Compositions – Radioactive compositions
Patent
1989-03-09
1991-09-03
Hunt, Brooks H.
Compositions
Radioactive compositions
252629, 252633, G21F 916
Patent
active
050452410
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to a method and apparatus for solidifying radioactive wastes, and more particularly to a method and apparatus for the solidification processing of non-combustible miscellaneous wastes by use of an inorganic matrix material such as cement.
2. Background Art
Among various radioactive wastes generated from a nuclear power plant, so-called metallic wastes such as used piping arrangement, valves, etc., and non-combustible solid wastes consisting of concrete are stored mostly in the nuclear power plant while they are put into drums at present.
It is the recent trend, however, to conduct solidification treatment of the non-combustible solid wastes, too. It has been a customary practice to solidify the non-combustible solid wastes by cement as the solidification treatment. Since the non-combustible miscellaneous solid wastes are generally great in size and cannot be mixed or kneaded by a mixer, a method has been employed conventionally which first puts the non-combustible miscellaneous solid wastes into a container and then pours the matrix material such as cement into the container. (Refer, for example, to "Research and Development on Processing of Radioactive Wastes", published by Sangyo Kijutsu, Feb. 5, 1983, pp. 63-65). FIG. 2 of the accompanying drawings is a conceptual view (cited from the reference described above) of a solidification apparatus for non-combustible solid wastes that has been employed conventionally. The conventional solidification apparatus for the non-combustible miscellaneous solid wastes includes a free fall pouring system utilizing the difference of heads of height and a pump pressure-feed system utilizing a monotype pump.
FIG. 3 shows schematically the result when miscellaneous solid wastes wrapped by a plastic sheet consisting of an organic polymer compound such as a polyethylene sheet are put into a drum and cement is then poured in accordance with the conventional system. It has been found that voids or spaces are formed at the portions where the cement mortar cannot enter easily such as between the polyethylene sheet 18 and the miscellaneous solid wastes 3 and below the miscellaneous solid wastes 3.
The conventional technique described above does not take into consideration the voids or spaces that occur in a matrix and inside the container when the cement mortar is poured. In other words, since the spaced which will cause a decreased in the strength of the matrix occur in the solidified waste forms, the conventional technique is not suitable for obtaining the waste form for land disposal. Disclosure of Invention:
It is therefore an object of the present invention to provide a method of producing a waste form which is suitable for land disposal and has less voids, and an apparatus for practising this method of producing the waste form.
The object of the invention described above can be accomplished by utilizing the change of a reduced pressure of the pressure in the voids after pouring of a matrix material with respect to the pressure in the spaces at the time of pouring of the matrix material when the matrix material is poured into the spaces defined between radioactive solid wastes or spaces defined between the radioactive solid wastes and a container, in order to pour the matrix material after the radioactive solid wastes are packed into the container. The object of the invention can be accomplished by, for example, charging a gas in advance which reacts with the matrix material and is eventually absorbed in the matrix material into the container for producing the solidified waste form into which the wastes are packed, and then by pouring the matrix material.
Pouring of the matrix material by utilizing the change of the reduced pressure will be explained about the case where a gas which reacts with the matrix material is in advance charged and the matrix material is then poured, by way of example.
Solid wastes such as miscellaneous solid wastes are put into a container for producing a solidified waste form (e.g. a drum) and a
REFERENCES:
patent: 4139488 (1979-02-01), Knolik et al.
patent: 4505851 (1985-03-01), Funabashi et al.
patent: 4581162 (1986-04-01), Kawamura et al.
patent: 4648990 (1987-03-01), Uetake et al.
patent: 4717510 (1988-01-01), James
patent: 4851155 (1989-07-01), Kanagawa et al.
Baba Tsutomu
Chino Koichi
Funabashi Kiyomi
Kikushi Makoto
Kuriyama Osamu
Hitachi , Ltd.
Hunt Brooks H.
Mai Ngoclan T.
LandOfFree
Method for solidifying radioactive wastes does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for solidifying radioactive wastes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for solidifying radioactive wastes will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1007408