“…Contamination of graphite with a fuel composition and fission products during "wet" accidents occurs due to the ingress of gamma-emitting nuclides into the graphite stack: 134 Cs, 137 Cs, 60 Co, 55 Fe, 154 Eu, 155 Eu, 151 Sm, 244 Cm, 241 Am, 243 Am, 239 Pu, 106 Ru, 90 Sr. Most often, such contamination is observed on the surface of graphite blocks [2].…”