An automated fuel element scanning system

This paper describes an automated fuel element scanning system, based upon gamma-ray spectroscopy, that has been developed at the Oak Ridge Research Reactor. The scanning system is located in the reactor pool and allows fuel elements to be scanned nondestructively at various intervals during their core life. Fuel elements are located 430 cm beneath the pool. Gamma-ray measurements (aided by a collimating assembly) are made using a GeLi detector positioned above the pool water. Measurements of¹³⁷Cs count rates from relatively cold elements indicate that the counting data obtained using this apparatus is reproducible within 5%. Power distribution in the reactor's core (element by element) has been derived from¹⁴⁰La counting data. The method of determining power is discussed briefly and some example results are presented.