Method and apparatus for obtaining a water sample from the core of a

Abstract

In a boiling water reactor, provision is made to sample the core bypass region immediate the top guide to determine the physical and chemical constituents of the moderating water. A conduit for a local power range monitor is fitted with a measurement assembly. The conduit and measurement assembly are inserted up to the vicinity of the top guide. A tube opening is provided to the bypass region immediate the top guide. During reactor operation, the saturated liquid in this region flashes to a steam water mixture (18% steam) at constant enthalpy and is rapidly removed from the reactor to measuring equipment in the reactor building. During removal, the radiolytic disassociated gases (namely hydrogen and oxygen) partition to the steam phase where their recombination is retarded and accurate measurement of their constituent content can be made. Also, temperature of the steam water mixture decreases thereby preserving unstable species like hydrogen peroxide that degrade much more rapidly a high temperatures. In the reactor building, the gases are further cooled, condensed and divided with a first stream being diverted and cooled for detailed chemical analysis and a second stream reheated and pressurized for measurement of electrochemical potential. A substantially real time measurement of the chemical state of the reactor to enable monitoring, measurement, and correction of harmful imbalance is provided.