DE1109279B - Process for solidifying liquid nuclear waste - Google Patents

Description

GERMAN

PATENT OFFICE

A 32425 Vmc / 21g

REGISTRATION DATE: JULY 8, 1959

NOTICE
THE REGISTRATION
ANDOUTPUTE
EDITORIAL: JUNE 22, 1961

The invention relates to rendering radioactive liquids harmless as they are in the form aqueous solutions or suspensions in isotope-producing or using plants. It is known to dump radioactive waste in steel drums or concrete containers into the sea. Here there is a risk of contamination of the water through leaching if the container leaks. In order to prevent this, it has already been proposed to concentrate radiative waste materials and subsequent firing to convert them into vitreous or ceramic solidified bodies, which are subject to leaching better resist. This process is relatively cumbersome and expensive because it is considerable Requires precautionary measures, once when concentrating the waste, further at yours Mixing with the fluxes required for melting or sintering together glassy or ceramic type and finally also during the firing itself because of the risk of aerosol formation.

Another known method of disposal of liquid nuclear waste is the aqueous Bringing waste into solid form by mixing it with cement and letting it set, and the resulting waste Burying or sinking blocks, usually within radiation-absorbing containers. To this The invention relates to the type of nuclear waste disposal. Avoiding the risk described leaching out of leaky containers and avoiding the difficulties outlined above Transferring the radioactive waste into vitreous or ceramic sintered bodies is supposed to result in the formation of the Cement blocks mentioned take place automatically and without endangering the operating personnel.

To take full advantage of the hydraulic binder used to form the blocks, one had to up to now stir when mixing with the aqueous nuclear waste, like any cement with the associated one Mixing water is stirred. This need for agitation is necessary in the case of radiant liquids cumbersome precautionary measures. The equipment used for mixing and stirring is also used contaminated and must be handled with care.

These difficulties in solidifying aqueous nuclear waste due to the need for mechanical assistance when mixing with the hydraulic binder is particularly troublesome in those cases in which only occasionally relatively limited amounts of aqueous nuclear waste are produced, but which then, in the interests of safety, enable procedures for Solidify
of liquid nuclear waste

Applicant:
Rudolf Alberti,
St. Andreasberg (Harz), laundry ground 463

Rudolf Alberti, St. Andreasberg (Harz),
has been named as the inventor

must be solidified immediately, because only in this solidified form can they be stored in the protective containers offers the required maximum level of security. If now every time the perfect one Mixing and wetting of the binder through special mechanical treatment such as stirring and If something like this has to be secured, experience has shown that it is repeated many times in such cases Mixing operations, the necessary precautionary measures are often not observed.

The aim of the invention is to allow the absorption of aqueous nuclear waste, e.g. B. of liquid exchanger sludge, which contains a dangerous content of radioactive isotopes in the recording material, which should then set to form the blocks, so that no mechanical tuition more is needed in the mixing process, but on the other hand it is ensured that the whole Absorption material, which contains the hydraulic binder, without the formation of non-wetted areas is penetrated quickly and evenly by the radioactive liquid to be removed. Included should also be given the possibility of a larger amount of recording material in portions and add the aqueous liquid to be removed at intervals without impairing the absorption capacity when adding the later portions it suffers from the fact that partial amounts of the total absorption capacity have already been added beforehand have been added. These conditions are not easy to meet because the finely divided cement used for setting due to its heterodisperse grain distribution sealed storage without stirring to clump

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penbildung and to form impermeable zones, use material, so z. B. a heavy metal

in which the first setting has taken place tends to. minerals (such as iron ores) or a heavy atom

It has now been found that one without mecha- minerals, such as. B. Barite. Since the radiant

niche support of the absorption process with fast absorbing effect for hard gamma rays

and automatically running, completely uniform comparison of the same layer thickness with the specific weight

mixture of the radiant wastewater to be removed increases, for soft gamma rays, however, with the

with the ordinal number for the subsequent solidification, so can the selection of the granular

seen material can be mixed, constituent from case to case on the respective nature

if the recording material itself is the essential part of the nuclear waste to be solidified, i.e. the respective

Part of a granular material isodisperse io tuned to predominant radioactive isotopes

Grain size distribution exists, which will be fine with the.

distributed cement is intimately mixed, and when the introduction of the aqueous nuclear waste into the aqueous nuclear waste the so composed recording recording material mixture has a device behaving material in a container from below, in which the receiving material is conveyed will. Due to the isodisperse distribution of the 15 tend container, e.g. B. a cylindrical iron pipe, in Most of the mixture forming the middle contains a filling tube that extends almost up to granular material is achieved that the receiving reaches the bottom of the container. The by the mixing up has a high absorbency and this tube also has take-up material through it at the top during the whole soaking and mixing a funnel to let in the radiant ones Process with the aqueous atomic liquid to be removed and is over the greater part of its length retains garbage. Further holes are made by inserting the. The liquid can now pass through this tube Liquid to be removed is ensured from below, filled in and essentially emerges from it that even with slow and possibly timed out into the receiving material of the container, Intermittent introduction of the liquid in As the experiments have shown, the act on the the receiving mixture the filling of the container in 25 lengths of the tubes above the lower mouth precisely monitorable way is going on in such a way that distributed holes essentially as Entniemals impermeable and therefore uniform ventilation openings for when filling the liquid soak of the entire intake mixture gradually disappears from below from the intake obstacle Zones arise, as it is especially with mixed displaced air. In any case, there is no slow movement and occasionally interrupted introduction 30 put these holes on, but the filling takes place the liquid by simply pouring it from the top in completely flawlessly from the bottom to the top, even if the container filled with the recording material are taken longer pauses. This gradual could easily happen. even absorption of the liquid from the

A method for solidifying liquid-absorbent absorbent material takes place without any

in accordance with nuclear waste by mixing it with cement and mechanical tutoring, so that

According to the invention, the container to be prepared is left to set with the funnel of the filling tube

solidifying liquid can simply be moved from below into a holder under a tap

Mixture introduced, which need besides the finely divided one from which the radiant liquid emerges.

Cement a fast, even and self- After reaching the intended degree of filling, the

active spreading and sucking up of the liquid by becoming wet on the surface of the

granular material serving to identify the essential intake mixture in the container,

borrowed isodisperse grain size distribution contains. the liquid cock is closed and the

As a granular component of the receiving material holder with the now completely impregnated receiving mixture, an isodisperse distributed material can leave the mixture to set,
NEN, the nature of which is inherently subordinate. B. galvanized iron pipes is interpretation, provided that when using a wall thickness of 1 mm, a height of 1 m and a suitable grain size of 15 cm, a sufficient absorbency width is used, which is present at the bottom along its central axis. Can be used, for. B. open insertion tube of 1 cm clear width expropriated sieve fractions of granular minerals, such as hold, which has a funnel at the top and on the quartz, ores or barite, but also granular 50 largest part of its length around with four through plastics, such as . B. a polystyrene product. Fractions, z. B. are equipped in from ring to ring. Such an order of magnitude of 1 to 5 mm is shown, the receiving drum is filled with a pourable top which then together with fine alumina cement the receiving material of the type mentioned above. Form the recording mixture, e.g. B. in a ratio of 55 capacity for aqueous nuclear waste, z. B. for from 2 parts by weight of quartz grain to 1 part by weight of liquid exchange sludge from an isotope cement flour. The proportion of cement is always obtained as extraction plant, is about 5 1. After the filling measurement that the amount of liquid introduced into a given volume of filling is generally left completely funnel in the container with the filling tube, as the precaution is bound . If one were not worth the 60 measures outlined that are necessary. Effect of the granular component on the even if you wanted to pull out the filler pipe for the purpose of the mixing process going on again and use it in a new Benoch to use an additional radiation-protective effect in the holder.

Inside the overall mixture or the radiating such devices have also proven themselves for Tied block containing liquid was 65 isotope laboratories, in which at times smaller

If you want to aim, you can accumulate portions of aqueous nuclear waste for the granular component. These of the receiving material mixture one can essentially batchwise into the container provided

isodisperse grain of a radiation-absorbing can be poured through the filler pipe and

then harden in the recording material from below. If the first portion has become hard, so can a second portion can be poured in after eight days without affecting the quick and smooth one The absorption capacity of the absorbent material mixture suffers. Neither will the pores of the material, the holes in the filling tube are still clogged, so that after setting the first introduced liquid parts can still be refilled later as long as liquid can be refilled, until the capacity of the receptacle is reached.

Instead of the finger-thick tube with a perforated wall to be filled from above through a funnel, can (for non-intermittent filling) introducing the liquid to be solidified into the with the receiving mixture filled container from below through a bottom valve, which is in this Container is attached and then to the supply line of the radiant to be removed Fluid is connected. In this case, too, the liquid rises evenly takes place within the absorbent mixture from bottom to top without any mechanical tuition.

Another intake mixture with a total density of a bulk weight of 2.4 kg / 1 is z. B. off 32 kg of isodisperse barite with a grain size between 2 and 5 mm and 10.5 kg of calcium aluminate cement. That Diameter ratio between the largest and the smallest grains of the essentially isodisperse Grain material should preferably not exceed a value of 2: 1. In the block to be consolidated Part of the dangerous radiation has already been held back by the heavy atomic barium of the heavy spar filling. The density of the hardened block is over 2.7.

Larger containers filled with receiving material of the type mentioned can also be used.

in which then several perforated and funneled filling tubes are embedded. The grain size the isodisperse constituent of the mixture of the recording material can be used within considerable limits vary. It can be easily determined by simple preliminary tests, depending on the requirements the rapidity of the absorption of the liquid in the mixture to be solidified can be set, and also depending on the nature of the nuclear waste to be disposed of or its viscosity, which is the case with sludge may be considerably larger than in the case of aqueous solutions.

Claims (3)

PATENT CLAIMS: 1. A method for solidifying liquid nuclear waste by mixing it with cement and letting it set, characterized in that the liquid to be solidified is introduced from below into a receiving mixture which, in addition to the finely divided cement, serves to distribute and absorb the liquid quickly, evenly and automatically contains granular material of essentially isodisperse particle size distribution. 2. Recording material for the method according to claim 1, characterized in that as granular Component of a mineral, such as quartz or barite, is used. 3. Apparatus for performing the method according to claim 1, consisting of a recording material mixture Containing container in which one or more filler tubes open at the bottom and perforated over most of their length are attached that carry a funnel at the top. Considered publications:
Journal: "Atompraxis", Vol. 2, pp. 272 to 274; Journal: "Atomics", Vol. 8, pp. 116 to 120. © 109 618/382 6.61