Comparison of Conventional and Advanced Nuclear Fuel Performance

Lead Research Organisation: University of Bristol
Department Name: Physics

Abstract

Accident Tolerant Fuels (ATF) are a key concept in the drive to improve safety in the nuclear industry. The 2011 Fukushima Daiichi accident highlighted the thermal limitations of the current UO2-Zr system and as such, significant effort is being invested in researching accident tolerant alternatives. In order to be widely adopted and offset any R&D costs, ATFs should ideally offer some economic benefit in the form of increased uranium density, allowing for either higher burn-up or lower fuel enrichment.

By definitions, accident tolerant fuels (ATFs) are fuels and claddings that can withstand a significant loss of coolant for a prolonged amount of time when compared to conventional UO2-Zr system, whilst maintaining or improving fuel performance during normal operation. This particular feature is often a result of the fuels advanced thermal properties. The ability to evacuate thermal energy from the fuel assembly could potentially permit for an extended 'grace period' in the case of a loss of coolant accident (LOCA) and, as a result, mitigate against the production of hydrogen and corium.

The two leading contenders currently considered as accident tolerant replacements fuel are uranium nitride (UN) and uranium silicide (U3Si2) due to their high thermal conductivity, high melting point, and high uranium density.

Thin film samples of each accident tolerant fuel will be engineered using DC magnetron sputtering facilities available at the University of Bristol. Thin films make ideal samples for irradiation studies. The limited sample thickness enables homogenous damage profiles to be induced using ion irradiation, allowing for precise measurements of the effect on thermal conductivity.

This project looks at the performance of the proposed ATFs, with a specific focus on comparing the thermal behaviour of UN and U3Si2 against conventional ceramic oxide compounds and investigating how the thermal behaviour changes as a function of irradiation.

Publications

10 25 50

Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/R511857/1 01/10/2017 30/09/2022
1952984 Studentship EP/R511857/1 01/10/2017 30/09/2021 Lottie Harding