Radioactive materials iodine

The teams should have instruments designed to monitor all radioactive material (iodine, cesium, strontium, and tellurium) that may be released during an accident. If air samples are taken, their analysis could take several hours. Monitoring teams typically will be dispatched into the emergency planning zone (EPZ) within an hour after initiation of a severe release. 

Half-lives span a very wide range (Table 17.5). Consider strontium-90, for which the half-life is 28 a. This nuclide is present in nuclear fallout, the fine dust that settles from clouds of airborne particles after the explosion of a nuclear bomb, and may also be present in the accidental release of radioactive materials into the air. Because it is chemically very similar to calcium, strontium may accompany that element through the environment and become incorporated into bones once there, it continues to emit radiation for many years. About 10 half-lives (for strontium-90, 280 a) must pass before the activity of a sample has fallen to 1/1000 of its initial value. Iodine-131, which was released in the accidental fire at the Chernobyl nuclear power plant, has a half-life of only 8.05 d, but it accumulates in the thyroid gland. Several cases of thyroid cancer have been linked to iodine-131 exposure from the accident. Plutonium-239 has a half-life of 24 ka (24000 years). Consequently, very long term storage facilities are required for plutonium waste, and land contaminated with plutonium cannot be inhabited again for thousands of years without expensive remediation efforts. 

In a technique known as medical imaging, tracers are used in medicine for the diagnosis of internal disorders. Small amounts of a radioactive material, such as sodium iodide, Nal, which contains the radioactive isotope iodine-131, are administered to a patient and traced through the body with a radiation detector. The result, shown in Figure 4.11, is an image that shows how the material is distributed in the body. This technique works because the path the tracer material takes is influenced only by its physical and chemical properties, not by its radioactivity. The tracer may be introduced alone or along with some other chemical, known as a carrier compound, that helps target the isotope to a particular type of tissue in the body. 

Most of the labeled antibodies used to date in immunoradiometric assays have been eluted at pH 2.0. In a few cases the recovery of antibodies has been measured and may be as high as 80%. Certain losses are inevitable and even desirable. Damage will occur due to iodine, radiation, and oxidation, and it is the aim of the procedure selectively to discard these along with antibodies of lower affinity. Although further radioactive material can be eluted by the reduction of pH below 2, such material has never been satisfactory for assays in the authors hands. It is not certain whether this represents antibodies of still higher affinity that have been irreversibly damaged by the extreme pH or small amounts of tightly adsorbed nonspecific protein or even breakdown of the immunoadsorbent itself. Naturally, because the immunoadsorbent is itself protein it is impossible to eliminate iodination of this protein. 

The Chernobyl accident involved the largest short-term release from a single source of radioactive materials to the atmosphere ever recorded. Of the materials released from the reactor core, four elements have dominated the short-term and long-term radiological situation in the affected areas of the USSR iodine (primarily caesium ( Cs, Cs), strontium (primarily Sr) and plutonium ( Pu, " Pu). In addition, highly radioactive fuel fragments (hot particles) were released. 

The destroyed reactor released a very large amount of radioactive material into the environment lO becquerels. Although the discharge included many radioactive chemical elements, just two of them—iodine (in the short term) and caesium (in the long term)—were particularly significant from a radiological point of view. 

Medical science also uses small traces of safe radioactive materials to track the passage of materials around a body or plant. Radio-thallium-201 is used to assess the damage to heart muscles after a person has had a heart attack. Radioactive iodine-131 is used in the treatment of thyroid disorders. 

Sodium Hodide in 40 mM NaOH, activity 2 mGi in 20pi. Gaution Radioactive material Store at ambient temperature, 15-20°G. Retains iodination efficiency for over 2 months in storage. 

Radloiodlne Treatment Radioiodine therapy is particularly well-suited for the treatment of autonomously functioning thyroid tissue. Radioactive iodine, like the natural element, is taken up by the thyroid gland via an active process (the sodium iodide symporter) and accumulates within the thyroid gland. The therapeutic effect occurs as a result of tissue destruction (radiation thyroiditis) caused by short-reached (3 radiation detection is enabled due to emission of a small portion of irradiation. The radioactive material is selectively trapped by the more active autonomously functioning cells and, to a lesser extent, by normal thyrocytes, which depend on TSH stimulation to increase iodine uptake. 

Medical uses of radioactive sources include sterilization, implants using radium, scans using iodine, and therapy using cobalt. X-rays are used in diagnostic medical procedures. In addition to medical facilities, radioactive materials may be found in research laboratories, educational institutions, industrial applications, and hazardous waste sites. 

Potassium iodide, also called KI, only protects a person s thyroid gland from exposure to radioactive iodine. KI will not protect a person from other radioactive materials or protect other parts of the body from exposure to radiation. It must be taken prior to exposure (for example, if people hear that a radioactive cloud is coming their way) or immediately after exposure to be effective. Since there is no way to know at the time of an incident whether radioactive iodine was used in the explosive device, taking KI would probably not be beneficial.Also, KI can be dangerous to some people. Taking KI is not recommended unless there is a risk of exposure to radioactive iodine. 

Because the thyroid will rapidly absorb any iodine that is in the body, people may need to take KI tablets soon after an incident that involves radioactive iodine. The KI will saturate the thyroid gland with iodine and help prevent it from absorbing radioactive iodine. However, KI does not prevent the effects of other radioactive elements. Using KI will only protect the thyroid gland from radioactive iodine. It will not protect other parts of the body from radioactive iodine, and it will not protect a person from other radioactive materials that may be released. 

Major accident External release of a large fraction of the radioactive material in a large facility (e.g. the core of a power reactor). This would typically involve a mixture of short and long lived radioactive fission products (in quantities radiologically equivalent to more than tens of thousands of terabecquerels of iodine-131). Such a release would result in the possibility of acute health effects over a wide area, possibly involving more than one country long-term environmental consequences. 

The Zone 1 exhaust fan inlet volume control damper is manually set to maintain the total SCB exhaust flow rate in order to achieve the necessary residence time for exhaust gas in the charcoal filters. This ensures that radioactive iodine is removed from the Zone 1 exhaust gas before the exhaust gas is released to the environment. An alarm is provided to alert the operations staff if the flow rate exceeds the established setpoint. Should this occur, HCF operations personnel will investigate the reason(s) for the abnormal condition and take appropriate corrective action, which may include re-adjustment of the volume control damper. Since such an occurrence is not an initiator for a radioactive material release event, operator action is an appropriate response. In addition, certain activities in the SCBs may be curtailed until the condition is corrected. 

In other cases where the radioactive material is released, it can he deposited upon environmental surfaces or skin. It could also he inhaled or ingested. The radioactive material on skin and environmental surfaces can usually he washed away, but the close contact with skin may give high doses of radiation to the skin from those isotopes that emit alpha and beta radiation. When radioactive material is inhaled or ingested, it continues to emit radiation and gives the internal areas of the body exposure. If the radioactive material has a chemical affinity for a particular organ of the body, it may accumulate there and selectively irradiate that particular organ. Examples are radioactive iodine (accumulates in tlie thyroid), radioactive cesium (accumulates in the liver), or radioactive strontium (accumulates in bone). 

Knowing about half-lives is importeuit because it enables you to determine when a sample of radioactive material is safe to handle. The rule is that a sample is saie when its radioactivity has dropped below detection limits. And that occurs at 10 half-lives. So, if radioactive iodine-131 = 8 days) is injected into the body to treat thyroid cancer, it ll be gone in 10 half-lives, or 80 days. 

Some organs concentrate radioactive materials. For example, iodine concentrates in the thyroid gland. This phenomenon offers physicians a treatment for hyperthyroidism (overactive thyroid) using radioactive iodine. The radioactive iodine destroys thyroid tissue as it concentrates in the thyroid. 

Another example is concentration of strontium-90 by mammary glands. Cows that consume food contaminated with Sr produce highly contaminated milk. Strontium-90 has a long half-life and becomes a more persistent contaminant than other radioactive materials, such as Iodine-131, which has a short half-life. 

Accelerator mass spectrometry (AMS) is useful to measure extremely low-abundance nuclides (isotope ratio of 10 to 10 relative to its stable isotope), such as Be, C, A1, C1, " Ca, and I, in natural samples. Small amounts of C and T can be measured by AMS on mg size samples of carbon and iodine extracted from 500-ml seawater samples (Povinec et al. 2000). Neutron activation analysis (NAA), radiochemical neutron activation analysis (RNAA), and inductively coupled plasma mass spectrometry (ICP-MS) are useful for the determination of ultra-trace Th and U in geological and cosmochemical samples, and for determination of the concentration of Pu and Pu. Reference marine-biological samples are necessary to test the performance of the analytical methods employed in surveying and monitoring radioactive materials in the sea. An ocean shellfish composite material containing 0.1% w/w Irish Sea mussel, 12% w/w White Sea mussel, and 87.9% w/w Japan Sea oyster has been prepared as the NIST SRM 4358 (The National Institute of Standards and Technology, SRM) in the natural-matrix, environmental-level radioactive SRM series (Altzitzoglou 2000). This NIST SRM 4358 sample will be useful for the determination of the activity of K, Cs, Pb, Ra, Th, and Am. 

Nuclear weapons present hazards in virtually all areas of their life cycle. Production and testing have their own impacts. The U.S. National Cancer Institute estimated that the release of iodine-131 in fallout from U.S. nuclear test explosions was by itself responsible for 49,000 excess cases of thyroid cancer among the U.S. popnlation [8]. A 1991 pubhcation by the hitemational Physicians for the Prevention of Nnclear War estimated that the strontium-90, cesium-137, carbon-14, and poloninm-239 released worldwide in all nuclear test explosions would be responsible for 430,000 cancer deaths by 2000 [9]. Additional widespread health and enviromnental effects of nuclear-weapons prodnction include massive contamination of land by radioactive materials and toxic chemicals. 

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