HTR-Based Power Plants’ Performance Analysis Applied on Conventional Combined Cycles

José Carbia Carril,Manuel Romero Gómez,Javier Romero Gómez,Álvaro Baaliña Insua

doi:10.1155/2015/716572

José Carbia Carril, Manuel Romero Gómez + Show 2 more

Open Access

https://doi.org/10.1155/2015/716572

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Abstract

In high temperature reactors including gas cooled fast reactors and gas turbine modular helium reactors (GT-MHR) specifically designed to operate as power plant heat sources, efficiency enhancement at effective cost under safe conditions can be achieved. Mentioned improvements concern the implementation of two cycle structures: (a), a stand alone Brayton operating with helium and a stand alone Rankine cycle (RC) with regeneration, operating with carbon dioxide at ultrasupercritical pressure as working fluid (WF), where condensation is carried out at quasicritical conditions, and (b), a combined cycle (CC), in which the topping closed Brayton cycle (CBC) operates with helium as WF, while the bottoming RC is operated with one of the following WFs: carbon dioxide, xenon, ethane, ammonia, or water. In both cases, an intermediate heat exchanger (IHE) is proposed to provide thermal energy to the closed Brayton or to the Rankine cycles. The results of the case study show that the thermal efficiency, through the use of a CC, is slightly improved (from 45.79% for BC and from 50.17% for RC to 53.63 for the proposed CC with He-H2O operating under safety standards).

Highlights

The main stimulus for applying nuclear energy to large thermal energy conversion plants is a result of the evermore increasing costs of fossil fuels along with the very restrictive emissions regulations
Mentioned improvements concern the implementation of two cycle structures: (a), a Rankine cycle (RC) with regeneration operated with carbon dioxide at ultrasupercritical pressure as the working fluid (WF), where condensation is carried out at quasicritical conditions, and (b), a combined cycle (CC), in which the topping closed Brayton cycle (CBC) operates with helium as the WF, while the bottoming RC is alternatively operated with carbon dioxide, xenon, ethane, water, or ammonia at ultrasupercritical pressure and quasicritical conditions
A research work focused on the performance analysis of conventional CC operating with helium at the topping BC and carbon dioxide, xenon, ethane, ammonia or water for the bottoming RC, powered by an High temperature reactors (HTRs) has been performed

Summary

Introduction

The main stimulus for applying nuclear energy to large thermal energy conversion plants is a result of the evermore increasing costs of fossil fuels along with the very restrictive emissions regulations. The reactor is helium cooled, with an outlet temperature of 1123 K and using a direct BC gas turbine for high thermal efficiency. The authors of [8] are working on a program consisting in the design of a helium based gas cooled GTMHR plant and R&D on a closed-cycle helium gas turbine system for the existing GT-MHR designed to operate with an outlet coolant temperature of 1123 K. A novel type of nuclear power plant for thermal to electric energy conversion has been recently proposed, known as the gas turbine modular helium reactor (GT-MHR). In this type of reactor, the heat of reaction is transferred to a WF (helium) which drives a gas turbine coupled to an electric alternator. The carried out design study aims to develop higher efficient CC architectures without significant modifications of the basic proven technologies

Proposed GT-MHR Power Plant Architectures

Cycle Efficiency

Findings

Case Studies

Discussion of Results and Conclusions