Delayed Hydride Cracking

Overview course for Engineers and Technical Managers | taught by A.N.T. International

Course description


This course gives an overview of Delayed Hydride Cracking (DHC) in zirconium alloys and will provide egineers and technical managers at utilities, reactor vendors and regulators who would like to get a deeper knowledge of DHC in Zr alloys. 

Some fuel cladding and structural components made from zirconium alloys have failed by DHC in nuclear reactors and chemical plants. This course will tackle the circumstances of the failures so that plant designers and operators can avoid such failures over the whole lifetime of their components, including post-operation storage, for example, dry storage of spent nuclear fuel. The approach is to avoid exceeding at least one limiting condition. The effect on DHC of other variables will also be discussed.

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 for practicing engineers and managers. 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

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

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.

  • Total time: approx. 1 week for full time studies
  • Webinars: 6 h

Course Parts

  1. Introduction to Delayed Hydride Cracking (DHC)
  2. Component failure by DHC
  3. Hydrogen in zirconium alloys: (a) Solubility limits and (b) Diffusivity
  4. Hydride properties: (a) Crystallography and (b) Mechanical properties
  5. Basic mechanism of DHC
  6. Implications of mechanism for behaviour of a crack
  7. Experimental methods
  8. Phenomenology and dependencies on: (a) Time, Stress and stress intensity factor, (b) Temperature history and distribution, (c) Microstructure, and Strength
  9. Models of crack growth by DHC
  10. Implications for structural integrity: (a) During operation - Leak-before-break and (b) During storage of spent nuclear fuel


Dr. Kit Coleman


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

ANT International Academy support team can be reached at