The invention discloses a nuclear fuel element. The nuclear fuel element (100) comprises an outer shell (1) and an inner shell (2), wherein a closed structure is formed between the outer shell (1) and the inner shell (2) so as to fill fuel pellets (3); the nuclear fuel element (100) is of a tubular structure; a hollow runner region (4) is formed in the inner shell (2) of the nuclear fuel element (100); and coolants are fed inside the hollow runner region (4) and outside the outer shell (1). In the invention, the nuclear fuel element is provided with the hollow runner region, and the coolants pass through the inside and outside of the nuclear fuel element, so that the heat transfer efficiency of the nuclear fuel element is greatly improved, and the probability of accidents caused by insufficient cooling effect of the nuclear fuel element can be effectively avoided.