Given a reward structure, this paper addresses an optimal replacement problem for complex multi-component systems. To maintain revenue stream resulting from system, the system is inspected at random times and certain actions are performed in response to the system state. Decisions are based on a performance measure described by a Squared Bessel process. Since there are some flow of income and increasing costs due to inspections, the problem is to optimally stop processing the system and carrying out a renewal to maximize the reward functional. In support of the model a numerical example is provided to demonstrate the application of the proposed model.