Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
  • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
  • G21F9/001—Decontamination of contaminated objects, apparatus, clothes, food; Preventing contamination thereof

Definitions

• Previously protective salves have been applied to the exposed skin areas of those working with or in the region of radioactive materials. These salves either in and of themselves provided a protective sheath against the penetration of radiation or contact of the contaminant with the skin, or alternatively or cumulatively provided an easy means of removal of contaminants upon removal of the salves themselves.
• the methods of cleaning are chemical or physical.
• To the chemical methods belong the use of acids and bases, complexing agents or ion exchange materials. Very often hydrochloric acid is used in a 1:1 dilution, which is, however, a very uncomfortable or even painful treatment of the skin surface.
• To the physical methods of cleaning belong the removal of the surface layer through scouring or rubbing with emery, and also the use of pumice stone. These methods have the disadvantage that they involve a drastic treatment of the skin, and also with pumice, that the radioactive material is only incompletely removed from the skin.
• it is proposed in accordance with the invention as a method for the removal of radioactive contaminants from human or animal skin and from articles, that the skin or the object be rubbed or scrapped with a porous, medium hard to hard, open-celled organic or inorganic, natural or synthetic foam body adapted for scrubbing purposes, especially a conveniently shaped body of a synthetic plastic foam, such that the contaminants be carried away with abraded particles of the foam body.
• the cleaning is carried out in conjunction with a flowing liquid, in particular, a soap solution.
• a hard and rigid polyurethane-foam with a pore structure of 0.2 to 3 mm., preferably 0.5 to 1 mm. in size.
• An open-celled plastic form of this type having a selected hardness, removes the contaminants from the skin by a scraping action of the sharp boundary edges of the incised or cut cells, even with a deep action, without essentially harming or carrying away the true skin, and thus a removal of contaminated skin surface proceeds withoutpain.
• a flushing liquid such as water
• apolyurethane base foam has additionally the advantage by virtue of its thermoplastic character, that with a cold liquid,
• the foam is hard, and with warm or hot water is somewhat softer; so that through selection of the temperature of the liquid, the hardness and thereby the scraping effect is continually adjustable upon use.
• a tough foam resistant to breaking up under scrubbing action is advantageous as holding and preventing spreading of the contaminants.
• the soft foam is particularly useful. If it should be desired to remove the radioactive contaminants with a very high abrading of the foam body, then in accordance with the invention it is proposed to use a phenol resin foam.
• foam bodies having a polystyrene-, cellulose acetate-, polyvinylchloride-, phenol resin-, polyethylene-, vinyl acetate-, Buna-rubberor natural rubber base.
• bodies of synthetic plastic foam particularly the phenol resin or polyurethane base types, have additionally the decisive advantage that substantially no activity is taken up and hence none remains in the cleaner structure.
• the foam body be comprised of a vitreous, i.e., slaggy or glass, foam.
• a body of slaggy or glass based foam can be used for the removal of radioactive contaminants from objects, for example, laboratory equipment or instruments, although a foam of this type is not as pain-free as the previously proposed bodies of synthetic plastic bases when used on human or animal skin.
• the cleaning process proceeds by attacking the fundamental cause, the time requirement is small, the treatment of the surface is mild, the same foam body is re-usable many times, and the cleaning body itself in the cleaning process picks up little or substantially no radioactive impurities.
• the foam bodies, as they are used up and new incised or broken cells are laid open, continually work a shaving or scraping effect and therefore are effective until completely used up.
• radioactive contaminants can also be removed from the skin or from objects with a high efiicacy by scrubbing the skin or object with a granulated form of a hard to medium hard synthetic plastic foam, particularly having a polyurethane or phenol resin base, either with a mixture of granulants of the aforementioned materials, or in conjunction with a soap, a fat, an oil, a thickening agent, an emulsifying agent, or a film forming agent or a combination of two or more of these perhaps with addition of a slight amount of water. This is especially advantageous in circumstances where no, or an insufficient amount of, water or no flowing water is available for removal of radioactive contaminants.
• the materials present in the mixture with the foam granulate as thickening or swelling agents are comprised of materials per se known, in greater part organic, highmolecular materials, which swell up and finally convert into homogeneous viscous colloidal solutions.
• organic materials of this type there are for example, natural products, semi-synthetic products, or completely synthetic preparations, and so also in the case of inorganic preparations, for example, polysilicic acids, colloidal clay or metal hydroxides.
• emulsions for example, dispersions in water or solvents of benzine, turpentine and other volatile oils, fatty oils, paraffin, waxes, vegetable-, animal-, and mineral-fats, nibber, fish lever oil and so forth, with dispersing agents.
• the best cleaning effect is obtained with a weakly acid pH of about 4.5 to 5:0.
• the further proposal in accordance with the invention of adding a film former to the granulate plastic foam, especially a polyurethane or phenol resin foam, has the particular advantage that the contaminants cling together, and adherent to or imbedded in the film, are removed therewith from the object or skin.
• the cleaner compositioncomprised of the foam granulate together with the film former either alone or in combination with the aforementioned addition materials-is rubbed onto the skin or the object by hand with a scrubbing action and after hardening or drying of the film former, the film is drawn off or by rubbing broken off the skin or the object with the granulate and radioactive contaminants and such other materials as happen to be present.
• Such a composition can be rubbed so long on the skin or the object that no coherent or cohesive film arises, but rather crumbs comprised of the composition and the aforementioned radioactive contaminants. These crumbs then either fall from the skin by themselves, or can be easily removed by hand or a cloth.
• film formers are methyl cellulose, polyvinyl alcohol, special gelatins, Konjacku, Hei Tao, tragacanth, and so forth. To make the film more pliable, addition of glycerin is recommended.
• methyl cellulose With the use of methyl cellulose the addition of wetting and emulsifying agents is omitted, because methyl cellulose has a particular characteristic of emulsifying skin fats. Thereby upon stripping of the film no stretching of the skin results.
• the combinations proposed for use where water is lacking has the advantage that the cleaning means can accommodate itself to the unevennesses of the skin, whereby the radioactive contaminants can be removed from those areas of the body or object which can only insufficiently be reached by a rigid formed foam, for example, parts of the upper or lower eyelids, or of the ears and the like.
• a foam granulate or of a pasty mixture of a granulate with the proposed addition materials has the further advantage that sensitive areas of the body can be treated in a comparatively gentle manner.
• the research on the human skin was carried out by experiments of the investigator upon himself as the subject.
• the radioactive substance in solution or in liquid carrier was applied on the skin from an injection syringe and then with a drop of a l-normal acid rubbed about on the skin.
• After measurement of the activity attained on the skin there were then carried out the operations with the cleaning means as hereinafter described in detail, and then a further measurement was made of the residual activity. These procedures were repeated one or more times depending upon the cleaning effect obtained.
• a gamma scintillation spectrometer served as the detector; in some cases a window counter tube; and in the case of tritium, a liquid scintillation spectrometer.
• the distance of the detector from the observed source on the subject was kept quite closely constant.
• the liquid scintillation counter skin traces or flakes were suspended or dissolved and brought into the counter, and in this manner the residual or remaining activity on the skin was measured.
• the null effect or background radiation count was from time to time separately determined for subtraction.
• the stated error is a statistical one and indicates that the true value, with 67% probability, lies in the range of the measured value, indicated through the given error.
• the isotope was present as the chloride in l-normal hydrochloric acid.
• the treatment was carried out by rubbing the foam block on the affected skin area for about 10 seconds. The results showed that the activity due to the applied contaminant was completely removed, that after the treatment only the background radiation effect was present, and no activity was transferred or carried over onto the treating stone or block.
• COBALT-60 Cobalt-60 having a half-life period of 5.3 years and emitting beta and gamma radiation, is also a frequently used isotope, for example, for radiation therapy in medicine.
• the isotope was present as a chloride in one normal hydrochloric acid solution; and the background radiation effect amounted to 19:3 pulses per minute.
• Table V presents the results obtained by the use of a window counting tube.
• the background radiation amounted to 186:14 pulses per minute.
• the cleaning process is also quite clear here. For the heavy contamination, after the first cleaning (Exp. 2), there remains about 1% radioactivity, which is removed by a second cleaning (see Exp. 2a). The cleaning means picks up substantially no radioactivity.
• TRITIUM Tritium is a beta emitter with a half-life period of 12.3 years, the radiation of which has only a slight energy and is, therefore from the standpoint of the radiation effects, relatively speaking not dangerous. 'It finds extensive applications in tracer techniques and in investigations of exchange processes in the atmosphere and hydrosphere. The most highly sensitive apparatus is necessary for its measurement, so that the error of a measurement through the slightest radioactive contamination becomes quite questionable. The need for the highest cleanliness in this case is therefore founded upon measurement techniques. The measurements presented in Table VI were undertaken in the manner described in the section given above on the measurement method. The background radiation of the equipment amount to 3310.4 pulses per minute.
• the cleansing result is here also quite uncomplicated. A subsequent measurement of a possible contamination of the polyurethane foam here was not possible for technical reasons.
• the cleaning means showed a light contamination, about 1% of the activity cleaned, which however is not very heavy.
• Table VIII presents data indicating that radioactive isotopes are differently incorporated in the surface dependent upon the chemical conditions under which they are applied to the surface material.
• radioactive isotopes are differently incorporated in the surface dependent upon the chemical conditions under which they are applied to the surface material.
• to the radioactive isotope applied to the skin surface there was further added one drop of a 10% or half-concentrated acid and this was rubbed on the skin.
• Cobalt-60 was used in conjunction with hydrochloric, sulfuric and nitric acids, and the background effect amounted to 21:2 pulses per minute.
• Table IX are presented successively the individual cleaning means with their cleaning effects and the occasional contamination of the cleaner.
• the background effect amounted to 26:2. pulses per minute.
• Table X shows the utility of different materials for decontaminating the skin surface of radioactive impurities or contaminations.
• the investigations were undertaken with a scintillation spectrometer and the use of cobalt-60 isotope in l-normal hydrochloric acid.
• the background effect or radiation amounted to 1911.4 pulses per minute.
• the above given description also is here applicable.
• the synthetic plastic foam materials capable of scraping and fabricated from medium to hard, as proposed for decontamination purposes, are at the same time suited also for the removal of non-radioactive contaminants from the skin.
• the foam material in say rectangular block form may have one side out across to provide a cleaning face in which broken or intersected edges of the cells are exposed for scraping action; and on the op posite side or face there is applied a film or foil, impenetrable to the fluids, dust or other form in which the radioactive contaminants might pass through the body of the foam, thereby providing on the side opposite the cleaning face a barrier to further migration of the contaminants.
• the foam in one form or the other may be applied to a pressure plate or base provided with a handle for use in mopping operations on floors, walls or ceilings.
• foams particularly the synthetic plastic organic foams such as polyurethane may take a granular or quasi-powdered form, which may be made up into tablets or into salves or pastes and still have some advantages by a'bsorbtive or protective properties apart from cleaning in the sense previously described by the abrading, scraping action.
• the particles making up the tablet form upon consumption of the tablet and its disintegration in the human body, are released and are able to some degree to absorb from the walls and linings of the throat, stomach and intestine radioactive contaminants there contained. Being so absorbed, they then pass out with the granular material carrier through the intestinal canal.
• Means for removing radioactive contaminants from the human skin mechanically by scrubbing rubbing comprising: a foam material open-pored on its scrubbing surface and fabricated to be from medium hard to hard so as to crumble at the surface during scrubbing, with formation by the foam cell walls at the surface of sharp, skin-scraping and -removing edges,
• said foam material being selected from the group consisting of polyurethane foam, phenol resin foam, polystyrene foam, buna rubber base foam, natural rubber base foam, and vitreous foam materials.
• said foam material is selected from the group consisting of polyurethane foam and phenol resin foam materials.
• said foam material is selected from the group consisting of slag foam and glass foam materials.
• foam material is a body of polyurethane pore size of from 0.2 to 1.5 mm.
• Means in accordance with claim 1, comprised of a body of said foam material, and on a surface of said body opposite the rubbing surface covered with a film impermeable to liquids and dust niigratable from the rubbing surface through the body.
• a decontamination device adapted for removal of wherein said foam with a radioactive materials from the surfaces of human skin by a rubbing-scraping operation comprised of a body of hard and rigid foam material, said material as described in claim 1, and to provide a cleansing face, having a cut face with exposed interrupted cut cell walls affording initial scraping edges.
• a cleaning composition for removal of radioactive contaminants from the surface of human skin consisting essentially of a granulated foam material as described in claim 1 and a film former in an effective amount.
• a method for removing radioactive contaminants from the human skin comprising the steps of: rubbing the area to be decontaminated with a foam material at least superficially open-celled and fabricated to be from medium hard to hard so as to crumble at its surface during rubbing with foamation by the foam cell walls at the surface of sharp skin-scraping and -removing edges,
• said foam material being selected from the group consisting of polyurethane foam, phenol resin foam, polystyrene foam, buna rubber base foam, natural rubber base foam, and vitreous foam materials.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Food Science & Technology (AREA)
• Physics & Mathematics (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Detergent Compositions (AREA)
• Cosmetics (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)

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Citations (11)

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• 1965
  • 1965-03-05 DE DEC35227A patent/DE1280682B/de active Pending
  • 1965-03-15 DE DEC35319A patent/DE1292005B/de active Pending
  • 1965-03-23 US US442212A patent/US3488219A/en not_active Expired - Lifetime
  • 1965-11-06 DE DEC37337A patent/DE1301989B/de active Pending
• 1966
  • 1966-01-19 AT AT50266A patent/AT284980B/de not_active IP Right Cessation
  • 1966-01-20 IL IL25022A patent/IL25022A/xx unknown
  • 1966-01-21 GB GB2912/66A patent/GB1135264A/en not_active Expired
  • 1966-01-21 CH CH82566A patent/CH443005A/de unknown
  • 1966-01-21 BE BE675437D patent/BE675437A/xx unknown
  • 1966-01-21 NL NL6600843A patent/NL6600843A/xx unknown
  • 1966-05-31 US US555645A patent/US3487916A/en not_active Expired - Lifetime

Patent Citations (11)

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