The Design Of Area Radiation Dose Monitor

Nuclear energy, as new and clean energy resources, has been widely utilizedaround the world. The development of nuclear efficiency would significantlycontribute to solve the growing problems such as energy crisis and severeenvironmental pollution. With the rapid development of nuclear power, nuclearsecurity has been attracting increasing attention. During nuclear reactor operation,there must be radioactive material production and emission. If excessive amounts ofradioactive material leak out, it will seriously harm to the natural environment andhuman health.According to the practical reactors’ requirements, a regional radiation dosemonitoring system that mainly consists of two multi-probe radiation monitors that areimplemented by combination of the software and hardware was designed in this thesis.This system is able to monitor radiation level of the key areas in reactor and ensurethe radiation safety in process of reactor operation. Furthermore, it can displayregional dose rate results in real-time by estimating the running status of reactor basedon monitoring change of radiation dose rate in key areas. On the basis of results, thesystem raising sound or light alarm warn people to make emergency treatment so as toavoid the nuclear radiation leakage.The monitor mainly consists of two components: probes and main controllingboard. The probe consists of G-M counter tube, high pressure ionization chamber andNaI scintillation counting tube comprising a composite probe. The main controllingboard using STC single-chip processor framework is combined with peripheralcircuits such as signal processing circuit,8253counting circuit, controlling signalprocessing circuit, memory circuit, parallel transmission circuit, RS-232communication circuit, alternative display, keys and LCD. The monitor is equippedwith eight complex probes, which are able to monitor radiation in key areas whilesending the corresponding signals to the processor respectively.In terms of hardware circuit design, modular design method was implementedand each module was debugged. After that, all the modules were connected to debugintegrally. The software design using functional sub-program method is divided intofunctional modules according to operation keys and the main program switches intocorresponding controlling procedures once interruption comes from keys. In the process of communication between two machines, correspondingcommunication protocols should be established during the data transmission in orderto prevent data loss and system breakdown. Thus, each machine would effectivelywork separately or collaboratively work and the efficiency of the entire system wasimproved.This user-friendly regional radiation monitor can meet the design requirementperfectly with stable performance and good human-machine interface.