Results 1 - 10 of 1920
Results 1 - 10 of 1920. Search took: 0.022 seconds
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[en] There was no consistent tendency of moisture reduction by heaters during the 10-hour operability test. The 10-hour heating during the test cannot reduce the humidity for a long time period. It is proved that the outside air affects the humidity more than the heating condition. The perturbed temperature and RH after the operability test recovered to initial state in 3-4 days. Therefore, it is not adequate to operate the system for a long time to remove moisture from the activated carbon. And longer than 15 minutes of the operability test is enough to demonstrate the function of the system
[en] Highlights: •ECC condensation research based on China PWR- CPR1000. •The correlation of condensation based on XJTU-ECC test was proposed. •Wide range of RT number from 0 to 3.5 were analyzed within condensation. •A new analysis method was proposed by using the mass fraction and RT number. •The test report a conservative results on ECC component than RELAP5 calculation.
[en] The AREVA NP Inc. realistic large-break loss-of-coolant-accident (LOCA) analysis methodology references the 1988 amended 10 CFR 50.46 allowing best-estimate calculations of emergency core cooling system performance. This methodology conforms to the code scaling, applicability, and uncertainty (CSAU) methodology developed by the Technical Program Group for the United States Nuclear Regulatory Commission in the late 1980s. In addition, several practical considerations were revealed with the move to a production application. This paper describes the methodology development within the CSAU framework and utility objectives, lessons learned, and insight about current LOCA issues
[en] US NRC has been working for the revision of the ECCS technical requirements (10 CFR 50.46) as a part of the implementation of Option 3 proposed from RIPBR and SECY-98-300. US NRC has been taking the lead at the study for changes of the regulatory technical requirements including the ECCS technical requirements. Because of the technical and economic effects to the nuclear industry, it is expected that most of the countries having NPPs will devote themselves in following and acquiring technology related to these according to American tendencies. Based on this situation, we have carried out the feasibility study on domestic application through reviewing and analyzing the background and status of the revision of ECCS technical requirements which has been carried out actively by US NRC
[en] The development of advanced reactors is considered to be of the key steps for revival of nuclear power through resolving the related safety and economic issues. More than 20 different reactor designs are being developed worldwide with significantly different developmental status. It is very difficult to categorize the various advanced reactor designs, but one can divide them into two groups, evolutionary and innovative, based on the requirement of a prototype. The evolutionary designs can be further divided into two groups: evolutionary active and evolutionary passive. In this article, the Carry and its research on the advanced reactors are briefly introduced with emphasis on the system design works, which can be summarized as follows: the Carry is an inter-univ. collaborative research body established to perform basic research and development related to the design of next-generation reactors in Korea
[en] KINS conducts regulatory periodic inspections of the safety and performance of each nuclear installation during the planned outage every 20 months, pursuant to the Atomic Energy Act. For CANDU reactors, planned outage or overhaul (O/H) have been performed every 15 months. KHNP has been making efforts to extend the O/H intervals of CANDU reactors into 20 months since 2001. Low ECCS availability is one of the regulatory pending issues in the related licensing
[en] The U. S. NRC is currently proposing rulemaking designated as ''10 CFR 50.46c'' to revise the LOCA/ECCS acceptance criteria to include the effects of higher burnup on cladding performance as well as to address some other issues. The NRC is also currently resolving the public comments with the final rule expected to be issued in the summer of 2016. The impact of the final 50.46c rule on the industry will involve updating of fuel vendor LOCA evaluation models, NRC review and approval, and licensee submittal of new LOCA evaluations or reanalyses and associated technical specification revisions for NRC review and approval. The rule implementation process, both industry and NRC activities, is expected to take 5-10 years following the rule effective date. The need to use advanced cladding designs is expected. A loss of operational margin will result due to the more restrictive cladding embrittlement criteria. Initial and future compliance with the rule may significantly increase vendor workload and licensee cost as a spectrum of fuel rod initial burnup states may need to be analyzed to demonstrate compliance. Consequently there will be an increased focus on licensee decision making related to LOCA analysis to minimize cost and impact, and to manage margin.
[en] In the framework of the IAEA Regional Project, WWER Design Basis Documentation Management System, the Guideline for Design Basis Document Collation and Maintenance was developed. Pilot development and review of these documents for the technology system 'low pressure emergency core cooling system' of WWER-1000 and WWER-440 plants was accomplished. The paper summarizes the experience gained. (author)
[en] A variety of materials present in a reactor building may dissolve or corrode when exposed to reactor coolant and spray water solutions in a post LOCA (Loss of Coolant Accident) environment, forming oxide particulate corrosion products and precipitates through chemical reactions with other dissolved materials. These chemical products could produce a considerable head loss through the emergency core cooling system filter screen. However, it is very difficult to predict the effects of chemical products on the head loss because of the variety of the chemical reactions occurred in the solution after a LOCA. The present study has been performed to evaluate experimentally the amount of chemical precipitates due to aluminum released from the post LOCA sump fluids and to compare the results of the present tests with the USNRC approved methodology of WCAP 16530 NP A