CONSIDERATIONS REGARDING THE HORIZONTAL FUEL CHANNELS IN THE CANDU 6 NUCLEAR REACTOR. PART 3 - MAIN STEPS OF THE FUEL CHANNEL ASSEMBL

Abstract

The scope of this paper is to obtain the needed information on main steps necessary to assembly the fuel channel into calandria of CANDU 6 nuclear reactor. The 380 fuel channels of the nuclear reactor are composed of pressure tubes, made of zirconium-niobium alloy, located inside the calandria tubes, with two end fittings mounted, that are connected by the pipes network of the cooling supply feeders. Each CANDU fuel channel consists of four major components: the pressure tube, the calandria tube, the annulus spacers and the end fittings. The install operations to a new fuel channel must comply with the described requirements from the specified documents by AECL. The main installation operations are the roll expansion of the pressure tube ends into the two end fittings, the welding of the end fittings to the bellows and the installation of the positioning assemblies. Following installation and inspection of all 380 channels, the feeder pipes of the cooling system are connected to the end fittings. After each operation, the resulting information must be recorded in the specific registration and verification documents of each component and each operation. The registration documents, the check documents and the related reports of the fuel channel installation are part of the processes records of the assembly history of the nuclear reactor. All these documents and reports will be archived in order to take anytime a sequential picture of each fuel channel. The radiological safety analyses are made by certified experts for assessment of radiation exposure of workers and public.