Preliminary analysis and design of the heat exchangers for the Molten Salt Fast Reactor

The unique design features of the molten salt fast reactor (MSFR) should enable higher coolant temperatures than in conventional water reactors, with a significant improvement in the achievable thermodynamic performance. The use of a molten salt as both fuel and coolant, however, poses several advanced heat transfer challenges, such as the design of innovative heat exchangers and energy conversion systems. In this work, we address a preliminary but quantitative analysis of the energy conversion system for the MSFR, based on reference design data from the SAMOFAR H2020-EURATOM project. We consider three main technologies, i.e., the supercritical steam cycle, the closed helium cycle and the helium/steam combined cycle. Preliminary design results are presented for each technology, based on a simplified modelling approach. The considered cycles show promising efficiency improvements, with the best performance being proven by the supercritical steam cycle. The analysis also highlights the critical issue related to the risk of freezing of the molten salts within the secondary heat exchangers, due to the low inlet temperatures of the working fluids. Results show potential incompatibility between the freezing point of molten salts and the temperatures typical of steam cycles, while helium cycles offer the best chances of freezing avoidance. The combined cycle promises intermediate performance in terms of thermodynamic efficiency and thermal compatibility with molten salts comparable with closed helium cycles.

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Heat exchanger design studies for molten salt fast reactor

EPJ Nuclear Sciences & Technologies ◽

10.1051/epjn/2019032 ◽

2019 ◽

Vol 5 ◽

pp. 12

Author(s):

Uğur Köse ◽

Ufuk Koç ◽

Latife Berrin Erbay ◽

Erdem Öğüt ◽

Hüseyin Ayhan

Keyword(s):

Heat Exchanger ◽

Molten Salt ◽

Fast Reactor ◽

Heat Exchangers ◽

Temperature Drop ◽

Freezing Temperature ◽

Fuel Temperature ◽

Design Studies ◽

The Core ◽

Heat Exchanger Design

In this study, conceptual design for primary heat exchanger of the Molten Salt Fast Reactor is made. The design was carried out to remove the produced heat from the reactor developed under the SAMOFAR project. Nominal power of the reactor is 3 GWth and it has 16 heat exchangers. There are several requirements related to the heat exchanger. To sustain the steady-state conditions, heat exchangers have to transfer the heat produced in the core and it has to maintain the temperature drop as much as the temperature rise in the core due to the fission. It should do it as fast as possible. It must also ensure that the fuel temperature does not reach the freezing temperature to avoid solidification. In doing so, the fuel volume in the heat exchanger must not exceed the specified limit. Design studies were carried out taking into account all requirements and final geometric configurations were determined. Plate type heat exchanger was adopted in this study. 3D CFD analyses were performed to investigate the thermal-hydraulic behavior of the system. Analyses were made by ANSYS-Fluent commercial code. Results are in a good agreement with limitations and requirements specified for the reactor designed under the SAMOFAR project.

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Feasibility of Lead Fast Reactor Heat Exchanger Tube Online Monitoring

10.1115/qnde2021-76573 ◽

2021 ◽

Author(s):

S. W. Glass ◽

M. S. Good ◽

E. H. Hirt

Keyword(s):

Heat Exchanger ◽

Molten Salt ◽

Fast Reactor ◽

Heat Exchangers ◽

Management Approach ◽

Corrosion Monitoring ◽

Heat Exchanger Tube ◽

Torsional Mode ◽

Higher Temperature ◽

Exchanger Tube

Abstract Online structural health corrosion monitoring in advanced lead fast reactor heat exchangers and molten salt reactor heat exchangers is desirable for detecting tube degradation prior to leaks that may allow mixing of heat exchanger fluids or release of radiological contamination beyond the design containment boundary. This program demonstrates feasibility for a torsional mode sensor to attach to the outside of a long (30-m) heat-exchanger tube in the stagnant flow area where the tube joins the heat-exchanger plenum and where it is possible to protect a sensor and cable from high-force flows. The sensor must be connected by a cable to a monitoring instrument near the heat exchanger. The sensor and cable management approach will be impractical to implement on existing heat exchangers; rather, sensors must be installed in conjunction with heat exchanger fabrication. Previous work has shown the ability of low-temperature lead zirconate titanate (PZT) piezoceramic sensors to detect anomalies of interest in 3-m tubes. These sensors have subsequently been extended to a 30-m tube more representative of commercial power heat exchanger designs. The program will continue to investigate higher-temperature piezoelectric ceramics and long-term performance of high-temperature adhesives and sealants for 350 C lead reactor environments and higher-temperature (700 °C) molten salt environments.

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