[en] Zircaloy fuel tubes in a nuclear reactor show excellent oxidation resistance under normal reactor operating conditions and there is little chance of failure of these tubes as a result of oxidation and consequent wall thinning. However if the operating temperatures were to be raised for purpose of better thermal efficiency or if the stay of the fuel tubes were to be extended for purpose of economy, oxidation would be a factor to be taken into account. Also, due to accidental shoot up of temperature as a result of power cooling mismatch, excessive oxidation can lead to higher oxygen or hydrogen pickup and embrittlement due to either of these is of concern. The present study discussed some aspects of high temperature oxidation of three Zr alloys (Zircaloy-2, Zr-2.5Nb and Zr-0.5Nb-1Cr) in steam in the temperature range 400-1200^oC. (author). 15 refs., 8 figs