TY - JOUR

T1 - Coated ZrN sphere-UO2 composites as surrogates for UN-UO2 accident tolerant fuels

AU - Costa, Diogo Ribeiro

AU - Hedberg, Marcus

AU - Adorno-Lopez, Denise

AU - Delmas, Mathieu

AU - Middleburgh, Simon

AU - Wallenius, Janne

AU - Olsson, Par

PY - 2022/8/15

Y1 - 2022/8/15

N2 - Uranium nitride (UN) spheres embedded in uranium dioxide (UO2) matrix isconsidered an innovative accident tolerant fuel (ATF). However, the interaction between UN and UO2 restricts the applicability of such composite in light water reactors. A possibility to limit this interaction is to separate the two materials with a diffusion barrier that has a high melting point, high thermal conductivity, and reasonably low neutron cross-section. Recent density functional theory calculations and experimental results on interface interactions in UN-X-UO2 systems (X = V, Nb, Ta, Cr, Mo, W) concluded that Mo and W are promising coating candidates. In this work, we develop and study different methods of coating ZrN spheres, used as a surrogate material for UN spheres: first, using Mo or W nanopowders (wet and binder); and second, using chemical vapour deposition (CVD) of W. ZrN-UO2 composites containing 15 wt% of coated ZrN spheres were consolidated by spark plasma sintering (1773 K, 80 MPa) and characterised by SEM/FIB-EDS and EBSD. The results show dense Mo and W layers without interaction with UO2. Wet and binder Mo methods provided coating layers of about 20 μm and 65 μm, respectively, while the binder and CVD of W methods layers of about 12 μm and 3 μm, respectively

AB - Uranium nitride (UN) spheres embedded in uranium dioxide (UO2) matrix isconsidered an innovative accident tolerant fuel (ATF). However, the interaction between UN and UO2 restricts the applicability of such composite in light water reactors. A possibility to limit this interaction is to separate the two materials with a diffusion barrier that has a high melting point, high thermal conductivity, and reasonably low neutron cross-section. Recent density functional theory calculations and experimental results on interface interactions in UN-X-UO2 systems (X = V, Nb, Ta, Cr, Mo, W) concluded that Mo and W are promising coating candidates. In this work, we develop and study different methods of coating ZrN spheres, used as a surrogate material for UN spheres: first, using Mo or W nanopowders (wet and binder); and second, using chemical vapour deposition (CVD) of W. ZrN-UO2 composites containing 15 wt% of coated ZrN spheres were consolidated by spark plasma sintering (1773 K, 80 MPa) and characterised by SEM/FIB-EDS and EBSD. The results show dense Mo and W layers without interaction with UO2. Wet and binder Mo methods provided coating layers of about 20 μm and 65 μm, respectively, while the binder and CVD of W methods layers of about 12 μm and 3 μm, respectively

U2 - 10.1016/j.jnucmat.2022.153845

DO - 10.1016/j.jnucmat.2022.153845

M3 - Article

VL - 567

JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

SN - 0022-3115

M1 - 153845

ER -