Economic Analysis of a Nuclear Reactor Powered High-Temperature Electrolysis Hydrogen Production Plant

Abstract

A reference design for a commercial-scale hightemperature 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 nuclear reactor coupled to a direct Brayton power cycle. The reference design reactor power is 600 MW t , 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 includes 4,009,177 cells with a per-cell active area of 225 cm 2 . 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 (oxygen) 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 (AC) to direct-current (DC) conversion efficiency is 96%. The overall system thermal-to-hydrogen production efficiency (based on the lower heating value of the produced hydrogen) is 47.1% at a hydrogen production rate of 2.356 kg/s.An economic analysis of this plant was performed using the standardized H2A Analysis Methodology developed by the Department of Energy (DOE) Hydrogen Program, and using realistic financial and cost estimating assumptions. 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.A cost of $3.23/kg of hydrogen was calculated assuming an internal rate of return of 10%.

High Temperature Electrolysis for Hydrogen Production from Nuclear Energy ? TechnologySummary

“…Based on this methodology, and the various assumptions discussed in detail in reference [35], the estimated price of the hydrogen leaving the plant gate at 5 MPa pressure would be $3.23/kg. Several sensitivity analyses were performed to evaluate the impact of various economic assumptions on hydrogen lifecycle production costs.…”

“…A preliminary economic analysis has been performed to estimate the cost of hydrogen based on high-temperature electrolysis coupled to an advanced hightemperature gas-cooled reactor [35]. The reference HTE plant is driven by a 600 MW t high-temperature helium-cooled reactor coupled to a direct Brayton power cycle with a reactor outlet temperature of 900°C.…”

“…This parameter incorporates the loss mechanisms in the cells. The ASR value used in the electrolyzer module is temperature-dependent per the following Arrhenius equation: (35) where ASR 1100K represents the user-specified cell ASR at the temperature 1100 K (e.g., 0.25 or 1.25). This constant allows one to shift the entire ASR curve to higher or lower ASR values, to mimic lower or higher performing cells, respectively.…”

Hydrogen Co-Production From Subcritical Water-Cooled Nuclear Power Plants In Canada

“…Similar integration of a reference HTSEP into a high temperature gas-cooled nuclear reactor (HTGR) has been reported by Harvego et al [22] from Idaho National Laboratory. This helium-cooled reactor, with 7 MPa pressure and 750 o C at the outlet, is linked to a subcritical steam power cycle.…”

“…It should be noted that the HTSEP used by Harvego et al [22] is a slightly different system, with more thermal recuperation from the oxygen stream and a sweep gas arrangement that permits mixing of the oxygen stream with inert gas to reduce fire hazards. The size of the HTGR in Table 6 is smaller than a typical CANDU power reactor because the HTGR is a reactor dedicated for hydrogen production, while the Sub-WCR NPP (with a minimum of four reactor units) considered in this work is intended for co-production of hydrogen with electricity being the main product.…”