Final Technical Report for the Period September 2002 through September 2005; H2-MHR Pre-Conceptual Design Report: SI-Based Plant; H2-MHR Pre-Conceptual Design Report: HTE-Based Plant

Richards, Matt; Shenoy, A.; Brown, L. C.; Buckingham, Robert; Harvego, Edwin A.; Peddicord, K.L.; Reza, Md. Selim; Coupey, Jean-Phillippe

doi:10.2172/881286

Cited by 4 publications

(8 citation statements)

References 8 publications

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“…Plant equipment costs summarized in Table 10 include equipment costs for both the nuclear island and the hydrogen production plant. As indicated in the table, the nuclear equipment costs are based on estimates developed by General Atomics in the referenced pre-conceptual design report [9]. For the nuclear equipment, an installation factor (the factor by which the uninstalled equipment costs are multiplied to arrive at the installed equipment cost) of 1.35 was used based on an interpretation of information in the General Atomics pre-conceptual design report.…”

Section: Input To H2a Lifecycle Analysismentioning

confidence: 99%

Economic Analysis of the Reference Design for a Nuclear-Driven High-Temperature-Electrolysis Hydrogen Production Plant

Harvego¹,

McKellar²,

Sohal³

et al. 2008

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A reference design for a commercial-scale high-temperature electrolysis (HTE) plant for hydrogen production was developed to provide a basis for comparing the HTE concept with other hydrogen production concepts. The reference plant design is driven by a high-temperature helium-cooled reactor coupled to a direct Brayton power cycle. The reference design reactor power is 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 540°C and 900°C, respectively. The electrolysis unit used to produce hydrogen consists of 4,009,177 cells with a per-cell active area of 225 cm 2 . A nominal cell area-specific resistance, ASR, value of 0.4 Ohm·cm 2 with a current density of 0.25 A/cm 2 was used, and isothermal boundary conditions were assumed. The optimized design for the reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes an air-sweep system to remove the excess oxygen that is evolved on the anode side of the electrolyzer. The inlet air for the air-sweep system is compressed to the system operating pressure of 5.0 MPa in a four-stage compressor with intercooling. The alternating-current to direct-current conversion efficiency is assumed to be 96%. The overall system thermal-to-hydrogen production efficiency (based on the low heating value of the produced hydrogen) is 47.12% at a hydrogen production rate of 2.356 kg/s.An economic analysis of the plant was also performed using the H2A Analysis Methodology developed by the Department of Energy (DOE) Hydrogen Program. The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a competitive cost using realistic financial and cost estimating assumptions. A plant-gate cost of $3.23 per kg of hydrogen produced was calculated assuming an internal rate of return of 10%. Approximately 73% of this cost ($2.36/kg) is the result of capital costs associated with the construction of the combined nuclear plant and hydrogen production facility. Operation and maintenance costs represent about 18% of the total cost ($0.57/kg). Variable costs (including the cost of nuclear fuel) contribute about 8.7% ($0.28/kg) to the total cost of hydrogen production, and decommissioning and raw material costs make up the remaining fractional cost.iii

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Section: Input To H2a Lifecycle Analysismentioning

confidence: 99%

Economic Analysis of the Reference Design for a Nuclear-Driven High-Temperature-Electrolysis Hydrogen Production Plant

Harvego¹,

McKellar²,

Sohal³

et al. 2008

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“…The tritium permeation rate reported by Richards et al (2006) is less than that of the as-received superheater tube of the Peach Bottom HTGR by a factor of about 0.5. Permeability reported by Richards et al (2006) includes the effect of surface film formed by steam. …”

Section: Heat Exchangermentioning

confidence: 74%

“…However, the core will include regions that operate at temperatures greater than 1,000°C for significant periods of time. The fractional tritium release is expected to be about 0.2 if fuel is maintained at 1,300°C for 100 days (Richards et al 2006).…”

Section: Tritium Birth and Release Ratementioning

confidence: 99%

“…The tritium permeation rate of Incoloy 800 was also described by Richards et al (2006) when calculating the permeation rate at the IHX as follows: …”

Section: Heat Exchangermentioning

confidence: 99%

“…However, an SI process flowsheet employing reactive distillation instead of the current extractive distillation is available (Richards et al, 2006) and is the one employed in this study. Figures 60, 61, and 62 show the SI process flowsheet: Section 1 for Bunsen reaction, Section 2 for sulfuric acid decomposition, and Section 3 for hydrogen iodine decomposition, respectively.…”

Section: And (80)mentioning

confidence: 99%

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Tritium Movement and Accumulation in the NGNP System Interface and Hydrogen Plant

Ohashi¹,

Sherman²

2007

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Tritium movement and accumulation in a Next Generation Nuclear Plant with a hydrogen plant using a high-temperature electrolysis (HTE) process and a thermochemical water-splitting Sulfur-Iodine (SI) process are estimated by the numerical code THYTAN as a function of design, operational, and material parameters. Estimated tritium concentrations in the hydrogen product and in process chemicals in the hydrogen plant of the Next Generation Nuclear Plant using the HTE process are slightly higher than the drinking water limit defined by the U.S. Environmental Protection Agency and the limit in the effluent at the boundary of an unrestricted area of a nuclear plant as defined by the U.S. Nuclear Regulatory Commission. However, these concentrations can be reduced to within the limits through use of some designs and modified operations. Tritium concentrations in the Next Generation Nuclear Plant using the SI process are significantly higher as calculated and are affected by parameters with large uncertainties (i.e., tritium permeability of the process heat exchanger, the hydrogen concentration in the heat transfer and process fluids, the equilibrium constant of the isotope exchange reaction between HT and H 2 SO 4 ). These parameters, including tritium generation and the release rate in the reactor core, should be more accurately estimated in the near future to improve the calculations for the NGNP using the SI process. Decreasing the tritium permeation through the heat exchanger between the primary and secondary circuits may be an an effective measure for decreasing tritium concentrations in the hydrogen product, the hydrogen plant, and the tertiary coolant.iv v EXECUTIVE SUMMARYThis study evaluated tritium concentrations in the hydrogen product and in process chemicals in the energy transport systems and the hydrogen plant associated with the Next Generation Nuclear Plant (NGNP). In this work, tritium generation and transport mechansisms in the NGNP are described. The mathematics of these mechanisms are outlined, and are then codified and analyzed using a Japan Atomic Energy Agency (JAEA) analysis code called THYTAN [Tritium and HYdrogen Transportation ANalysis code ]. As a preliminary step, the THYTAN code was benchmarked against data available from the Peach Bottom HTGR. After benchmarking, various configurations of the NGNP employing a hightemperature electrolysis (HTE) hydrogen plant and an NGNP employing a Sulfur-Iodine (SI) hydrogen plant were analyzed, and the concentrations of tritium in the process and product streams were compared to current regulatory effluent limits in ground water and in air.Tritium is generated in the core of the reactor from the ternary fission of nuclear fuel (e.g., e.g., 233 B. Tritium from these reactions diffuses from the core materials into the primary coolant, where it can migrate to other parts of the system through bulk transport, diffusion, and isotope exchange mechanisms. Tritium is lost from the system when it diffuses through barrier materials to the outside environ...

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Scoping Analyses on Tritium Permeation to VHTR Integarted Industrial Application Systems

Oh¹,

Kim²

2011

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EXECUTIVE SUMMARYTritium permeation is currently an important issue in the development of the Very High Temperature Reactor (VHTR) because tritium is easily permeated through high temperature metallic surfaces. Tritium permeation in VHTR-integrated systems was investigated in this study using the tritium permeation analysis code (TPAC) that was developed by Idaho National Laboratory (INL). The INL TPAC is a numerical tool based on the mass balance equations of tritium-containing species and hydrogen (i.e., HT, H 2 , and HTO) coupled with a variety of tritium sources, sink, and permeation models. In the TPAC, ternary fission and thermal neutron caption reactions with 6 Li, 7 Li 10 B, 3 He were taken into consideration as tritium sources. Purification and leakage models were implemented as main tritium sinks. Permeation of tritium and H 2 through pipes, vessels, and heat exchangers were considered as main tritium transport paths. In addition, electrolyzer and isotope exchange models were developed for analyzing hydrogen production systems including high-temperature steam electrolysis (HTSE) and sulfur-iodine processes.Three different systems were considered in this study: (1) the VHTR (gas Brayton cycle)/HTSE system, (2) the high-temperature gas-cooled reactor (HTGR) (steam Rankin cycle)/HTSE system, and (3) the HTGR (steam Rankin cycle)/methanol-to-gasoline (MTG) System. The VHTR/HTSE system is based on the VHTR design with a 900qC core outlet temperature and a Brayton cycle. The VHTR provides heat and electricity to the HTSE system for generating hydrogen. The HTGR/HTSE system is based on the HTGR design with a 750qC core outlet temperature and steam Rankin power cycle. The HTGR provides heat and electricity to the HTSE system for hydrogen production. As part of the nuclear-assisted industry process application, the VHTR was coupled with the MTG process. The VHTR/MTG system is also based on the 750qC core outlet temperature and the steam Rankin cycle. However, the VHTR provides only heat to the MTG system for generating gasoline and natural gas. This scoping study is focused on the following areas without tritium barriers:x Tritium concentrations in the industrial final products x Tritium distributions in the entire coupled system x Identification of important factors affecting tritium permeation and distributions.Global sensitivity analysis techniques were used in this study based on the variance decomposition and the Monte Carlo method. Two sensitivity indices were considered as importance measures: the first order index and the total index. The first order index was used for quantifying the main effect, and the total index was used for quantifying the total effect including interactions. More than 15,000 random samples were used for each case. As a result, important parameters were identified and well quantified with their rankings.This report presents preliminary results along with the Monte Carlo-based sensitivity for three nuclear-assisted process applications: VHTR/HTSE, HTGR/HTSE, HTGR/MTG, and HTGR/Impr...

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Final Technical Report for the Period September 2002 through September 2005; H2-MHR Pre-Conceptual Design Report: SI-Based Plant; H2-MHR Pre-Conceptual Design Report: HTE-Based Plant

Cited by 4 publications

References 8 publications

Economic Analysis of the Reference Design for a Nuclear-Driven High-Temperature-Electrolysis Hydrogen Production Plant

Economic Analysis of the Reference Design for a Nuclear-Driven High-Temperature-Electrolysis Hydrogen Production Plant

Tritium Movement and Accumulation in the NGNP System Interface and Hydrogen Plant

Scoping Analyses on Tritium Permeation to VHTR Integarted Industrial Application Systems

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