Analysis of advanced power conversion systems for flexible nuclear energy applications

Background

As efforts to build a fully decarbonized energy system continue, nuclear power is increasingly emerging as a cornerstone of clean electricity generation, supporting renewable fluctuating power. In 2024, 40% of electricity generation came from nuclear power (8%) and renewables (32%). Together, they supported 80% of the annual global growth in electricity generation, with 7 GW of new nuclear power brought online worldwide, a third more than in 2023. By the end of 2024, 75 GW of nuclear power was under construction, with an acceleration in annual capacity addition foreseen in all IEA future energy scenarios.

In this context, generation IV reactors have the potential to offer significant advantages to traditional light water reactors (LWRs), including enhanced sustainability, economics, reliability and safety, and proliferation resistance. Among the proposed technologies, molten salt reactors (MSRs) are attracting considerable attention from both industry and academia. In MSRs, either the coolant alone or the coolant and the fissile fuel are present in the form of a molten salt. A molten salt coolant offers the immediate advantage of operation close to atmospheric pressure even at elevated operating temperatures of up to 600°C, due to its high boiling point. In comparison with LWRs, this results in enhanced thermal efficiency, improved safety and the potential for enhanced economic efficiency due to the reduction in the thickness of the reactor vessels. Other advantages may include the capability to continuously remove fission gases from the coolant and to breed thorium to produce fuel, given that thorium is more abundant than uranium.

The future deployment of advanced nuclear technologies will be contingent on the technology readiness level and the economic viability of these solutions. The latter will also depend on the capability of MSRs to flexibly perform load variations in an energy system with high renewable penetration. In this context, the integration of advanced power conversion systems and nuclear-renewable hybrid energy systems that leverage thermal energy storage technologies has the potential to enhance the flexibility of MSR plants. This enhancement can be achieved while concurrently constraining rapid dynamics at the reactor level. Consequently, this approach can lead to an improvement in the economic and safety performance of the system.

Objective and goals

This thesis provides an opportunity to participate in a nationally funded research project. The objective is to analyse the technical feasibility of integrating advanced power cycles and thermal components, such as molten-salt-to-gas heat exchangers and thermal energy storage, with MSRs to create flexible nuclear energy solutions. The project will be conducted in cooperation with industrial partners.

Methodology

• A thorough literature review on past and present MSRs designs to identify the necessary operating conditions for the power conversion cycle.

• Assessment of potential power conversion cycles and architectures for the identified design, and of 1-D simulation tools.

• Optimization and simulation of power cycles under various loading conditions, with a comparison on the performance of different architectures.

• Further, a likely inclusion of an analysis on the potential integration of thermal energy storage and transient analysis with dynamic simulation tools.

Expected outcomes

The work is anticipated to offer:

• In depth knowledge of power cycles for advanced energy applications

• Experience in power cycle modelling with 1-D simulation tools

• Experience of collaboration in an academic and industrial R&D project

• Potential scope of a journal publication.

Deliverables

The main deliverables of the project include:

• Final project report and presentation.

• 1-D simulation models

Timeline

January 2026 – June 2026 (flexible)

Supervisors / Contact people