Dear Zainab

in radioactive waste management, performance assessment is a main part of the safety case and usually we follow modular concept in which we divide the whole system into  subsystem and evaluate the performance of the materials/ barriers under different  conditions.

a large number of publication was devoted to guide in this field,

this is applied to different system so you need to state in which area are you interested, I might be able to send you some links

Thank you dears Monika and Rehab. 

@Rehab, we'll I'd like to start a general reading about the topic at first, but my goal is contractual projects. When two parties sign some contract to do a scientific project, how can the performing side follow the steps of performance and according to what scales.

Please see if it can help you:

http://www.tandfonline.com/doi/pdf/10.1080/01446193.2011.648947

Thank you @Nahila