Journal of Applied Physics · 1962 · 87 citations · 11 references
Reactor DamageEngineeringNuclear PhysicsRadiation Materials ScienceNuclear DataRadiation SystemsRadiation Damage EffectsNuclear FissionCorrosionNuclear MaterialsThermodynamicsFusion Reactor MaterialNuclear ReactorsMaterials SciencePhysicsNeutron SourceNuclear ReactionsNuclear EngineeringNuclear AstrophysicsNuclear EnergyMicrostructureThermal NeutronsNatural SciencesApplied PhysicsLiquid Helium CryostatReactor SafetyMetallurgical ProcessNuclear ExperimentsNeutron Scattering
By relocating fuel near a liquid helium cryostat in the Oak Ridge Graphite Reactor, the authors isolated thermal and fast neutron fluxes and demonstrated that thermal neutron damage originates from atomic recoils during (n,γ) capture, with recoil energies ranging from ~50 eV in heavy elements to several hundred eV in light elements. The experiments revealed that thermal neutrons contribute a significant portion of reactor damage, exhibit greater low‑temperature recovery with distinct annealing peaks, and that increased cadmium concentration suppresses annealing; fission‑neutron damage recovers less well than reactor fast‑neutron damage, while recoil effects from decay events are minor.
By relocating the fuel in the vicinity of a liquid helium cryostat located in the Oak Ridge Graphite Reactor it has been possible to separate the thermal and fast components of the reactor neutron flux. Studies of the radiation damage effects arising from each type of flux have been made. It has been found that an appreciable fraction of the reactor damage in several metals arises from thermal neutrons. The effect results from the recoil of an atom from the (n,γ) reaction at the time of thermal neutron capture. The low temperature recovery of thermal neutron damage is greater and shows more annealing peak structure than the recovery of fast neutron damage. Thermal neutron damage concentration studies have been made on cadmium, and pronounced suppression of the annealing is found as the concentration is increased. The mean primary recoil energy from a thermal neutron capture event has been calculated for several elements. Values range from about 50 eV for the heavier elements to several hundred eV for the lighter elements. The relative effects of atomic recoils from decay events and decay beta-atom collisions are estimated and found to be small compared to (n,γ) recoil effects. Damage from fission neutrons has been studied in copper, and it was found that the recovery of this damage is suppressed compared to that obtained from reactor fast neutrons.
11
The Displacement of Atoms in Solids by Radiation
G.H. Kinchin, R. S. Pease · Reports on Progress in Physics · 1955 · 1.6K citations
G. J. Dienes · Annual Review of Nuclear Science · 1953 · 558 citations
Low-Temperature Reactor Irradiation Effects in Metals
T. H. Blewitt, R. R. Coltman, C. E. Klabunde et al. · Journal of Applied Physics · 1957 · 105 citations
Engineering, Nuclear Physics, Radiation Materials Science +18