Fabrication of bulk delta-phase Zirconium Hydride from Zircaloy-4 for use as moderators in microreactors

TL;DR

This paper reports a method to produce bulk delta-phase Zirconium Hydride from Zircaloy-4, characterizes its single-phase structure, and discusses implications for microreactor moderators in nuclear technology.

Contribution

It introduces a novel fabrication process for delta-phase Zirconium Hydride from Zircaloy-4 and validates previous theoretical predictions about hydrogen incorporation effects.

Findings

Fabricated single-phase delta-ZrH from Zircaloy-4.

Observed Sn-rich segregation zones due to hydriding.

Validated ab initio predictions on H influence in Zircaloy-4 elements.

Abstract

The fabrication of bulk delta-phase Zirconium Hydride ($\delta$-ZrH) using Zircaloy-4 as a precursor is herein reported. Characterization using electron-microscopy methods indicate that the fabricated material is of a single-phase. Sn-rich segregation zones have been observed to form as a direct result of the hydriding process. These findings experimentally validate previous \textit{ab initio} calculations on the influence H incorporation in Zircaloy-4 constitutional elements such as Sn, Fe and Cr. The effect of hydriding and Sn segregation on pre-existing Zr(Fe,Cr)$_{2}$ Laves phases is also evaluated. Major implications on the development of moderators for use in microreactors within the nuclear industry are discussed.