Vanadium Alloys for Fusion Blanket Applications

Abstract

Vanadium alloys are attractive candidate structural materials for breeding blanket of fusion reactors because of their low activation properties and high temperature strength. Studies on various blanket designs are being carried out using vanadium alloys as structural materials and liquid lithium or molten salt Flibe as breeding and coolant materials. Recently significant progress in fabrication technology has been made for vanadium alloys through a program of producing large ingots of high purity V-4Cr-4Ti (NIFS-HEATs). Fundamental understandings on the effects of interstitial impurities (C, N, O) on mechanical properties, radiation effects on microstructure and mechanical properties, corrosion and compatibility in various environments were enhanced. New promising candidates were identified for the MHD insulator coating. Among the remaining critical issues are the effects of transmutant helium on mechanical properties and development of long life MHD coating. Development of vanadium alloys will be carried out in coordination with IFMIF and ITER-TBM schedules as essential tools for verification of their performance in fusion blanket environments.

Microstructure and texture evolution during accumulative roll bonding of aluminium alloy AA5086

“…Much stronger anisotropy in strength has been noted for ARB processed material with the specimen tested along 90• possesses the highest yield strength. [36][37][38][39][40][41] Strength of the specimens tested along 0• or 45• is almost the same. The ductility, on the other hand, varies with testing direction for both starting and ARB processed material.…”

“…Such interface debonding has been frequently observed during tensile testing of ARB processed materials with interfaces being originally parallel to the loading direction [12,39]. Strain hardening due to redundant deformation does not contribute much in ductility reduction because of the positive effect from submicron grains in the microstructure [39]. However, presence of dislocation substructure can restrict uniform elongation and result in early initiation of plastic instabilities (e.g.…”

Mechanical and tribological properties of crystalline aluminum nitride coatings deposited on stainless steel by magnetron sputtering

“…Similarly, the Test Blanket Modules (TBMs) based on liquid metal breeder blanket concept have been proposed by many of the participating countries. This includes LeadLithium Cooled Ceramic Breeder (LLCB) TBM proposed by India [4], Dual Coolant Lead Lithium (DCLL) TBM by the USA [5], Dual Functional Lithium-Lead (DFLL) TBM by China [6] and liquid lithium self-cooled breeder blanket design by the Russian Federation [7]. These blanket designs require flow of liquid metal through the TBM channels with finite velocity.…”

“…This in turn can impact the heat transfer, tritium transport and corrosion related issues. In the case of Li/V blanket design proposed by the Russian Federation [7], the currently being focussed upon [11]. Development of electrical insulation coatings on RAFM steel has been mostly limited to Al 2 O 3 , originally oriented as a tritium permeation barrier.…”

Effects of interstitial impurity on behavior of helium-defect complexes in vanadium studied by THDS

“…Vanadium alloys are considered to be one of the leading candidates for the fusion reactor blanket material [1,2]. Although vanadium has many attractive features for the fusion application, its use at high temperature will be limited by the helium embrittlement [3].…”