Conceptual design of hydrogen production system with thermochemical water-splitting iodine–sulphur process utilizing heat from the high-temperature gas-cooled reactor HTTR

Sakaba, Nariaki; Kasahara, Seiji; Onuki, Kaoru; Kunitomi, Kazuhiko

doi:10.1016/j.ijhydene.2007.06.005

Cited by 76 publications

(34 citation statements)

References 7 publications

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“…For this analysis, T s,1 is the temperature at a point very close to the pebble center (r 1 = 0.000001) and T s,2 is the fuel pebble surface temperature. Rearranging the terms in Equation , one can approximate the temperature difference, ΔΤ, as shown in Equation (2)(3). (2)(3) The reference model that is used in this research is based on the 268 MWth power PBMR (Reitsma, 2004).…”

Section: Central Ring Near Bottommentioning

confidence: 99%

“…Rearranging the terms in Equation , one can approximate the temperature difference, ΔΤ, as shown in Equation (2)(3). (2)(3) The reference model that is used in this research is based on the 268 MWth power PBMR (Reitsma, 2004). The number of fuel pebbles in the core is estimated to be 330,000 pebbles (Nichols, 2001).…”

Section: Central Ring Near Bottommentioning

confidence: 99%

“…The maximum temperatures are more likely to occur where the power profile is the highest in the core and the coolant has the highest temperature or lowest flow rate. Heat rate generated per pebble can be approximated by dividing the total generated power by the number of fuel pebbles (Equation (2)(3)(4) …”

Section: Central Ring Near Bottommentioning

confidence: 99%

“…The thermal conductivity for the fuel in a PBMR can be calculated as a function fuel temperature using the correlation by in Equation (2)(3)(4)(5). This is an empirical correlation for an average fuel thermal conductivity for fuel pebbles in a packed bed as a function of fuel temperature.…”

Section: Central Ring Near Bottommentioning

confidence: 99%

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Development of design and simulation model and safety study of large-scale hydrogen production using nuclear power.

Gelbard¹,

Rodríguez³

et al. 2007

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Before this LDRD research, no single tool could simulate a very high temperature reactor (VHTR) that is coupled to a secondary system and the sulfur iodine (SI) thermochemistry. Furthermore, the SI chemistry could only be modeled in steady state, typically via flow sheets. Additionally, the MELCOR nuclear reactor analysis code was suitable only for the modeling of light water reactors, not gas-cooled reactors. We extended MELCOR in order to address the above deficiencies. In particular, we developed three VHTR input models, added generalized, modular secondary system components, developed reactor point kinetics, included transient thermochemistry for the most important cycles [SI and the Westinghouse hybrid sulfur], and developed an interactive graphical user interface for full plant visualization. The new tool is called MELCOR-H2, and it allows users to maximize hydrogen and electrical production, as well as enhance overall plant safety. We conducted validation and verification studies on the key models, and showed that the MELCOR-H2 results typically compared to within less than 5% from experimental data, code-to-code comparisons, and/or analytical solutions.

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Section: Central Ring Near Bottommentioning

confidence: 99%

Section: Central Ring Near Bottommentioning

confidence: 99%

Section: Central Ring Near Bottommentioning

confidence: 99%

Section: Central Ring Near Bottommentioning

confidence: 99%

See 2 more Smart Citations

Development of design and simulation model and safety study of large-scale hydrogen production using nuclear power.

Gelbard¹,

Rodríguez³

et al. 2007

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“…6,7) JAEA has constructed Japan's first HTGR, the high-temperature engineering test reactor (HTTR), with a thermal output of 30 MW and an outlet coolant temperature of 950 C. 8,9) JAEA also has been developing a thermochemical water-splitting iodine-sulfur (IS) process, which can produce hydrogen from water at a temperature lower than 1000 C. 10,11) Since connecting the IS process to the HTGR can produce a large amount of hydrogen without CO 2 emission, this system is a promising candidate for CO 2 -free energy production. The HTTR-IS system 12) is planned as a coupling of the IS process with the HTTR in order to demonstrate hydrogen production with the HTGR and to obtain technical and capital cost data for such future commercial plants as the GTHTR-300C. 13) A serious concern in the HTGR hydrogen production system is tritium behavior in the system.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on Tritium Behavior by Using Isotope Exchange Reactions in Thermochemical Water-Splitting Iodine–Sulfur Process

Ohashi

Sakaba

Nishihara

et al. 2007

J. Nucl. Sci. Technol.

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One potential problem in the hydrogen production system coupled with the high-temperature gascooled reactor (HTGR) is transmission of tritium from the primary coolant to the product hydrogen by permeation through the heat transfer tubes. Tritium accumulation in the process chemicals in the components of a hydrogen plant, a thermochemical water-splitting iodine-sulfur (IS) process, will also be a critical issue in seeking to license the hydrogen plant as a non-nuclear plant in the future. A numerical analysis model for tritium behavior in the IS process was developed by considering the isotope exchange reactions between tritium and the hydrogen-containing process chemicals, i.e., H 2 O, H 2 SO 4 and HI. The tritium activity concentration in the IS process coupled with the high-temperature engineering test reactor (HTTR), the HTTR-IS system, was preliminarily evaluated in regard to the effects of some indeterminate parameters, i.e., equilibrium constants of the isotope exchange reactions, permeability of tritium through heat transfer tubes, tritium and hydrogen concentrations in the secondary helium coolant, and the leak rate from the secondary coolant loop. The results describing how the tritium activity concentration changes with variations in these parameters and which component has the maximum tritium activity concentration in the IS process are described in this paper.

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Equilibrium conversion and reaction analysis in sulfur‐iodine thermochemical hydrogen production cycle

2015

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Equilibrium conditions of the main reactions of the SI cycle were studied in this paper. The extent of reaction for two main reactions of this cycle including sulfuric acid decomposition and hydrogen iodide decomposition was evaluated as a function of temperature, pressure, and initial mole number of reactants. In the reaction modelling of sulfuric acid and sulfur trioxide decompositions, two models including simple and multiple reaction models were considered. In the simple model, it was assumed that two decomposition reactions proceeded independently. However, in the multiple reaction model, both reactions were considered simultamneously. It was shown that the Bunsen reaction completely proceeded in the range of operating conditions of the Bunsen reactor. Also, sulfuric acid was demonstrated to be decomposed at a higher rate when the reaction temperature and initial concentration of the sulfuric acid and sulfur trioxide increased. Furthermore, the operating pressure had to be maintained at lower values and the generated sulfur dioxide had to be withdrawn from the reactor in order to have a higher yield of product in this reactor. Finally, in the hydrogen iodide decomposition, the operating pressure, temperature, and concentration of hydrogen iodide had to be maintained at higher values to have a complete reaction. Moreover, the generated hydrogen was shown to be withdrawn from the hydrogen iodide reactor to prevent from backward reaction.

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Conceptual design of hydrogen production system with thermochemical water-splitting iodine–sulphur process utilizing heat from the high-temperature gas-cooled reactor HTTR

Cited by 76 publications

References 7 publications

Development of design and simulation model and safety study of large-scale hydrogen production using nuclear power.

Development of design and simulation model and safety study of large-scale hydrogen production using nuclear power.

Numerical Study on Tritium Behavior by Using Isotope Exchange Reactions in Thermochemical Water-Splitting Iodine–Sulfur Process

Equilibrium conversion and reaction analysis in sulfur‐iodine thermochemical hydrogen production cycle

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