The IRMM-1027 Large-sized dried (LSD) spikes are certified reference materials applied to measure the uranium and plutonium content of dissolved fuel solutions using isotope dilution mass spectrometry. High quality starting metals of uranium and plutonium are dissolved to produce a stock solution, which is dispensed into individual vials and dried down. The present spikes are mixtures of typically 50 mg 20% enriched U and 2 mg enriched ²³⁹Pu as dried nitrates, conditioned in an organic substance for stability. Each vial of an IRMM-1027 LSD spike comes with certified masses of uranium (²³⁵U and ²³⁸U) and ²³⁹Pu and isotopic composition with associated uncertainty. This article will discuss major developments since the production of the first batch of LSD spikes and will reflect on the current preparation and certification approaches.

IRMM-1027 大尺寸干燥 (LSD) 标样是经过认证的参考材料，用于使用同位素稀释质谱法测量溶解燃料溶液中的铀和钚含量。铀和钚的高质量起始金属被溶解以产生储备溶液，将其分配到单独的小瓶中并干燥。目前的尖峰是典型的 50 毫克 20% 富集 U 和 2 毫克富集²³⁹ Pu 的混合物，作为干燥的硝酸盐，在有机物质中调节以保持稳定性。每瓶 IRMM-1027 LSD 加标都带有经过认证的铀（²³⁵ U 和²³⁸ U）和²³⁹Pu 和同位素组成以及相关的不确定性。本文将讨论自第一批 LSD 尖峰生产以来的主要发展，并将反思当前的准备和认证方法。