Report of GETHC meeting December, 1963 review of IPD Ball 3X safety philosophy

摘要

Information resulting from recent graphite investigations in the K Reactors were presented to the Council. Separations as much as three to four inches were reported. Contraction of the graphite within the fueled regions of these reactors is now about one per cent in the direction transverse to the extrusion axis of the graphite and about two per cent in the parallel direction. Saturation is not expected until shrinkage of at least two to three per cent is observed in the transverse direction. The contraction is resulting in two principal operating problems; control rod entry and loss of 3(times) balls in the separations following a ball drop. The principal purpose of the review concerned only the ball system and particularly the philosophy governing the system's use. Following a historical review of the ball system philosophy, our present views were developed by the consideration of six questions and answers. Our points extracted from these questions were (1) the IPD reactors require a backup safety control system (2) the backup system should be separate from the primary safety control system, (3) the backup system should be activated automatically upon accidents capable off disabling the safety rod system, (4) the system actuation should be direct upon coolant loss, and (5) the system actuations should be upon seismic indication if coincident with safety rod system failure.