Fuel assembly for VVER-440 type nuclear reactor

摘要

The invention relates to the field of atomic energy, more specifically to designs for working cassettes for reactors of the VVER-440 type. The cassette contains interconnected supporting corner members and a tail part and a head part with a framework situated therebetween, which comprises spacer grids made up of cells that are arranged according to a triangular mesh so as to form coaxial hexagonal rows about the centre of the grid. In the second or third or fourth row from the centre or in the corners of the third and fourth rows from the centre or in the corners of the third and second rows from the centre or in the corners of the fourth and second rows from the centre or in the middle of the fourth and second rows from the centre there are framework tubes which are connected to the tail part and are rigidly connected to the adjacent cells. This results in an increase in the rigidity and strength of the working cassette, an increase in safety under both normal and emergency operating conditions, more efficient use of fuel as a result of an improved water to uranium ratio and the possibility of spectrally controlling reactivity, and an increase in fuel cycle length and burn-up.