Characterization on the melting failure of CuCrZr cooling tube of W/Cu monoblocks during plasma operations in EAST. (December 2020)

• Record Type: Journal Article
• Authors: Li, Changjun; Zhu, Dahuan; Ding, Rui; Wang, Baoguo; Chen, Junling; Gao, Binfu; Lei, Yang
• Is Part Of: Nuclear materials and energy. Volume 25(2020)
• Publication Date: 2020-12
• Subjects: EAST -- W/Cu monoblocks -- Leading edges -- Melting -- Thermal analysis; Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2020.100847
• Languages: English
• ISSNs: 2352-1791

Abstract

Highlights: Melting of both W armor and CuCrZr cooling tube occurred on W/Cu monoblock during plasma operations in EAST. With the migration of the melted Cu through gaps, the CuCrZr cooling tube of W/Cu monoblock was severely destroyed and had to be replaced. Thermal simulation illustrates the leading edge-induced thermal loading can lead to the melting of CuCrZr cooling tube of W/Cu monoblock with loss of cooling. Abstract: The behavior of ITER-like W/Cu plasma facing components under complex conditions in current tokamaks is one of the main concerns for ITER. EAST has installed a full upper W divertor with the ITER-like W/Cu monoblocks as targets since 2014. A melting failure of CuCrZr cooling tube of W/Cu monoblocks has occurred during the plasma campaigns in 2019. Due to the loss of cooling water, the leading edge-induced thermal loading can lead to the melting of both W armor and CuCrZr cooling tube, which has been confirmed by thermal simulation and analysis. With movement and migration of the melted Cu through gaps, the structure and function of the CuCrZr cooling tube for W/Cu monoblocks was severely destroyed. As a result, those failed W/Cu monoblocks had to be replaced. Such case in EAST just simulates the extreme condition of accidental loss of coolant in future devices. The melting failure of CuCrZr cooling tube was caused by operation without coolant water at largely misaligned monoblocks, which is a key lesson referenced to other tokamaks which adopt or plan to apply such type of W/Cu monoblocks.