Lithium ion-selective membrane for the determination of the lithium concentration in a fluid of the primary coolant circuit of a pressurized water reactor of a nuclear power plant.

Abstract

A lithium ion-selective membrane for the detn. of the lithium concn. in a fluid of the primary coolant circuit of a pressurized water reactor of a nuclear power plant consists of a polymeric support, a plasticizer, a conducting compd., as well as a lithium-specific ionophore 6,6-dibenzyl-14-crown-4. The membrane contains 0.5-3 wt.% of the ionophore. The polymeric support is made of PVC, and the plasticizer can be o-nitrophenyloctylether or bis 1-butylpentyl adipate. The conductive compd. is potassium tetrakis(4-chlorophenyl)borate. The membrane is produced by completely dissolving the support polymer, the plasticizer, the conductive compd., and the ionophore in THF under magnetic agitation and at ambient temp., and evapg. the solvent at ambient temp. for crystn. to form the membrane. The membrane is used in a lithium-selective electrode