Notice of the NSSC No.2021-14 defines the term ‘Neutron Absorber’ as a material with a high neutron absorption cross section, which is used to prevent criticality during nuclear fission reactions and includes neutron absorbers as target items for manufacture inspection. U.S.NRC report of the NUREG-2214 states that the subcriticality of spent nuclear fuel (SNF) in Dry Storage Systems (DSSs) may be maintained, in part, by the placement of neutron absorbers, or poison plates, around the fuel assemblies. This report mentions the need for Time-Limited Aging Analysis (TLAA) on depletion of Boron (10B) in neutron absorbers for HI-STORM 100 and HISTAR 100. Also, this report mentions that 10B depletion occurs during neutron irradiation of neutron absorbers, but only 0.02% of the available 10B is to be depleted through conservative assumptions regarding the neutron flux or accumulated fluence during irradiation, which supports the continued use of the neutron absorbers in the SNF dry storage cask even after 60 years of evaluated period. There are several types of commercially available neutron absorbers, broadly classified into Boron Carbide Cermets (e.g., Boral®), Metal Matrix Composites (MMC) (e.g., METAMIC), Borated Stainless Steel (BSS), and Borated Al alloy. While irradiation tests for neutron absorbers are primarily conducted during wet storage systems, there are also some prior studies available on irradiation tests for neutron absorbers during dry storage systems. For examples, there is an analysis of previous research on high-temperature irradiation test of metallic materials and identification of limitations in existing methodologies were conducted. Furthermore, an improvement plan for simulating the high-temperature irradiation damage of neutron absorbers was developed. In report published by corrosion society summarizes the evaluation results of the degradation mechanisms for Stainless Steel- and Al-based neutron absorbers used in SNF dry storage systems.

The effects of fast neutron irradiation on the electrical and optical properties of Li (3 at%) doped ZnSnO (ZTO) thin films fabricated using a sol-gel process are investigated. From the results of Li-ZTO TFT characteristics according to change of neutron irradiation time, the saturation mobility is found to increase and threshold voltage values shift to a negative direction from 1,000 s neutron irradiation time. X-ray photoelectron spectroscopy analysis of the O 1s core level shows that the relative area of oxygen vacancies is almost unchanged with different irradiation times. From the results of band alignment, it is confirmed that, due to the increase of electron carrier concentration, the Fermi level (EF) of the sample irradiated for 1,000 s is located at the position closest to the conduction band minimum. The increase in electron concentration is considered by looking at the shallow band edge state under the conduction band edge formed by fast neutron irradiation of more than 1,000 s.

Effects of doping on the electromagnetic properties in the BiSrCaCuO superconductors. The electromagnetic properties of doped and undoped BiSrCaCuO superconductor were evaluated to investigate the contribution of the pinning centers to the magnetic effect. It was confirmed experimentally that a large amount of magnetic flux was trapped in the doped sample than that in the undoped one, indicating that the pinning centers of magnetic flux are related closely to the occurrence of the magnetic effect. It is considered that the area where normal conduction takes place increases by adding and the magnetic flux penetrating through the sample increases. The results suggested that Ag acts to increase pinning centers of magnetic flux, contributing to the occurrence of the electromagnetic properties.

Magnetic characteristics observed in BiSrCaCuO superconductor were studied. In the measurement of differential conductance, it was cleared that the mechanism of magnetic memory effect couldn't be explained by using conventional flux flow model. By changing the density of external magnetic flux, changes in inductance of a coil in which a superconducting bar inserted were also measured. The results showed that the filament model was valid to explain the mechanism of the occurrence of a voltage in superconducting sample. It was concluded that the electromagnetic characteristics arose from the interaction between the trapped magnetic flux and weak link of the filament formed in the superconducting bulk.