Studies on U-Zr and U-Pu-Zr alloys for determination of Cl and F using pyrohydrolysis

Abstract

Pyrohydrolysis method was studied for the separation of Cl and F from U-Zr and U-Pu-Zr alloy nuclear fuels and determination by ion chromatography. A detailed study was performed on pyrohydrolysed products of U-Zr alloy, obtained on heating in moist argon and oxygen atmospheres using X-ray powder diffraction (XRD) and thermogravimtric methods. Using oxygen as the carrier gas pyrohydrolysis performed at 900 ∘ C was complete within 30 min. It was found that, moist oxygen as carrier gas only could open the matrix completely within stipulated time.This was attributed to the formation of -U 3 O 8 , which was not possible in moist argon heating for 30 min. The pyrohydrolysis in moist Ar required 60-90 min for complete removal of halides. The method was then successfully extrapolated to U-Pu-Zr alloys. The results showed recovery up to 90% or above for the optimized conditions.

Pyrohydrolysis, a clean separation method for separating non-metals directly from solid matrix

“…The study also showed in addition to the pyrohydrolisability, the matrix opening is also a crucial factor for achieving the complete recovery of halogens. 52 An ion chromatographic study deals with the separation and identification of pyrohydrolysis products of (U, Pu) C has been reported 53 and the study further reported that the pyrohydrolytic conditions are responsible for the formation of organic acids during the pyrohydrolysis of metal carbides. Another study reports about the pyrohydrolytic separation of boron in U 3 Si 2 required for the determination of isotopic composition of boron by ICP-MS. 54 Pyrohydrolysis was used for generation of zirconia from ZrF 4 .…”