1946-07-31 Director of Ship Material Reducing Radiation on Ships by crews on Ships used in Atomic Tests, that were being sent to San Francisco, Pearl Harbor etc.

pp. 8-13
Citation: https://archive.org/download/DTIC_AD0473908/DTIC_AD0473908.pdf

014Kl/EJH/naa/S88 4 August 1946.


From: Director of Ship Material.
To : CTU 1.2.7
TU 1.2.7
All DSM Initial Boarding Teams
All Target Vessels.

Subject: Preliminary Decontamination of Target Vessels by Ships of TU 1.2.7.
Ref: (a) DSM Memorandum No. 13 of 31 July 1946.

Encl: (A) Instructions for mixing and applying Paint Removal Mixture.

  1. Reference (a) outlined the procedures to be followed by the ship’s force in rehabilitating the various contaminated target vessels, once a tolerable level of radioactivity obtains. Many of the target vessels at present have such radioactive contamination that the ship’s forces cannot work aboard a sufficient length of time to safely and effectively use the procedures given in reference
    (a) Therefore, it will be necessary to take preliminary steps to clear the vessels sufficiently to permit the ship’s force to pick up the ball. This preliminary decontamination procedure should reduce the radiation intensities to permit at least four hours’ working time for the ship’s force over substantial areas of the topsides of the target vessels.
  2. The preliminary decontamination procedure that shows promise of accomplishing the desired results is best accomplished by vessels of TU 1.2.7. The steps that comprise this procedure are as follows:

Enclosure (C) of Enclosure (F) to Director of Ship Material Serial 00447

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(a) A through wash down with plain water. This removes some of the likelihood of contamination of boarding personnel.

(b) The radiological monitor, DSM representative, and ship’s force representative will then make a quick preliminary survey of the target vessel noting general average Roentgen readings and also any hot spots which may be present. Together with the Commanding Officer of the salvage vessel, a plan of action will be laid out prior to going to work; on the ship which in some cases would use up tolerance time needlessly.

(c) If conditions permit, the ship’s force working party will then board the target vessel and remove all life rafts, canvas not protecting an interior space, exposed manila, fire hose, and the like for which no suitable decontamination procedure has been devised and which have been fi ind to be uniformly hot. The working party will be worked in relays to avoid over exposure and will be returned to the hotel transport upon completion. When the target ship is too lot to permit this to be done at this time, the operation will be accomplished after (f) below.

(d) After removal of canvas, life rafts, etc., the target vessel is sprayed with the paint removal mixture in accordance with enclosure (A).

(e) After an interval of approximately two hours the ship is again hosed down. This wash down is for the purpose of removing paint. The maximum force of the fire monitors must be applied to all painted surfaces to accomplish this end. All decks and platforms should be swept with the hose upon completion to remove all paint chips possible from the ship. This washing should proceed from the top of the target vessel downward to avoid recontamination an area that has been cleaned below. Where contaminated paint chips are washed down on a wood deck they should be frequently swept clear
(by the fire monitors) to avoid transferring contamination to the wood. Care should be taken to avoid holidays in the removal job as it is more effective to do a comparatively small part of the ship thoroughly than the whole ship in a haphazard manner. When the paint removal mixture has been properly applied, at least the top coat of paint should be removed by this washing, and the radioactivity level substantially reduced.

(f) The target vessel should then be reboarded by the DSM representative with a monitor and a responsible officer from the target vessel. The general radiation level will be checked at. this boarding to ascertain whether or not the vessel is suitable for application

Enclosure (C) to Enclosure (F) to Director Ship Material Serial 00447
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of decontamination methods outlined in reference
(a) All hot spots should be noted and the source of the excessive radiation determined if practicable. If the hot spot is extensive and apparently due to holidays in removal of paint from large surfaces it may be necessary to. Repeat the applicable steps in the procedure to clear up the hot spot.

  1. When the first preliminary survey of radiological conditions is made, consideration must be given to the length of time a salvage or firefighting vessel can lay alongside without exceeding the tolerance. Step (e) in the procedure will require the longest time interval estimated at about four hours per destroyer and a correspondingly longer time for larger vessels. It is very desirable to actually put a line over to the target vessel to permit laying alongside and performing an effective job of washing down. Care should be exercised in all washing down to avoid washing contaminated materials into the target vessels or upon the salvage vessel concerned. In some cases danger exists of introducing large amounts of water into the ships. It may be necessary to skip certain areas of the ship, such as around open hatches on APA’s, large air intakes on all vessels which are not fitted with suitable closures, etc.
  2. During the entire decontamination a representative of the Director of Ship Material and an officer representative of the target vessel being worked on will be present. Radiological safety monitors are aboard all TU 1.2.7 vessels which are assigned to this work. The duties of these officers will be to see that the provisions of this memorandum are safely and effectively carried out. They will maintain liaison with the DSM organization and the commanding officer of the target vessel, make such reports and recommendations as are normally made by Initial Boarding Teams and, as circumstances warrant, arrange for working parties from the target vessel, etc.
  3. Many of the life rafts, some of the canvas and other materials removed in step (c) above will be required if the target ship is to return under her own power to the port designated for ultimate disposition. The life rafts should be secured close aboard astern of the target ships. Contaminated fire hose, manila and essential canvas may be loaded into them. Somewhat limited ex-

Enclosure (C) to Enclosure (F) to Director Ship Material Serial 00447

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perience would indicate that this may be a satisfactory decontamination procedure for these materials. Care must be exercised in hand ling these highly radioactive materials to avoid insofar as practicable, contamination of the clothes and persons of the working party.

Rear Admiral, U.S. Navy.

Copy to: CJTF-1
CTG 1.2
CTG 1.3
CTG 1.8

Enclosure (C) to Enclosure (F) to Director Ship Material Serial 00447

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Enclosure (A) To DSM Memorandum No.__.
Subject: Instructions for Mixing and Applying the Paint Removal Mixture.

  1. All vessels which are to be assigned to apply the Paint Removal Mixture have been fitted with tanks of about 1000 gallon capacity for preparing and holding the Paint Removal Mixture, This mixture will be applied by using a Chrysler salvage pump taking suction from the tank and supplying a 1 1/2” hose at suitable pressure to reach the surface it is desired to coat. The l 1/2” hose may be fitted with an all-purpose nozzle or a long handled applicator, with a modified fog nozzle attachment as appropriate for the work to be accomplished. All painted surfaces of the target vessel should be thoroughly coated, although it is undesirable to apply so much that pools of the mixture form on the deck or pour out of the scuppers, inasmuch as the supply of materials in the area is limited and effort is expended in mixing wasted material. The maneuvering of the salvage or firefighting vessel and the pressure on the pump should be varied as circumstances warrant to secure complete coverage of all the painted surfaces and to reduce the wastage to a minimum. It will probably be found desirable and necessary to make several passes at the ship to be sprayed in order to obtain the desired results with the least exposure.
  2. The Paint Removal Mixture is composed of lye, boiler compound and cornstarch. The amounts required for 1000 gallons of mixture are 450 lbs. of lye, 600 lbs. of boiler compound and 75 lbs. of cornstarch. About 500 gallons of fresh water should be put in the tank and the lye and boiler compound added gradually and thoroughly mixed and dissolved. The cornstarch should be made into a thin suspension separately in buckets or GJ cans and added gradually with continuous stirring to obtain a final mixture free of lumps. Fresh water to make 1000 gallons should be added at this time. The whole batch should then be heated by a steam hose until the starch swells and the boiler compound completely dissolves. The mixture will now have the consistency of a thin paste. It will be uniform and capable of

Enclosure (C) to Enclosure (F) to Director Ship Material Serial 00447
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being applied in the manner outlined. If a ready source of steam is not available for cooking tie formula, the cornstarch will have to be cooked separately in a galley kettle until thickened and then added and stirred into the mixture until it has a uniform consistency.

  1. In mixing and supplying the Paint Removal Mixture it must be borne in mind that the lye mixture will produce painful burns if splashed on the skin. If it gets into the eyes, it may be dangerous as well as painful. Therefore, it will be necessary to take due precautions to prevent injuries by wearing of suitable protective clothing by necessary personnel. All unnecessary men should be kept clear of the areas where the mixture is being handled. Suitable first aid materials such as boric acid ointment and eyewash should be broken out and the pharmacist’s mate should be alerted to take care of any minor casualties should they occur.

Enclosure (C) to Enclosure (F) to Director Ship Material Serial 00447


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