The reliability indices Mean-Time-Between-Failures ( MTBF) and Forced Outage Rate ( FOR), which have already been used during useful life period, are spread so that conditional Mean-Time-Between-Failures ( MTBFt) and interval average Forced Outage Rate ( FORa) are suggested. 由此,本文推广了处于使用寿命期的可修复元件的可靠性指标MTBF及强迫停运率FOR,提出了条件平均故障间运行时间MTBFt及区间平均强迫停运率FORa等可靠性指标。