Measuring density on-line to nuclear industry standards

An on-line system of ultrasonic density measurement which has been developed with the severe limitations of access and reliability imposed by the nuclear fuel reprocessing environment is described. The ultrasonic transducer is introduced into a thimble which passes through several feet of concrete biological shielding and is coupled to the associated electronic instrumentation, based on the modular Harwell 6000 series, which excites the transducer with short high-voltage pulses causing it to emit the necessary high-frequency ultrasonic pulses. Such equipment can be used in a fuel reprocessing environment not only for the original requirement of measuring the concentration of uranium and plutonium in a slowly flowing stream of organic solvent, TBP/OK, but also for measuring the position of liquid surface levels and liquid/liquid interfaces in large vessels. (U.K.)