A new fuel pin failure model, the Los Alamos Failure Model (LAFM), based on a linear life fraction rule failure criterion, has been developed to provide a reliable and inexpensive prediction of the time and axial location of liquid-metal fast breeder reactor fuel pin failure in a hypothetical transient overpower (TOP) accident. Code testing analyses for a number of TOP Transient Reactor Test Facility tests have resulted in excellent agreement between calculated and observed pin failure time and location. Because of the nature of the failure criterion used, the code has also been used to investigate the extent of cladding damage incurred in terminated as well as unterminated TOP transients in the fast test reactor. The results of these analyses show that 3 dollar/s and 50 and 5 cent/s transients terminated by the secondary trip point (25% overpower) result in negligible calculated cladding damage.