#radionuclide

[pacifistic-pineapple]

Hanford Nuclear Reservation 1944-1987

Part of the Manhattan Project, the Hanford site is the worlds first full-scale nuclear reactors that generated two thirds of the plutonium generated in the US. The operation resulted in tanks of toxic, radioactive sludge near the banks of the Columbia river, on of Americas largest rivers. Over time, improper storage resulted in leaching of over 60 different radionuclides. Hanford contains 60 percent of the nation’s high-level radioactive waste and is considered by many to be one of North America’s most contaminated nuclear sites.

Potential pathways of uptake for radionuclides in the area are present in sediments, soil, waters, and in the wildlife. While concentration of radionuclides flux in the Columbia River, on average 300,000 curies of activity is discharged per year. Benchmark for radionuclide exposure is 1 rad/year. Biota in the area were measured in 1992 by the DOE's contracted laboratory observed salmon eggs exposed to 0.00443 rad/d, 0.73 rad/d for the highest exposed fish and 1 rad/d for plant eating ducks. Most reproductive effects for adult fish are observed at 0.4 rad/d.

Once its closure in 1987, the Hanford site was placed in the National Priorities list in 1989. In 2003, the Department of Energy made an effort to reclassify all waste at the Hanford site in order to have no oversight by the EPA, states of Washington and Oregon, or by the Yakama Nation. Yakama Nation, the Shoshone-Bannock tribes, and the Snake River Alliance together sued the DOE and won: Courts noted that only Congress has the authority to reclassify waste. Though, in 2019 the DOE “reclassified” the toxic nuclear waste in Hanford’s tanks without any oversight by the U.S. EPA, the state or by the Yakama Nation, contradicting explicit directions of the Nuclear Waste Policy Act passed by Congress in 1982 and violating the Yakama treaty.

Though it is estimated to cost  $240 billion to clean up the site by the US Government Accountability Office, as of 2009 over $100 Billion have been invested in the site to remove/replace leaky storage tanks.

[whats-in-a-sentence]

Table 27.1 gives the half-lives of some naturally occurring and synthetic radioactive nuclei and their modes of decay.

"Chemistry" 2e - Blackman, A., Bottle, S., Schmid, S., Mocerino, M., Wille, U.

[proteusolm]

It's kind of fun having a special interest in something very complicated which I lack the education background to fully understand. It means there will be more to enjoy learning about it for the forseeable future!

[smbhax]

Fallout from U.S. atmospheric nuclear tests in New Mexico and Nevada (1945-1962)

-- https://arxiv.org/ftp/arxiv/papers/2307/2307.11040.pdf

[nuclearmedicinetherapy]

PRRT is a molecular technique in which a radioisotope which is labeled with a small body that actually targets a particular receptor which is known as the somatostatin receptors is used to treat a specific kind of tumor known as a Neuroendocrine Tumor.

[emed123]

Everything you need to know about subspecialties of Radiology

Radiology is the art of interpreting visual information by using very complex equipment creating very complex images. The field of radiology is a lot more complicated than reading an x-ray and determining a problem. Undeniably, radiology is complex and includes several subspecialties to choose from.

The Basics

After completing high school studies, on average, it will take 13 years to become a Radiologist. The 13 years includes completing an undergraduate degree, which usually takes four years, followed by four years of Medical school, then a one-year internship, followed by four years of residency training in Diagnostic Radiology. Additionally, more than 95% of physicians who complete residency always prefer to pursue a Fellowship in radiology sub-specialty. In addition, a minimum of one year of additional training.

Radiology Categories:

Radiology generally falls into 2 categories: Diagnostic and Interventional Radiology. Diagnostic radiologists use imaging technologies, such as ultrasounds, CT scans, MRIs, and PET scans to diagnose a patient's health condition. Interventional radiology uses image-guided procedures (angioplasty, ablation, and stent placements) to diagnose and treat various patients' conditions.

Both diagnostic radiology and interventional radiology have further subspecialties. Most of the radiology subspecialties require a one to two-year fellowship completion.

Radiology subspecialty options include the following:

Diagnostic Radiology

A diagnostic radiologist uses x-rays, ultrasound, radionuclides, and electromagnetic radiation to diagnose and treat a patient’s health problems. The required training for diagnostic radiology is five years: one year of clinical training, followed by four years of radiology training.

Interventional Radiology

Interventional radiology (IR) is the most procedure-oriented and fast-paced radiology subspecialty. An incumbent can directly go into an integrated interventional radiology residency after medical school, which is a 6-year path. After completing your radiology residency, you can also do this as a 2-year fellowship.

Procedures in interventional radiology are minimally invasive and can be performed using wires and catheters. Interventional radiology helps you cure cancers, salvage critical limbs, stop life-threatening hemorrhage, and reverse disabling genitourinary conditions through an incision merely centimeters long.

Neuroradiology

Neuroradiology is for those who are highly intellectual, driven by curiosity, and have a great passion for learning. The main job is to diagnose pathologies involving the brain and spinal cord and guide clinical decision-making. Neurological radiology is an interdisciplinary approach to apply radiology in the diagnosis and cure of neurological challenges.

Diagnosing strokes is one such condition, where neuroradiologist deploys his radiology related acumen to diagnose the patient’s condition. If you are interested in more procedural interventions with the brain and spinal cord, you can pursue a neuro-interventional fellowship afterward.

Radiology for Diagnosis and treating Breast cancers

Radiology is applied under the clinical settings to perform mammograms and biopsies on female patients. Radiologists that specialize in treating breast cancers may lead a comfortable career path with occasional night shifts, as there would not be many emergency conditions while treating breast cancer cases.

Pediatric Radiology

Pediatric radiology is strictly for those who enjoy the pathology of pediatrics but not necessarily the clinical aspect. Pediatric radiologists use imaging and interventional procedures related to diagnosing, caring, and managing congenital abnormalities and diseases particular to infants and children. A pediatric radiologist also treats diseases that begin in early childhood and cause impairments in adulthood.

Musculoskeletal Radiology

Musculoskeletal radiologists’ responsibilities revolve around orthopedics and sports medicine in diagnosis and management. As a result, musculoskeletal radiologists will be working side by side with the orthopedic specialists. It’s a highly procedural field, with joint aspirations for diagnosis, joint injections for pain, and kyphoplasties to treat vertebral fractures.

Body Imaging & Body MRI

Body imaging and MRI is the work-horse of radiology and the backbone of the clinic. Radiation oncologists use ionizing radiation and other modalities to treat malignant and benign diseases. Radiation oncologists may also use computed tomography (CT) scans, ultrasound, magnetic resonance imaging (MRI), and hyperthermia (heat) as additional interventions to aid in treatment planning and delivery.  

Summary

Radiology has been a fast-growing field, and it plays a critical role in the health system. The demand for professional radiologists in clinics, hospitals, and physicians' offices is at an all-time high.

With the advent of technology, the demand for radiology will continue to increase and extend its impact on inpatient care – from prevention and diagnosis to treatment and recovery of chronic and acute cancerous diseases. Significance of radiologists will continue to increase in the future. So, choosing a profession as a radiologist will be the best decision ever for all upcoming medical professionals.

[fis-paprikas]

K-40/Ar-40 dating????? congrats to them. Yuri wins <3

[rnmcenterrohtak]

Radionuclide therapy, also known as targeted radiotherapy, is a specialized medical treatment that employs radioactive substances (radionuclides) to selectively deliver radiation to specific diseased tissues within the body. In Rohtak, this advanced form of therapy is offered as part of a comprehensive approach to managing various medical conditions, particularly cancer.

[oncozine]

In this –this episode of the Onco’Zine Brief, Peter Hofland is talking with Dr. Matthias Bucerius. Dr. Bucerius is Vice President and General Manager at MilliporeSigma. He is responsible for Contract Development and Manufacturing Organsation (CDMO) business of the company, leading a fully integrated global team with Manufacturing Operations, Commercial, Marketing & Strategy, Technology & Innovation organizations. The company is helping its clients in developing and manufacturing a variety of products, including antibody-drug conjugates. Antibody-drug conjugates or ADCs are targeted therapies that have opened new ways in targeting diseases like cancer and hematological malignancies. What is unique about ADCs is that they leverage the specific targetability benefits offered by antibodies and combine that with the high potency of small-molecule drugs. This combination makes these agents uniquely targetable therapies. And unlike traditional chemotherapy, these ADCs target tumors by delivering the attached payload to destroy cancer cells while sparing the healthy or normal cells, thereby potentially reducing negative side effects for patients.

[mrunalnerkarblog]

The market opportunities for key players to enter into this market are high owing to less competition and increasing demand for peptide receptor radionuclide therapy in the Italy market. Moreover, increasing incidence of cancer in Italy is directly contributing to demand for PRRT therapy. These factors are creating growth opportunities for companies to focus on research and development of new drugs. As per the Italian Association of Medical Oncology’s report, in April 2019, 71,000 new cases were diagnosed with new additional cancer cases.

[theproblematicone]

"Radionuclides". That's a new thing to be afraid of!

you know a report is about to get bad when they mention a technicians mass

[ohsalome]

It would be intentionally dishonest to say that the Chornobyl Disaster of 1986 was an accident, as official party line stated. According to the nuclear scientists who analyzed the event, not only was it inevitable, but "it was just a matter of time and which power unit that would not withstand the first". The problems were present on every single level - starting from the materials used for the plant, and ending with the work protocols.

The higher-ups at Moscow not only knew that the Chornobyl Nuclear Plant was one of the most dangerous NP in ussr, and that "the radioactive danger of a potential disaster is 60 times than that of Hirosima and Nagasaki" - according to the results of the official KGB investigation; at the moment of the disaster the project managers had reports of at least 29 emergency shutdowns, 9 accidents and 68 key equipment failures that had already happened on the Chornobyl NP. The real number could be much higher but is currently unknown due to many KGB archives remaining classified.

For example:

On September th 9th 1982 at 18:18 during a trial run of the reactor of the first power unit there was a significant release of radioactive substances into the environment. The total activity of beta-emitting radionuclides exceeded natural levels by dozens of times, and in the area of Chystohalivka village, located 5 kilometres from the Chornobyl power plant, the figure was exceeded by hundreds of times. The investigation team found about 20 gross violations in the operation of the power unit. Instead of following the protocol of alerting the civillians and declaring the village a "temporarily contaminated territory", KGB implemented measures to hide the fact of an accident ever happening.

Every report of the KGB investagative teams that we have access to ended the same: taking measures to conceal the very fact of the accident occurence. It came to the absurd situations when the workers were unaware of the fact that the previous shift's team had encountered an emergency situation.

------

Source: The KGB dossier on Chornobyl - from construction to accident

[proteusolm]

I’ve come back around to the obsessively reading wikipedia pages about nuclear incidents and everything related to radioactivity part of the hyperfixation cycle 

[nuclearmedicinetherapy]

Neuroendocrine Tumors often present with large volume Liver Metastases and because these are relatively Indolent Tumors the patient often does not know that he has a Neuroendocrine Tumors specially those who have non-functioning Neuroendocrine Tumors.

[reactor-four-official]

The Search for the Fuel: The Elephant’s Foot

From the first days of the accident, locating and monitoring the 190 tons of nuclear fuel that had been in the fourth reactor at the time of the explosion was a top priority for the commission overseeing the cleanup. They wanted to ensure that no further disasters would unfold at Chernobyl; with the Soviet Union's international prestige already significantly battered, it was critical that they felt in control of the situation once more. After the initial plume of radionuclides from the burning reactor declined significantly in the early days of May 1986, it was established by the scientists assisting the Commission that the nuclear fuel had three distinct hazards that it could present. These were a radioactive hazard, a nuclear hazard, and a thermal hazard.

Perhaps the most obvious, the radioactive hazard was that of the aforementioned radioactive cloud rising from reactor 4. Although it had decreased significantly, it was still a danger and could potentially flare up again unless measures were taken to prevent it.

The nuclear hazard was the fear of a new uncontrolled nuclear chain reaction like the one that had initially destroyed the reactor. The state of the core was unknown at this time, and scientists had to determine if any of the reactor assembly was still in place and if it or any other mass of fuel had the necessary elements to sustain another catastrophic reaction. Basically, it was a possibility that the fuel could gather in such a way that a new nuclear chain reaction would start.

Finally, the thermal hazard was that of the hot nuclear fuel melting through the concrete of the unit block and into the Earth below. This is known as the “China Syndrome” after a movie of the same name. It was also feared at the time that the fuel could melt down into the bubbler tanks below the reactor, which stored a large reservoir of cooling water, and cause a significant steam explosion. This was the main concern of the government commission and the most effort was put in place to reduce this hazard first.

Having established the potential dangers of the fuel the Commission wanted absolute assurance that the hazard was not an immediate threat to the safety of the workers at Chernobyl and the world at large.

This undertaking was assigned to the team of experts assembled by the Kurchatov Institute, a scientific institute for the study of nuclear physics. It was established early on that most fuel was somewhere within the ruins of the fourth unit, since very little was ejected by the explosion. The building itself was enormous, with winding passages known only to those who worked for years in its labyrinthine walls.

Below: A schematic diagram of the fourth unit block seen from the west. The dimensions of the building are marked in meters. Note the enormous region of rooms located below the reactor core (Closed Reactor Space on this diagram). The area at the bottom of the building with the large vertical pipes are the bubbler tanks that held emergency cooling water for the reactor. This was the area scientists feared a steam explosion if the fuel lava gained access.

Adding to the problem of the scale of the search area was the fact that the building was potentially unstable due to the explosion of the fourth reactor. Rubble filled hallways and walls and ceilings sagged dangerously. Radiation levels fluctuated wildly within the building, with some areas almost entirely safe and others able to cause sickness and death in minutes. Even more pressing was that starting in the spring of 1986, the lower levels of the fourth unit began to slowly fill with fresh concrete. The Ministry of Medium Machine Building unit US-605, who were building the Sarcophagus to cover the radioactive remains of the unit, poured concrete into the structures of the Sarcophagus 24 hours a day. However, huge gaps and sinkholes existed in their work area, and a good portion of the concrete pumped into the Sarcophagus ended up deep in the lower levels of the block. This concrete blocked hallways, doors, and even (as they would later come to learn) covered up some of the melted fuel.

It was not until late spring of 1986 that exploration of the fourth unit block began. In June of 1986, two men were probing a steam distribution corridor in the southeast corner of the block from another corridor just below it using a powerful dosimeter which could detect radiation levels of up to 3,000 roentgens per hour. Since radiation levels in the stairway up to the corridor they were probing were already quite high (~25 roentgens per hour) they decided to send the detection head of the device up the stairs ahead of them via an assembly of metal rods. As soon as the device entered the corridor above, it went off the scale and burnt out. From this result the team was able to pinpoint a source of extreme gamma radiation.

In December of 1986, and expedition was mounted to room 217/2 to make visual contact with the suspected fuel concentration. Moving along the steam corridor this time, the team spotted a large metallic gray mass sitting neatly within the corner of the room. This formation was dubbed the "Elephant's Foot" (though some source translate it as"Elephant's Leg") due to its similarity to the leg of an elephant. The black glassy mass emitted over 8,000 roentgen an hour, deadly after just one and a half minutes (this is the maximum recorded emission, the levels would decrease significantly in the months after the disaster). For the first time, the theory of fuel lava was visually confirmed. The team branded the materiel "lava-like fuel containing masses" (LFCM).

Below: A picture of the Elephant's Foot from the direction which it was first observed. The railings just behind the main formation (Label 1) is the railing around the metal stairs from which the formation was first detected via dosimeter. Note the streaks of fuel above the formation showing where the fuel had dripped down from above. Label 4 denotes the "fresh" concrete that made its way into the building during the construction of the Sarcophagus.

Below: a view of room 217/2 from above. The red is the Elephant’s Foot, the orange is the fresh concrete, and the gray are the walls of the block. The Foot itself is the accumulation closest to the bottom left of the photograph. You can see there is more lava in an unnamed formation next to it.

After locating the fuel and taking some pictures, the team was tasked with analyzing what the lava was composed of. This may seem kind of obvious, but really it was not known what was in the LFCM. Presumably the fuel of course, but what else? It had been debated from the early days of the accident if the efforts to douse the fire and melting fuel with lead, boron, and sand had been effective (I refer here to the April 26th-May 12th aerial bombardment campaign of the reactor via helicopter- I will make a post on this effort at a later time and link it here). The contents of the fuel is an interesting topic which I will not go over more in this post. You can find more info on the quest to get a piece of the LFCM here.

After procuring a sample, one issue remained. They had found some of the fuel, but nowhere near the total amount. The grand majority of the fuel had yet to be located. By the summer of 1987 the fresh concrete that had run into the lower levels of the block began to cause real obstacles to the scientists. Many rooms suspected to contain fuel were inaccessible or could not be reached safely. A new approach was needed.

At the end of 1987 the Kurchatov team was reassigned to be part of the adventurously named Chernobyl Complex Expedition (CCE), an enormous liquidation effort that was tasked with exploring the interior of the Sarcophagus and locating the rest of the fuel in the years after the disaster. The CCE was composed to representatives from all the major Soviet scientific institutions, as well as builders and engineers. At its peak over 3,000 people worked as part of the Expedition. Through it all, the main core of this group was the scientists from the Kurchatov Institute.

Backed by resources of the entire CCE, the scientific team sought new approaches for searching for the fuel. After extensive discussion, the scientists came up with a rather ingenious solution. They would use coring drills like those used in oil drilling exploration set up in specially decontaminated rooms in the fourth unit block to drill so called ‘wells’ into inaccessible rooms. Through these they would send specially built monitoring equipment. These included thermometers, periscopes, and radiation sensors. Not only could they monitor the LFCM with this equipment, they could also obtain information about the building and the LFCM via analysis of the cores made by the drill. This allowed them to remotely locate, monitor, and sample the LFCM with minimal risk to personnel.

Below: A schematic of the wells drilled at the 9 meter mark below the reactor containment vessel. The purple lines are the wells themselves, with the gray being the concrete walls of the block. The large blue cross is the metal support Scheme S. I provided this as an example of how the wells were drilled and laid out. For more info, feel free to contact me.

Below: a member of the CCE operates a drill in the bowels of the fourth unit block. Note the protective clothing he is wearing to prevent the spread of airborne radiological contamination.

Between 1988 and 1992 a total of 134 wells were drilled between the 9 and 16 meter marks (the method by which levels of the plant are identified) and at the 20, 21, and 25 meter marks. It was eventually determined that over 180 of the 190 tons of fuel remained in the reactor block. The missing ten tons had either been blown out of the active zone and into the area around the reactor by the explosion, or had vaporized into the radioactive column that had emerged from the reactor in 1986. The remaining fuel within the block took the form of the LFCM, as well as dust. The dust created by the fuel is the main radiological enemy post 1986 and continues to be an issue to this day. Primarily composed of plutonium, the dust has thankfully remains mostly within the Sarcophagus. The LFCM, initially almost indestructible, has started to crumble and decay. As time goes on this creates even more dust, and the formations slowly erode away. This has contributed to a significant drop in gamma radiation emissions from the fuel masses and allowed for further study of the premises of the fourth unit block.

In 1994, the Complex Expedition used data collected from these wells to compile an official report on the status of the fourth unit block. With their findings published (and the Soviet Union dissolved) the CCE disbanded. Many of the scientists who worked on the expedition (and even some who were on the original Kurchatov Institute team) continued to work at Chernobyl for years. Expeditions are still sometimes mounted into the Sarcophagus, but they have not been carried out with any regularity since the early 2000s. However, visual inspection remains the only way to accurately monitor the condition of the LFCM.

You may be left wondering: how exactly did these men navigate such a radioactive environment without adverse effects? Once again I shall make a post on this in the future, but the main answer is: speed! Defense against radiation (with some exceptions) is as simple as not lingering in high radiation areas. To facilitate safe movement through the block, the scientists located and marked safe areas of reduced radiation levels (such as the room in this post) as well as dangerous areas to avoid. In the end, only a select few “Stalkers” actually set foot within the ruins of Reactor 4.

This post serves as the (admittedly lose) historical context for the exploration of the fourth unit block and the location of the LFCM. I will be making another post about the fuel rest of the fuel soon. I always feel bad for the other fuel formations because the Elephants Foot gets all of the attention. This will be a lot more technical, with locations and diagrams (joy of joys!) of the fuel as well as more context to its identification.

[timberwind]

This is a fun paper - I'd always kind of assumed the reason Io and Europa are relatively* dry is because of their high tidal heating having desiccated their surfaces. Seems this is plausibly not actually the case! More likely that they just formed inwards of the ice-line of the jovian circumplanetary disk, similarly to how the inner planets in the Solar System are rocky and the outer planets and moons are volatile-rich.

Particularly interesting to me for worldbuilding was this bit:

Actual numbers for the correlation between tidal heating and ice shell thickness! I've always wondered just how much internal heat flux you'd need for a super-thin ice shell that could let some visible light through (like you see under the thin sea ice in the Arctic and Antarctic oceans) in areas with locally thinned ice above hydrothermal upwellings. Turns out the answer is "quite a bit, probably a bit more than 10x the heat flow of present-day Io", but plausibly not completely unachievable**, especially with the mention of periods of high-eccentricity - and concomitant high tidal heating - in the histories of moon systems that exhibit Laplace resonance. The more exciting thing is that this implies that a moon with a higher water mass fraction could migrate into an Io-like orbit and not be desiccated, which could yield some interesting cryovolcanism from the thinned out ice shell - plausibly even temporary melt lakes like the ones which we've seen frozen-out remnants of on Triton!

(*) Europa is of course famous for being a wet moon with an ocean, but notably it only has a water mass fraction of about 5-9 percent. While being about three times the mass of all the water in all the oceans on Earth, this is teeny-tiny in comparison to Ganymede's water mass fraction of 50 to 30 percent - tens of times the total surface water inventory of the Earth! Io, on the other hand, is very very dry to the best of our knowledge. Unpleasant place.

(**) This becomes far more reasonable with a larger icy moon in a younger star system like Epsilon Eridani (age cca 400-800 million years), where the residual heat of formation and radionuclide decay in the hearts of these worlds has had less time to diminish.