085ME163) and the National Natural Science Foundation of China (Grant No. 51777207).
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