A fraction of the UK Pu inventory may be immobilised in a zirconolite ceramic matrix prior to disposal. Two zirconolite compositions, targeting CaZr_0.80Ce_0.20Ti₂O₇ and CaZr_0.80U_0.20Ti₂O₇, were fabricated by hot isostatic pressing, alongside a reformulated composition, nominally Ca_0.80Zr_0.90Ce_0.30Ti_1.60Al_0.40O₇, with an excess of Ti and Zr added to preclude the formation of an accessory perovskite phase. Materials were subjected to accelerated leaching in a variety of acidic and alkaline media at 90 °C, over a cumulative period of 14 d. The greatest Ce release was measured from CaZr_0.80Ce_0.20Ti_2.00O₇ exposed to 1 M H₂SO₄, for which 14.7 ± 0.2% of the original Ce inventory was released from the wasteform into solution. The extent of Ce leaching into the solution was correlated with the quantity of perovskite present in the wasteform, and associated with the incorporation and preferential dissolution of Ce³⁺. CaZr_0.80U_0.20Ti_2.00O₇ exhibited improved leach resistance relative to CaZr_0.80Ce_0.20Ti_2.00O₇, attributed to the decreased proportion of accessory perovskite, with 7.1 ± 0.1% U released to in 8 M HNO₃ after 7 d. The Ca_0.80Zr_0.90Ce_0.30Ti_1.60Al_0.40O₇ composition, with no accessory perovskite phase, presented significantly improved leaching characteristics, with < 0.4%Ce released in both 8 M HNO₃ and 1 M H₂SO₄. These data demonstrate the need for careful compositional design for zirconolite wasteforms with regard to accessory phase formation and surrogate choice.

在处理之前，可以将一部分英国Pu库存固定在锆石陶瓷基质中。通过热等静压制备了两种分别针对CaZr _0.80 Ce _0.20 Ti ₂ O ₇和CaZr _0.80 U _0.20 Ti ₂ O _7的锆石组合物，以及经过重新配方的组合物，名义上为Ca _0.80 Zr _0.90 Ce _0.30 Ti _1.60 Al _0.40 O ₇，添加过量的Ti和Zr以防止形成辅助钙钛矿相。在90℃下，经过14 d的累积时间，将材料在各种酸性和碱性介质中进行加速浸出。从暴露于1 MH ₂ SO _4的CaZr _0.80 Ce _0.20 Ti _2.00 O ₇测得最大的Ce释放量，其原始Ce存量的14.7±0.2％从废料形式释放到溶液中。Ce浸入溶液中的程度与废料中钙钛矿的含量有关，并与Ce ³⁺的掺入和优先溶解有关。CaZr _0.80 U _0.20相对于CaZr _0.80 Ce _0.20 Ti _2.00 O ₇，Ti _2.00 O ₇表现出更好的耐浸出性，这归因于辅助钙钛矿的比例降低，7 d后在8 M HNO _3中释放出7.1±0.1％U 。不含钙钛矿相的Ca _0.80 Zr _0.90 Ce _0.30 Ti _1.60 Al _0.40 O ₇组成具有显着改善的浸出特性，在8 M HNO ₃和1 MH ₂ SO ₄中均释放<0.4％Ce。这些数据表明，对于锆石废料形式的辅助相形成和替代选择，需要进行仔细的成分设计。