DE102011117522A1 - Method for producing subsurface waste disposal region for e.g. high-level radioactive wastes in nuclear power plant, involves diffusing high heat production rate of wastes from structure by using composite building materials - Google Patents

Abstract

The method involves diffusing high heat production rate of radioactive wastes from a structure (7) and a surrounding excavation backfilling to biosphere by using composite building materials on a surface of the structure. Spherical-shaped steel plate segments, a thick reinforced concrete casing (8) and a thick inner steel casing are formed on a base of the structure, where outer diameter of the steel plates is 115m. An inner side of the steel casing is provided with thermal insulation boards or froth glasses. An independent claim is also included for an arrangement for producing a subsurface waste disposal region for intermediate- and high-level radioactive wastes by using a multi-barrier system to protect biosphere from radiation exposure of the radioactive wastes.

Description

• 1. Arrangement and method for producing an underground repository, which protects the biosphere by a multi-barrier system from the radiation exposure of medium and high-level radioactive waste. It is characterized in that the high heat production rate of the waste from the structure and the surrounding excavation pit backfill can diffuse to the surface by using new composite building materials.
• 2.1 So far, the fuel elements were transported in security containers, but unprotected spent in the former salt tunnel (pit Asse II or Morsleben) with the known problems.
• 2.2 New paths are taken in the former ore mine near Salzgitter, "Schacht Konrad". In deep geological strata, a "repository" for medium-level radioactive waste, with negligible heat generation, is being developed. The existing excavation chambers of the ore pit in the storage fields are filled with waste packages and then the remaining cavities are concreted out with salt concrete.
• 3.1 The storage of highly radioactive waste requires the greatest possible safety, but this is not the case for above-ground storage.
• 3.2 There is a high risk potential from existing above-ground interim storage facilities.
• 3.3 Underground disposal of highly radioactive waste in larger containers leads to a change in the host rock due to the strong heat radiation.
• 3.4 The requirements for an underground repository are listed in the final report of the Working Group on the Selection of Repository Sites (AkEnd).
• 3.5 The high requirements regarding the choice of location of the repository in the natural geological strata for the realization of the targeted multi-barrier system are difficult to implement, because very few host rocks have a homogeneous structure.
• 4.1 The task was to design a repository for medium- and high-level radioactive waste, which ensures adequate safety over time.
• 4.2 In order to meet these high requirements, an underground structure was to be designed that protects the biosphere against the radiation exposure of medium- and high-level radioactive waste by means of a multi-barrier system.
• 4.3 The possible time frame of the storage results from the contamination of the building envelope and its backfilling.
• 4.4 The spherical shape of the structure and the strength of the outer shell provide the greatest static certainty to withstand the tectonic pressure of centuries.
• 4.5 Even an external act of violence would survive this structure.
• 4.6 No repository, whether as a building or in subterranean geological strata, is stable until the end of its half-life. Therefore, the repository must be technically equipped so that the retrievability of the radioactive waste can be carried out without direct use of personnel. This must also be ensured for future generations.
• 4.7 The basic requirement for this type of storage is the constant monitoring and maintenance of the structure and its facilities.

In the near-surface strata of the Quaternary and Tertiary ( 1 ), a pit ( 2 ) of at least 230 m depth with a corresponding guidance of surface and layer water by collecting lines ( 3a ) and feed pumps ( 3b ) created.

At the founding level ( 4 ), a 14 m thick reinforced concrete slab ( 4a ) produced. On this reinforced concrete slab ( 4a ) is a spherical cap ( 5 ) made of lean concrete.

In the negative form of the spherical cap ( 5 ) is a layer of a bentonite-aluminum mixture ( 6 ) applied at a thickness of 0.2 m.

On this basis, a building ( 7 ) with an outer diameter of 115 m and a 6 m thick reinforced concrete shell ( 8th ) and an inner 44 mm thick steel shell ( 8a ) made of welded structural steel segment plates in spherical form.

The inside of the steel shell ( 8a ) is fitted with thermal insulation panels ( 8b ) made of 10 cm thick foam glass (foam glass).

Floor ceilings ( 9 ) and honeycomb walls ( 10 ) made of reinforced concrete subdivide and stabilize the structure ( 7 ).

With the arrangement of reinforced concrete ceilings ( 9 ) arise:
In the basement is a cooling pool H ( 11a ) (hot) in the center, this serves the underwater storage of 12 pieces of glass kokillen ( 12a ) HAW with graphite shield molding ( 24 ).

The waste heat from the 12 glass canisters is used to heat the absorption chillers ( 16 ) used.

In the outer area of the basement, a sinking pool C ( 11b ) (cold) for the underwater storage of 232 pieces of glass kokillen ( 12a ) HAW arranged with graphite shield shaped body. This Area is absorbed by the absorption chillers ( 16 ) cooled.

In the reinforced concrete ceiling ( 9a ) above the basement, the storage openings and closure lid ( 9b ) arranged.

The first floor is the distributor level, on which the glass kokillen ( 12a ) HAW are introduced into the sinking basins.

The projectiles 2 to 16 are used to store 30,000 pieces of glass kokillen ( 12b ) MAW of medium-level radioactive waste with negligible heat generation.

On the 17th floor, the machine and the control of the goods lift are housed.

With a special arrangement of the reinforcement ( 13 ) made of special steel mats in spherical segment form and spiral reinforcement baskets ( 13a ) with integrated cooling pipes ( 14 ) in the concrete outer shell ( 8th ) and the inner steel shell ( 8a ) becomes a statically high-strength structure ( 7 ) created.

The concrete of the outer shell ( 8th ) obtained by additions of barite (barite concrete EN 12620 ) a greater radiation density. The carbon fiber bundles (carbonroving) ( 15b ) enclosed steel cores ( 15a ) increase the thermal conductivity of the outer shell ( 8th ) (see additional patent).

The cooling pipes ( 14a ) made of ceramic sheet (AvM 1415N from WEC Pritzkow) serve after concreting the outer shell ( 8th ) the derivation of the heat of hydration. After the storage of highly radioactive waste ( 12a ) and ( 12b ), the cooling lines ( 14a ) used indirectly to dissipate the process heat.

For greater heat dissipation is between the reinforcement cages 13 and the cooling pipes ( 14a ) a braid of carbon fibers ( 15 ).

The air conditioning technology of the ventilation system ( 17 ) and the cooling of the cooling pool ( 11b ) are replaced by 4 pieces of commercially available LiBr absorption chillers ( 16 ) with the substance pair of water-lithium bromide (H ₂ O / LiBr), where water is the refrigerant and lithium bromide is the solvent. Use find equipment of the company York International GmbH, type YIA / 4C1, or equivalent.

Part of the process heat from the decay pool ( 11a ) is used in the evaporator and expeller for heating and separating the working fluid in the 2-stage AKM ( 16 ).

The system connection of the 2-stage compact AKM ( 16 ) provides an external water cycle to dissipate heat from the absorber and condenser component. By means of heat exchangers in the aforementioned components and connection to the cooling water pipes ( 14a ) in the outer shell ( 8th ), a pump is used to produce a water cycle from one AKM to the opposite AKM. The amount of circulation in the cooling water pipes ( 14a ) conducts the heat over the concrete shell ( 8th ) to the construction pit filling ( 33 ).

"Fresh air ducts" ( 18 ) are placed vertically on the inside of the concrete outer shell ( 8th ). Outlet openings on all floors distribute the "fresh air" over the corridors ( 19 ). Over the shaft ( 20 ) of the goods lift ( 21 ), the used air is sent to the ventilation systems ( 17 ) returned.

In the upper part of the concrete outer shell ( 7 ) there is an overpressure safety valve ( 22 ) to relieve any overpressure caused by gases from the stored radioactive waste.

For the transport and storage of glass jars ( 12b ) MAW with the graphite shield moldings ( 24 ) 8 pieces per steel container ( 23 ) stacked.

About one in the core of the building ( 7 ) goods lift ( 21 ) the containers ( 23 ) distributed and stored with computer-controlled materials handling in the floors.

The access structure ( 25 ) from a steel gate ( 26 ) and reinforced concrete gate ( 27 ) is located on the 7th floor.

In front of the entrance building ( 28 ), an access shaft ( 29 ) to the near-surface entrance structure ( 30 ) and control buildings ( 31 ), the access shaft ( 29 ).

In the course of the backfilling works, the outer sides of all structures with bentonite material ( 6 ) in a thickness of 0.5 m and sealed.

The backfilling of the excavation pit ( 33 ) by incorporation of fractionated bauxite sedimentary rock at a thickness of 50 m. About backfilling ( 33 ) becomes a "bell" ( 34 ) from a clay mineral carbon fiber mixture ( 34a ) with a thickness of 30 m and a "lost steel formwork" ( 35 ) of 10 mm thickness.

After completion of the storage work, the entrance building ( 25 ) hermetically sealed.

The control lines ( 32 ), which are located in the control building ( 31 ), allow a permanent monitoring of the repository.

After a review period, the dismantling and backfilling of the entire excavation takes place according to item [0027]. The access shaft ( 29 ) remains for control work.

A soil layer ( 36 ) of> 60, - m with a 10 m thick reinforced concrete sign plate ( 37 ) secures the near-surface entrance structure ( 30 ), Control building ( 31 ) and the access shaft ( 29 ).

In the control building ( 31 ) 2 diesel emergency generators ( 38 ) and fuel storage containers ( 39 ) for self-sufficient supply of all technical equipment installed.

The invention is represented by:

Overview / interface

2 cut

3 Floor plan 7th floor

• 5.0 Die Vorteile, die sich aus dem Konzept des Endlagers ergeben, sind:
• 5.1 Die Sicherheitsanforderungen an die Endlagerung wärmeentwickelnder radioaktiver Abfälle gemäß der atomrechtlichen Anforderungen des Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit vom 30. Sept. 2010 können erfüllt werden
• 5.2 Die oberirdische Zwischenlagerung der mittel- und hochradioaktiven Abfälle könnte, in das sichere Endlager in einem überschaubaren Zeitraum, überführt werden.
• 5.3 Das Gefährdungspotenzial der Kernkraftwerke würde sich durch Räumung der Zwischenlager beträchtlich reduzieren.
• 5.4 Das unterirdische Bauwerk bietet als Endlager für mittel- und hochradioaktive Abfälle für die nächsten Generationen die größtmögliche Sicherheit.
• 5.5 Bei einem technischen Bauwerk dieser Art können die Kenntnisse und Erfahrungen und die Qualität der Materialien entsprechend der EN- und DIN-Vorschriften und ihrer Verwendung zu einem sicheren Mehrbarrierensystem konsequent umgesetzt werden.
• 5.6 Die in Kernkraftanlagen üblichen Sicherheitsstrategien mit dem Mehrstufenprinzip, Redundanz, Diversität und Fail-Safe können bei diesem Konzept der Endlagerung verwirklicht werden.
• 5.7 Das Exergiekonzept ist so ausgelegt, dass ein Teil der Prozesswärme der hochradioaktiven Abfälle im inneren Bereich des Abklingbeckens zur Beheizung der LiBr-Absorptionskältemaschinen genutzt, während die Temperatur im äußeren Bereich des Abklingbeckens durch Kühlleitungen reduziert wird.
• 5.8 Die große Oberfläche des Bauwerks und die Verwendung der neuen Verbundbaustoffe der Betonaußenschale und der Baugrubenverfüllung ermöglichen einen hohen Strahlenschutz und auf der anderen Seite eine wirkungsvolle thermische Diffusivität der eingelagerten mittel- und hochradioaktiven Abfälle.
• 5.9 Die Lüftungsanlagen begrenzen die Raumtemperatur im 3. bis zum 17. Obergeschoss, dadurch können die Ausgasungen der mittelradioaktiven Abfälle minimiert werden.
• 5.10 Ein Sicherheitsventil im oberen Teil der Betonaußenschale verhindert den Aufbau eines Überdrucks im Baukörper. Die entweichenden ionisierten Gase können durch die Bauxitverfüllung und der Tonglocke zurückgehalten werden.

Ground floor basement

• 5.0 The benefits of the concept of the repository are:
• 5.1 The safety requirements for the final storage of heat-generating radioactive waste in accordance with the nuclear requirements of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety of 30 Sept. 2010 can be met
• 5.2 The above-ground interim storage of medium- and high-level radioactive waste could be transferred to the safe disposal facility within a manageable period of time.
• 5.3 The risk potential of nuclear power plants would be considerably reduced by clearing the interim storage facilities.
• 5.4 As a repository for medium- and high-level radioactive waste, the underground structure provides the greatest possible security for the next generations.
• 5.5 In the case of a technical construction of this kind, the knowledge and experience and the quality of the materials can be consistently implemented in accordance with the EN and DIN regulations and their use as a safe multi-barrier system.
• 5.6 The usual safety strategies in nuclear power plants with the multi-stage principle, redundancy, diversity and fail-safe can be realized with this concept of final disposal.
• 5.7 The exergy concept is designed so that part of the process heat of the high-level radioactive waste in the inner part of the decay pool is used to heat the LiBr absorption chillers while the temperature in the outer area of the decay tank is reduced by cooling lines.
• 5.8 The large surface area of the structure and the use of the new composite construction materials of the concrete outer shell and the construction pit filling enable high radiation protection and, on the other hand, effective thermal diffusivity of the stored medium- and high-level radioactive waste.
• 5.9 The ventilation systems limit the room temperature from the 3rd to the 17th floor, thus minimizing the outgassing of medium-level radioactive waste.
• 5.10 A safety valve in the upper part of the concrete outer shell prevents the build-up of overpressure in the structure. The escaping ionized gases can be retained by the bauxite filling and the clay bell.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• EN 12620 [0015]

Claims (2)

Arrangement and method for the production of an underground repository, which protects the biosphere against the radiation exposure of the medium- and high-level radioactive waste by means of a multi-barrier system. It is characterized in that the high heat production rate of the waste from the structure and the surrounding excavation pit backfill can diffuse to the surface by using new composite building materials. In the near-surface strata of the Quaternary and Tertiary ( 1 ), a pit ( 2 ) created by at least 230 m depth. At the founding level ( 4 ) is a reinforced concrete slab ( 4a ) with spherical cap ( 5 ) produced. On this basis, a building ( 7 ) with an outer diameter of 115 m and a strong reinforced concrete shell ( 8th ) and an inner 44 mm thick steel shell ( 8a ) made of welded structural steel segment plates in spherical form. The inside of the steel shell ( 8a ) with thermal insulation panels / foam glass ( 8b ) disguised. The floors ( 9 ) and honeycomb walls ( 10 ) made of reinforced concrete subdivide and stabilize the structure ( 7 ). In the center of the basement is a sinking pool ( 11a ), this is the underwater storage of glass kokillen ( 12a ) HAW. The exergy concept is designed so that a part of the process heat of the highly radioactive waste in the inner region of the decay tank for heating the LiBr absorption chillers ( 16 ) is being used. The AKM ( 16 ) is equipped with an external water circuit to transfer the heat from the absorber and condenser components via the cooling water pipes ( 14a ) to the outer shell ( 8th ) to pay off. The high rate of heat production of the waste can be determined by using the new composite building materials (see additional patent) from the building ( 7 ) diffuse over the construction pit filling to the biosphere. The access shaft ( 29 ) remains for control work.

Images