Thermal desalination technologies are very energy intensive. The utilisation of nuclear energy for seawater desalination provides a safe, feasible and economic solution for the production of very good quality water. The Multi-Stage Flash (MSF) desalination plant of the Nuclear Desalination Demonstration Project (NDDP) of the Department of Atomic Energy (DAE), Government of India, is coupled with a nuclear power plant on the south east coast of India to share the common facilities and steam. The MSF desalination plant is under construction. This paper describes a case study of the coupling aspects of the MSF desalination plant with the existing nuclear power plant and gives an estimate of the loss of electrical power generation due to extraction of steam. Loss of electrical power is also compared with the Desalination Economic Evaluation Program (DEEP) of the IAEA.