Chemical interaction of D9 alloy clad with B₄C in liquid sodium: Studies employing XPS, XRD, and SEM

Abstract

A cell representing typical control rod subassembly of the prototype fast breeder reactor is designed to probe the liquid sodium-mediated chemical interaction of boron carbide (B 4 C) control rod with the D9 alloy clad. The cell was equilibrated at 973 K for 5000 hours with liquid sodium in the annular gap. XRD shows the formation of Cr 3 C 2 and Fe 2 B along with oxides of Ni, Cr, and Fe. XPS studies reveal the diffusion of boron and carbon up to a depth of about 160 and 120 μm, respectively. A boron-rich region is observed up to a depth of about 40 μm which consists of B 3+ arising from oxides and a nearly constant elemental boron region, extending up to a depth of 160 μm. The highly reacted zone extends up to a depth of about 40 μm consisting of oxides of most of the elements of D9 clad exhibiting a higher valence states. As the cell is helium leak tested, oxygen out gassed from B 4 C at 973 K played a major role in chemical oxidation of the constituents of the D9 alloy which can be minimized by using high-density B 4 C. K E Y W O R D S boron and carbon diffusion, boron carbide, D9 alloy, XPS depth profiling studies

The improvement mechanism of mechanical properties of B4C ceramics by constructing core–shell powders

“…Figure 3B is the B 1s spectrum of the sample, which can be deconvoluted into two peaks. The binding energy of the larger intensity (187.3 eV) belongs to the B-C bond in B 4 C. 31 The peak at 188.0 eV is from the B-Ti bond in TiB 2 . Figure 3C shows that the C 1s spectrum of the sample can be deconvoluted into four peaks.…”

Nickel Precipitation on the Surface of 15-15Ti Stainless Steel with B4C Exposed to Sodium

“…The cladding materials of control rod is advance austenitic steel 15-15Ti [2]. The compatibility of the 15-15Ti\Na\B4C ternary system is the key factor for the lifetime evaluation of the cladding materials [3][4].…”