A Laboratory Simulation Research Method for Speciation Distribution of Ultratrace Pu in Groundwater and Its Application

Abstract

The migration rate difference of various Pu species in contaminated groundwater can be up to 3 orders of magnitude. Accurately obtaining speciation distribution of Pu is the first problem to be solved in site safety assessment. However, the in-situ chemical properties of groundwater are easily affected by the external environment, and Pu content in the contaminated groundwater is usually at ultra-trace level, the existing sampling-laboratory analysis method cannot directly determine the speciation distribution of Pu. Here a laboratory simulation research method for speciation distribution of ultratrace Pu in groundwater was established, in which a nitrogen assisted sampling and storage device was designed and employed to sample groundwater, and the groundwater sample was transported and kept in Anaerobic Glove Box, into which spiked Pu was added and the speciation distribution of Pu were monitored at various aging time by series speciation analysis techniques we improved and integrated. Using the method, the in-situ chemical properties of groundwater are well maintained, and the speciation distribution of ultratrace Pu in a contaminated groundwater from a granite area, NW China was obtained successfully. The results were basically consistent with the modelling results by geochemical software and/or analysis results by related instruments. Not only the method can continuously be used in the field of speciation distribution of Pu in contaminated water, but also can be used in other fields such as the treatment of waste liquor from Nuclear Plant, Reactor study, and so on.