The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform
Hideki Tatsumoto - One of the best experts on this subject based on the ideXlab platform.
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Performance evaluation of a developed orifice type heater for thermal compensation control at J-PARC cryogenic hydrogen system
IOP Conference Series: Materials Science and Engineering, 2015Co-Authors: Hideki Tatsumoto, Kohei Ohtsu, Y. KawakamiAbstract:Supercritical hydrogen with a temperature of less than 20 K and a pressure of 1.5 MPa is used as Moderator Material at J-PARC. Total nuclear heating of 3.75 kW is generated by three Moderators for a 1-MW proton beam operation. We have developed an orifice-type high-power heater for thermal compensation to mitigate hydrogen pressure fluctuation caused by the abrupt huge heat load and to reduce the fluctuation in the temperature of the supply hydrogen to less than 0.25 K. Through a performance test, we confirmed that the developed orifice-type heater could be heated uniformly and showed fast response, as expected. Furthermore, a simulation model that can describe heater behaviors has been established on the basis of the experimental data. The heater control approach was studied using the aforementioned heater simulation model and a dynamic simulation code developed by the authors.
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development of the cryogenic hydrogen system for a spallation neutrton source in j parc
TRANSACTIONS OF THE CRYOGENIC ENGINEERING CONFERENCE—CEC: Advances in Cryogenic Engineering, 2010Co-Authors: Hideki Tatsumoto, H Sakurayama, T. Uehara, Kohei Ohtsu, Y. Kawakami, T. Kato, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical hydrogen at around 20 K and 1.5 MPa was selected as a Moderator Material in JSNS. Three kinds of hydrogen Moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the Moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The cryogenic hydrogen system, where the hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical hydrogen for the Moderators and absorbs nuclear heating in the Moderators. The off‐beam commissioning has confirmed that the cryogenic hydrogen system can be cooled down to 18 K within 19 hours. The supercritical hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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DEVELOPMENT OF THE CRYOGENIC HYDROGEN SYSTEM FOR A SPALLATION NEUTRTON SOURCE IN J‐PARC
2010Co-Authors: Hideki Tatsumoto, H Sakurayama, T. Uehara, Kohei Ohtsu, Y. Kawakami, T. Kato, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical hydrogen at around 20 K and 1.5 MPa was selected as a Moderator Material in JSNS. Three kinds of hydrogen Moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the Moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The cryogenic hydrogen system, where the hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical hydrogen for the Moderators and absorbs nuclear heating in the Moderators. The off‐beam commissioning has confirmed that the cryogenic hydrogen system can be cooled down to 18 K within 19 hours. The supercritical hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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Development of a simulation code for a cool-down process of the cryogenic hydrogen system
2010Co-Authors: Hideki Tatsumoto, Kohei Ohtsu, T. Kato, Masatoshi FutakawaAbstract:Supercritical hydrogen with a pressure of 1.5 MPa and a temperature of 20 K has been selected as a Moderator Material in an intense spallation neutron source (JSNS), which is one of main experimental facilities in J‐PARC. The cryogenic hydrogen system, in which a hydrogen circulation system is cooled by a helium refrigerator with the refrigeration power of 6.45 kW at 15.5 K, has been designed to provide the supercritical hydrogen to the Moderator and to remove the nuclear heating generated there. In this study, we have developed a simulation code that predicts temperature behaviors in the hydrogen circulation system during its cool‐down process. Cool‐down process analyses have been performed, and an operational method for the cool‐down process has been studied. The analytical results indicate that the hydrogen circulation system would be able to be cooled down to 18 K within 19 hours.
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DEVELOPMENT OF A SIMULATION CODE FOR A COOL‐DOWN PROCESS OF THE CRYOGENIC HYDROGEN SYSTEM
2010Co-Authors: Hideki Tatsumoto, Kohei Ohtsu, T. Kato, Masatoshi FutakawaAbstract:Supercritical hydrogen with a pressure of 1.5 MPa and a temperature of 20 K has been selected as a Moderator Material in an intense spallation neutron source (JSNS), which is one of main experimental facilities in J‐PARC. The cryogenic hydrogen system, in which a hydrogen circulation system is cooled by a helium refrigerator with the refrigeration power of 6.45 kW at 15.5 K, has been designed to provide the supercritical hydrogen to the Moderator and to remove the nuclear heating generated there. In this study, we have developed a simulation code that predicts temperature behaviors in the hydrogen circulation system during its cool‐down process. Cool‐down process analyses have been performed, and an operational method for the cool‐down process has been studied. The analytical results indicate that the hydrogen circulation system would be able to be cooled down to 18 K within 19 hours.
Masatoshi Futakawa - One of the best experts on this subject based on the ideXlab platform.
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development of the cryogenic hydrogen system for a spallation neutrton source in j parc
TRANSACTIONS OF THE CRYOGENIC ENGINEERING CONFERENCE—CEC: Advances in Cryogenic Engineering, 2010Co-Authors: Hideki Tatsumoto, H Sakurayama, T. Uehara, Kohei Ohtsu, Y. Kawakami, T. Kato, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical hydrogen at around 20 K and 1.5 MPa was selected as a Moderator Material in JSNS. Three kinds of hydrogen Moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the Moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The cryogenic hydrogen system, where the hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical hydrogen for the Moderators and absorbs nuclear heating in the Moderators. The off‐beam commissioning has confirmed that the cryogenic hydrogen system can be cooled down to 18 K within 19 hours. The supercritical hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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DEVELOPMENT OF THE CRYOGENIC HYDROGEN SYSTEM FOR A SPALLATION NEUTRTON SOURCE IN J‐PARC
2010Co-Authors: Hideki Tatsumoto, H Sakurayama, T. Uehara, Kohei Ohtsu, Y. Kawakami, T. Kato, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical hydrogen at around 20 K and 1.5 MPa was selected as a Moderator Material in JSNS. Three kinds of hydrogen Moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the Moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The cryogenic hydrogen system, where the hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical hydrogen for the Moderators and absorbs nuclear heating in the Moderators. The off‐beam commissioning has confirmed that the cryogenic hydrogen system can be cooled down to 18 K within 19 hours. The supercritical hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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Development of a simulation code for a cool-down process of the cryogenic hydrogen system
2010Co-Authors: Hideki Tatsumoto, Kohei Ohtsu, T. Kato, Masatoshi FutakawaAbstract:Supercritical hydrogen with a pressure of 1.5 MPa and a temperature of 20 K has been selected as a Moderator Material in an intense spallation neutron source (JSNS), which is one of main experimental facilities in J‐PARC. The cryogenic hydrogen system, in which a hydrogen circulation system is cooled by a helium refrigerator with the refrigeration power of 6.45 kW at 15.5 K, has been designed to provide the supercritical hydrogen to the Moderator and to remove the nuclear heating generated there. In this study, we have developed a simulation code that predicts temperature behaviors in the hydrogen circulation system during its cool‐down process. Cool‐down process analyses have been performed, and an operational method for the cool‐down process has been studied. The analytical results indicate that the hydrogen circulation system would be able to be cooled down to 18 K within 19 hours.
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DEVELOPMENT OF A SIMULATION CODE FOR A COOL‐DOWN PROCESS OF THE CRYOGENIC HYDROGEN SYSTEM
2010Co-Authors: Hideki Tatsumoto, Kohei Ohtsu, T. Kato, Masatoshi FutakawaAbstract:Supercritical hydrogen with a pressure of 1.5 MPa and a temperature of 20 K has been selected as a Moderator Material in an intense spallation neutron source (JSNS), which is one of main experimental facilities in J‐PARC. The cryogenic hydrogen system, in which a hydrogen circulation system is cooled by a helium refrigerator with the refrigeration power of 6.45 kW at 15.5 K, has been designed to provide the supercritical hydrogen to the Moderator and to remove the nuclear heating generated there. In this study, we have developed a simulation code that predicts temperature behaviors in the hydrogen circulation system during its cool‐down process. Cool‐down process analyses have been performed, and an operational method for the cool‐down process has been studied. The analytical results indicate that the hydrogen circulation system would be able to be cooled down to 18 K within 19 hours.
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pressure fluctuation behavior in the cryogenic hydrogen system caused by a 100 kw proton beam injection
TRANSACTIONS OF THE CRYOGENIC ENGINEERING CONFERENCE—CEC: Advances in Cryogenic Engineering, 2010Co-Authors: Hideki Tatsumoto, H Sakurayama, T. Uehara, Kohei Ohtsu, Y. Kawakami, T. Kato, S. Hasegawa, Masatoshi FutakawaAbstract:Supercritical hydrogen (1.5 MPa and around 20 K) has been selected as a Moderator Material for the intense spallation neutron source (JSNS) in J‐PARC. The cryogenic hydrogen system provides the supercritical hydrogen for the Moderators and removes the nuclear heating at the Moderators, which is estimated to be 3.8 kW for a proton beam power of 1 MW. The pressure control system was designed to mitigate pressure fluctuation caused by suddenly turning a proton beam on and off, which is composed of a heater as an active controller for thermal compensation and an accumulator as a passive volume controller. A 109 kW proton beam was injected to the JSNS in December 2007. The pressure fluctuation behaviors were studied for the 109 kW proton beam operation. As soon as the proton beam was injected, the accumulator spontaneously started to constrict. The heater control succeeded in maintaining a constant heat load applied to the cryogenic hydrogen system. The pressure control system successfully reduced the pressure...
T. Kato - One of the best experts on this subject based on the ideXlab platform.
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development of the cryogenic hydrogen system for a spallation neutrton source in j parc
TRANSACTIONS OF THE CRYOGENIC ENGINEERING CONFERENCE—CEC: Advances in Cryogenic Engineering, 2010Co-Authors: Hideki Tatsumoto, H Sakurayama, T. Uehara, Kohei Ohtsu, Y. Kawakami, T. Kato, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical hydrogen at around 20 K and 1.5 MPa was selected as a Moderator Material in JSNS. Three kinds of hydrogen Moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the Moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The cryogenic hydrogen system, where the hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical hydrogen for the Moderators and absorbs nuclear heating in the Moderators. The off‐beam commissioning has confirmed that the cryogenic hydrogen system can be cooled down to 18 K within 19 hours. The supercritical hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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DEVELOPMENT OF THE CRYOGENIC HYDROGEN SYSTEM FOR A SPALLATION NEUTRTON SOURCE IN J‐PARC
2010Co-Authors: Hideki Tatsumoto, H Sakurayama, T. Uehara, Kohei Ohtsu, Y. Kawakami, T. Kato, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical hydrogen at around 20 K and 1.5 MPa was selected as a Moderator Material in JSNS. Three kinds of hydrogen Moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the Moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The cryogenic hydrogen system, where the hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical hydrogen for the Moderators and absorbs nuclear heating in the Moderators. The off‐beam commissioning has confirmed that the cryogenic hydrogen system can be cooled down to 18 K within 19 hours. The supercritical hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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Development of a simulation code for a cool-down process of the cryogenic hydrogen system
2010Co-Authors: Hideki Tatsumoto, Kohei Ohtsu, T. Kato, Masatoshi FutakawaAbstract:Supercritical hydrogen with a pressure of 1.5 MPa and a temperature of 20 K has been selected as a Moderator Material in an intense spallation neutron source (JSNS), which is one of main experimental facilities in J‐PARC. The cryogenic hydrogen system, in which a hydrogen circulation system is cooled by a helium refrigerator with the refrigeration power of 6.45 kW at 15.5 K, has been designed to provide the supercritical hydrogen to the Moderator and to remove the nuclear heating generated there. In this study, we have developed a simulation code that predicts temperature behaviors in the hydrogen circulation system during its cool‐down process. Cool‐down process analyses have been performed, and an operational method for the cool‐down process has been studied. The analytical results indicate that the hydrogen circulation system would be able to be cooled down to 18 K within 19 hours.
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DEVELOPMENT OF A SIMULATION CODE FOR A COOL‐DOWN PROCESS OF THE CRYOGENIC HYDROGEN SYSTEM
2010Co-Authors: Hideki Tatsumoto, Kohei Ohtsu, T. Kato, Masatoshi FutakawaAbstract:Supercritical hydrogen with a pressure of 1.5 MPa and a temperature of 20 K has been selected as a Moderator Material in an intense spallation neutron source (JSNS), which is one of main experimental facilities in J‐PARC. The cryogenic hydrogen system, in which a hydrogen circulation system is cooled by a helium refrigerator with the refrigeration power of 6.45 kW at 15.5 K, has been designed to provide the supercritical hydrogen to the Moderator and to remove the nuclear heating generated there. In this study, we have developed a simulation code that predicts temperature behaviors in the hydrogen circulation system during its cool‐down process. Cool‐down process analyses have been performed, and an operational method for the cool‐down process has been studied. The analytical results indicate that the hydrogen circulation system would be able to be cooled down to 18 K within 19 hours.
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pressure fluctuation behavior in the cryogenic hydrogen system caused by a 100 kw proton beam injection
TRANSACTIONS OF THE CRYOGENIC ENGINEERING CONFERENCE—CEC: Advances in Cryogenic Engineering, 2010Co-Authors: Hideki Tatsumoto, H Sakurayama, T. Uehara, Kohei Ohtsu, Y. Kawakami, T. Kato, S. Hasegawa, Masatoshi FutakawaAbstract:Supercritical hydrogen (1.5 MPa and around 20 K) has been selected as a Moderator Material for the intense spallation neutron source (JSNS) in J‐PARC. The cryogenic hydrogen system provides the supercritical hydrogen for the Moderators and removes the nuclear heating at the Moderators, which is estimated to be 3.8 kW for a proton beam power of 1 MW. The pressure control system was designed to mitigate pressure fluctuation caused by suddenly turning a proton beam on and off, which is composed of a heater as an active controller for thermal compensation and an accumulator as a passive volume controller. A 109 kW proton beam was injected to the JSNS in December 2007. The pressure fluctuation behaviors were studied for the 109 kW proton beam operation. As soon as the proton beam was injected, the accumulator spontaneously started to constrict. The heater control succeeded in maintaining a constant heat load applied to the cryogenic hydrogen system. The pressure control system successfully reduced the pressure...
Kohei Ohtsu - One of the best experts on this subject based on the ideXlab platform.
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Performance evaluation of a developed orifice type heater for thermal compensation control at J-PARC cryogenic hydrogen system
IOP Conference Series: Materials Science and Engineering, 2015Co-Authors: Hideki Tatsumoto, Kohei Ohtsu, Y. KawakamiAbstract:Supercritical hydrogen with a temperature of less than 20 K and a pressure of 1.5 MPa is used as Moderator Material at J-PARC. Total nuclear heating of 3.75 kW is generated by three Moderators for a 1-MW proton beam operation. We have developed an orifice-type high-power heater for thermal compensation to mitigate hydrogen pressure fluctuation caused by the abrupt huge heat load and to reduce the fluctuation in the temperature of the supply hydrogen to less than 0.25 K. Through a performance test, we confirmed that the developed orifice-type heater could be heated uniformly and showed fast response, as expected. Furthermore, a simulation model that can describe heater behaviors has been established on the basis of the experimental data. The heater control approach was studied using the aforementioned heater simulation model and a dynamic simulation code developed by the authors.
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development of the cryogenic hydrogen system for a spallation neutrton source in j parc
TRANSACTIONS OF THE CRYOGENIC ENGINEERING CONFERENCE—CEC: Advances in Cryogenic Engineering, 2010Co-Authors: Hideki Tatsumoto, H Sakurayama, T. Uehara, Kohei Ohtsu, Y. Kawakami, T. Kato, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical hydrogen at around 20 K and 1.5 MPa was selected as a Moderator Material in JSNS. Three kinds of hydrogen Moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the Moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The cryogenic hydrogen system, where the hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical hydrogen for the Moderators and absorbs nuclear heating in the Moderators. The off‐beam commissioning has confirmed that the cryogenic hydrogen system can be cooled down to 18 K within 19 hours. The supercritical hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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DEVELOPMENT OF THE CRYOGENIC HYDROGEN SYSTEM FOR A SPALLATION NEUTRTON SOURCE IN J‐PARC
2010Co-Authors: Hideki Tatsumoto, H Sakurayama, T. Uehara, Kohei Ohtsu, Y. Kawakami, T. Kato, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical hydrogen at around 20 K and 1.5 MPa was selected as a Moderator Material in JSNS. Three kinds of hydrogen Moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the Moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The cryogenic hydrogen system, where the hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical hydrogen for the Moderators and absorbs nuclear heating in the Moderators. The off‐beam commissioning has confirmed that the cryogenic hydrogen system can be cooled down to 18 K within 19 hours. The supercritical hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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Development of a simulation code for a cool-down process of the cryogenic hydrogen system
2010Co-Authors: Hideki Tatsumoto, Kohei Ohtsu, T. Kato, Masatoshi FutakawaAbstract:Supercritical hydrogen with a pressure of 1.5 MPa and a temperature of 20 K has been selected as a Moderator Material in an intense spallation neutron source (JSNS), which is one of main experimental facilities in J‐PARC. The cryogenic hydrogen system, in which a hydrogen circulation system is cooled by a helium refrigerator with the refrigeration power of 6.45 kW at 15.5 K, has been designed to provide the supercritical hydrogen to the Moderator and to remove the nuclear heating generated there. In this study, we have developed a simulation code that predicts temperature behaviors in the hydrogen circulation system during its cool‐down process. Cool‐down process analyses have been performed, and an operational method for the cool‐down process has been studied. The analytical results indicate that the hydrogen circulation system would be able to be cooled down to 18 K within 19 hours.
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DEVELOPMENT OF A SIMULATION CODE FOR A COOL‐DOWN PROCESS OF THE CRYOGENIC HYDROGEN SYSTEM
2010Co-Authors: Hideki Tatsumoto, Kohei Ohtsu, T. Kato, Masatoshi FutakawaAbstract:Supercritical hydrogen with a pressure of 1.5 MPa and a temperature of 20 K has been selected as a Moderator Material in an intense spallation neutron source (JSNS), which is one of main experimental facilities in J‐PARC. The cryogenic hydrogen system, in which a hydrogen circulation system is cooled by a helium refrigerator with the refrigeration power of 6.45 kW at 15.5 K, has been designed to provide the supercritical hydrogen to the Moderator and to remove the nuclear heating generated there. In this study, we have developed a simulation code that predicts temperature behaviors in the hydrogen circulation system during its cool‐down process. Cool‐down process analyses have been performed, and an operational method for the cool‐down process has been studied. The analytical results indicate that the hydrogen circulation system would be able to be cooled down to 18 K within 19 hours.
L.a. Charlton - One of the best experts on this subject based on the ideXlab platform.
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Moderator Materials for the Spallation Neutron Source
Transactions of the American Nuclear Society, 1999Co-Authors: L.a. CharltonAbstract:The Spallation Neutron Source (SNS) is a neutron source providing intense neutron fluxes that will be used for performing a large variety of neutron scattering experiments. SNS is to be completed and start operation in 2005. Protons will be accelerated to 1 GeV, stored in an accumulator ring, and then injected into a neutron-producing target. After leaving the target (Hg in the ca/se of SNS), the neutrons are prepared for experiments by first using a Moderator to impose energy and width requirements on the neutron pulse. One of the most important ingredients is the Moderator Material. Four Materials that are commonly used and that were considered for use in SNS are liquid hydrogen (L-H{sub 2}), liquid water (L-H{sub 2}O), liquid methane (L-CH{sub 4}), and solid methane (S-CH{sub 4}). The spectra (neutron current versus neutron energy) for these four Materials are shown. As may be seen, at low neutron energies (
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Initial neutronic target station studies for the national spallation neutron source (NSNS)
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 1997Co-Authors: L.a. Charlton, J.m. Barnes, T. A. Gabriel, J.o. Johnson, John M. Carpenter, R.k. CrawfordAbstract:Abstract Results found during initial NSNS target station neutronic design efforts are reported including the success of comparing neutron sources at 1 eV and Moderator performance normalized to 1 eV. The usefulness of an analytic form is demonstrated. The angular dependence of the neutron current from a Moderator face is presented together with the changes in neutron current with variation of Moderator width, poison plate location and Moderator Material. The formation of an equilibrium state at low neutron energy is also discussed.