Hydrogen Content in As -Manufactured Fuel Elements

Abstract

The definitions of "total hydrogen gas" and of "overall hydrogen content" in the fuel element are discussed. Under normal manufacturing conditions, the sheath, i.e. Zircaloy and graphite coating are the main source of hydrogen. However, only a small part of it contributes to the "hydrogen gas" content. The paper describes how to determine the "hydrogen gas" for QA purposes, and how to formulate the specification requirement. A method is described that offers information on both the overall hydrogen content and the fraction that can be present as gas.