[en] With the issue in USA of the Maintenance Rule (10CFR50.65), new requirements for monitoring the effectiveness of maintenance for important to safety equipment have been established. Plants shall monitor the performance or condition of structures, systems or components against licensee-established goals that will be commensurate with safety and will take into account industry-wide operating industry. The objective of preventing failures has to be balanced against the objective of minimising unavailability. Additionally, an assessment of the impact on risk caused by total plant equipment that is out of service has to be performed. Risk Monitor is the general term that has been more successfully adopted to describe those diverse software applications that support the on-line risk-informed management of operational system reconfiguration and equipment outages due to maintenance activities. The software MARE (EA Risk Analysis Monitor) has been developed by Empresarios Agrupados (EA) to allow easy implementation of the Maintenance Rule requirements of Consejo de Seguridad Nuclear (Spanish Nuclear Regulatory Body). This tool supports the analysis and evaluation of risk level changes expected during system reconfiguration for equipment maintenance during plant operation. This assessment is based on the specific plant Probabilistic Safety Analysis (PSA) model, uses the Risk Spectrum code and allows a tracking of the risks due to the maintenance history of the plant. The implementation of such systematic and continuous assessments will provide an historical performance of components within PSA scope, in a detailed database. (Author)