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[en] We demonstrate a simple, low-cost, and passive radiative cooler based on a monolithic design consisting of thin nanoporous anodic alumina (NAA) films grown on aluminium sheets. The NAA/Al structure maintains a high broadband reflectivity close to 98% within the solar spectrum (0.4–2.2μm) and simultaneously exhibits a high average emissivity of 88% within the atmospheric infrared (IR) transmission window of 8–13μm with the peak IR emission approaching 99% at a wavelength of 10μm. Optical modelling of the system using optical parameters of the materials confirms that the high solar reflectance arises due to the transparent nature of NAA and high reflectivity of bottom Al, while the large thermal IR emissivity arises from the interference effects of the NAA film and the high absorption of IR light due to phonon resonances in alumina at wavelength larger than 10μm. Further, we estimate the average cooling power of NAA/Al to be about 136 W m−2 at ambient temperature even after including the contribution to heat input from external non-radiative processes. This robust and light weight NAA/Al can be projected as an excellent alternative to optical solar reflectors used in spacecraft for thermal heat management and rooftop cooling green technologies. (author)
[en] The International Atomic Energy Agency (IAEA) and the Generation IV International Forum (GIF) have jointly committed to collaboration between their respective programmes, and to share information in selected areas of mutual interest. One of the key areas of emphasis in both the GIF and the IAEA programmes is the safety of liquid metal cooled fast reactors (LMFRs) including sodium cooled fast reactors (SFRs) and lead or lead-bismuth eutectic (LBE) cooled fast reactors (LFRs). A particularly important area of mutual interest is the harmonization of safety approaches, safety requirements, Safety Design Criteria (SDC), and Safety Design Guidelines (SDG) for the next-generation advanced LMFRs under development worldwide. This topic has gained increased importance in the aftermath of the accident that occurred in 2011 at the Fukushima Daiichi nuclear power plant, which drew renewed attention to nuclear safety and to the importance of an international safety framework for reactors currently in operation as well as for new designs.
[en] Three-step development of fast reactor: Experimental, Demonstration, Commercial. CEFR Project: One of the largest item of China national ''863'' hi-tech plan; Pool type, sodium cooled experimental fast reactor with tertiary circuit; Main parameters (Reactor core); Main test programs in the CEFR Physical start-up. China Demonstration Fast Reactor (CFR600); Design for High Safety: Goal Elimination of Off-site Emergency; Three shut-down methods including Fluid suspension control safety rods; Passive designs applied in pressure protection of main vessel, siphon breaker, rupture disk to avoid large sodium-water reaction. CFR1200 Preconception design: Requirements - Review GIF SDC for CFR1200, Review Guidance for Developing Principal Design Criteria for Advanced (Non-Light Water) Reactor, Top requirements for CFR1200 pre-concept design, System requirements for CFR1200 pre-concept design.; TRA - Methodology, Assessment S-CO2 conversion system and passive shutdown system.; S-CO2 conversion system - Implementation plan of the S-CO2 conversion system research: scope and contents of the research, parameter package, technical specification document.
[en] The main objectives of this meeting/workshop are to: Discuss the development of the draft GIF report provisionally entitled Safety Design Guidelines on Key Structures, Systems and Components; Discuss the review comments of external stakeholders on GIF report on Safety Design Guidelines on Key Structures, Systems and Components; Discuss the development of the Safety Design Criteria and Safety Design Guidelines for lead and lead-bismuth cooled fast reactors; and Share information on the implementation of SDG for SFRs and SDC for LFRs by the designers of the innovative LMFR concepts.
[en] Contents: National status of SFR development in Japan. Prospects of Japan Sodium-cooled Fast Reactor -Introduction: JAEA has developed conceptual design of an advanced loop-type SFR, named JSFR.; R&Ds for innovative technologies adopted in JSFR have been conducted as well as design study for improving maintainability and repairability and safety measures based on lessons learned from the Fukushima Daiichi Nuclear Power Plants accident.; JAEA is developing the design concept of a pool-type SFR based on the technology obtained from the above.; The development of this concept will broaden not only options for reactor types in Japan but also the range and depth of international cooperation. Design concept of a pool-type SFR; Study of reactor structure - Structural design and seismic evaluation, - Thermal hydraulic evaluation; Study of safety design - Safety design concept, - Applicability evaluation of SASS. Concluding Remarks: JAEA is developing the design concept of pool-type sodium-cooled fast reactor (SFR) that addresses Japan's specific siting conditions such as earthquakes and meets safety design criteria (SDC) and safety design guidelines (SDGs) for Generation IV SFRs.; The development of this concept will broaden not only options for reactor types in Japan but also the range and depth of international cooperation.
[en] The Dukovany nuclear power plant was put into operation in 1985-1987. These are 4 units of WWER-440 reactor type. The specific feature of the WWER-440 design is six reactor cooling loops, that means each reactor is connected to six circulating pumps and six steam generators (SGs). Equipment DEKOZ PG, as shown, was designed for the chemical decontamination of the SGs of the plant. It separates the primary part of SG from the remaining part of the reactor cooling loop, serves for filling and draining the decontamination solutions into and from SG separated section and ensures also their circulation. Used decontamination solutions are drained by compressed air from the SG into the liquid waste draining lines. The device does not allow the recovery of the used decontamination solutions.
[en] General Comments: Many comments are related to the use of language or terminology that is not standard or clear. The document would benefit from a technical editorial review; Revision of several IAEA safety guides of interest was not completed when the guidelines were developed. It is recommended that alignment with the new revisions of the IAEA safety guides and the IAEA Safety Glossary is verified and that references to IAEA Safety Standards and Safety Glossary are updated; The report is generally written as a guide for design (as indicated in the title) but sometimes as a guide for safety assessment of the design. If the purpose is to cover both aspects, it should be clear in the scope and be ensured that the different aspects are systematically covered; Some design requirements in IAEA SSR 2 1 or design criteria in GIF SDC for SFRs are formulated as recommendations or even as optional aspects (e.g. reactor shutdown) rather than providing guidance to meet the requirements or criteria; Recommendations just about ''considering'', ''take into account'' some aspects or ''been designed to behave as expected'' are vague or not very useful. Recommendations should be practical; Statements or recommendations are frequently formulated in relation to plant operational states and design basis accidents when it appears that they should be also applicable to design extension conditions without significant core damage; Some recommendations/topics seem to be misplaced, e.g. parts in relation to coolant under core design.
[en] Severe accident analyses for the spent fuel pool of the VVER-440/213 plant have been performed with the MAAP5-VVER code. The selected sequence was an unmitigated loss-of-cooling accident. MAAP5 modelling of the SFP is quite advanced due to several features including the possibility of modelling rectangular pool geometries. The SFP input deck for the MAAP5 code has been set up using plant specific data concerning SFP dimensions, parameters and materials. Accident progression has been analyzed by tracking thermal-hydraulic parameters and fission product release during the sequence. Results of the calculations have been found physically reasonable. Additional check of the results has been performed via code-to code comparison with a similar MELCOR analysis. Computer run times of MAAP5-VVER for a typical SFP transient lasting 200 h have been less than 20 min on a usual PC under Microsoft Windows. Graphical capabilities of the code are flexible and efficient enabling the analyst to review and study physical parameters. (author)
[en] Contents: Safety Standards in scope of the review. Technologies in scope of the review - Sodium Fast Reactors (SFR), Lead Fast Reactors (LFR), High Temperature Gas Cooled Reactors (HTGRs), Molten Salt Reactors ,Water-cooled SMRs, Transportable SMRs, Micro-sized reactors. Review approach - Key Questions: Do current requirements and recommendations cover the safety issues related to the new possibilities opened by the novel designs? (areas of novelty); Are there gaps that need to be addressed to ensure that the level of safety established by the IAEA fundamental safety principles and safety objective will be complied with?. Outcomes from the March Consultancy Meeting - Areas of Novelty WC SMRs; Areas of Novelty Non-Water-Cooled Reactors; Applicability of Siting and Design for External Hazards Safety Standards; Applicability of Waste Management Safety Standards.
[en] Fuel pool cooling is an essential task in the scope of nuclear power applications. During the first years of commercial nuclear power implementation robust fuel pool cooling systems have been developed and used for several decades. Two decades ago the development of a new cooling technology/concept was initiated to ensure prevention of accidents, including fuel damage. The so-called advanced cooling technology offers a modular design system which enables tailor-made robust and cost efficient cooling solutions. However, all the advanced cooling systems feature an indispensable and distinctive fall back option of a passive heat removal in case of a station blackout as most important feature. In contradiction to conventional cooling systems the advanced cooling solutions use immersed heat exchangers to establish an additional safety barrier inside the heat removal chain. This results in the necessity of a free convective heat transfer on pool water side. This in turn requires a special design approach and methodology. Because of the huge nominal heat load and the size of the heat removal systems itself full size test are under economical aspects nearly impossible. In this paper a purpose-built simulation and design methodology is presented, which has been developed and proved in the scope of several first-of-a-kind projects during the last years.