Thank you for clarifying the question. I do not think it is necessary to replace the reactor control immediately if it is used for the production of an intermediate. Recommendation: Assess all systems and equipment and arrange them according to priority classes (for instance by using a rather simple FMEA). This is used to define when to deal with the priority classes, for example Prio 1= until the end of 2017, Prio 2= until the end of 2018 etc…