The DIDO water loop at Harwell and its use in particular for PWR crud-deposition experiments

A major facility in the DIDO reactor at Harwell is a high-pressure water loop which can operate under typical PWR thermohydraulic and water-chemistry conditions. The first part of the paper describes the basic DIDO water loop and the various supporting facilities. The construction and layout is discussed and the main parameters listed. The second part concerns a PWR experiment to investigate crud deposition on both a single, irradiated, fuel rod and a parallel, out-of-pile, fuel rod simulator. Details of the irradiation rig, out-of-pile test section, and other special equipment required for the experiment are presented. A special feature was the necessity to develop a system for generation and injection into the loop water of crud precursors, to form a nickel-iron spinel comparable to that found in a typical PWR circuit. (Auth.)