Development and applications of energy-specific fluence monitor for field monitoring

Abstract

A portable energy-specific fluence monitor is developed for field monitoring as well as to serve as stand-alone data acquisition system to measure dose rate due to routine releases at various locations in and around Nuclear Power Reactors. The data from an array of such monitors deployed over a region of interest would help in evolving a methodology to arrive at the source term evaluation in the event of a postulated nuclear incident. The other method that exists for this purpose is by conducting tracer experiments using known release of a gas like SF(6) into the atmosphere and monitoring their concentrations downwind. The above instrument enables one to use the routine release of (41)Ar as a tracer gas. The Argon fluence monitor houses a CsI(Tl) detector and associated miniature electronics modules for conditioning the signal from the detector. Data logging and in-situ archival of the data are controlled by a powerful web enabled communication controller preloaded with Microsoft Windows Compact Edition (WIN CE). The application software is developed in Visual Basic.NET under Compact Framework and deployed in the module. The paper gives an outline of the design aspects of the instrument, associated electronics and calibration of the instrument, including the preliminary results obtained using the instrument. The utility of the system is established by carrying out field survey around Madras Atomic Power Station (MAPS), consisting of two Pressurized Heavy Water Reactors (PHWR), by mapping the (41)Ar plume. Additional features such as enhancing the monitor capability with embedded GPS along with real-time linking using wireless networking techniques are also being incorporated.