Iodine Trapping

The only radionuclidic impurity detected in the 1-122 is less than 0.1% radioxenons and other radioiodines, which neither interfere with scintigraphic imaging nor result in a high radiation exposure to the patient. Further improvement of the radioiodine contamination could be attained with an iodine trap between the storage reservoir and the growth chamber. The milking efficiency is about 40%. We consider this generator assembly to be a preliminary version that can be refined considerably. Further details may be obtained from Richards and Ku (8). 

It has been known for a long time that decomposition and polymerization processes occur as a result of irradiation of acetaldehyde. The polymerization process, diminishing in importance towards shorter wavelengths, is induced by free radicals. Iodine traps the free radicals, therefore, no polymerization is observed in the iodine-inhibited reaction . Woolgar and Allmand suggested that the polymer formed was probably paraldehyde. On account of insufficient data, a detailed discussion of the polymerization processes is not justified. 

These data are in reasonable agreement with the results from the iodine-trapping experiments. 

All of the reaction products can be rationalized in terms of primary cleavage to acetyl radicals and analogy to the photolysis of acetone. However, the fact that appreciable carbon monoxide was observed 113> in iodine trapping experiments, in contrast to the results with acetone, suggests that some other primary dissociation also occurs. 

Thus, 6-iodolactone seems to be generated within the thyroid cell membrane dependening on iodine supply, and inhibits not only cAMP-independent growth, but also induces apoptosis and seems to be involved in goiter involution induced by iodine. The same 6-iodolactone might also inhibit mammary breast cancer cells, and therefore seems not to be unique to the thyroid, but to all iodine trapping tissues. 

Fire in an SCB releases volatile contents of the target, iodine trap, and/or acid cocktail Fire CP-7... 

Target volatile release prior to or during process connection to cold trap or iodine trap in extraction SCB (CP-4, CP-6, CP-11) II, V, ill C-D 3-4... 

The material in-process inventory is that of a maximally irradiated target. During the one hour initial processing period, the entire radiological inventory is potentially available for release. Once the iodine has been collected in the iodine trap, it would not be vulnerable to DBE effects. Thus, for the remainder of the processing period only the residual process liquid, containing about 75% of the total fission product inventory and totaling about 14,000 curies, is available as a potential source term. This source term is present until the waste is solidified (approximately 3 hours). 

Since the fission products from a maximum of six in-process targets were assumed to be available in the HCF at one time, the multiple simultaneous errors or events of the beyond DBA could release the contents of only six in-process targets. Trapped fission products from targets processed on previous days are stored in SCBs in iodine traps (i-traps) and cold traps (for noble gases). The l-trap holds trapped iodine by a chemical bond in a steel cylinder and the cold trap holds noble gases in an evacuated, cryogenicaily cooled bed. Because of the physical form of the iodine compound (copper iodide) and the relatively low dose consequences of the noble... 

Iodine Trap operator error/ fixtures Rad. distance to (1 target) ... 

CP-5 Inventory 1 iodine-trap with volatile halogens from 1 to 10 targets trapped and held by a chemical bond so not available for airborne release. 

Sequence A Nominal processing of a target. No release to SCB except in event where subsequent operator handling damages target or tree, or improperly connects tree to iodine trap, releasing volatile contents. 

During the one-hour initial processing period, the entire radiological inventory is potentially available for release. Once the iodine has been collected in the iodine trap, it would not be... 

The quantitative analyses were performed on acid solutions resulting from the leaching of filter cartridges. One set of samples contained 1 M HNO3 + 2 x 10 M HF and another, with a higher nuclide concentration 1 M HNO3 and 0.002 M HF. The samples also included iodine trap samples in 4 M NaOH. 

A. Zoulalian and E. Belval-Haltier, Interaction between Molecular Iodine in Gaseous Phase and a Coat of Paint - Influence of Tempeiatuie, Humidity, and Hydrothermal Treatment on Iodine Trapping Kinetics , Nuclear Technology, 122 196 (1998). 

The exact location of the iodine-trapping mechanism within the thyroid gland is not known, but it is generally assumed that the membranes of the epithelial cells of the thyroid follicles are involved. Attempts to solve this important problem have included the use of radioautographic techniques. After administration of radioactive iodine, greater con-... 

A number of inborn errors have been described in patients with sporadic cretinism (1) a defect in the iodine-trapping mechanism (2) an inability to convert inorganic iodide to iodine (3) a lack of thyroid peroxidase [178] (4) an inability to couple iodotyrosine to form iodothyronines and thyroglobulins (5) a lack of dehalogenase (6) an interference with thyroglobulin metabolism and (7) a defect in thyrotropin secretion [179-180]. 

Elemental iodine trapped in an alkaline spray solution is rapidly hydrolyzed to... 

A.403. The design and operation of the ventilation systems, including requirements for containment or confinement, shall be described. If applicable, distinction shall be made between the system used during normal operation and the system used for emergencies. The specific efficiencies of the air filters and iodine traps shall be given. 

In the most simplistic physiological model, inadequate intake of iodine results in a reduction in thyroid hormone production, which stimulates increased TSH production. TSH acts directly on thyroid cells, and without the ability to increase hormone production, the gland becomes hyperplastic. In addition, iodine trapping becomes more efficient, as demonstrated by increased radioactive iodine uptake in deficient individuals. However, this simplistic model is complicated by complex adaptive mechanisms which vary depending on the age of the individual affected. In adults with mild deficiency, reduced intake causes a decrease in extrathyroidal iodine and reduced clearance, demonstrated by decreased urinary iodine excretion, but iodine concentration in the gland may remain within normal limits. With further reduction in intake, this adaptive mechanism is overwhelmed, and the iodine content of the thyroid decreases with alterations in iodination of thyroglobulin, in the ratio of DIT to MIT, and reduction in efficient thyroid hormone production. The ability to adapt appears to decrease with decreasing age, and in children the iodine pool in the thyroid is smaller, and the dynamics of iodine metabolism and peripheral use more rapid. In neonates, the effects of iodine deficiency are more directly reflected in increased TSH. Diminished thyroid iodine content and increased turnover make neonates the most vulnerable to the effects of iodine deficiency and decreased hormone production, even with mild deficiency. 

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