## 1 Introduction
[13] presented a literature review paper where they analyzed what had been done the first time and what needs to be done the second time in the field of disassembly in remanufacturing. Therefore, [PERSON] et al. [14] studied the problem of disassembly process planning considering the states or quality of the products to be disassembled. Meanwhile, the problem of disassembly process planning and the definition of the disassembly sequences have been studied in numerous works; we cite [PERSON] et al. [15], [PERSON] et al. [16], [PERSON] et al. [17] and [PERSON] et al. [18]. In other studies [19; 20], authors also considered the problem of disassembly scheduling under a single period of disassembly. In the same context, [PERSON] et al. [11] treated the problem of determining the quantity and timing of disassembling each parent item for a given disassembly structure in order to satisfy the demand of leaf items over a planning horizon with discrete time periods. However, these above-mentioned studies have treated the disassembly process under different uncertainties independently of the manufacturing process. Indeed, in real-life systems, the disassembly operation depends on the demand for manufacturing of finished products. Our paper is based on Material Requirements Planning (MRP) taking into account remanufacturing components. Within recent decades, MRP systems were among the most popular methods of production and inventory planning for companies, and of interest to many researchers [21; 22; 23; 24; 25]. However, MRP tends to be an assembly-oriented scheduling system [17]. Some studies noted that most MRP does not provide capabilities to plan disassembly [18]. [PERSON] and [PERSON] [26] proposed a mathematical analysis of remanufacturing within the MRP framework to develop control rules for undertaking production of new components, refurbishing returned cores, and disposing of excess cores. Their model is also limited to remanufacturing processes that maintain a finished good identity. In the work of [PERSON] et al. [27], they presented an MRP optimization model where they treated a particular production system. In addition to manufacturing a final product, its main assembling component can be recovered from parts of the returned product. [PERSON] and [PERSON] [28] developed an extended MRP model for a hybrid single-stage multi-period production and remanufacturing system. Compared to those studies cited above, the MRP examined in our system considering not only finding release dates of new components, but also the order date of used product from the suppliers. To solve this kind of problem, [PERSON] and [PERSON] [29] proposed an algorithm whose objective it is to determine the quantity and the disassembly schedule for the item to fulfill that demand on time. In another paper [30], they proposed two companion algorithms to obtain the quantity and disassembly operations schedule; they treated a more complex problem with the existence of multiple product structures and common parts and/or materials. In addition, [PERSON] [19] dealt with the same problem and proposed a modified version of the algorithm of [PERSON] and [PERSON] [30]. Indeed, [PERSON] et al. [20] proposed a cost objective function to minimize the sum of setup, inventory holding costs, and disassembly operation. They implemented a heuristic algorithm based on linear programming relaxation to solve the proposed cost function. [PERSON] et al. [31] treated a production planning problem in disassembly systems with a branch and bound algorithm. [PERSON] et al. [32] presented a new form of constraint-based simulated annealing (CBSA) in his paper to determine the ordering and disassembly schedule, to minimize inventory level for products with general assembly product structure. This paper aims to bridge the gap in research on the disassembly-assembly system by developing an optimal disassembly-assembly plan. Indeed, we consider stochastic lead-times of intermediate disassembled and assembled components.