# The Core Design of a Small Modular Pressurised Water Reactor for Commercial Marine Propulsion

## TL;DR

This paper presents a novel small modular pressurized water reactor designed specifically for large container ships, emphasizing safety, simplicity, and long core life, to enable nuclear propulsion in commercial shipping.

## Contribution

It introduces a new, soluble-boron free, low power density core design that operates for 15 years without refueling using conventional UO2 fuel.

## Key findings

- Successfully designed a 110 MWe reactor core meeting marine requirements.
- Achieved a 15-year core life with no refueling needed.
- Reduced coolant outlet temperature to enhance cladding survivability.

## Abstract

If international agreements regarding the need to significantly reduce greenhouse gas emissions are to be met then there is a high probability that the shipping industry will have to dramatically reduce its greenhouse gas emissions. For emission reductions from ships greater than around 40\% then alternatives to fossil fuels - such as nuclear energy - will very likely be required. A Small Modular Pressurised Water Reactor design has been developed specifically to meet the requirements of a large container ship with a power requirement of 110~MWe. Container ships have a number of requirements - including a small crew size and reduced outages associated with refuelling - that result in a greater focus on design simplifications, including the elimination of the chemical reactivity control system during power operation and a long core life. We have developed a novel, soluble-boron free, low power density core that does not require refuelling for 15 years. The neutronic and fuel performance behaviour of this system has been studied with conventional UO2 fuel. The size of the pressure vessel has been limited to 3.5 metres in diameter. Furthermore, to ensure the survivability of the cladding material, the coolant outlet temperature has been reduced to 285degC from 320degC as in conventional GWe-class PWRs, with a resulting reduction in thermal efficiency to 25%. The UO2 core design was able to satisfactorily meet the majority of requirements placed upon the system assuming that fuel rod burnups can be limited to 100 GWd/tHM. The core developed here represents the first workable design of a commercial marine reactor using conventional fuel, which makes realistic the idea of using nuclear reactors for shipping.