[en] Most Nordic-type BWRs rely on sea water for the final heat sink. This paper discusses the situation where the both ends of the sea water inlet must be closed, which results in the loss of the final heat sink. We propose an accident mitigation strategy which guarantees that the rooms containing the most important safety-related pumps can be cooled. It is shown that the accident will not result in a large emission of radioactive substances. (authors)

[en] Highly reliable over pressure protection system for moisture separator reheater (MSR) is developed which prevents MSR shell from over pressure by function to tripping the turbine when the shell pressure increases up to the set point. The maximum design pressure of MSR is nearly equal to that of current design by suitably selecting the set point pressure of the protection system. The system could eliminate numerous numbers of large capacity relief valves, their main pipes and succeeding periodical maintenance works such as disassembly and function test, without failing unit reliability and availability. (authors)

[en] The SAMG entry condition of the OPR1000 (Optimized Power Reactor 1000) was evaluated with a comparison to other conditions by using the SCDAP/RELAP5/MOD3 computer code. Dominant severe accident sequences, such as a station blackout, a total loss of feed water, a small break, and a medium break loss of coolant accidents without a safety injection were evaluated in this study. The results showed that the core exit temperature of 480 deg.C for the SAMG entry condition was too early, but the core exit temperature of 1, 000 deg.C was too late. The SAMG entry condition of the core exit temperature of 650 deg.C for the OPR1000 was suitable for the operator action timing point in order to mitigate a severe accident. (authors)

[en] A high-efficiency jet pump has been developed to widen the core flow window by increasing the maximum core flow rate in boiling water reactors. The higher efficiencies of the jet pumps with the new nozzle shapes (the 6-nozzle or the ring nozzle) and the improved throat were confirmed using the 1/3-scaled water test facility at room temperature. (authors)

[en] The proceedings of the 2010 International Congress on Advances in Nuclear Power Plants - ICAPP '10 - covers the following topics: Water Cooled Reactor Programs and Issues, High Temperature Gas Cooled Reactors, LMFR and Longer Term Reactor Programs, Operation, Performance and Reliability Management, Plant Safety Assessment and Regulatory Issues, Reactor Physics and Analysis, Thermal Hydraulics Analysis and Testing, Fuel Cycle and Waste Management, Materials and Structural Issues, Nuclear Energy and Global Environment, Near Term Deployment, and Plant Licensing and Regulatory Issues

[en] Issues that may happen during the construction of civil works of a nuclear power plant are numerous: concrete, reinforcement bars positioning, welding of the liner... On top of the above, quality and nuclear safety assurance is increasingly required by nuclear authorities to keep the current nuclear renaissance steady regarding public opinion. The speaker will present the benefits of using a third party during these civil works phases and about the value created for the circle of actors through a risk based inspection program. Going through the main stages of design and construction of civil works of a nuclear power plant, the main actors involved, their positioning and the role of a voluntary independent third party inspection body, the speaker demonstrates that an independent third party, voluntarily chosen by a Utility and nuclear power plant engineering company, may give confidence to each party. (authors)

[en] The Southwestern U.S. is an arid region with limited surface water resources and groundwater resources that are being depleted at an unsustainable rate. Nuclear desalination has the potential to generate electricity and reduce greenhouse emissions associated with climate change. Although desalination is often associated with the processing of seawater, the Southwest has considerable brackish groundwater resources that offer an additional option that requires less energy input compared to seawater. Analyses with DEEP show reverse osmosis technology to be the most economical. (authors)

[en] Recently, in Korea, a study on the tritium storage and delivery system (TSDS) for the recycle of tritium, which is collected by Wolsong Tritium Removal Facility (WTRF), is in progress. For the efficient operation of TSDS, the inventory estimation code is required. In this study, the developed inventory estimation code include the function for the estimation of the tritium inventory of the storage tanks of TSDS in real time and the calculation of the reorder point (ROP) of tritium from WTRF for the seamless supply to individual customers. The developed inventory estimation system is applied for the efficient management of tritium inventory. (authors)

[en] New reactor designs aim to reach a higher safety level than the existing nuclear power plants. This requires very reliable safety systems. Reliability, achievable by redundancy is limited by common cause failures (CCF). Therefore, diversity needs to be introduced in the design of safety systems or safety functions. A systematic deterministic approach, called 'Deterministic Common Cause Failure Analysis ', has been developed which is not only restricted to the front-line safety system part but analyzes the safety systems including their necessary support system functions to be sufficiently diverse. (authors)

[en] An underwater vehicle system to inspect nuclear power plants has been developed. In this work, a function to show the moving vehicle's position to operators is proposed and the new position detection method described. The method consists of a horizontal position detection part and a vertical position detection part. In the former, map matching is used which consists of the cross-sectional shape data cut from a 3-D CAD and the inner surface shape measured by a laser range system. In the latter part, a pressure sensor is used. It was confirmed that the position was detected with an accuracy of 48 mm based on results of a fundamental examination using the sensor unit. Finally, in an experiment using the vehicle- mounted sensor unit, it was confirmed that the position was detected with an accuracy of 60 mm. (authors)