Development of an Original Laboratory Prototype for a Field Tritium Detector Containing a Proton Exchange Membrane Electrolyzer Mounted in Series With a Gas Flow Proportional Counter.EPA Grant Number: F6D50256
Title: Development of an Original Laboratory Prototype for a Field Tritium Detector Containing a Proton Exchange Membrane Electrolyzer Mounted in Series With a Gas Flow Proportional Counter.
Investigators: Soreefan, Aurelie M
Institution: Clemson University
EPA Project Officer: Zambrana, Jose
Project Period: September 1, 2006 through September 1, 2008
Project Amount: $111,172
RFA: STAR Graduate Fellowships (2006) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Drinking Water , Fellowship - Environmental Monitoring , Fellowship - Health Physics , Fellowship - Radiation Detection , Ecological Indicators/Assessment/Restoration
This research describes the development of a laboratory prototype for an in-situ tritium in water field sensor. The laboratory prototype is constituted of a proton exchange membrane (PEM) electrolytic cell mounted in series with a proportional gas counter. The research consists in studying the tritium enrichment characteristics of a PEM electrolytic cell to determine whether the latter can be used for sample enrichment before use to reduce the aqueous solution to tritiated hydrogen gas for the gas proportional counter. The research project describes a simple treatment of water samples before admission into the PEM electrolytic cell.
The objective of this research is to build a laboratory prototype for a field tritium detector containing a PEM electrolyzer mounted in series with a gas flow proportional counter. The instrument is being designed for near real time measurements of tritium concentrations in water at a level down to 20,000 pCi/L, which corresponds to the Safe Drinking Water Act Maximum Contaminant Level of 4 mrem/year. This tritium monitoring system should be designed for future field installation in a well. Important constraints in the conception of the device, such as: size, little to no consumables, minimal energy consumption, autonomous operation, and maintenance free operation will be observed.
The research will be split into 3 parts. The first part of the project will consist in a laboratory study to qualify an electrolytic cell containing a proton exchange membrane for the tritium enrichment of water samples. The second part of the project will consider the possibility of using the same electrolytic cell to produce hydrogen gas, which will be subsequently analyzed in a gas-filled proportional counter. This part will also evaluate the most suitable shielding design required for appropriate detection limits. The shield provided by the ground, for both environmental and cosmic ray backgrounds, will have to be studied. Finally a third part will consider the field application with the sample preparation before enrichment process. This part is a critical part to the analysis of tritiated water sample since the electrolytic cell can only receive pure water.
Tritium enrichment in the electrolytic cell is expected. Preliminary results show that enrichment is limited in the PEM cell. We expect to be able to report a minimum detectable activity in water samples, as low as 20,000 pCi/L, with short counting time.