Chronic illness climbs closer to a former nuclear site in California
Residents within five miles of the Santa Susana Field Laboratory report elevated autoimmune and endocrine disorders, new research in Risk Analysis finds
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SSFL and surrounding areas
view moreCredit: Dane Lazarus Science, Research, and Policy Specialist with USC Sea Grant
August 26, 2026 (Herndon, VA) -- Superfund sites typically cluster in low-income communities, where 62% of households earn less than $50,000 annually. But near the Santa Susana Field Laboratory in the hills northwest of Los Angeles people are much wealthier. This anomaly gave University of Southern California researchers an opportunity to study how wealthy residents respond when money cannot buy their protection from an environmental hazard.
Rocket testing (1949–2006) and nuclear reactor operations (1953–1980) left radioactive and chemical waste in the soil and groundwater at SSFL. A 1959 partial meltdown, considered the worst in U.S. history, contaminated both on- and off-site areas. And despite Superfund eligibility since 2007, the site remains un-listed on the National Priorities List, which means that any form of remediation is managed at the state and local levels.
Early investigations at SSFL found no significant increases in most cancers of concern, though bladder, blood and thyroid cancers were linked to living closer to the facility. Although there were significant data limitations, a 1992 state health report found cancer rates inconsistent with community-wide exposure. Despite the absence of definitive epidemiological evidence, many residents and advocacy organizations remain convinced that SSFL contamination has adversely affected community health.
This forthcoming research, published in Risk Analysis, aimed to answer three questions previous research had left unanswered. First, does health risk extend beyond the cancers typically studied, and does it scale with proximity to the site? Second, how do wealthier groups perceive and respond to environmental health risks? Third, do the residents in this sample area perceive and respond to contamination risk as predicted by Protection Motivation Theory, or do their responses differ?
In this study, researchers at USC surveyed 475 residents living within 15 miles (24 kilometers) of SSFL. Of the population sampled, 56% earned $100,00 or more annually.
“We expected to see wealthier people take more actions to protect themselves given their greater capacity to cope and affect change,” said lead author Jenna Blyler of the USC Wrigley Institute for Environment and Sustainability. “Instead, fear of the contamination was what motivated protective action, rather than their perceived ability to manage the risks.”
Key Findings
Illness tracked with proximity. Autoimmune disorders were reported by 18% of residents living within five miles of SSFL, compared with 4% of those 11 to 15 miles out. Metabolic and endocrine disorders followed the same pattern, 15% versus 2%.
More than a third of residents reported at least one chronic diagnosis since moving in. That is on par with the national rate of 38%, even though chronic illness is normally far less common in high-income communities.
Fear drove action more than confidence did. Residents who saw the contamination as severe and felt personally vulnerable were the most likely to take precautions, such as filtering tap water, leaving shoes at the door, skipping garden produce or staying inside on windy days. Usually, one’s confidence in their ability to effectively manage its risk also creates a powerful motivation to act.
Health anxiety helped explain the pattern. Residents reporting higher health anxiety took more precautions, and anxiety accounted for part of the link between existing illnesses and protective behavior.
The more expensive residents believed protection would be, the more of it they took. That runs counter to decades of risk research. It may reflect a community that can absorb the cost, or one that reads a higher price tag as a sign that something is effective.
The study is based on self-reported diagnoses collected at a single point in time and does not establish that SSFL contamination caused the health conditions residents reported.
Authors Available for Interview:
Jenna Blyler, corresponding author, Wrigley Institute for Environment and Sustainability and Department of Psychology, University of Southern California.
Joseph Árvai, Wrigley Institute for Environment and Sustainability, Department of Psychology, University of Southern California, and Decision Research.
"Silver spoons in toxic soups: Predictors of protective action in affluent neighborhoods near a contaminated research facility," Risk Analysis
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About Risk Analysis
Risk Analysis is a peer-reviewed journal publishing original research on the assessment and management of risks across disciplines including public health, engineering, environmental science, social science and policy. Risk Analysis, founded in 1980, is published by Wiley on behalf of the Society for Risk Analysis.
Journal
Risk Analysis
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
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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.
view moreCredit: 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).
Journal
Engineering Failure Analysis
Method of Research
Computational simulation/modeling
Subject of Research
Not applicable
Article Title
Impact of input uncertainties on the failure frequency of Korean nuclear piping systems based on probabilistic fracture mechanics
Article Publication Date
1-Nov-2026
$25M grant reinvigorates nuclear science, security research
University of Tennessee part of consortium awarded DOE grant
University of Tennessee at Knoxville
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University of Tennessee, Knoxville professors work on resarch that is part of a five-year, $25 million grant by the US Department of Energy’s National Nuclear Security Administration.
view moreCredit: University of Tennessee
The University of Tennessee, Knoxville is part of a consortium led by the University of California, Berkeley that was awarded a five-year, $25 million grant by the US Department of Energy’s National Nuclear Security Administration in December 2025.
This is the fourth time the federal government has awarded such a grant to the Nuclear Science and Security Consortium (NSSC) for research and development in nuclear science, engineering, and security. The NSSC includes six national laboratories and nine universities, including UT.
Work on the new grant began in July 2026. MSE Professor Mariya Zhuravleva is the principal investigator (PI) of UT’s efforts under the consortium; joint MSE-Department of Nuclear Engineering (NE) Research Professor Chuck Melcher and NE Assistant Professor Sandra Bogetic are co-PIs.
“Participation in the NSSC consortium connects us with leading experts in diverse fields of nuclear non-proliferation,” Zhuravleva said. “It helps expand the impact of (our) scintillation (radiation detection) materials research.”
In fact, one of UT’s focus areas under the grant is developing and characterizing new scintillators. This work relies on the facilities and experts in UT’s Scintillation Materials Research Center (SMRC), which Melcher directs.
“The SMRC has built an international reputation (for) development of scintillation materials due to a combination of its scientific impact, rare experimental capabilities for crystal growth and characterization, and hands-on student training,” said Zhuravleva. “It is not just a strong university lab, but a globally recognized center for scintillator research.”
Innovative Scintillators
Using the extensive laboratory infrastructure of the SMRC, the UT research team will pursue fundamental materials discovery and identify the best ways to scale up the production of high-performance scintillators that are expected to eventually replace the current state of the art.
“Very few universities in the United States still maintain this level of crystal growth infrastructure and hands-on training,” Zhuravleva said. “(Our) expertise in growth methods such as Czochralski, Bridgman, and micro-pulling-down, along with advanced scintillator characterization, (set UT apart).”
UT’s scintillation team will also collaborate with Los Alamos National Laboratory (LANL) and Lawrence Berkeley National Laboratory (LBNL) to identify new processing methods that can be used to optimize scintillators.
“For more than five years, MSE and NE will continue to collaborate (with the NSSC) to advance materials for radiation detection and nuclear energy systems,” Melcher said. “Innovation in detector materials is at the core of developing novel detector capabilities.”
Educational Benefits
In addition to fundamental research and new scintillator development, the NSSC grant supports the SMRC’s continuing efforts to expand knowledge of scintillator materials and methods beyond Rocky Top.
UT, ORNL, and the Air Force Institute of Technology jointly held the first Scintillator Summer School in the summer of 2025; thanks to the DOE’s ongoing support, the program will be held again this August.
“The Scintillator Summer School (brings) graduate students from other US universities to UT and ORNL for hands-on training in synthesis and scintillation characterization, exposure to cutting-edge applications, and networking with experts,” Zhuravleva said.
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