Power reactor fuel requires a number of special considerations. These include: (1) Economic factors such as fabrication cost and fuel cycle cost and very severe operating conditions due to decreasing designed thermal margin; (2) quality control problems raised by requirements of mass production, which on one hand affect fabrication cost, and on the other, relates to questions like engineering hot channel factor; (3) reliability requirements that widen the time gap between the newest fuel technology and present day fuel design.
The Japan Atomic Power Co. has experienced these problems with its Tokai (hollow, natural uranium metal, Magnox) fuel R & D program, and are also experiencing similar questions related to light-water reactor. The fabrication of power reactor fuel in Japan is the topic of the time, and this article explains the actual experience with the Tokai fuel. The mode of swelling of tubular fuel, creep collapse of U under coolant pressure, and end welding of the tube were three new problems unexperienced in U. K. reactors. Deformation of heat transfer surfaces, post irradiation examination, inspection experiences at the Springfields Works, and interpretation of the specifications are also discussed. Part II will deal with light water reactor fuel.