[ RadSafe ] Re: I-131 Spill Neutralization

[Michael Bohan]

Hello John and RadSafers,

Here's the recipe, paraphrased from a Feb. 1987, 3M memo by Dave 
Kubiatowicz.   You may want to double or triple it up to get the 
necessary volume:

1.  500 ml distilled or deionized water

2.  0.4 grams of sodium hydroxide

3.  15.8 grams of anhydrous sodium thiosulfate

4.  1 gram Pluronic F-68 detergent
      (This is an industrial detergent.  You can probably use any 
detergent, like Tide as a substitute, although the result may not be 
colorless)

5.  Swirl materials to dissolve and mix ingredients.

6.  Add distilled or deionized water to make 1 liter total volume.

7.  The result should be transparent and colorless.

8.  The solution should be good for up to 12 months, if refrigerated.

Solution Rational:

1.  Sodium Thiosulfate - Thiosulfate converts molecular iodine to ionic 
iodide by chemical reduction.  This serves to minimize loss of 
radioactive molecular iodine by volatilization.

2.  Sodium Hydroxide - The alkaline solution, formed by the presence of 
sodium hydroxide, stabilizes the sodium thiosulfate and enhances 
cleaning.

3.  Pluronic F-68 - The detergent enhances the cleaning process by 
lowering the surface tension of the solution.  This causes better 
wetting of the item to be decontaminated and helps to suspend debris.

Regards,

Mike Bohan, RSO
Yale-New Haven Hospital
Radiological Physics
20 York St. - WWW 204
New Haven, CT 06510
Tele: (203) 688-2950
Fax: (203) 688-8682
Email: mike.bohan at yale.edu

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