The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform
Yu V Parfenov - One of the best experts on this subject based on the ideXlab platform.
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the computational and experimental investigation into the head flow characteristic of the two stage ejector for the emergency core cooling system of the npp with a water moderated water cooled Power Reactor
Thermal Engineering, 2013Co-Authors: Yu V ParfenovAbstract:The results of the computational-and-experimental investigation into the two-stage ejector for the emergency cooling system of the core of the water-moderated water-cooled Power Reactor. The results of experimental investigations performed for the ejector model at the JSC “EREC” and the result of calculations performed using the REMIX CFD code are presented.
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the computational and experimental investigation into the head flow characteristic of the two stage ejector for the emergency core cooling system of the npp with a water moderated water cooled Power Reactor
Thermal Engineering, 2013Co-Authors: Yu V ParfenovAbstract:The results of the computational-and-experimental investigation into the two-stage ejector for the emergency cooling system of the core of the water-moderated water-cooled Power Reactor. The results of experimental investigations performed for the ejector model at the JSC “EREC” and the result of calculations performed using the REMIX CFD code are presented.
Zuhair Zuhair - One of the best experts on this subject based on the ideXlab platform.
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ASSESSING THE OTTO OPTION: THORIUM-CYCLE EXPERIMENTAL Power Reactor SPENT FUEL CHARACTERISTICS
'National Atomic Energy Agency of Indonesia (BATAN)', 2020Co-Authors: Dwijayanto, Andika R. Putra, Husnayani Ihda, Zuhair ZuhairAbstract:Two main refuelling option considered for use in a High Temperature Gas-cooled Reactor (HTGR) are multi-pass and once through-then-out (OTTO) cycle. The former possesses superiority in term of fuel utilisation whilst the latter is considered better in term of system simplicity. HTGR-based Experimental Power Reactor (Reaktor Daya Eksperimental/RDE) is supposed to adopt multi-pass refuelling scheme. However, OTTO-scheme shall also be considered for the simplicity it offers and thus potentially lower cost. Due to different neutronic and burnup profile between the two, the resulting spent fuel characteristic is also different and possibly requires different handling mechanism. This paper assesses the characteristics of OTTO-scheme RDE spent fuel using thorium fuel cycle. The assessment is performed employing ORIGEN2.1 code. At day 30 of cooling after determined end-of-cycle (EOC), each spent fuel yields 234.9 Curies of radioactivity, emitting 66.26 neutrons/second, 1x1013 photons/second, and releasing 0.7675 watts of decay heat. These numbers must be taken into consideration regarding spent fuel management and spent fuel cask design. Tl-208 isotope characteristics, whose existence is unique to thorium fuel cycle, were also determined. It is found to be yielding 3.42x10-3 Curie of radioactivity and releasing 1.2x108 photons/second at its peak. Understanding its high-energy gamma release, proper radiation protection mechanism must be implemented
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CHARACTERISTICS OF RADIONUCLIDES ON THORIUM-CYCLE EXPERIMENTAL Power Reactor SPENT FUEL
'National Atomic Energy Agency of Indonesia (BATAN)', 2019Co-Authors: Dwijayanto, S.t., Andika R. Putra, Husnayani Ihda, Zuhair ZuhairAbstract:CHARACTERISTICS OF RADIONUCLIDES ON THORIUM-CYCLE EXPERIMENTAL Power Reactor SPENT FUEL. There are several options of nuclear fuel utilisation in the HTGR-based Experimental Power Reactor (Reaktor Daya Eksperimental/RDE). Although mainly RDE utilises low enriched uranium (LEU)-based fuel, which is the most viable option at the moment, it is possible for RDE to utilise other fuel, for example thorium-based and possibly even plutonium-based fuel. Different fuel yields different spent fuel characteristics, so it is necessary to identify the characteristics to understand and evaluate their handling and interim storage. This paper provides the study on the characteristics of thorium-fuelled RDE spent fuel, assuming typical operational cycle. ORIGEN2.1 code is employed to determine the spent fuel characteristics. The result showed that at the end of the calculation cycle, each thorium-based spent fuel pebble generates around 0,627 Watts of heat, 28 neutrons/s, 8.28x1012 photons/s and yield 192.53 curies of radioactivity. These higher radioactivity and photon emission possibly necessitate different measures in spent fuel management, if RDE were to use thorium-based fuel. Tl-208 activity, which found to be emitting potentially non-negligible strong gamma emission, magnified the requirement of proper spent fuel handling especially radiation shielding in spent fuel cask.Keywords: RDE, spent fuel, thorium, HTGR, Tl-208
K Tobita - One of the best experts on this subject based on the ideXlab platform.
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first wall issues related with energetic particle deposition in a tokamak fusion Power Reactor
Fusion Engineering and Design, 2003Co-Authors: K Tobita, Satoshi Nishio, S Konishi, M Sato, T Tanabe, K Masaki, N MiyaAbstract:Abstract Energetic particle deposition to the wall due to toroidal magnetic field (TF) ripple was assessed for a 2 GW fusion Power Reactor. When the present allowance for the loss is applied, the alpha particle flux to the wall can be as high as 2×10 18 m −2 s −1 in the Reactor, eroding tungsten by ∼20 μm per year. The peak particle fluence over a 2-year operation cycle can reach 10 26 m −2 , probably being larger than a critical fluence for blister formation. The result suggests that, for the steady-state tokamak fusion Reactor, we should introduce a new design methodology of determining an acceptable level of TF ripple on the basis of particle fluence to the wall, instead of the present one based on a tolerable heat flux.
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conceptual design of tokamak high Power Reactor a sstr2
Journal of Plasma and Fusion Research, 2002Co-Authors: Satoshi Nishio, K Tobita, S Konishi, K Ushigusa, Reactor Design TeamAbstract:Based on the last decade of JAERI Reactor design studies, an advanced commercial Reactor concept (A-SSTR2) that meets both economical and environmental requirements has been proposed. The A-SSTR2 is a compact Power Reactor (Rp = 6.2 m, ap = 1.5 m, Ip = 12 MA) with a high fusion Power (Pf = 4 GW) and a net thermal efficiency of 51%. The machine configuration is simplified by eliminating the center solenoid (CS) coil system. An SiC/SiC composite for the blanket structure material, helium gas cooling with a pressure of 10 MPa and an outlet temperature of 900°C, and TiH2 for the bulk shield material are introduced. For the toroidal field (TF) coil, a high temperature (TC) superconducting wire made of bismuth with a maximum field of 23 T and a critical current density of 1,000 A/mm2 at a temperature of 20 K is applied. In spite of the CS-less configuration, a computer simulation gives satisfactory plasma equilibria, plasma initiation process, and current ramp-up scenario. The current rampup time is about 22 hours. The MHD stabilities for the ballooning mode and the ideal low n kink-modes are confirmed. The stabilization of n = 1 and n = 2 kink modes requires a shell position closer than 1.4 times and 1.2 times the plasma minor radius, respectively. With regard to the divertor thermal condition, it was found that a neon gas-seeded divertor plasma with a fraction of ˜ 2.5% gives a thermal load reduction at the divertor plate from 460 MW to 100 MW and a plasma temperature drop at the divertor plate from 200 eV to 20 ˜ 30 eV. By increasing the shield thickness by about 15 cm, the total radwaste is dramatically reduced. The radwaste percentage relative to the total waste is reduced from 92 wt.% to 17 wt.%.
Satoshi Nishio - One of the best experts on this subject based on the ideXlab platform.
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first wall issues related with energetic particle deposition in a tokamak fusion Power Reactor
Fusion Engineering and Design, 2003Co-Authors: K Tobita, Satoshi Nishio, S Konishi, M Sato, T Tanabe, K Masaki, N MiyaAbstract:Abstract Energetic particle deposition to the wall due to toroidal magnetic field (TF) ripple was assessed for a 2 GW fusion Power Reactor. When the present allowance for the loss is applied, the alpha particle flux to the wall can be as high as 2×10 18 m −2 s −1 in the Reactor, eroding tungsten by ∼20 μm per year. The peak particle fluence over a 2-year operation cycle can reach 10 26 m −2 , probably being larger than a critical fluence for blister formation. The result suggests that, for the steady-state tokamak fusion Reactor, we should introduce a new design methodology of determining an acceptable level of TF ripple on the basis of particle fluence to the wall, instead of the present one based on a tolerable heat flux.
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conceptual design of tokamak high Power Reactor a sstr2
Journal of Plasma and Fusion Research, 2002Co-Authors: Satoshi Nishio, K Tobita, S Konishi, K Ushigusa, Reactor Design TeamAbstract:Based on the last decade of JAERI Reactor design studies, an advanced commercial Reactor concept (A-SSTR2) that meets both economical and environmental requirements has been proposed. The A-SSTR2 is a compact Power Reactor (Rp = 6.2 m, ap = 1.5 m, Ip = 12 MA) with a high fusion Power (Pf = 4 GW) and a net thermal efficiency of 51%. The machine configuration is simplified by eliminating the center solenoid (CS) coil system. An SiC/SiC composite for the blanket structure material, helium gas cooling with a pressure of 10 MPa and an outlet temperature of 900°C, and TiH2 for the bulk shield material are introduced. For the toroidal field (TF) coil, a high temperature (TC) superconducting wire made of bismuth with a maximum field of 23 T and a critical current density of 1,000 A/mm2 at a temperature of 20 K is applied. In spite of the CS-less configuration, a computer simulation gives satisfactory plasma equilibria, plasma initiation process, and current ramp-up scenario. The current rampup time is about 22 hours. The MHD stabilities for the ballooning mode and the ideal low n kink-modes are confirmed. The stabilization of n = 1 and n = 2 kink modes requires a shell position closer than 1.4 times and 1.2 times the plasma minor radius, respectively. With regard to the divertor thermal condition, it was found that a neon gas-seeded divertor plasma with a fraction of ˜ 2.5% gives a thermal load reduction at the divertor plate from 460 MW to 100 MW and a plasma temperature drop at the divertor plate from 200 eV to 20 ˜ 30 eV. By increasing the shield thickness by about 15 cm, the total radwaste is dramatically reduced. The radwaste percentage relative to the total waste is reduced from 92 wt.% to 17 wt.%.
Kengo Hashimoto - One of the best experts on this subject based on the ideXlab platform.
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experimental study of neutron counting in a zero Power Reactor driven by a neutron source inherent in highly enriched uranium fuels
Journal of Nuclear Science and Technology, 2019Co-Authors: Atsushi Sakon, Kunihiro Nakajima, Sinya Hohara, Kengo HashimotoAbstract:ABSTRACTEven a zero-Power Reactor core containing highly enriched uranium has a weak neutron source inherent in uranium 235, and consequently, a neutron counter placed closely to the core without external neutron source registers a certain counting rate. The study of the counting is very important for zero-Power Reactor physics experiments with a high precision. In this experimental study, first, at a shutdown state of the UTR-Kinki Reactor without start-up neutron source, a pulse height distribution of output signals from a neutron proportional counter was measured to confirm that these signals resulted from neutron detections. At several subcritical states of the UTR, then, the Feynman-α analysis was carried out to confirm that the neutrons detected by the counter must be fission neutrons multiplied by fission chain reactions. The correlation amplitude measured in the Feynman-α analysis was much higher than that measured in a previous drive by start-up source. Further, it was also confirmed that the sub...
