Influence Of Neutron Radiation Research Articles

Recovering the performance of irradiated high-temperature superconductors for use in fusion magnets

Magnets confining the plasma in future fusion devices will be exposed to a significant destructive flux of fast neutrons. In particular, in cost-efficient compact reactor designs, the degradation of the superconductor becomes an issue and directly impacts the commercial viability. We report on the influence of neutron radiation on the superconducting transition temperature, , and the critical current density, , and discuss possibilities to counteract the degradation using thermal treatments. We found that the degradation in and are closely related to each other, likely due to the expected loss of superfluid density; thus, is a very useful indicator for the magnets’ degradation. It increases linearly with the annealing temperature, and around 25% of the decrease can be recovered by annealing at 150 ∘C and about 60% at 400 ∘C, which would more than double the magnet’s lifetime. However, a loss of oxygen has to be impeded in the latter case.

Alanine/electron spin resonance dosimetry for environmental qualification of electric equipment in a nuclear power plant

One of the objectives of the Environmental Qualification Program of Electrical Equipment in a Nuclear Power Plant (NPP) is to demonstrate that electric equipment and cables are not damaged due to the accumulated radiation dose. This work aimed to assess photon doses to electronic equipment and cables during an operation cycle (∼1 year) at the NPP Angra 1, Eletronuclear, Brazil, using alanine/electron spin resonance (ESR) dosimetry. The influence of neutron radiation was evaluated and a dose survey at the NPP was performed. Alanine dosimeters were placed at 85 positions adjacent to the reactors room. Neutron influence was assessed using hydroxyapatite dosimeters. For a 1-year operation cycle, doses ranged from <0.5 Gy to ∼7 kGy, according to the position of the dosimeters, demonstrating alanine's ability to operate over a wide dose range. Alanine/ESR dosimetry can be used as part of the Environmental Qualification Program of Electrical Equipment in an NPP.

Influence of neutron radiation on majority and minority carrier traps in n-type 4H-SiC

We report on influence of neutron radiation on majority and minority carrier traps in n-type 4H-SiC. Together with the increase of the well-known carbon vacancy (VC) majority carrier related trap, neutron irradiation has introduced two deep traps, labeled as EH1 and EH3 with the activation energies for electron emission estimated as 0.4 and 0.7 eV bellow the conduction band, respectively. Based on Laplace deep level transient spectroscopy (DLTS) results, we have assigned EH1 trap to silicon vacancy (VSi). Two minority carrier traps labelled as B and D-center were detected by minority transient spectroscopy (MCTS) and assigned to substitutional boron BSi and BC, respectively. Activation energies for hole emission for B and D-center are estimated as 0.27 and 0.60 eV above the valence band, respectively. We have identified two emission lines for D-center by Laplace-MCTS measurements and assigned them to BC sitting at hexagonal (−h) and cubic (−k) lattice sites.

Influence of Neutron Radiation on the Stability of the Erythrocyte Membrane and an Oxyhemoglobin Formation --- Petkau Effect Studies

Influence of Neutron Radiation on the Stability of the Erythrocyte Membrane and an Oxyhemoglobin Formation --- Petkau Effect Studies

Influence of neutron radiation on breakdown voltage of silicon voltage limiter

Experimental study of silicon voltage limiters’ breakdown voltage dependence on neutron radiation was conducted. It revealed that with increase of radiation density from 0.1×1014 to 2×1015 N/cm2 the breakdown voltage monotonously increases: the smaller the breakdown voltage, the higher radiation density is needed to provide nominal breakdown voltage. Test curves which may be used for stabilization (normalization) of the breakdown voltage for samples with technological variations are suggested.

Influence of neutron radiation upon the characteristics of galvanic cells made from stabilized zirconium dioxide

Influence of neutron radiation upon the characteristics of galvanic cells made from stabilized zirconium dioxide

Radiation effects in oxide ferrimagnets

The influence of neutron radiation on the value of an average molecular magnetic moment nB, the Curie temperature TC, and the structural parameters of mixed Mn-Zn and NiZn ferrites was studied. It is shown by methods of structural neutronography and small-angle diffuse magnetic neutron scattering that essentially irreversible changes of all quantities measured experimentally observed at irradiation doses higher than 1018 cm−2 are caused mainly by the creation of disordered phase microregions during irradiation. The appearence of such regions is assumed to be caused by the so-called “displacement spikes”. [Russian Text Ignored].

The influence of neutron radiation on the yield stress and on some activation parameters of polycristalline vanadium

On neutron irradiated polycrystalline vanadium a thermal activation analysis was performed using the stress relaxation method. Irradiation influences both the thermal and the athermal stress component. The radiation hardening at low and intermediate doses can be described according to the dispersed barrier model by a (φ t) 1 2 -dependence. For high doses saturation phenomena are observed. The rate determining process is not influenced qualitatively by irradiation at doses up to 1 × 10 18 n/cm 2. The strength of the rate determining obstacles is reduced at low doses, perhaps as a result of the formation of oxygen-radiation defect complexes. Whereas interstitial oxygen atoms, elementary radiation defects, and complexes composed from both suffer a contribution to the thermal stress component, visible defect clusters in this case probably affect only the athermal stress component. As one can imagine, these findings are dependent on the content of relevant interstitial impurities. In this case the dominating role being played by the oxygen atoms.