Abstract
RR-4, which is a swimming pool type reactor (2.5 MWt), is particularly suitable as source for neutron radiography. The first phases of neutron radiography experiments at JRR-4 are reported in this paper.
A simple Al tube (I.D.=60 mm) with a graphite block (100 x 100 x 700 mm) attached at the end was inserted in the pool (10m deep) and the graphite block was positioned close to the reactor core. The upper part of the tube was curved to avoid direct radiation streaming from the core.
Using both direct exposure method (DEM) and transfer (indirect) exposure method (TEM), the device thus arranged was tested to determine its performance in terms of sensitivity, resolution and contrast. Two examples of application are described : namely, determination of the enrichment of UO2 pellets, and detection of small quantities of hydrogeneous material.
