Reactor Meltdown Research Articles

ANALYSIS OF METHODS FOR SIMULATING THE DECAY HEAT IN CORIUM WHEN MODELING A SEVERE ACCIDENTS AT NUCLEAR POWER PLANT

It is known that during development of a severe accident at a nuclear power plant, the melting of core materials and theformation of corium occurs. A feature of corium is the presence of a decay heat, which contributes a lot to the nature of its interaction with the structural materials of the reactor facility. In this regard, quite serious requirements are imposed on methods for simulating decay heat in the corium prototype, which relate to both the uniformity of the volume distribution and its intensity. This paper presents a comparative analysis of existing methods for decay heat simulation in corium, which are used at various experimental facilities investigating the operation of passive protection systems in severe accidents with reactor meltdown at nuclear power plants. By comparing the advantages and disadvantages, a more practical method of decay heat simulation is determined and ways are proposed to further improve the chosen method to fully simulate the thermal field of a real corium.

Nuclear Meltdown Relocation and Core Catcher Analysis

Nuclear meltdown with the potential human and environmental harm is one of the major accident hazard (MAH) faced by nuclear power plants. Limiting (or entirely avoiding) criticality events are the main design strategies for reactors of generations 3½ and 4 (Gen3½ and Gen4). These include ensuring negative void and negative temperature coefficients (for both moderator and fuel) regardless of operational conditions, which provide a self-regulating mechanism that helps preventing accidents occurrence (i.e., to address safety and reliability aspects of Gen4’s goals). However, in severe accident scenarios (e.g. during loss-of-coolant, LOCA, events) where failure to extract heat from the reactor may lead to core degradation, strategies to mitigate reactor meltdown and relocation are critical in the design of safety protocols. This work aims to numerically investigate core relocation as an integrated multi-fluid and heat dynamics problem in which flow of melted materials (UO2, Zircaloy and graphite) are modelled through interface capturing/tracking methods. Two interface tracking/capturing methods were compared, the level-set volume of fluid method (VOF) in Ansys Fluent, and the compressive advection method (CAM) in Fluidity/ICFERST. Both methods are in good agreement for the core relocation simulation. An in-vessel core catcher (IVCC) of tungsten alloy was also proposed to demonstrate core degradation control strategy through cooling of the melted multi-materials. The IVCC was simulated with a multifluid model in Ansys Fluent, in a specified applied heat flux model. The thickness of the IVCC is 0.20 m and the heat flux used is 600 kW m-2. The tungsten material used was able to withstand both thermal and mechanical loads on the lower plenum by extracting decay heat from the corium.

Seeing Through the In/Visible: Akagi Shūji and the Limits of ‘Environmental Restoration’

This essay will explore the material and affective dimensions of the ongoing disaster caused by TEPCO’s Fukushima Dai’ichi reactor meltdowns from the perspective of Akagi Shūji’s photography. Mobilizing Twitter to record the uncanny traces of Fukushima city’s decontamination and recovery efforts, Akagi’s photography affords a renewed consideration of the lived struggles and unsettled realities of the ongoing disaster. Akagi’s work challenges the ideologies of recovery by recording the residual traces of the state’s decontamination process. His photographs constitute a record of bodily encounters with the visible and invisible remnants of disaster, disclosing limits within Fukushima’s ‘environmental restoration’ and its representation. I will explore how Akagi ‘traces’ the processes of physical and affective labor at work in decontamination through the specific context of the Twitter platform. I consider the ways this work operates as a place-based praxis to incite multi-layered and indefinite forms of affect, meaning, and value, elaborated through the aporia of the processes of decontamination and ‘recovery,’ thus recasting the prospects of the ‘environmental restoration’ of Fukushima in a decidedly different light. This novel practice is read as an ethical-aesthetic response that captures the ongoing disaster’s manifold dimensions as an event rife with deeply unsettled futurities.

Melt-mediated re-equilibration of zircon produced during meltdown of the Chernobyl reactor

Abstract The mineral zircon is used widely to constrain the age of rocks and the processes that formed them. Although zircon is robust to a range of physical and chemical processes, it may show evidence for rapid re-equilibration that is generally considered to reflect interaction with hydrous fluids. Here, we show that zircon grains that crystallized from melt produced during the catastrophic meltdown of the Chernobyl nuclear reactor exhibit re-equilibration textures that occurred in an environment without free water. The process of re-equilibration involved a melt-mediated interface-coupled dissolution-reprecipitation that took place over a few days to produce textures that are commonly observed in igneous and anatectic systems. Thus, the composition of zircon can be modified even in the absence of hydrous fluids in a short time frame. Through this process, zircon crystals may track the timing of the last silicate melt they interacted with.

Diffuse-interface modelling of multicomponent diffusion and phase separation in the U-O-Zr ternary system

The ternary mixture of uranium, oxygen and zirconium is investigated as a minimal model for corium, the mixture that forms after the meltdown of a nuclear reactor. Like corium, U-O-Zr exhibits a liquid–liquid phase separation between a metal-rich and an oxide-rich phase at high temperatures. A CALPHAD database built on an associate model is used to set up a ternary Cahn–Hilliard model, which can describe two-phase patterns in U-O-Zr. The interface structure and properties, which depend on the choice on the gradient energy coefficients in the free-energy functional, are studied in detail. It is found that interface adsorption is generally present due to the diffuse character of the interface, but that its magnitude is small, such that the model remains a robust and useful tool for future simulations of corium pool stratification dynamics.

Shielding of Ionizing Radiation in Nuclear Power Reactor Environments (A Technical Memorandum)

Since release of movie known as “China Syndrome” in early march of 1979, and was about story of a reporter who finds what appears to be a cover-up of safety hazards at a Nuclear Power Plant (NPP), and a hypothetical sequence of events following the meltdown of a nuclear reactor, in which the core melts through its containment structure and deep into the earth causing all kind of nuclear radiation. Nuclear accidents are one of the greatest debates that in several decades ago has risen around the world in past until now, we encountered with the worst nuclear accident in Three Mile Island (TMI) in 28 March of 1979, which was less than two weeks after release of the movie, which start raising the concern of radiation leak to environment from TMI-2 reactor. This start putting future of nuclear power industry driven energy producing electricity, into serious doubt and the matter become worst, when on 26 April 1986 the Chernobyl nuclear disaster occurred at the No. 4 reactor of this power plant and released huge amount of radiation into surrounding environment very dangerously that still exists today. We almost were about forgetting about these incidents by putting them in backburner of our mind, then on 11 March 2011 a huge tsunami hits cost of Fukushima, Japan, where Fukushima Daiichi nuclear power plant was residing and consequently caused its accident and it was the most severe nuclear accident in the world so far to this point that is still consider that was this event another China Syndrome? Radiations released from these accidents internally and externally to its environment is serious matter and needs serious attention by scientist, engineers and creators of these reactor and what could be done to shield them, when come to ionizing radiation, which is subject of this Technical Memorandum (TM)

Preserving Ukraine's Electric Grid During the Russian Invasion

In February 2022, the Russian Federation invaded Ukraine, a country with an interconnected electric grid.1 While most analysts have concentrated on the military dimensions of Russia's attack, the implications for energy infrastructure are both unprecedented and critically important. Russia has incentives to preserve reliable operation of Ukraine's electric grid. Both sides have shown restraint in attacking energy infrastructure. An apparent Russian objective is keeping hard‐to‐replace infrastructure intact, especially hydroelectric and nuclear plants. Ukraine's natural gas pipeline system depends on grid electricity for its centralized control. Russia profits from transmission of its natural gas through Ukraine's pipelines to Europe. All countries seek to avoid infrastructure accidents and human migrations that are disruptive to their own societies. Nonetheless, by export ban, naval blockade, and physical attack, Russia has disrupted fuel supplies for Ukraine's generating plants. Interconnected electric grids are vulnerable to cascading collapse after forced outages of generating plants, transmission system disruptions, and deliberate attacks. As winter approaches, fuel supplies for Ukraine's electric grid will be constrained and the possibility of grid collapse increases. If Ukraine's electric grid were to be inoperable for a prolonged period, the result could be widespread death by famine, disease, and, in winter, hypothermia. Nuclear reactor meltdowns and spent fuel pool fires could also result, with radiation release extending beyond Ukraine's borders. Millions of refugees would cross the borders of Poland, Russia, Belarus, and other regional neighbors. Ukraine should develop a robust plan for electric grid restoration, including asking the Ukrainian people for their assistance during emergencies. To this end, financial and other targeted support for Ukraine's electricity sector by European and other allies may be essential to reduce the prospect of long‐term grid collapse. Events in Ukraine have public policy lessons for all nations with electric grids vulnerable to cascading collapse and long‐term outage.

Editorial

Editorial

Sir Frederick Edward Warner. 31 March 1910—3 July 2010

Frederick Edward (‘Ned’) Warner's childhood home was a London County Council flat in north London. He won a scholarship to Bancroft's School, where he was successful in both academic and sporting activities and was awarded an Exhibition to read chemistry at University College London. Following this chemistry degree he took a diploma in chemical engineering. Sport, debates and left-wing politics dominated his student years. Warner was at the forefront in developing health, safety, risk assessment and environmental policies, particularly in their implementation to chemical process plant; early professional experience in several chemical manufacturing companies and extensive wartime work associated with acid manufacture had driven this commitment. He was a leading figure in the creation of the consulting company Cremer and Warner, and was appointed court expert to the Court of Enquiry following the Flixborough explosion in 1974. As treasurer of the Scientific Committee on Problems of the Environment, he chaired three of its major projects: Environmental Consequences of Nuclear War; Pathways of Artificial Radionucleotides; and Radiation from Nuclear Test Explosions. His expertise in the environmental effects of radiation put him in a position to lead the first international team to Chernobyl after the reactor meltdown in 1986. Warner served on many governmental, professional and academic bodies, particularly the Institution of Chemical Engineers, of which he was president in 1966–1967. He was knighted in 1968 for services to chemical engineering, was elected to the Royal Society in 1976 and was a founder fellow of the Fellowship of Engineering (now the Royal Academy of Engineering). He died in 2010, aged 100.

The Cosmology of Evidence: Suffering, Science, and Biological Witness After Three Mile Island.

The 1979 partial nuclear reactor meltdown at Three Mile Island was simultaneously hyper-visible and hidden from public view. It was the subject of non-stop media attention, but its causes and consequences required expert explanation. No fire or explosion marked the moment when insensible radionuclides escaped the facility. Yet, residents recalled a variety of troubling sights, sounds, odors, tastes, and sensations. Public distrust percolated in the interstices between government assertions that little radiation had escaped the facility and residents' sense memories of the incident. This article traces intertwined networks of activists from Japan and Pennsylvania as they mobilized legally, politically, and scientifically to develop evidence about the offsite effects of Three Mile Island. Exploring the distinct cosmology of evidence that activists marshaled, the article shows how they placed the messy, contingent, dynamic living world at the center of inquiries about the meltdown's consequences. Activists developed new practices of biological witness that reconfigured the interplay between scientific, legal, and moral authority, while concurrently reformulating sufferers' subjectivities and notions of scientific objectivity. In the process, they suggested that environmental justice entailed epistemic justice. Their cosmology of evidence served as an argument and a material proof that the beloved but suffering living world, and the sciences used to understand it, could and should frame the governance of industrial society's invisible harms.

New highly radioactive particles derived from Fukushima Daiichi Reactor Unit 1: Properties and environmental impacts

A contaminated zone elongated toward Futaba Town, north-northwest of the Fukushima Daiichi Nuclear Power Plant (FDNPP), contains highly radioactive particles released from reactor Unit 1. There are uncertainties associated with the physio-chemical properties and environmental impacts of these particles. In this study, 31 radioactive particles were isolated from surface soils collected 3.9 km north-northwest of the FDNPP. Two of these particles have the highest particle-associated 134+137Cs activity ever reported for Fukushima (6.1 × 105 and 2.5 × 106 Bq per particle after decay-correction to March 2011). The new, highly-radioactive particle labeled FTB1 is an aggregate of flaky silicate nanoparticles with an amorphous structure containing ~0.8 wt% Cs, occasionally associated with SiO2 and TiO2 inclusions. FTB1 likely originates from the reactor building, which was damaged by a H2 explosion, after adsorbing volatilized Cs. The 134+137Cs activity in the other highly radioactive particle labeled FTB26 exceeded 106 Bq. FTB26 has a glassy carbon core and a surface that is embedded with numerous micro-particles: Pb–Sn alloy, fibrous Al-silicate, Ca-carbonate or hydroxide, and quartz. The isotopic signatures of the micro-particles indicate neutron capture by B, Cs volatilization, and adsorption of natural Ba. The composition of the micro-particles on FTB26 reflects the composition of airborne particles at the moment of the H2 explosion. Owing to their large size, the health effects of the highly radioactive particles are likely limited to external radiation during static contact with skin; the highly radioactive particles are thus expected to have negligible health impacts for humans. By investigating the mobility of the highly radioactive particles, we can better understand how the radiation dose transfers through environments impacted by Unit 1. The highly radioactive particles also provide insights into the atmospheric conditions at the time of the Unit 1 explosion and the physio-chemical phenomena that occurred during reactor meltdown.

Reconstruction and revitalization in Fukushima a decade after the “triple disaster” struck: Striving for sustainability and a new future vision

While disasters occur relatively frequently almost none are of a scale as serious or complex as the triple disaster that devastated coastal regions of Tohoku, Japan. How can a region recover from a disaster as horrific as that triggered by the earthquake, tsunami and radioactive contamination linked to the explosions and reactor meltdowns at the Fukushima Dai-ichi nuclear power plant? Recovery and reconstruction in cases of large-scale disasters involves multiple activities which extend over long periods of time. This article focuses on one aspect of this -- the efforts that are being made to bring about deeper transformative changes that aim to make the region in and around Fukushima both more sustainable and resilient. The region is betting on becoming a leader of global significance in several areas: tsunami disaster management and recovery, nuclear disaster recovery know-how (technological, scientific, and social), renewable energy development, and hydrogen fuels and battery storage technologies. This effort is made difficult, however, by many evacuees’ reluctance to return to the region and the complex challenges associated with dealing with the aftermath of the nuclear accident.

Survey of awareness of radiation disasters among firefighters in a Japanese prefecture without nuclear power plants.

Japanese firefighting organisations are essentially run as village, town, or city units. The Great Hanshin Earthquake of 1995 led to the establishment of emergency support teams to ensure rapid action in response to disasters beyond the capacities of local fire departments. The 2011 Great East Japan Earthquake involved both a tsunami and a radiation disaster caused by a nuclear reactor meltdown, underscoring the need for responses in complex disasters. This study aimed to assess Nagasaki Prefecture firefighters' preparedness for, awareness of, and anxiety regarding radiation disaster response with the aim of elucidating the factors affecting individuals' decisions to accept or reject assignment to a radiation disaster response team. A questionnaire survey was carried out with 1,122 firefighters in three firefighting departments in Nagasaki Prefecture, which does not have nuclear power plants. In total, 920 questionnaires were returned, and the 784 that were valid were analysed. Among the participants, 39% replied that they would have no difficulty accepting assignment to a radiation disaster response team; most of them were under 30 years old and unmarried. This group also included significantly higher percentages of participants who were confident about radiation disaster response or, if anxious, believed things would turn out fine, as well as those who replied that they were able to use the necessary equipment. Furthermore, this group had significantly higher percentages of participants who replied that they would definitely participate in seminars and those who replied that their level of preparedness for radiation disasters was sufficient. The willingness to be assigned to a radiation disaster response team was linked to confidence about radiation disaster response and about handling materials and/or equipment. Therefore, it is considered that measures to increase firefighters' confidence regarding response to radiation disasters will be linked to more proactive measures if and when such disasters occur.

Transfer RNA Abundance Alters Modification Levels in Response to Peroxide Stress in the Radiation Resistant Fungus Cryptococcus neoformans

Cryptococcus neoformans is a radiation resistant fungus that has been found growing at the site of the nuclear reactor meltdown in Chernobyl, Ukraine. The Defense Threat Reduction Agency (DTRA) funds research on this organism to gain fundamental knowledge on radiation survival. Many DTRA projects cause soldiers to be exposed to radiation, therefore, gaining this information may have future therapeutic implications. Radiation causes cellular damage through the radiolysis of water into reactive oxygen species (ROS) – such as hydrogen peroxide. Cells have mechanisms such as antioxidants to regulate ROS levels. When ROS is too high, nucleic acids may be damaged. Transfer RNA (tRNA) – the molecule that carries the amino acid to the translational machinery – directly affect protein production. Hence, the integrity of tRNA is critical to antioxidant defenses and general protein synthesis. Chemical modifications to tRNA are abundant and crucial in all domains of life. Peroxide is known to cause changes in tRNA modification 5‐methylcytidine (m5C) levels in the model fungus S. cerevisiae. This work sets out to evaluate the effects of peroxide exposure on tRNA modification and tRNA transcript abundance in C. neoformans. Using liquid chromatography coupled with mass spectrometry (LC‐MS), modifications were relatively quantified and found to respond differently than in S. cerevisiae. Moreover, RNA sequencing information indicated that there are changes in tRNA abundance in response to peroxide. Since the modifying enzyme transcripts were not altered, the tRNA transcript abundance was reflected in the detected modification levels. Therefore, C. neoformans exhibits an increase in certain tRNA transcripts which then causes an increase in those tRNAs’ modifications. In conclusion, C. neoformans responds to peroxide stress via regulation of the tRNA pool – consequently altering the modifications within it.Support or Funding InformationThis work was funded by the Defense Threat Reduction Agency (DTRA) ‐ a branch of the US Department of Defense (DoD). Further support has been provided by the University of Cincinnati.

Meltdown: Earthquake, Tsunami, and Nuclear Disaster in Fukushima by Deirdre Langeland

Reviewed by: Meltdown: Earthquake, Tsunami, and Nuclear Disaster in Fukushima by Deirdre Langeland Elizabeth Bush Langeland, Deirdre Meltdown: Earthquake, Tsunami, and Nuclear Disaster in Fukushima. Roaring Brook, 2021 illus. with photographs Trade ed. ISBN 9781626727007 $19.99 E-book ed. ISBN 9781626726994 $9.99 Reviewed from digital galleys R Gr. 5-9 In 2011, twin disasters slammed Japan's Fukushima Prefecture, located near the offshore epicenter of a 9.1 earthquake, in rapid succession—a tsunami of greater height and force than local containment efforts could handle, and the rapid unraveling of the Fukushima Daiichi power plant, which lost its own power, and with that, the ability to secure its six nuclear reactors. Langeland has a lot of scientific heavy lifting to do: explaining the earth science behind the quake; hydraulics and geomorphology behind the tsunami; and engineering, chemistry, atomic physics, and human resources management behind the reactor meltdowns and the seat-of-the-pants scramble to minimize local and global danger in an environment too toxic to enter. She's up to the task, though, with well-placed science lesson insertions, supported by clear graphics and a deep well of often clever analogies aimed squarely at middle school readership. Plenty of color photographs are included, but this title is lighter on browser appeal than accessible science integrated with a tense, cautionary disaster narrative. A timeline, glossary, bibliography, sources notes, are included; the final book will contain an index. Copyright © 2021 The Board of Trustees of the University of Illinois

Cleanup and Complexity: Nuclear and Industrial Contamination at The Santa Susana Field Laboratory, California.

Environmental contamination, a legacy of industrial activity borne by numerous sites around the world, poses health risks for surrounding communities and presents serious cleanup challenges. One such site, the Santa Susana Field Laboratory (SSFL), served as an aerospace and nuclear energy research facility for over 50 years, during which time radioactive and other hazardous materials were unintentionally and intentionally released into the surrounding environment. These releases, including the partial meltdown of a sodium reactor, were hidden from the public for three decades. The site is now located in suburban Los Angeles, with 730,000 people living within a 10-mile radius. This paper evaluates the technical and social challenges underlying site cleanup at SSFL, including a complex geological setting, uncertain contaminant information, and a convoluted, evolving regulatory framework. These challenges, paired with historical secrecy on the part of responsible organizations and unclear layers of responsibility, have led to uncertainty and distrust within the surrounding community. Lessons learned from other remediated sites are assessed and recommendations for the SSFL cleanup are provided.

The Autoignition of Nuclear Reactor Power Plant Explosions

Abstract Explosive research proves that there is a common cause for most explosions in nuclear reactor power plants during normal operations and accident conditions. The autoignition of flammable hydrogen is a common cause for nuclear power plant explosions, where complex corrosion processes, nuclear reactions, and thermal-fluid transients autoignite explosions. Research evaluated increasingly complicated accidents. First, piping explosions occurred at Hamaoka and Brunsbuttel. Fluid transients compressed oxygen and flammable hydrogen to heat these gases to autoignition, where resultant explosions shredded steel pipes. This identical mechanism was responsible for pipe and pump damages to U.S. reactor systems since the 1950s, where water hammer alone has been assumed to cause damages. Small explosions inside the piping actually cause damages during nuclear reactor startups and flow rate changes. Second, explosions are caused by thermal-fluid transients during nuclear reactor restarts, following accidental nuclear reactor meltdowns. Disastrous explosions destroyed nuclear reactor buildings (RBs) at Fukushima Daiichi. Previously considered to be a fire, a 319 kilogram hydrogen explosion occurred at Three Mile Island (TMI). The explosion cause following each of these loss-of-coolant accidents was identical, i.e., after meltdowns, pump operations heated gases, which in turn acted as the heat source to autoignite sequential hydrogen explosions in reactor systems to ignite RBs. Third, the Chernobyl explosion followed a reactor meltdown that was complicated by a high energy nuclear criticality. The hydrogen ignition and explosion causes are more complicated as well, where two sequential hydrogen explosions were ignited by high-temperature reactor fuel.

Unexpected source of Fukushima-derived radiocesium to the coastal ocean of Japan

There are 440 operational nuclear reactors in the world, with approximately one-half situated along the coastline. This includes the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), which experienced multiple reactor meltdowns in March 2011 followed by the release of radioactivity to the marine environment. While surface inputs to the ocean via atmospheric deposition and rivers are usually well monitored after a nuclear accident, no study has focused on subterranean pathways. During our study period, we found the highest cesium-137 (137Cs) levels (up to 23,000 Bq⋅m-3) outside of the FDNPP site not in the ocean, rivers, or potable groundwater, but in groundwater beneath sand beaches over tens of kilometers away from the FDNPP. Here, we present evidence of a previously unknown, ongoing source of Fukushima-derived 137Cs to the coastal ocean. We postulate that these beach sands were contaminated in 2011 through wave- and tide-driven exchange and sorption of highly radioactive Cs from seawater. Subsequent desorption of 137Cs and fluid exchange from the beach sands was quantified using naturally occurring radium isotopes. This estimated ocean 137Cs source (0.6 TBq⋅y-1) is of similar magnitude as the ongoing releases of 137Cs from the FDNPP site for 2013-2016, as well as the input of Fukushima-derived dissolved 137Cs via rivers. Although this ongoing source is not at present a public health issue for Japan, the release of Cs of this type and scale needs to be considered in nuclear power plant monitoring and scenarios involving future accidents.

Radioactively-hot particles detected in dusts and soils from Northern Japan by combination of gamma spectrometry, autoradiography, and SEM/EDS analysis and implications in radiation risk assessment

After the March 11, 2011, nuclear reactor meltdowns at Fukushima Dai-ichi, 180 samples of Japanese particulate matter (dusts and surface soils) and 235 similar U.S. and Canadian samples were collected and analyzed sequentially by gamma spectrometry, autoradiography, and scanning electron microscopy with energy dispersive X-ray analysis. Samples were collected and analyzed over a five-year period, from 2011 to 2016. Detectable levels of 134Cs and 137Cs were found in 142 of 180 (80%) Japanese particulate matter samples. The median radio-cesium specific activity of Japanese particulate samples was 3.2kBqkg−1±1.8kBqkg−1, and the mean was 25.7kBqkg−1 (σ=72kBqkg−1). The U.S. and Canadian mean and median radio‑cesium activity levels were <0.03kBqkg−1. U.S. and Canadian samples had detectable 134Cs and 137Cs in one dust sample out of 32 collected, and four soils out of 74. The maximum US/Canada radio-cesium particulate matter activity was 0.30±0.10kBqkg−1. The mean in Japan was skewed upward due to nine of the 180 (5%) samples with activities >250kBqkg−1. This skewness was present in both the 2011 and 2016 sample sets.>300 individual radioactively-hot particles were identified in samples from Japan; composed of 1% or more of the elements cesium, americium, radium, polonium, thorium, tellurium, or strontium. Some particles reached specific activities in the MBqμg−1 level and higher. No cesium-containing hot particles were found in the U.S. sample set. Only naturally-occurring radionuclides were found in particles from the U.S. background samples. Some of the hot particles detected in this study could cause significant radiation exposures to individuals if inhaled. Exposure models ignoring these isolated hot particles would potentially understate human radiation dose.

Twenty-five years of environmental radionuclide concentrations near a nuclear power plant.

The areas in and along a 262-km length of the Susquehanna River in Pennsylvania were monitored for the presence of radioactive materials. This study began two months after the 1979 Three Mile Island (TMI) partial reactor meltdown; it spanned the next 25 y. Monitoring points included stations at the PPL Susquehanna and TMI nuclear power plants. Monthly gamma measurements document concentrations of radionuclides from natural and anthropogenic sources. During this study, various series of gamma-emitting radionuclide concentration measurements were made in many general categories of animals, plants, and other inorganic matter. Sampling began in 1979 before the first start-up of the PPL Susquehanna power plant. Although all species were not continuously monitored for the entire period, an extensive database was compiled. In 1986, the ongoing measurements detected fallout from the Chernobyl nuclear accident. These data may be used in support of dose or environmental transport calculations.