Reliability of High Power, Extended Burnup and Advanced PHWR Fuels

Closed for proposals

Project Type

Coordinated Research Project

Project Code




Approved Date

3 July 2013


4 - Closed

Start Date

8 May 2014

Expected End Date

8 May 2018

Completed Date

8 June 2018

Participating Countries

Republic of Korea


There is increased interest among the Member States to introduce advanced fuels and extend the discharge burn up of fuel assemblies in PHWRs for better resource utilization and improved economics. Higher burn up and advanced fuels pose new challenges to fuel design and manufacturing techniques, and may require new cladding materials. Fuel reliability issues include release of gaseous and volatile fission products, pellet-clad interaction, build-up of internal pressure, fuel swelling, degradation of thermo-physical properties of fuel, cladding corrosion and stress corrosion cracking, etc. Attention is also required for the performance of fuels under off-normal and accident conditions. Similar issues have been addressed for LWR fuel and fuel assemblies. PHWR fuel characteristics are quite different from LWR fuel characteristics with respect to clad thickness, high linear power, high centre line temperature, absence of plenum volume, on-line re-fuelling, etc., which affect fuel performance. This CRP is intended to encourage the development and sharing of work on resolving the above challenges.


To encourage the development and sharing of research work on resolving the challenges in deploying advanced fuels for extended burnup and for enhanced operational margin in PHWRs.

Specific objectives

(1) Fuel concepts for higher burnup (design, materials and fabrication)

(2) Life limiting aspects of extended burnup

(3) Fuel concepts leading to enhanced operational margins


Higher burnup and enhanced operational margin in PHWRs are important research targets for national programmes for PHWR fuel in all participating Member States. The CRP results are found to be consistent with such national programmes, and provide desirable directions with technical basis for further deployment of advanced fuels for higher burnup and for enhanced operational margin in PHWRs. Exchange of experimental data conducted under this CRP will enable Member States to save a significant effort in performing similar activities.


The objectives and output of this CRP are in line with the technical contents of the Agency programme (project 33, subproject Nuclear Power Reactor Fuel Engineering and Operation). This CRP was supported by the Technical Working Group on Fuel Performance Technology (TWG-FPT), the advisory experts working group of the Department of Nuclear Energy on nuclear fuel design, fabrication and in-reactor performance issues.

Stay in touch