Fuel Reliability

Course for PWR fuel engineers and technical managers | taught by A.N.T. International

Course description


The purpose of this course is to provide insight how increased fuel reliability can be obtained by:

  • Reducing the primary fuel failure frequency and minimise the consequences of fuel failures when they occur and
  • Minimizing operational effects due to factors such as fuel assembly and channel bowing, that can affect thermal margins (LOCA, DNB, Dryout) and core control capabilities (control rod insertion).

In this course, reliability is considered in terms of:

  • The ability of the cladding and end plugs comprising a fuel rod to isolate the fuel material and fission products from the primary coolant and to maintain the fissile material in the intended configuration. Failure is defined as the loss of the barrier between the rod interior and coolant such that fission products, fuel material or both are released to the primary coolant.
  • Assuring that the fuel system  dimensions remain within operational tolerances, and that functional capabilities are not reduced below those assumed in the safety analysis.

Poor fuel reliability can have adverse effects on:

  • Reduced thermal and safety margins,
  • Power generation,
  • Outage time,
  • Chemistry and radiation monitoring costs,
  • Personnel exposure,
  • Handling, transportation, storage and reprocessing.

The cost per failure typically ranges from $1 500 000 to approximately $15 000 000 depending upon the type of reactor, the need for power suppression or a mid-cycle outage, reduced cycle length, the cost of replacement energy and the impact of the leaking fuel on subsequent core designs, operation and post-irradiation handling.

Maintaining and improving fuel reliability requires an understanding of the behaviour of fuel and materials as related to in-reactor conditions and the mechanisms that have been observed to cause fuel failures. With such an understanding, fuel investigation and development programs can be focused on the likely causes of failure or degradation, while unnecessary costly and time consuming work can be minimized. One of the objectives of this course is to provide such an understanding.

This course involves watching webinars. Complementary reading is optional to even deepen your knowledge. The course material including the online content can be accessed at times convenient. The PowerPoint-presentations are available for download on almost all lectures. You will find them just before the lecture starts.

If you need a printed certificate, please don’t hesitate to contact us and we will send it to you via regular mail. You may reach us at support@antinternational.com.

Please note that these PowerPoint-presentations are the actual file from the seminar that has been recorded. Therefore, there may occur spelling errors and/or less perfect pictures or slides. As the presentations are the expert’s own material we have not edited them before making these lectures available online. If you have any questions regarding this course, please contact support at support@antinternational.com.


The Authors and Lecturers of the report/webinars are World Class Experts in their fields and are as follows:

Mr. Peter Rudling

Course duration

The below listed time for the lectures is the actual running time. More time may be needed to digest the information provided in this course and you may have to watch some lectures more than once.

  • Total time: About 15 hours of materials, estimated time to finish, up to 1 week (full time studies) 
  • Webinars: 14 h

Course parts

  • Section 1 gives an introduction to fuel reliability
  • Section 2 provides an introduction to water cooled reactor designs (PWR/VVER, BWR and PHWR/CANDU), the respective coolant chemistries, the fuel assembly structures and materials.
  • Section 3 gives an overview of how the neutron irradiation in the core impacts the properties of fuel and zirconium-based alloy materials and affects the performance of fuel assembly components.
  • Section 4 provides information about fuel design criteria and the type of data fuel vendors need for their fuel performance codes.
  • Section 5 discusses fuel reliability and the failure characteristics and which type of examination techniques and supporting data are needed to assess the primary failure cause.
  • Section 6 describes the mechanisms behind degradation of failed fuel, factors that contribute to degradation and action that can be taken to minimize the likelihood and mitigate the effects of degradation.
  • Section 7 provides information on fuel reliability monitoring
  • Section 8 guidelines on how to improve fuel reliability
  • Section 9 contains a discussion and summary of fuel reliability issues
  • Section 10 contains a list of references


The information presented in this course has been compiled and analysed by Advanced Nuclear Technology International Europe AB (ANT International®) and its subcontractors. ANT International has exercised due diligence in this work, but does not warrant the accuracy or completeness of the information. ANT International does not assume any responsibility for any consequences as a result of the use of the information for any party, except a warranty for reasonable technical skill, which is limited to the amount paid for this course.

A.N.T. International
A.N.T. International