Method of underground radioactive waste isolation

 

(57) Abstract:

The invention relates to the field of underground isolation of solidified radioactive waste containing long-lived radionuclides. The method involves the placement of radioactive waste in underground excavations completed in geological formations. In the area selected for underground radioactive waste isolation, are conducting a study of geological formations with a quantitative assessment of the parameters of physical processes in the rock mass. Then determine the risk of release of radionuclides from underground structures of expression

< / BR>
where r is the risk of release of radionuclides from underground workings, 1/year; Vpthe rate of groundwater corresponding to the most probable value, m/year; L is the radius of the proposed stable impermeable geological unit, m; R - factor arrest radionuclide in the planes of fractures in a rock mass, EP; a - constant Weibull. Excavation for placement of radioactive waste held in the zone of the rock mass, in which r 106. The technical result consists in increasing the reliability of the disposal of radioactive waste. 2 C.p. f-crystals.

The invention relates to the field of underground is preimushestvenno hardened and containing long-lived radionuclides, in the geological formations of the earth's crust, particularly in underground mines.

There is a method of disposal of radioactive wastes, including drilling, placement of containers with radioactive waste, leaving over them barrier pillar, filling the free volume of the borehole backfill material, sealing the wellhead, and the containers with radioactive waste and barrier pillar is placed in the zone of plastic deformation of the surrounding rocks, and as backfill material used expanding on solidification of the mixture (see RF patent N 2063077).

In the known method remains the possibility of infiltration of groundwater to the containers with radioactive waste and the further spread of liquids contaminated with radionuclides in the environment, which significantly reduces the reliability of RW disposal in this way.

Closest to the claimed combination of essential characteristics is a method of disposal that is enclosed in a container, comprising placing them in the tunnel made in the mountain, and the containers placed in the trench, passed in soil production, closed top plates (see patent USSR N 803874, G 21 F 9/24).

The main disadvantage of this method is the On is selected without quantitative account of the natural features of the structure of the rock mass, which can lead to the violation of the integrity of the rock mass, and hence the integrity of a repository RAO, as a result of natural or man-made disaster impacts.

The present invention is to provide a method of underground radioactive waste isolation, providing a high degree of reliability even under conditions of emergency, natural or man-induced impacts.

The problem is solved by creating a method of underground isolation of radwaste, including the placement of radioactive waste in underground structures (wells, or excavations), passed in geological formations, a difference which, according to the invention is that selected for underground radioactive waste isolation area to conduct the study of geological formations with a quantitative assessment of the parameters of physical processes in the rock mass and determine the risk of release of radionuclides from the underground workings from the expression:

,

where r is the risk of release of radionuclides from underground workings, 1/year;

Vpthe rate of groundwater corresponding to the most probable value, m/year;

L is the radius of the proposed stable impermeable geological unit, m;
Bulla,

and underground development for radioactive waste disposal are in the zone of the rock mass, in which r10-6.

Features of the invention for the first time in the practice of underground radioactive waste isolation provide a quantitative assessment of the suitability of the chosen site of the rock mass for underground isolation of radioactive waste from the point of view of reliability with regard to the structure of the rock mass and total risks from natural and man-made disaster impacts, which in turn provides almost absolute reliability of underground isolation of radwaste.

It is expedient in the zones of the rock mass, in which r10-6radioactive waste is to be placed for long-term storage.

When data values of r, the stability of the insulation properties of the rock mass is determined by its place in the physical processes and is provided for the period of storage of radioactive waste.

It is expedient in the zones of the rock mass, in which g<<10 -6to accomplish the disposal of radioactive waste.

When data values of r, the stability of the insulation properties of the rock mass considering the fact that all potential emergency situations happen, is provided on pivate for underground radioactive waste isolation.

Underground isolation of radioactive waste in the proposed method is as follows.

Choose the area for underground radioactive waste isolation, usually in the region with a stable, impermeable geological formations. In the selected area to conduct a detailed study of geological structures, for this well-known methods (geophysical, geodetic and other) determine the location and ranking of the fracture, the degree of fracture and defects of the rock mass, fluiconnecto rocks, measured parameters geomechanical, hydrogeological and geochemical processes in the rock mass, determining the safety of radioactive waste isolation.

According to research results, determine the area of the rock mass, the most acceptable for underground radioactive waste isolation. This consists of a list of potential natural and man-made emergencies and their sequences. Under emergency situations are understood as natural or man-made events leading to the depressurization of the storage of radioactive waste, the ingress groundwater for radioactive waste - earthquakes, geodynamic changes the locale of the occurrence and the risk of release of radionuclides from the underground workings for each emergency.

The probability of occurrence of an emergency situation or events that lead to depressurization of the store, is determined by the formula:

< / BR>
where T - time storage of radioactive waste (underground storage) or the time during which the buried radionuclides remain active (for burial), years;

t is the period of the frequency of occurrence of critical values of physical processes, years.

Thus t is determined from historical data, field conditions, mathematical modeling and limit parameters of the rocks studied array.

The risk of release of radionuclides from underground tunnels in which they are placed, is determined by the formula:

< / BR>
where g is the risk of release of radionuclides from underground workings, 1/year;

Vpthe rate of groundwater corresponding to the most probable value, m/year;

L is the radius of the proposed stable impermeable geological unit, m;

R - factor arrest radionuclide in the planes of fractures in a rock mass, e,

a - constant Weibull.

The velocity of groundwater V is determined experimentally in natural conditions, the size of the proposed unit L is determined during the drilling of slim through the most permeable parts of the rock.

On the basis of valid values risk E = 10-61/year, excavation for placement of radioactive waste are known methods using known technologies in the area of the rock mass, in which r10-6and placed in the radioactive waste, for example, in containers.

The zones of the rock mass, in which r10-6suitable for long-term storage of radioactive waste. And in areas in which r<<10 -6advisable to dispose of radioactive waste, i.e. to build the mounds.

1. The way underground isolation of radioactive waste, including the placement of radioactive waste in underground excavations completed in geological formations, characterized in that selected for underground radioactive waste isolation area to conduct the study of geological formations with a quantitative assessment of the parameters of physical processes in the rock mass, determine the risk of release of radionuclides from the underground workings of expression

< / BR>
where r is the risk of release of radionuclides from underground workings, 1/year;

Vpthe rate of groundwater corresponding to the most probable value, m/year;

L is the radius estimated with the communities in mining er;

a - constant Weibull,

and underground development for radioactive waste disposal are in the zone of the rock mass, in which r 10-6.

2. The method according to p. 1, characterized in that in the workings completed in the zones of the rock mass, in which r 10-6radioactive wastes are placed for long-term storage.

3. The method according to p. 1, characterized in that in the workings completed in the hony of the rock mass in which r << 10-6carry out the disposal of radioactive waste.

 

Same patents:

The invention relates to nuclear energy, in particular to methods of radioactive waste management (RW), located in the basins of storage in the form of aqueous solutions and suspensions of sediment

The invention relates to containers-storage uranium ore processing waste factories

The invention relates to a method and apparatus for storing hazardous wastes, including radioactive wastes, such as, for example, used fuel rods and the like, which may need to be stored securely for a long period of time such as decades or even centuries

The invention relates to methods of samosohraneniya radioactive materials of high and medium level of activity in the deeper layers of the lithosphere
The invention relates to the protection of the environment, and in particular to methods of purification of waters from radioactive and toxic waste, burial and reburial

The invention relates to the construction, namely, to designs of storage of cylindrical tanks for the storage of environmentally hazardous materials (radioactive and toxic waste, oil and oil products, liquefied gas and t

The invention relates to containers-storage of liquid industrial waste containing radionuclides of strontium and cesium in natural soils, and can be used for building system-induced geochemical barriers that purify water from radionuclides

The invention relates to containers storage of soil or plant residues, contaminated with radioactive isotopes of strontium and cesium in natural soils, and can be used for the construction of a system of man-made barriers limiting distribution in surface and ground waters, soils radioactive isotopes

The invention relates to the disposal of solid radioactive waste in the ground

FIELD: monitoring the ecological safety.

SUBSTANCE: it is proposed a new method for monitoring the safety of sites for storage of radioactive wastes. The method is based on determination of the Cr(VI) nonsorbed ion concentration in the soils, surrounding the storage sites.

EFFECT: reliability of monitoring the safety of sites for radioactive waste storage.

4 cl, 4 dwg, 3 ex, 2 tbl

FIELD: evacuation of radioactive wastes.

SUBSTANCE: proposed method for container-free subsurface burial of solid radioactive wastes in abandoned deep workings of cryolite zone involves delivery of solid radiation sources pre-cooled in winter to abandoned mine workings. Radiation sources are placed in layer-by-layer manner on prepared falsework paled floor, leveled, compacted, flooded with water, and frozen by natural cold before piling radioactive wastes to full height of subsurface workings. In the process, burial ground is shaped in the form of pillar. Split ice is added in the course of placing layers of solid radioactive wastes including their forced cooling with cold atmospheric air.

EFFECT: enhanced reliability and safety.

1 cl, 1 dwg

FIELD: disposal of radioactive wastes.

SUBSTANCE: proposed method for building radioactive waste disposal structure involves formation of horizontal helical system of round-section transport and room tunnels penetrated by single mechanized tunneling machine including erection of grade-crossing elimination structures. Helical system of tunnels is made in the form of ellipse with variable distance between adjacent tunnels of helical system. Grade-crossing elimination structures are erected at two diametrically opposite points of system where each pair of tunnels is joined to form single tunnel communicating with adjacent coupled tunnel through crossover. Tunnel-to-tunnel distance is predetermined at several points by simulation including heat and radiation load on soil mass.

EFFECT: enhanced radiation safety and reduced construction charges.

1 cl, 2 dwg

FIELD: methods of the radioactive waste disposal.

SUBSTANCE: the invention is pertaining to the field of the radioactive waste disposal. Substance of the invention: the method of the radioactive waste disposal includes boring of a borehole, placement of containers with the A-waste and leaving of a barrier pillar in the zone of the plastic deformations of the surrounding rocks, filling of the free volume of the borehole with an expanding plugging material and sealing of a the borehole head. At that the A-waste disposal is conducted in a clay bed, which is in a plastic state. The containers with the A-waste are placed in the middle part of the clay bed in its section with a length of l = m -2hδ, where "m" is the clay bed thickness, hδ is the thickness of argillaceous rocks. The plugging of the free volume of the borehole is conducted using the extracted from the borehole dried and crushed rock. At that on the section of placement of the containers the plugging is performed by substitution of the drilling mud, and on the section of the barrier pillar after an evacuation of the drilling mud - by portioned feed with water addition in the volume corresponding to the natural humidity. Advantages of the invention consist in an increased degree of reliability at the radioactive waste land disposal.

EFFECT: the invention ensures an increased degree of reliability at the radioactive waste land disposal.

5 dwg, 1 ex

FIELD: long-term storage of radioactive wastes.

SUBSTANCE: spent nuclear fuel storage has vertical well with bridge in top part of well, containers with spent nuclear fuel boxes disposed in well, and well ventilating system. Containers are made in the form of cylinders with perforated sections in bottom part which are vertically installed on well face. Boxes holding spent nuclear fuel are disposed within container one on top of other. At least one empty container is placed in well and bridge is installed in top part of well below upper ends of containers.

EFFECT: enhanced reliability and long time of radioactive wastes isolation.

2 cl, 2 dwg

FIELD: burying liquid radioactive wastes; waste recovery at radiochemical plants.

SUBSTANCE: proposed method for burying liquid radioactive wastes incorporating hydrolyzing admixtures into deep-seated container bed includes correction of waste pH by nitric acid solutions and pre-treatment of container bed by forcing nitric acid solutions therein. Nitric acid solution is introduced into container bed in amount sufficient for neutralizing carbonates contained in soil which enters in reaction with waste and for attaining void liquid pH of 1.5, as well as into wastes until their pH is brought to 1 - 1.5. Under such conditions wastes are passed into deep-seated formations without precipitating over long distances.

EFFECT: elongated working time of well, enhanced safety of burying wastes into deep-seated beds.

1 cl, 3 ex, 3 tbl

FIELD: physics; construction.

SUBSTANCE: process of crashed atomic reactor entombment includes construction of underground mortuary in the form of vertical underground excavation. Internal volume of the excavation is filled with ice which forms a new temporary ice foundation under the basis of the crashed reactor. The weight of the latter is shifted to the new ice foundation, heat is conducted to it, and gradually the height of ice foundation is decreasing till the complete removal of ice. At that, the crashed reactor is set at the mortuary made previously at the basement of excavation. Before deposition of the crashed reactor underground, solidity (thickness) of frozen soil body under the reactor basis is improved, and then, after the new ice foundation is ready, the load is increased, and the previous ground base is destroyed by adjoining of excavation ice body to the crashed reactor basis via flexible load-bearing cables laid through the vertical wells.

EFFECT: reduces amount of work in immediate proximity to a crashed atomic reactor.

FIELD: underground disposal of biologically hazardous sewage.

SUBSTANCE: process of underground disposal of biologically hazardous sewage into geological formations, which do not have distinct aquifiers above the working floor, includes drilling of injection wells and pumping sewage into the working floor. The process is distinguished by sewage pumping into working floor simultaneously with technical fluid injection into a stratum above the working floor. Pressure of technical fluid injection into the buffering floor is sustained at the level of 0.9-1.1 of sewage injection pressure in the working floor.

EFFECT: prevents disposed sewage penetration into higher aquifiers.

2 cl, 2 dwg

FIELD: construction, hydrotechnics.

SUBSTANCE: invention is attributed to cleaning methods for beds of minor rivers in permafrost zone with seasonal flow from sediments contaminated with radionuclides from radioactive solid waste handling. Removal of contaminated sediments is executed in winter by segments in downstream direction after discharge cancellation and their dewatering. Bottom ground is loosened and mechanically shaved by layers as it is freezed by natural cold with stocking it in temporary piles and subsequent transportation outside river floodplain for burying or laying in surface burial hills. To speed-up layer-by-layer freezing the net of trenches with vertical walls is cut in parallel in bottom ground depth as it freezes. Trench width is defined by parameters of equipment being used, their depth is not less than half a meter and distance between trenches corresponds to double trench depth. The invention allows to isolate from biota (for a period of not less than 100 years) the most migration suspectable solid radioactive wastes and hence to lower the risk of people irradiation.

EFFECT: lowering the risk of people irradiation.

1 dwg

FIELD: construction.

SUBSTANCE: invention can be used for protection of fresh groundwater, ground and soils from pollution by toxic and radioactive substances in areas of technical wastes storage. In expected place of landfill it is created barrier, formed samples set of ground strata for depth till first water-bearing stratum of protected territory and set of local clay samples from the nearest region. Samples of ground strata are divided into layers presented by different lithological members and then territory is divided into separated sections and for each of them functioning critical time as natural geochemical barrier is defined. Then territorial sections (k) are defined, for them variation range ΔTs of territory required operation life Toper from critical time of its operating as natural geochemical barrier Tscrit exceed previously agreed acceptable value ΔTs= Toper - Tscrit > Tacc. Then it is formed database of potential contaminant migratory parameters for local clays and materials for artificial barriers, each section of being protected territory is covered by barrier material.

EFFECT: providing criterion of predictability territory operation critical time, appraisal ability of contaminants migration velocity in ground strata and increasing of being protected territory operating time.

7 cl, 2 dwg

Up!