Design Development and Verification of a System Integrated Modular PWR

An advanced PWR with a rated thermal power of 330 MW has been developed at the Korea Atomic Energy Research Institute (KAERI) for a dual purpose: seawater desalination and electricity generation. The conceptual design of SMART ( System-Integrated Modular Advanced ReacTor) with a desalination system was already completed in March of 1999. The basic design for the integrated nuclear desalination system is currently underway and will be finished by March of 2002. The SMART co-generation plant with the MED seawater desalination process is designed to supply forty thousand (40,000) tons of fresh water per day and ninety (90) MW of electricity to an area with approximately a ten thousand (100,000) population or an industrialized complex. This paper describes advanced design features adopted in the SMART design and also introduces the design and engineering verification program. In the beginning stage of the SMART development, top-level requirements for safety and economics were imposed for the SMART design features. To meet the requirements, highly advanced design features enhancing the safety, reliability, performance, and operability are introduced in the SMART design. The SMART consists of proven KOFA (Korea Optimized Fuel Assembly), helical once-through steam generators, a self-controlled pressurizer, control element drive mechanisms, and main coolant pumps in a single pressure vessel. In order to enhance safety characteristics, innovative design features adopted in the SMART system are low core power density, large negative Moderator Temperature Coefficient (MTC), high natural circulation capability and integral arrangement to eliminate large break loss of coolant accident, etc. The progression of emergency situations into accidents is prevented with a number of advanced engineered safety features such as passive residual heat removal system, passive emergency core cooling system, safeguard vessel, and passive containment over-pressure protection. The preliminary safety analyses for the SMART design have been performed and the results demonstrated that the key safety parameters of the limiting design base events do not violate the safety limits. Various fundamental thermal-hydraulic experiments were carried out during the design concept development to assure the fundamental behavior of major concepts of the SMART systems. Most technologies implemented into the SMART concept have been proven through the design and operation of the existing PWRs. Advanced design features require tests to confirm the performance of the design and to produce data for the design code verification. Tests including core flow distribution test, test of flow instability in steam generator, test of self-pressurizer performance, two-phase critical flow test with non-condensable gases, and high-temperature/high pressure integral thermal-hydraulic test are currently under preparation by installing equipment and facilities. The performance tests for key parts of MCP(Main Coolant pump) and CEDM(Control Element Drive mechanism) were performed. And also mechanical performance tests for the reactor assembly and major primary components will be carried out. Technical and economical evaluation for the commercialization of SMART were conducted by the Korean Nuclear Society (KNS) from August of 2000 to July 2001. Based on the results of the evaluation, the SMART technology is technically sound and has sufficient economic incentives for pursuing further development. Upon the completion of the basic design phase in March of 2002, the SMART design/engineering verification phase will be thus followed to conduct various separate effect tests and comprehensive integral tests as well as construction of the one fifth scaled pilot plant for demonstration of overall SMART performance. (author)