A radiation shield consists of borated polyethylene (7 % wt of boron) and lead was used for the HPGe detector in Isfahan MNSR's PGNAA facility in order to remove scattered neutrons and gamma rays, respectively. Therefore, the boron peak in gamma spectroscopy is related to both resources in the sample and in the shield, and it has caused a challenge in determination of boron concentration in the samples. In this research, various methods have been investigated to remove the effect of boron in the shield of the detector. For this purpose, Monte Carlo simulations of radiation transportation have been used. The results showed that by covering the detector shield using a cadmium sheet can greatly (99.32 %) reduce the height of the boron peak in prompt gamma spectrum recorded in the detector that come from the shield. The experiments have been done to validate the results obtained from the simulations.

The safety of nuclear energy, as a low-carbon energy source, has received widespread attention. One of the concerns is the appropriate handling of volatile radioactive elements (e.g., I and I) generated during the operation of nuclear reactors. These radioactive iodine isotopes are potentially hazardous to the environment and human health, so their effective removal is essential. Adsorption has become a popular method for capturing radioiodine due to its simplicity and low cost, which eliminates the need for highly corrosive solutions. Porous solid adsorbents have been widely studied and applied in practice for the efficient removal of radioactive iodine elements. However, most of these adsorbents are expensive, have limited capture capacity, and can burden the environment. Currently, researchers have now begun to experiment with the use of lignin as a substrate to develop new green and inexpensive adsorbents to enhance the capture efficiency of radioactive iodine. This review article begins by discussing the design of lignin-based iodine capture materials, detailing their application in iodine capture, and analyzing their performance, mechanisms, and practical application cases. Considering the challenges and opportunities in the field of radioactive iodine capture, it is hoped that this work can provide a reference point for future research.

Molten salt reactors are an emerging advanced nuclear reactor concept in which the fuel is dissolved into the working fluid in the form of a high-temperature molten salt. The complex, mobile, and corrosive nature of this fluid presents a fundamental challenge for analytical measurements. Tracking species throughout the reactor is important for ensuring proper operation. This article presents laser-induced breakdown spectroscopy (LIBS) used to monitor the elemental composition of a molten salt and corresponding hydrogen isotopic shifts in real-time. A NaNO-KNO eutectic salt was saturated with protium and deuterium gases, then the effluent aerosol stream formed using an argon sparging vessel was monitored with LIBS. This modular LIBS system permitted several spectrometers to be used simultaneously to capture high-resolution isotopic shifts and provide broadband elemental coverage. The results exhibit how LIBS can be used to understand salt-gas chemical and physical interactions such as diffusion. Furthermore, LIBS' broad elemental coverage can provide greater insight into the chemical reactions within the salt vessel such as the formation of water vapor by monitoring hydrogen and oxygen signatures simultaneously. Ultimately, this study demonstrates the analytical possibilities of LIBS for real-time monitoring of isotopes and elemental composition in molten salt systems.

In fast reactor investigation with lead-bismuth eutectic(LBE) coolant, understanding the source term within the reactor and its environmental migration is crucial for managing radiation hazards from Po aerosols. The numerical simulations using empirical parameters have proffered insights into the theoretical migration and settling rates of Po aerosols. However, the scarcity of platform tests has impeded the acquisition of particle size distributions and settling velocity, thus weakening the mutual confirmation between experimental and theoretical validation. In this study, an LBE aerosol testing platform (LATP) was designed and established to obtain the particle concentration data to predict Po migration, where Te was employed as an experimental surrogate. The particle concentration and size distribution function of PbTe-doped LBE aerosol were measured by an aerosol spectrometer and a universal scanning mobility particle sizer, revealing the particle size distribution spanning from 0 to 800 nm. Under normal operating conditions (873 K), the pinnacle particle size of the aerosol concentration is 47 nm, which shifted to 41 nm under accident conditions (1223 K). Notably, the highest mass concentration of particles under both circumstances falls within the 200-300 nm range. The settling velocity of PbTe-doped LBE aerosol increase with the particle size, and ranging from 5.0 × 10 to 7.1 × 10m/s. First-principles calculations and X-ray photoelectron spectroscopy results indicate that PbTe-doped LBE aerosols should preferentially generate TeO during the interaction with oxygen. This work provide a reasonable prediction method for the migration characteristics of polonium under severe accident.

Ionizing radiation is a human carcinogen, and there is a public concern but limited evidence that it increases the incidence of cancer among those who live near nuclear power plants (NPPs). Previous analyses of thyroid cancer in these populations have been inconsistent, and the last synthesis was published nearly a decade ago. To address these gaps, we undertook a systematic review and meta-analysis.

The cladding of fast reactor fuel rods, made of stainless steel, presents significant challenges in cutting due to its ductility, which leads to increased tool wear and poor cut quality with traditional mechanical methods. Laser cutting has emerged as a superior alternative, offering non-contact precision, high efficiency, and suitability for radioactive environments. This study systematically investigates the effects of laser cutting parameters-cutting speed, focal position, power, and gas pressure-on the cutting quality of simulated fast reactor fuel rods. The results show that optimal cutting is achieved with a cutting speed of 1 m/min, a focal position between - 20 and - 25 mm, a laser power between 7200 and 9600 W, and a gas pressure of 10 MPa. These parameters provide the best balance between cutting efficiency, surface roughness, and minimal slag formation. This study contributes valuable insights into optimizing laser cutting technology for nuclear fuel rod processing, with potential applications in fuel reprocessing and decommissioning.

To address the issue of soil contamination caused by associated elements during the extraction and processing of radioactive minerals, this study employed two types of chemical leaching methods, one based on organic acids and the other on carbonates, to remediate radium-contaminated soil. Large-scale soil slurry reactors were used in field experiments to investigate the effects of acidic and alkaline leaching agents on the removal of Ra from naturally contaminated soil, and the optimal operational conditions were determined. The combined use of organic acids, salts and solubilizers has demonstrated high removal rates of radionuclide on a laboratory scale. Pilot scales revealed that using FeCl, oxalic acid, NaClO, and HEDP, or NaCO, NaHCO, HO, and deep eutectic solvent (DES) as leaching agents achieved the best remediation outcomes for radium-contaminated soil. Under optimal conditions, the radium removal efficiencies of the two leaching systems reached 93.02% and 90.66%, respectively. Characterization analyses using X-ray diffraction (XRD), fourier transform infrared spectrometer (FT-IR), and scanning electron microscope (SEM) demonstrated that the chemical leaching methods are both safe and reliable, effectively removing radium while having minimal impact on the soil's original structure. Additionally, these methods have the potential to replenish soil nutrients and restore its functional use.

The radiation dose reduction factor represents a building's shielding capability against radiation in scenarios of potential nuclear accidents. Notably, the radiation dose reduction for school buildings and gymnasiums have not yet been determined, even though the building types are planned to be used as evaluation shelters in Japan. This study evaluated dose reduction factors in relation to the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP). In this study, we separately measured the indoor and outdoor ambient dose equivalent rates and the dose rates from natural radionuclides at two school sites in an evacuation-order-lifted area in Fukushima Prefecture, Japan, to evaluate the dose reduction factors of the school buildings and gymnasiums. The factors depended not only on the structure and materials of the buildings, but also on the geographical characteristics of the building locations, which could govern the geometries of irradiation. We noted a non-negligible overestimation of the dose reduction factors by the conventional method, due to the presence of natural radiation in areas with low dose rates (<1 μSv/h). Note that the dose reduction factor is used as an uncertainty source for external dose evaluation related to the FDNPP accident. This study can serve as a foundation for future investigations on improving the resilience of buildings confronted by artificial radiation due to scenarios of nuclear plant accidents.

Currently, advanced optimization methods are limited for isotope production (IP) campaigns at the US Department of Energy's High Flux Isotope Reactor (HFIR) located at Oak Ridge National Laboratory (ORNL), leading to years of conservative and historical approaches with minimal innovation. Moreover, the growing demand for new and existing isotopes is beginning to challenge the capacity of HFIR. This work explores the development and integration of metaheuristic (MH) optimization techniques for more efficient target design and irradiation strategies. As a test case, the optimization framework was applied to a routinely produced isotope at HFIR, W, with the objective of maximizing the specific activity (SA), a key production metric. The framework includes Gnowee, a Python-based MH optimization algorithm, coupled with the Monte Carlo N-Particle version 6 (MCNP6) and Oak Ridge Isotope Generation (ORIGEN) activation/depletion/decay codes to design, simulate, and evaluate thousands of potential target design and irradiation scheme candidates. The framework relies on mock input files, design and irradiation variables for the algorithm to select, as well as a user-defined objective function to score each candidate based on the returned SA. Given the inherent complexities and computational time required when modeling and simulating the full HFIR model, a novel simplified MCNP6 model is presented in this article to increase the computational efficiency of the framework. The variables explored include irradiation location, number of cycles, and the number of W samples. Over 1,000 simplified model candidates were simulated in the same amount of time as a single full HFIR model run. By comparing the simplified model optimization's top candidate(s) with the full HFIR model results, the framework was verified to accurately explore the design space and converge on the top performing candidates. Lastly, past experimental data was compared to the data generated by the framework/model and both show that fewer W rings return higher SA, as expected. The verified and validated techniques provide a standardized solution to increase IP efficiencies by exploring thousands of unique target designs and irradiation strategies in a similar time as that required to run a single case in the full HFIR MCNP6 model. Both the novel simplified model and the full HFIR model show a more than 30% increase in SA if all presented modifications are applied to the current design and strategy. Thus, the objective of building a general-use, computationally efficient optimization framework for HFIR IP was accomplished, and has the potential to be applied to other IP campaigns.

Thurso/Caithness in the United Kingdom has gone through a lot of changes and transitions in the last decades. The decision to build a nuclear reactor test facility in the 1950's in Dounreay/Caithness UK, as well as the current phase of decommissioning impacted not only the technology development but also the social fabric of the community and individuals within it. This study aimed to explore the lived experiences of people impacted by the nuclear project at Dounreay. The results will form the basis for the discussion about locating future experimental or development facilities, possibly at historic sites. This study employed an exploratory qualitative research approach based on the constructivist grounded theory methodology. Constructivist grounded theory applies a systematic, inductive, iterative, and comparative approach to investigate the meanings behind people's experiences. It was chosen as the method to explore an under-researched area: the host community for nuclear research in Thurso/Caithness. Purposeful snowball sampling from March 2023 till November 2023 through gatekeepers, media and social media was used. 19 participants including 10 women and 9 men in the age range 36-71 took part. The semi-structured interviews were conducted via phone or online platforms. Participants fondly recalled the hey-day when the Dounreay site was built and the population increased rapidly. They shared memories of how the town of Thurso/Caithness was thriving then which had a huge impact on individuals' opportunities to receive a very good education, earn a good salary, indirect benefits beyond the nuclear project, and a cosmopolitan sense of community. However, the changes over time and the process of decommissioning had more complex implications for individuals as well as for the community. The work opportunities are still favourable. However, this study also highlights new challenges such as decaying infrastructure, a lack of hope of prosperity, and a feeling of being forgotten. This unique study highlights how a politically driven project impacts a community fundamentally. We identified two themes: mostly positive nostalgic views and Changes and Challenges for the community.