Iodine removal

The Japan Nuclear Fuel Service Company reprocesses LWR fuel in faciUties which take advantage of French shear and dissolver designs, German iodine removal technology, and British reduced-pressure evaporation. 

Dithiol is a less selective reagent than thiocyanate for molybdenum. Tungsten interferes most seriously but does not do so in the presence of tartaric acid or citric acid (see Section 17.34). Tin does not interfere if the absorbance is read at 680 nm. Strong oxidants oxidise the reagent iron(III) salts should be reduced with potassium iodide solution and the liberated iodine removed with thiosulphate. 

Phenylethyl Iodide. Use 146 g. (142 ml.) of (J-phenylethyl alcohol (b.p. 216 5-217°), 16 54 g. of purified red phosphorus and 154 g. of iodine. Lag the arm C (Fig.///, 40, 1) with asbestos cloth. Heat the alcohol - phosphorus mixture to boiling until sufficient alcohol (usually one-third to one-half of the total volume) passes into the reservoir B to dissolve all the iodine. Remove the flame and add the iodine solution at such a rate that the mixture boils gently. A little hydrogen iodide is evolved towards the end of the reaction. Allow the mixture to cool, add water and filter off the excess of phosphorus. Decolourise the filtrate with a little sodium bisulphite and add ether to assist in the separation of the water layer. Wash the ethereal solution with water, dry with anhydrous potassium carbonate, and distil under diminished pressure. B.p. 114 116°/12 mm. Yield 215 g. 

A 1-g. sample is dissolved in concentrated nitric acid, the resulting iodine removed by filtration through a sintered-glass funnel, washed with water, and the washings added to the yellow filtrate. The latter is diluted with water and the copper determined by electrolytic reduction. Anal. Calcd. for Cul Cu, 33.4. Found Cu, 33.1. 

Iodine [ ] is a most useful medicine. The alteration in his water was Iodine removing some mischief from Liver, which had to be carried off by kidneys. There is intimate connection between liver and kidneys. When I had obstruction of gall-duct by gall-stone and jaundiced bile passed thro kidneys and bladder. There is reciprocal action between the 2 organs. 

A pinch of finely powdered iodine is placed in the test tube with 10 mL of the concentrated ammonia solution and either shaken well or allowed to stand overnight. If it is allowed to stand the test tube must be stoppered. The precipitate is then filtered off, excess iodine removed by washing with a few mL of ethanol and the residue treated with 5 mL of diethyl ether to dry it rapidly. The filter paper is removed from the funnel at once and carefully placed on a stable support. 

Offgas treatment is extensive and involves use of sintered metal filters, quench systems, venturi scrubbers, a condenser, a mist eliminator, an offgas heater, parallel HEPA filters, a carbon filter for radioactive iodine removal, a baghouse, and a selective catalytic reduction unit a packed tower scrubber system is used as a backup. 

Monad negative dements, euoh as iodine, remove suoees. sively the two atoms of ethyl —... 

Of the numerous iodine-removal methods discussed by Goode and Clinton [G9], the most significant are characterized below. 

Elemental iodine removal during spraying of fresh solution... 

During injection, the removal of elemental iodine by wall deposition may be estimated by AIV. (Note this is the fraction of iodine removed by the spray in one second, order of magnitude = 3 X 10 ). 

Positive iodine contamination control maintained due to increased charcoal filter iodine removal efficiency... 

C. F. Baes, et al, Removal of Iodide From LiF-BeF2 Melts by HF-H2 Sparging - Application to Iodine Removal From Molten-Salt Breeder Reactor Fuel, Nuc. Sci. and Eng. 56(4), p. 399 (April 1975). 

The iodine in the iodo-compound may be determined in the ordinary manner, or the following simpler method, first used in the investigation of diazoacetamide, may be employed. A weighed quantity of the substance is placed in a tared beaker, dissolved in a little absolute alcohol, and iodine added until a permanent red coloration is obtained. The alcohol is volatilized on the water-bath, the excess of iodine removed by cautious heating, and the crystalline residue weighed. In this case, also, the compound employed must be pure. 

Pathways for venting the containment atmosphere may be provided for a number of reasons, and these pathways may be equipped with filters to remove iodine from the vented gas. Filters for iodine removal can be present in both passive systems (in which flow continues only as long as there is a pressme difference) and active systems (in which there is a continuous forced flow at a controllable rate). Dry filters intended for the removal of aerosol particles are not likely to be effective for the removal of gaseous forms of iodine, especially organic iodides. Even if gaseous iodine will absorb on the filter mediiun, heat loads on the filter medium caused by radioactive decay can lead to revaporization of the absorbed iodine. Filters that involve water must be maintained at high pH to avoid the formation of volatile forms of iodine by processes identical to those that occur in reactor containment smnps. 

The purpose of this question is to find out whether any passive sink for the iodine has been provided to supplement the natural iodine removal mechanisms, like deposition, adsorption, chemical reaction, mass transfer into the water pool or into the droplets, and pool scrubbing, etc. Table 6 presents a summary of the responses. Except the borax used in the ice condenser of the Loviisa units (Finland) no other passive means have been reported. 

Plant Name Passive iodine removal Iodine mitigation measures implemented/ planned Measurement of airborne iodine (gaseous and particulate form) activity in containment Measurement of controlled iodine (gaseous and particulate form) release into environment Other AM measures to mitigate airborne iodine (in gaseous/particulate form) activity in containment Comments... 

No containment venting filters, no passive iodine removal, no controlled iodine release into environment, no other AM measures to mitigate airborne iodine activity in containment... 

Dukonavy 4 units no intentional passive Iodine removal Hydrazine addition to the spray solutions (implemented) Measurement of aerosol deposition on filters and of gaseous iodine No measurement of corttrolled iodine release No other dedicated AM measures ... 

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