Saturday, August 29, 2026

 

Seoul National University of Science and Technology researchers explore how probabilistic analysis can help improve nuclear safety



Researchers evaluate the rupture probability of coolant pipes in nuclear power plants using a probabilistic framework



Seoul National University of Science & Technology

Proposed probabilistic framework for rupture frequency estimation in nuclear power plants 

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The proposed approach offers insights into how uncertainties and modeling assumptions can lead to variations in predicted rupture frequency. This will help engineers distinguish extremely unlikely events from more credible events, informing better design strategies.

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Credit: Professor Nam-Su Huh from Seoul National University of Science and Technology, Korea





In nuclear power plants, the primary coolant piping systems are designed to maintain the structural integrity of the nuclear reactor under normal operating conditions.  A pipe rupture that can result in a loss-of-coolant accident is a key consideration in this design and also an important safety concern.

Traditionally, the double-ended guillotine break of the largest primary pipes, which assumes a complete break of the pipe into two sections, has been considered a key design-basis accident. However, such large breaks are extremely unlikely. Assessing the frequency of pipe rupture can therefore help engineers better understand the likelihood of different failure scenarios and focus resources on events that are more relevant to actual risks. Deterministic leak-before-break (LBB) and statistical approaches based on operating experience have been used previously to evaluate rupture frequency, but these methods do not account for degradation mechanisms or the influence of individual parameters.

To address these limitations, a research team led by Professor Nam-Su Huh from the School of Mechanical Systems Engineering at Seoul National University of Science and Technology in South Korea utilized probabilistic fracture mechanics-based sensitivity analysis to investigate rupture behavior of the Korean nuclear power plant piping systems. “Probabilistic fracture mechanics makes it possible to estimate rupture frequency while accounting for the stochastic nature of material behavior, degradation over time, loading conditions, and even effectiveness of inspections,” explains Prof. Huh. Their study was made available online on July 01, 2026, and will be published in Volume 197, Part B of Engineering Failure Analysis on November 01, 2026.

The researchers utilized the eXtremely Low Probability of Rupture (xLPR) code to conduct their assessment. To this end, the researchers selected two LBB-approved piping systems from a reference Korean nuclear power plant—SC piping and a surge nozzle. The SC piping consisted of two pipes made of stainless steel welded together, also using the same stainless steel as the weld material. The surge nozzle was made up of a dissimilar metal weld composed of a low-alloy steel and stainless steel, and the weld metal for this case was a nickel alloy.

The team first established a base case as a reference condition for sensitivity analysis. It included a fixed set of parameters, including piping geometry, loading conditions, and material properties. The researchers simulated 80 years of plant operation, considering stress corrosion cracking (SCC) as the only degradation mechanism. Sensitivity analysis was then conducted to evaluate the effect of weld residual stress (WRS), crack growth rate (CGR), weld overlay (WOL) repair, and inspection performance.

WRS was the most influential parameter governing rupture predictions. Since residual stress affects the local stress state relevant to crack initiation and the crack-driving force for subsequent crack growth, variations in WRS can lead to large differences in predicted crack growth behavior. For the 95th-percentile, geometry-specific WRS profile, the predicted rupture frequency for the SC piping decreased considerably compared with the base case. In contrast, the mean, 5th-percentile, and probabilistic WRS cases showed no rupture during the 80-year simulation period.

CGR was also significant. The 95th percentile CGR profile increased rupture frequency compared to the base case, while the probabilistic case reduced it. The 5th percentile case showed no rupture.

The surge nozzle showed no rupture in all cases. In addition, WOL analysis also showed no rupture for either piping system. Interestingly, for the SC piping, periodic inspections significantly reduced the rupture frequency by several orders of magnitude, highlighting the effectiveness of inspections in reducing rupture frequency. Overall, the results show how uncertainties and modeling assumptions can lead to variations in predicted rupture frequency. 

A probabilistic framework can help engineers identify which factors govern the predicted failure behavior. In addition, rupture-frequency estimates can help distinguish extremely unlikely large breaks from more credible break sizes and provide a technical basis for treating them differently in plant design and safety evaluations,” remarks Prof. Huh. “In the long term, this type of research could contribute to risk-informed approaches to nuclear safety. Specifically, it can help maintain the safety of aging plants, and for new plants it could help incorporate structural safety into an earlier design stage.

By highlighting the importance of probabilistic rupture frequency assessments, this study contributes to the development of better design and maintenance strategies for making nuclear power plants safer and more economical.

 

Reference:
Title of original paper: Impact of input uncertainties on the failure frequency of Korean nuclear piping systems based on probabilistic fracture mechanics
Journal: Engineering Failure Analysis
DOI: https://doi.org/10.1016/j.engfailanal.2026.111197

About the institute Seoul National University of Science and Technology (SEOULTECH)
Seoul National University of Science and Technology, commonly known as 'SEOULTECH,' is a national university located in Nowon-gu, Seoul, South Korea. Founded in April 1910, SEOULTECH has grown into a large and comprehensive university with a campus size of 504,922 m2.
It comprises 10 undergraduate schools, 35 departments, 6 graduate schools, and has an enrollment of approximately 15,108 students.
Website: https://en.seoultech.ac.kr/

About Professor Nam-Su Huh
Dr. Nam-Su Huh is a Professor in the School of Mechanical Systems Engineering at Seoul National University of Science and Technology and also the Principal Investigator of the Reliability-Based Mechanical System Design Laboratory (REMSYS Lab). His research focuses on the structural integrity and reliability of mechanical components, particularly in nuclear and energy systems, including fracture mechanics, structural assessment, and life evaluation of piping and pressure-boundary components. He has also worked at the Korea Atomic Energy Research Institute (KAERI) and Materialprüfungsanstalt Universität Stuttgart (MPA Stuttgart).

 

Chonnam National University researchers investigate how biodiesel feedstocks and production pathways affect their life cycle sustainability



Study provides biofuel producers with a practical, multi-dimensional framework for choosing feedstocks by weighing both climate impact and air pollution together



Chonnam National University, The Research Information Management Team, Office of Research Promotion

Impact of feedstock choice in biodiesel sustainability 

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Researchers reveal that waste-derived pathways exhibit the lowest greenhouse gas emissions while plant-based pathways dominate by Scope 3 contributions from farming and indirect land-use change.

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Credit: Professor Boreum Lee from Chonnam National University, Republic of Korea






For mitigating climate change and limiting global warming to within 1.5 °C, scaling up global renewable energy capacity is an important goal. However, this effort towards transition to clean energy faces significant resource constraints. To address this challenge, diverse approaches are required like biodiesel, which can serve as a crucial bridge technology for decarbonization of the transportation sector while renewable energy is scaled up.

Biodiesel is compatible with already existing diesel infrastructure and can be deployed quickly without extensive modifications, making it a particularly promising solution. However, not all biodiesel is equally sustainable. Its environmental impact depends strongly on the feedstock used and the way it is produced.  This creates a complex decision-making landscape for policymakers and stakeholders, necessitating comprehensive life-cycle assessments (LCAs) of different biodiesel pathways. Although previous LCAs have compared biodiesel pathways, most have focused primarily on total greenhouse gas (GHG) emissions and a limited range of feedstocks. They have also rarely examined feedstock-specific mitigation strategies or air-pollution impacts.

To address this gap, a research team led by Professor Boreum Lee along with Mr. Sanghyuk Koh, both from the Department of Environment and Energy Engineering, Chonnam National University, Republic of Korea, presents a comprehensive Greenhouse gases, Regulated Emissions, and Energy use in Technologies (GREET)-based framework for LCA across five different biodiesel feedstocks. Their study was made available online on July 01, 2026 and was published in Volume 422 of Applied Energy on November 01, 2026.

The study considered three plant-based feedstocks, namely soy oil, carinata oil, and palm oil, representing diverse agricultural systems, and two waste-derived feedstocks, namely used cooking oil (UCO) and beef tallow. A Well-to-Tank approach, based on the GREET model, was adopted aiming to capture emissions across the full life cycle. The full life cycle was divided into three categories: Scope 1 that covers direct emissions during biodiesel production, Scope 2 that encompasses indirect emissions from energy use, and Scope 3, which integrates emissions from major upstream and downstream processes.

For plant-based feedstocks, the upstream processes included farming, oil extraction, refining, transportation, and emissions from indirect land use change (ILUC). In contrast, waste-derived feedstocks included rendering, oil extraction, and refining as upstream processes, while overseas import and long-distance international transport were excluded.

Emissions analysis showed that waste-derived feedstocks consistently demonstrated lower GHG emissions than plant-based oils. This is mainly due to the absence of emissions from upstream agriculture and land use. Among plant-based options, carinata oil showed the lowest emissions as it avoids ILUC emissions. For plant-based feedstocks, Scope 3 farming processes had the greatest contribution to GHG emissions, while for waste-derived feedstocks Scope 1 and the Scope 3 refining stage were dominant.

“Waste-derived pathways, when paired with renewable energy inputs in processing, can achieve net-negative emissions, meaning they could actually remove more carbon from the atmosphere than they emit with a reduction of up to 346–352% relative to their own baseline (conventional-input) production,” says Prof. Lee.

Interestingly, air-pollution analysis showed that low GHG intensity did not necessarily mean uniformly low pollution. For example, carinata oil, despite its lowest plant-based GHG emissions, had the highest volatile organic compound (VOC) and carbon monoxide (CO) levels across all pathways. These findings highlight the importance of considering air-pollution impacts alongside GHG emissions when evaluating biodiesel sustainability.

Furthermore, Monte Carlo simulation-based uncertainty analysis, aimed at capturing the effect of data variability, showed wider emission ranges for plant-based pathways, compared to much narrower distributions for waste-derived feedstocks.

Importantly, best-case GHG mitigation scenarios revealed emission reduction potentials ranging from 66% to 352%. Waste-derived feedstocks offered the greatest mitigation potential, achieving net-negative GHG emissions through the use of renewable energy in rendering and refining processes.

“Our findings argue against one-size-fits-all biofuel mandates: regions with strong waste-collection infrastructure should prioritize used-oil-based biodiesel, while agricultural regions may benefit more from dedicated energy crops. In the near future, this feedstock-specific, region-aware analysis approach will help policymakers design smarter policies and foster the broader biofuel industry, including aviation and marine fuels, paving the way towards a more sustainable future,” concludes Prof. Lee.

 

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Reference

Title of original paper: Decarbonizing biodiesel supply chains: a GREET-based life cycle assessment with Scope 1–3 emissions and best-case mitigation

Journal: Applied Energy

DOI: https://doi.org/10.1016/j.apenergy.2026.128326

                                

About the institute
Chonnam National University (CNU), established in 1952, is one of South Korea's leading national universities located in Gwangju. Building on its founding commitment to cultivating leaders of integrity and professional excellence, CNU contributes to national development and global progress through the pursuit of knowledge, ethical responsibility, and inclusive excellence. Guided by the core motto “Truth, Creativity, and Service,” the university advances research, education, and public engagement that strengthen resilient societies, foster sustainable development, and promote the well-being of future generations. As a trusted partner in the global community, CNU remains dedicated to addressing complex challenges in an increasingly interconnected world.

Website: https://global.jnu.ac.kr/jnumain_en.aspx

 

About Professor Boreum Lee
Dr. Boreum Lee is a Professor at the Department of Environment and Energy Engineering, Chonnam National University, Republic of Korea. His research focuses on the design and evaluation of carbon-neutral process systems, including hydrogen production, CO₂ capture, utilization and storage, ammonia synthesis and cracking, Power-to-X technologies, and water treatment. By integrating Aspen Plus process simulation with techno-economic and environmental assessments, he works to develop and optimize sustainable energy and chemical processes.

Website: https://boreumlee.com/

 

About Mr. Sanghyuk Koh
Mr. Sanghyuk Koh is a master’s candidate at the Department of Environment and Energy Engineering, Chonnam National University, Republic of Korea. His research focuses on the life cycle assessment and techno-economic analysis of biodiesel supply chains and green hydrogen production to evaluate their environmental and economic sustainability.

OUTLAW PALM OIL

Indonesia’s forest-zone oil palm dilemma needs more than stricter laws, Hasanuddin study finds

Analysis shows that effective restoration must balance forest protection with smallholder livelihoods, land rights, and economic interests


Hasanuddin University

Indonesia’s Forests Face an Oil Palm Governance Dilemma 

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A policy analysis by researchers from Hasanuddin University along with other institutes in Indonesia finds that neither gradual rehabilitation nor stricter state enforcement fully addresses the challenges created by oil palm cultivation in forest zones, underscoring the need for more integrated forest governance.

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Credit: "Palm oil plantations" by europeanspaceagency via Flickr Image source link: https://openverse.org/image/09da85bc-774d-4d7e-a764-bc20dd0ecaa9





A policy analysis by Hasanuddin University finds that Indonesia's shift from gradual rehabilitation to stricter enforcement has not fully addressed the underlying drivers of oil palm expansion in state forest zones and has created new uncertainties for smallholder farmers. The study argues how sustainable forest restoration can only be achieved when environmental protection is pursued alongside social equity, secure livelihoods, and effective governance. These findings were made available online on June 13, 2026, and was published in Volume 189 of the journal Forest Policy and Economics on August 1, 2026.

To put these findings into context, Indonesia is the world’s largest palm oil producer, with an estimated 3.4 million hectares of oil palm cultivated within state forest zones. As international pressure for sustainable palm oil sourcing increased, the Indonesian government has introduced policies to address oil palm cultivation in these areas.

One such approach was Strategi Jangka Benah (SJB) or “Rehabilitation Period Strategy,” introduced in 2020–2021. Rather than immediately removing oil palm plantations, SJB allowed existing cultivation to continue for a transitional period while farmers gradually transformed monoculture plantations into mixed agroforestry systems. In early 2025, the government shifted toward stricter enforcement with Presidential Regulation No. 5/2025 (Perpres 5/2025), which introduced administrative penalties, potential criminal enforcement against violations, and state reclamation of forest land.

Shining light on these approaches, the research team led by Professor Muhammad Alif K. Sahide at the Forest and Society Research Group (FSRG) of Faculty of Forestry Hasanuddin University, Indonesia, examined how both approaches have struggled to reconcile forest restoration with the economic realities of smallholder farmers. They find that SJB faced implementation challenges because oil palm was deeply embedded in smallholder livelihoods, while the newer enforcement-oriented approach could create further uncertainty over land and livelihoods.

By engaging with stakeholders in Central Kalimantan and West Sulawesi, two regions where SJB was implemented, the researchers found a fundamental disconnect between the policy’s ecological objectives and the economic realities facing smallholders. SJB promoted a gradual shift from monoculture oil palm to agroforestry but offered few economic incentives for farmers to make the transition. With palm oil remaining profitable and alternative livelihoods being limited, replacing productive plantations with slower-growing timber or food crops was economically difficult.

Similarly, Perpres 5/2025 frames forest reclamation primarily through law enforcement and territorial control, while leaving the implications for smallholder livelihoods uncertain. The researchers warn that reclaimed land could potentially become concentrated among state-owned companies or other actors with greater political, bureaucratic, or financial influence, potentially marginalizing smallholders further.

The researchers argue that SJB and Perpres 5/2025 reflect a fragmented approach to forest governance. SJB prioritized gradual rehabilitation and social inclusion, while Perpres 5/2025 places greater emphasis on law enforcement and state control. Neither policy, however, addresses the underlying drivers of forest conversion.

To break this cycle, the researchers call for a more integrated approach that protects forests while also addressing farmer’s livelihoods, land rights, and economic needs. This would include clarifying who has legal rights to the land before imposing penalties, using social forestry programs to give smallholder farmers more secure land rights, involving local communities in forest restoration planning, and ensuring that they share in the benefits of restored land. The researchers also call for better coordination between the agriculture, forestry, and energy ministries so that policies on farming, palm oil, biodiesel, and forest protection work toward the same goals.

Overall, the study suggests that forest restoration cannot be separated from the livelihoods and land rights of the communities that depend on these landscapes. Without addressing land rights and economic needs, new regulations could create uncertainty without resolving the underlying challenges.

As Professor Alif puts it, “The challenge, then, is not merely to design better policies, but to build governance architectures that can navigate the inherent trade-offs between economic, social, and ecological goals in a transparent, accountable, and equitable manner.”

 

Reference
Title of original paper: Policy forum: Between incorporation and reappropriation – The unresolved dilemma of oil palm in Indonesia's forest zones
Journal: Forest Policy and Economics
DOI: https://doi.org/10.1016/j.forpol.2026.103835

About Hasanuddin University, Indonesia
Hasanuddin University (Universitas Hasanuddin or Unhas) is one of Indonesia’s largest autonomous universities, located in Makassar. Established on September 10, 1956, and named after Sultan Hasanuddin of the Gowa Kingdom, the university has grown into a major center for higher education with 18 faculties, including medicine, engineering, law, agriculture, and natural sciences. Its origins date back to 1947 with an economics faculty linked to the University of Indonesia. Today, Unhas focuses on advancing science, technology, arts, and culture, with a strong emphasis on the Indonesian Maritime Continent, aiming to develop innovative and globally competitive graduates.
Learn more, here: https://www.unhas.ac.id/about/

About Professor Muhammad Alif K. Sahide from Hasanuddin University, Indonesia  
Muhammad Alif K. Sahide is a Full Professor at the Faculty of Forestry, Universitas Hasanuddin, and leads the Forest and Society Research Group. His research focuses on forest and land-use governance, community forestry, institutions, international environmental regimes, and bureaucratic politics in Indonesia. He actively contributes to forest policy and education across Southeast Asia through the ASEAN Social Forestry Network and national policy committees. Prof. Alif is also a founding and chief editor of Forest and Society and regularly supports research and writing capacity-building initiatives for young researchers and local organizations across Southeast Asia.

Funding information
Hasanuddin University

 

'Like uprooting tree stumps' – a simpler method to manufacture biosensors




KTH, Royal Institute of Technology
Xinxin Liu in the lab 

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Xinxin Liu prepares a newly-fabricated nanopore membrane for evaluation. The new method simplifies production of large arrays of nanopores for sensing and analysis technologies used in medical research and, increasingly, in specialized clinics. Photo: David Callahan

 

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Credit: David Callahan





A new manufacturing method could help move the production of nanoscale sensors from specialized fabrication facilities to conventional semiconductor manufacturing plants.

Publishing in Science Advances, researchers from KTH Royal Institute of Technology liken their technique to uprooting a tree stump with rope.

The work aims at solving a bottleneck in fabricating nano-scale holes in thin membranes, a key component in a range of sensing and analysis technologies used in medical research and, increasingly, in specialized clinics where sequencing systems are used for outbreak surveillance, cancer genomics or infectious disease identification, among other things. Nanopores are valuable tools in these settings because their extremely small openings in ultra-thin materials can be used to detect and analyze individual molecules such as DNA and proteins.

Frank Niklaus, professor of micro and nanosystems at KTH Royal Institute of Technology, says the study demonstrates the unique approach of using built-in mechanical stress to create nanoholes.

A typical sensor device membrane has a single nanopore, which acts as a single molecule detector. These openings are produced one-at-a-time, using slow, expensive or difficult-to-scale nanofabrication techniques, such as electron-beam drilling and Transmission Electron Microscope (TEM) sculpting, says Xinxin Liu, a doctoral student at KTH Royal Institute of Technology and first author of the study.

But the study demonstrated that this technique can produce large arrays of nanopores in parallel by harnessing fracture mechanics generating openings as small as about 6 to 10 nanometers.

The process begins with a stack of layers placed on a silicon wafer. The top layer is deliberately stretched under tension. Underneath is a second layer of material that will be etched away until a small pre-defined shape remains, which is meant to define the shape of the nanopore in the third layer of material underneath. This third layer is the sensor membrane in which the nanopore will be formed.

“The beam pulls on until it tears a nanoscale fragment from the membrane, creating the hole,” Liu says. “Much like a removing a tree stump with a rope – the beam attaches to the nanoscale anchor, pulling it away from the membrane, which serves as the ground.”

The technique was tested successfully in multiple materials, including dielectric, metallic and semiconductor sensor membranes. The study shows these nanopores were effective at DNA analysis and molecule detection. 

Liu says the researchers have patented the technique and formed a startup to progress it toward commercial implementation. “We have already shipped samples to a collaborator for testing, so it has moved beyond the lab stage.”

SEM image of a 3D surface with the patterned letters ‘KTH’, each letter patterned in a different thin-film material. 

Credit

Xinxin Liu

 

A surprising twist in the quantum world



Paul Scherrer Institute



Table tennis professionals are true masters at redirecting fast-moving projectiles. Putting a targeted spin on a serve can make the little white ball fly straight towards the edge of the table but then, at the last moment, take a sharp curve into the left corner. The physical phenomenon behind this sporting trick is known as the Magnus effect. It acts on balls of all sizes and has helped decide more than a few football matches.

An international research collaboration at the Paul Scherrer Institute PSI has now taken the leap from ball to atom, experimentally demonstrating the so-called optical Magnus effect for the first time. In this case, however, there is no atom flying along a curved trajectory. Instead, the researchers direct a tightly focused laser beam at a single ion and observe the resulting interaction.

With this they were able to show that the point of maximum interaction is shifted sideways – an important finding for the development of quantum computers in which laser light is used to precisely control qubits. The researchers report their findings in the journal Physical Review Letters.

When the centre is suddenly off-centre

With a tightly focused laser beam directed at an ion, one would expect the strongest interaction to occur where the laser beam is most intense: at its centre. However, tightly focusing the laser also changes the spatial structure of its electromagnetic field. As a result, the interaction with the ion is strongest not exactly at the centre of the laser beam, but slightly to one side. This sideways shift is the optical counterpart of the Magnus effect seen in the flight of a table tennis ball.

And just as an unexpected deviation in sports can mean losing the ball, in quantum computers it can mean the loss of control. There laser light is used to selectively change the state of qubits. The optical Magnus effect could interfere with this precise control and contribute to errors if it is not taken into account.

At the same time, the effect also presents an opportunity: “The forces it generates could be used to couple qubits to one another, enabling more complex computations,” explains first author Philip Leindecker from the PSI Center for Photon Science and the Department of Physics at ETH Zurich.

A map of laser light

To make the optical Magnus effect visible, the researchers used a single calcium ion as a tiny and extremely sensitive probe. The electrically charged atom is held almost motionless at a fixed position in a so-called ion trap using electromagnetic fields. Such trapped ions are also used in quantum computers, where they can serve as qubits whose quantum states can be precisely manipulated using laser light.

For their experiment, the researchers investigated how strongly the calcium ion interacts with the light from a tightly focused laser at different positions. “Our ion acts like a tiny sensor that we can use to feel out the structure of the laser light,” Leindecker explains. “This makes it possible to measure a shift of just a few hundred nanometres.” The experiment also revealed a surprising characteristic of the effect: the magnitude of the shift depends solely on the wavelength of the light, not on how tightly the laser is focused.

Researchers at the University of Amsterdam had theoretically predicted the optical Magnus effect several years earlier. Now, using the trapped calcium ion, the team has succeeded in observing the effect for the first time and characterising it more precisely.

Text: Paul Scherrer Institute PSI/Benjamin A. Senn

 

About PSI

The Paul Scherrer Institute PSI develops, builds and operates large, complex research facilities and makes them available to the national and international research community. The institute's own key research priorities are in the fields of future technologies, energy and climate, health innovation and fundamentals of nature. PSI is committed to the training of future generations. Therefore about one quarter of our staff are post-docs, post-graduates or apprentices. Altogether PSI employs 2300 people, thus being the largest research institute in Switzerland. The annual budget amounts to approximately CHF 450 million. PSI is part of the ETH Domain, with the other members being the two Swiss Federal Institutes of Technology, ETH Zurich and EPFL Lausanne, as well as Eawag (Swiss Federal Institute of Aquatic Science and Technology), Empa (Swiss Federal Laboratories for Materials Science and Technology) and WSL (Swiss Federal Institute for Forest, Snow and Landscape Research).