The Analysis and Development of a Small Modular Nuclear Reactor Suitable for Marine Propulsion Applications

Abstract

Over the last 10 years, the GHG emission concerns regarding maritime transport has gained increasing attention. The world's total shipping emitted 938 million tonnes of CO2 in 2012 and it is projected to increase significantly in the coming decades. The possible decarbonisation solution of using LNG as an alternative energy resource (change of fuel mix) for international shipping can reduce the CO2 emissions, however, at a cost of the increase of CH4 emission. Thanks to the minimal emission nature, civil nuclear shipping may play an increasingly important role in the future. Therefore, the feasibility study of civil nuclear shipping fitted with different types of reactor is becoming increasingly necessary, especially for large container vessels. A Russian-design LFR SVBR-100 is selected as the reference design in this study. The neutronic features of SVBR-100 core loaded with various fuels are simulated and compared using industry standard software MONK and WIMS, regarding core lifetime, reactivity swing, MAs production, maximum DpA for cladding, etc. Nitride fuel with good physical, irradiation and neutronic features are regarded as a suitable fuel candidate for powering a nuclear ship. Thereinto, mono-nitride fuel (UN) produces the least MAs, has the largest effective DNF, but features a short lifetime; mixed Pu-U nitride fuel (Pu-U-N) characterized with a "optimal shape" of reactivity versus burnup curve manifest a perfect balance between core lifetime and reactivity swing. Based on the study of the SVBR-100 core, the design and optimization of a LFR suitable for civil marine propulsion application is conducted. The main design objectives are, first of all, to extend the core life in order to make the nuclear powered ship more economically attractive, giving consideration to the maximum allowable DpAs for FBRs; secondly, minimizing the lifetime reactivity swing by maintaining the "optimal shape" of flat burnup distribution associated with mixed nitride fuel; lastly, the shape of the active core is also improved and is more suitable for operating on seawater because that it is more balanced between minimizing outlet coolant temperature distribution change due to the seawater wave and minimizing the pressure drop along the coolant flow channel. This is particularly important for heavy metal cooled ship reactors because the outlet coolant temperature distribution change is particularly associated with ship reactors. After the optimization, the total core lifetime is largely extended and the lifetime reactivity swing is kept minimum by maintaining the "optimal shape". The optimized design is also discussed in terms of the maximum DpA, the production of weapon grade plutonium and the Doppler coefficient.

Date of Award	31 Dec 2017
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Timothy Abram (Supervisor)