P-DEMO for demonstration of fast spectrum transmutator PEACER

The concept of proliferation-resistant, environment-friendly, accident-tolerant, continual and economical reactors (PEACER) has been developed by the NUTRECK, aiming at converting all spent nuclear fuels (SNF) into Low and Intermediate Level Waste (LILW) by integrating an advanced pyrochemical recycling and heavy liquid metal cooled fast reactor technology into a multi-national transmutation facility. It is proposed that the PEACER mandate - transmutation leaving no high level waste behind - can be demonstrated by a multinational facility designated as P-DEMO. P-DEMO is an integral pool-type reactor cooled by LBE coolant in primary cooling system with approximately 8m in height and 4m in diameter. P-DEMO will be started up with initial 19.75% enriched U-Zr (38-62 w/o) metallic fuels and its normal operation entirely relies on the natural circulation capability of liquid LBE. Total power of P-DEMO is 100MW thermal equivalent to 35MW electric power rating and is to be located within an underground containment facilities with strict security control and physical protection. One of the most important design features of P-DEMO is a central test assembly for fuel and materials qualifications which is cooled by LBE forced convection in the independent square assembly. As shown, the primary heat transport system is sealed by double wall reactor vessel for excluding the loss of coolant accidents from potential accident scenarios. Natural circulation also eliminates potential risk of loss of flow accident scenarios in primary cooling system. Double containment also protects the emission of radioactive isotopes in the case of significant abnormal conditions. If the hypothetical core melting accidents, the molten core distribution and cooling structure designated as COASIS will spread and solidify the molten core to curb the situation into stable long-term cooling mode with the help of RVACS. This COASIS is placed in the bottom of reactor vessel. Twelve helical type steam generator modules are equipped at the above downcomer where the cooled coolant flows downward to the core. Heated LBE storage tank and cover gas control system (CGCS) are established on the upward reactor enclosure and transporter system for refueling also is in this region. The CGCS controls the dissolved oxygen level in LBE by flowing hydrogen and oxygen and traps radio-toxic polonium vapors. For the all potential accidents, the reactor vessel air cooling system (RVACS) is designed to remove decay heat by natural circulation of air. The primary shutdown control assemblies are established above the core held by magnetic drive mechanisms during normal operation. They are dropped with the loss of magnetic power into the core by gravity upon a demand. In the above core, the secondary shutdown assemblies are located with different holding mechanism, self-actuated bi-metal latches, and are dropped into the core in the case of accidents accompanying coolant temperature rises. P-DEMO operates at the low temperature range of 300 ∼ 450 deg. C in order to assure no corrosion problem for structural materials with LBE coolant throughout the 60 years of lifetime. Considering large density and inertial mass of LBE coolant, a three dimensional seismic isolation system is employed for both reactor and the preprocess units to assure their structural robustness