Determination of nuclear graphite impurities by prompt gamma activation analysis to support decommissioning operations

Elemental composition of non-irradiated nuclear grade graphite was determined by Prompt Gamma Activation Analysis (PGAA) to quantitively assess some neutron activation precursors. The knowledge of these data is paramount for an accurate radiological characterization of the material before decommissioning of graphite-moderated nuclear reactors. Bulk results of most of the nuclides were consistent with benchmark Inductively Coupled Plasma–Mass Spectrometry (ICP-MS) and literature data. In the case of 14 N and 35 Cl, depth distribution profiles were observed and quantified for the first time. These outcomes could shine a light on 14 C and 36 Cl depth distribution profiles and fractional release during leaching experiments. Article highlights A complete dataset of virgin graphite impurities distribution serves as input data for activation computational codes. A complete elemental characterization is achievable by the complementary PGAA and ICP-MS techniques. N and Cl depth distribution profiles have been discovered in graphite, untangling 14 C and 36 Cl activation mechanism.