CA1169693A - Apparatus for storing heat-releasing radionuclide configurations - Google Patents
Apparatus for storing heat-releasing radionuclide configurationsInfo
- Publication number
- CA1169693A CA1169693A CA000394464A CA394464A CA1169693A CA 1169693 A CA1169693 A CA 1169693A CA 000394464 A CA000394464 A CA 000394464A CA 394464 A CA394464 A CA 394464A CA 1169693 A CA1169693 A CA 1169693A
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- Prior art keywords
- storage
- air
- ceiling
- draft
- heat
- Prior art date
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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
- G21F9/28—Treating solids
- G21F9/34—Disposal of solid waste
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- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Cooling Or The Like Of Electrical Apparatus (AREA)
- Ventilation (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
For storing heat-releasing radionuclide configurations, particularly burned-out fuel elements, with free cooling with ambient air,apparatuses are required which visually comprise a housing provided with charging passage, supply-air and spent-air ducts and closed storage cells which contain storage racks, which contain horizontally arranged or inclined storage shafts to receive the radionuclide configurations. These apparatuses are intended to assure a reliable emission of heat with a supply of cooling air as optimal as possible and to protect the ambient air against direct irradiation. For this purpose the ceilings of the storage cells have been designed as heat exchangers and within the storage cells at the storage shaft orifices there are disposed functionally separated up-draft chimneys and down-draft chimneys.
For storing heat-releasing radionuclide configurations, particularly burned-out fuel elements, with free cooling with ambient air,apparatuses are required which visually comprise a housing provided with charging passage, supply-air and spent-air ducts and closed storage cells which contain storage racks, which contain horizontally arranged or inclined storage shafts to receive the radionuclide configurations. These apparatuses are intended to assure a reliable emission of heat with a supply of cooling air as optimal as possible and to protect the ambient air against direct irradiation. For this purpose the ceilings of the storage cells have been designed as heat exchangers and within the storage cells at the storage shaft orifices there are disposed functionally separated up-draft chimneys and down-draft chimneys.
Description
J~i93 The presen-t invention relates to an apparatus for storing heat-releasing radionuclide configurations, whl.ch when required are enclosed in containers wi-th free coo].i.ng with ambient air, and comprising subs-tantially a housing with charg-ing passage, supply-air and spent-air ducts and.closed storage cells provided wlth ceilings and containing ,to-~age racks (storage blocks) wi-th horizontally arranyed or inclined storage shafts as storage positions for the radionuclide configurati.ons or for the containers with radioactive materials, cooling ai.r flowing in the axial direction through the storage shafts.
Radioactive materials and radionuclide configurations, as for example, burned-out nuclear fuel elements or vitrified highly radioactive waste produce heat when disintegrating so that constant cooling is required during this storage. This requires that the continuous presence of a coo].ing medium is assured and that no inadmissible amounts of radioactivity are carried off with tlle cooling medium. These requirements are satisfied, for example, by a storage depot cooled directly or indirectly with ambient air.
Various plans have been proposed for the dry inter-mediate storage of heat-releasing radionuclide configurations.
Thus, for example in German offenlegungsschrift No. 2,730,729 it has been proposed to store the containers with radioactive waste in vertical shafts, through which air flows axially from the bottom to the top, -the containers being stacked either individually or multiply one above the other. In German Offen-legungsschrift No. 2,906,629 the containers are stored in horizontal shafts with cross flow from the outside in the vertical direction, the containers bei.ng individually or multiply arranged in tandem. A direct cooling system or an indirect cooling system can be used in these two cases.
- 1 - ~x~
3 i~ 6i93 German Offenlegungsschrift 2,837,839 describes the storage of containers in horizontal storage blocks having later-ally arranged cooling elements with cross flow in the vertical dircction. The storaye of vertical storage containers having Front--end shic]diny gatcs serv;ng sirnultaneously as cooling clemcnts is a]so known (Nuclear Technology, Vol. 24, December 1974) and so is the storage horizontally with cross flow within a closed space and emission of heat to the environment by means of heat pipes (Atom and Strom, 26th annual publication (1980)4).
The main disadvantage of the storage described in German Offenlegungsschrift No. 2,730,729 lies in the cooling with laterally arranged heat exchangers (walls) and in the flow direction thus required. The cell air emerging with maximal temperature and velocity of flow from the laterally arranged shafts irnpinyes on the flat ceiling and ;s thcn conducted hori-~.ontally to tlle Jateral hcat cxchal~gers. Kinetic energy is destroyed hy the flow impinging on the flat ceiling. Furthermore, the ]-,orizontal flow to the heat exchangers is not promoted by the external field of forces (gravitation)since the heated air tends to rise upwardly.
A further disadvantage of the apparatus cited in German Offenlegungsschrift No. 2,730,729 is that a distinct co-ordination of the heat removed from the storage stack region to one of the two heat exchangers is not possible.
The main disadvantage of the apparatus described in German Offenlegungsschrift No. 2,837,839 and of that described in "Nuclear Technology" is that for the heat flow from the storage containers to the cooling elcment,steep temperature gradients, which can result in thermal s-tresscs of the stored material, are required. The fact that in the storaye concept accordlng to German OEfenle~ungsscilrift No. 2,837,839 the cooling elellle3lt cons;sts of a solid properly heat-collductillg material, ~ 3f;~33 usually metal, resulting in high costs is particularly unfavour-ahle. Furthermore, because of the heavy weight of the storage hlocks with cooling elements,special structural requi.rements must be met hy the storaye racks.
'l'he substantial disadvantages of the apparatus describ-ed in "~tom and Strom" lie ;n that a distinct coordination of the heat to be removed from the region of the storage racks to one of the two heat exchangers is not possible and that no practical experience exists with regard to the behaviour of heat pipes in the radiation field. Furthermore, in this case, the emission of heat also is lateral so that the conduction of the flow is not optimal.
In the apparatus described in German Offenlegungs-schrift No. 2,906,629 the fact that the ambient air is exposed t~ t]lC' r~diation fi.eld of the rad;.oactive materials Wit]lOUt any large-sca].e shielding measures also is a disadvantage.
In all the apparatus for the intermediate storage of heat-producing radionuclide configurations with indirect cooling due to free convective flow,substantial disadvantages have resulted primarily with regard to an optimal conduction of flow and thus also with regard to both optimal heat removal, and shielding of theambient air against direct irradiation by radio-active substances.
Therefore, the present invention provides an apparatus for storing neat-releasing radionuclide configurations, which are enclosed in containers when required, with free cooling by means of ambient air, i.e., an apparatus comprising substan-tially a housi.ng provided witll charging passage, supply air and spent-air ducts and closed storage cells provided with ceilings and conta.i.ning s-torage racks or storac3e blocks with horizontally arranged or inclined storage shaEts as storac3e posi.t.ions for the radionuclide conf:iguratiolls or Eor tlle colltaill-g~
ers with radioactive ma-terials, coo]ing air Elowinc~ -through the storage shafts in the axial direc-tion. With this apparatus an improvement of -the conduction of coo]ing air Llow should be at-tained, -thus assuring a reliable heat removal.
Thus, according to the present invention the ceilings of the storage cells are heat exchangers and within the s-torage cells there are disposed at the openings of the s-torage shafts vertical up-draft and down-draft chirnneys, which are separated in space and function and are open in the region of -the storage racks with respect thereto and are provided with ]ockable charg-ing orifices with respect to the charging passage.
It is favourable to arrange a separate up-draft chimney and down-draft chimney for each storage rack or to design the charging passage as a common up-draft or down-clraft chimney for two storage racks.
Furthermore, it is advantageous to incline the storage cell ceiling in the direction of down--draft chimney; an angle of ~ 15 has been found to be favourable for this purpose.
By providing both a separate up-draft chimney through which the warmed air is passed to the storage cell ceiling, which is designed as a heat exchanger, and a separa-te down-draft chimney, a distinct separation o-f the functioll of the up-draft chimney for the warmed cooling medium and that of tlle down--draft chimney for the cooling medium cooled at the ceiling is at-~ained.
Both the up-draft chimney and the down-draft chimney are aligned in the direction of -the field of gravity, i.e., vertically.
This is particular]y favourable wi-th regard to the e~tent of the pressure losses and thus favourably affects the temperatuIe level in the storage depot.
The installation of the heat exchan~er at -the point of the higllest temperature withinthe cooling cycle, narnely above -the storage racks, has been found -to be partic~larly favourable 3~,;93 for reasons of thermodynamics since the thermodynamic efficiency of -the heat exchanger thus is at a maximum.
In order to protect more effectively the ambient air ~low~.ng through the heat exchanger ~ceiling) against the effect of di,rect radiation from the stored material it is advantageous to install be]ow the ceiling and laterally thereof baffles to shield the ceiling against radiation. The construction of up-draft chimney and down-draft chimney then is such -that effects of scattered radiation are avoided.
The apparatus according to the present invention is explained in greater detail by means of examples represented diagrammatically in the Figures I to VI.
The apparatus comprises one or several storage cells (15), norma],ly separated by charging passages (10) and housed in a builc~ing. The storage cells (15) contain storage racks (9) or storage blocks with storage shafts (2). The storage containers (1) filled with the material for storage are put into the storage shafts (2), which preferably are s],ightly inclined, and continuously passed through them when required. Spacers (12), which can simultaneously serve as ribs of the container surface, are used for centering the storage containers (1) in the storage shaft (2). Storage container (1) and storage shafts
Radioactive materials and radionuclide configurations, as for example, burned-out nuclear fuel elements or vitrified highly radioactive waste produce heat when disintegrating so that constant cooling is required during this storage. This requires that the continuous presence of a coo].ing medium is assured and that no inadmissible amounts of radioactivity are carried off with tlle cooling medium. These requirements are satisfied, for example, by a storage depot cooled directly or indirectly with ambient air.
Various plans have been proposed for the dry inter-mediate storage of heat-releasing radionuclide configurations.
Thus, for example in German offenlegungsschrift No. 2,730,729 it has been proposed to store the containers with radioactive waste in vertical shafts, through which air flows axially from the bottom to the top, -the containers being stacked either individually or multiply one above the other. In German Offen-legungsschrift No. 2,906,629 the containers are stored in horizontal shafts with cross flow from the outside in the vertical direction, the containers bei.ng individually or multiply arranged in tandem. A direct cooling system or an indirect cooling system can be used in these two cases.
- 1 - ~x~
3 i~ 6i93 German Offenlegungsschrift 2,837,839 describes the storage of containers in horizontal storage blocks having later-ally arranged cooling elements with cross flow in the vertical dircction. The storaye of vertical storage containers having Front--end shic]diny gatcs serv;ng sirnultaneously as cooling clemcnts is a]so known (Nuclear Technology, Vol. 24, December 1974) and so is the storage horizontally with cross flow within a closed space and emission of heat to the environment by means of heat pipes (Atom and Strom, 26th annual publication (1980)4).
The main disadvantage of the storage described in German Offenlegungsschrift No. 2,730,729 lies in the cooling with laterally arranged heat exchangers (walls) and in the flow direction thus required. The cell air emerging with maximal temperature and velocity of flow from the laterally arranged shafts irnpinyes on the flat ceiling and ;s thcn conducted hori-~.ontally to tlle Jateral hcat cxchal~gers. Kinetic energy is destroyed hy the flow impinging on the flat ceiling. Furthermore, the ]-,orizontal flow to the heat exchangers is not promoted by the external field of forces (gravitation)since the heated air tends to rise upwardly.
A further disadvantage of the apparatus cited in German Offenlegungsschrift No. 2,730,729 is that a distinct co-ordination of the heat removed from the storage stack region to one of the two heat exchangers is not possible.
The main disadvantage of the apparatus described in German Offenlegungsschrift No. 2,837,839 and of that described in "Nuclear Technology" is that for the heat flow from the storage containers to the cooling elcment,steep temperature gradients, which can result in thermal s-tresscs of the stored material, are required. The fact that in the storaye concept accordlng to German OEfenle~ungsscilrift No. 2,837,839 the cooling elellle3lt cons;sts of a solid properly heat-collductillg material, ~ 3f;~33 usually metal, resulting in high costs is particularly unfavour-ahle. Furthermore, because of the heavy weight of the storage hlocks with cooling elements,special structural requi.rements must be met hy the storaye racks.
'l'he substantial disadvantages of the apparatus describ-ed in "~tom and Strom" lie ;n that a distinct coordination of the heat to be removed from the region of the storage racks to one of the two heat exchangers is not possible and that no practical experience exists with regard to the behaviour of heat pipes in the radiation field. Furthermore, in this case, the emission of heat also is lateral so that the conduction of the flow is not optimal.
In the apparatus described in German Offenlegungs-schrift No. 2,906,629 the fact that the ambient air is exposed t~ t]lC' r~diation fi.eld of the rad;.oactive materials Wit]lOUt any large-sca].e shielding measures also is a disadvantage.
In all the apparatus for the intermediate storage of heat-producing radionuclide configurations with indirect cooling due to free convective flow,substantial disadvantages have resulted primarily with regard to an optimal conduction of flow and thus also with regard to both optimal heat removal, and shielding of theambient air against direct irradiation by radio-active substances.
Therefore, the present invention provides an apparatus for storing neat-releasing radionuclide configurations, which are enclosed in containers when required, with free cooling by means of ambient air, i.e., an apparatus comprising substan-tially a housi.ng provided witll charging passage, supply air and spent-air ducts and closed storage cells provided with ceilings and conta.i.ning s-torage racks or storac3e blocks with horizontally arranged or inclined storage shaEts as storac3e posi.t.ions for the radionuclide conf:iguratiolls or Eor tlle colltaill-g~
ers with radioactive ma-terials, coo]ing air Elowinc~ -through the storage shafts in the axial direc-tion. With this apparatus an improvement of -the conduction of coo]ing air Llow should be at-tained, -thus assuring a reliable heat removal.
Thus, according to the present invention the ceilings of the storage cells are heat exchangers and within the s-torage cells there are disposed at the openings of the s-torage shafts vertical up-draft and down-draft chirnneys, which are separated in space and function and are open in the region of -the storage racks with respect thereto and are provided with ]ockable charg-ing orifices with respect to the charging passage.
It is favourable to arrange a separate up-draft chimney and down-draft chimney for each storage rack or to design the charging passage as a common up-draft or down-clraft chimney for two storage racks.
Furthermore, it is advantageous to incline the storage cell ceiling in the direction of down--draft chimney; an angle of ~ 15 has been found to be favourable for this purpose.
By providing both a separate up-draft chimney through which the warmed air is passed to the storage cell ceiling, which is designed as a heat exchanger, and a separa-te down-draft chimney, a distinct separation o-f the functioll of the up-draft chimney for the warmed cooling medium and that of tlle down--draft chimney for the cooling medium cooled at the ceiling is at-~ained.
Both the up-draft chimney and the down-draft chimney are aligned in the direction of -the field of gravity, i.e., vertically.
This is particular]y favourable wi-th regard to the e~tent of the pressure losses and thus favourably affects the temperatuIe level in the storage depot.
The installation of the heat exchan~er at -the point of the higllest temperature withinthe cooling cycle, narnely above -the storage racks, has been found -to be partic~larly favourable 3~,;93 for reasons of thermodynamics since the thermodynamic efficiency of -the heat exchanger thus is at a maximum.
In order to protect more effectively the ambient air ~low~.ng through the heat exchanger ~ceiling) against the effect of di,rect radiation from the stored material it is advantageous to install be]ow the ceiling and laterally thereof baffles to shield the ceiling against radiation. The construction of up-draft chimney and down-draft chimney then is such -that effects of scattered radiation are avoided.
The apparatus according to the present invention is explained in greater detail by means of examples represented diagrammatically in the Figures I to VI.
The apparatus comprises one or several storage cells (15), norma],ly separated by charging passages (10) and housed in a builc~ing. The storage cells (15) contain storage racks (9) or storage blocks with storage shafts (2). The storage containers (1) filled with the material for storage are put into the storage shafts (2), which preferably are s],ightly inclined, and continuously passed through them when required. Spacers (12), which can simultaneously serve as ribs of the container surface, are used for centering the storage containers (1) in the storage shaft (2). Storage container (1) and storage shafts
(2) thus form a free f]ow space through which the cooling air can flow in the axial direction. In circular storage containers (1) and circular storage shafts (2) an annular c],earance (17) results as a free flow cross section. Other suitable shaft cross sections, for example, for rectangular storage conatiners, are feasible. The arrangement of the storage shafts (2) is optional but prirnarily horizontal, square or hexagollal (Fig. II).
The cooling air is warmed on passing through the ree flow Cl`OSS sect;olls (17) along ~he heated storage con~aillers an~
storage shaft surfaces. The inside shaft surface is heated i93 secondarily by heat transport due to radiation of heat from the storaye container surfaces. The warmed cooling air flows from the storage shaft (2) into the vertical up-draft chimney (3), whcrein it rises upwards.
The apparatus according to the present invention is an indirectly cooled storage depot, in which the warmed cooling air is passed to the ceiling (4), which preferably is slightly inclined in -the direction of flow and is designed as a cooling surface. Along said cooling surface the cooling air is cooled to the inlet temperature of the storage shaft. On emerging from the cooling duct (5) disposed along the ceiling (4) and formed by the ceiling (4) and the storage block (9) and baffles (21) the cooling air passes via the down-draft chimney (8) back to the storage shafts (2). The ambient air, which sweeps over the ceil,;~ng (4) as the e~texnal cooling air for tll~ coollng surace, passes via a supply-air duct (7) to the ceiling (4), where it is warmed. The ambient air thus warmed is returned to the outside via a spent-air duct (6).
Up-draft chimney (3) and down-draft chimney (8) are separated from the charging passage (10) and, when required, from a removal passage (11), by limiting walls (14) containing charging orifices (13).
If a continuous storage operation is not required, then the removal passage (11) and the charging orifices in said limiting wall are dispensed with.
Howcver, it is also possible to dispense with the local separation between up-draft chimney (3) or down-draft chimney (8) and charging passage (10) and to design the charging pclssage directly as the up-draft chimney (3) or down-draft chim-ncy (8) (Fig. V). The limiting walls (14) with the chargingorifices (13) are then dispensed with in this case as wcll.
3t~3 ~ ecause of the inc1ina-tion of the ceiling (4) and of -the storage shafts (2) a speciEic direction of -the amhient air flow can be a-ttained.
The prerequisite of a spec:ific direction of the ambient air flow can also be attained when the individual storage shaf-ts (2) in the storage rack (~) and the cooling duc-t (5) are so designed that the resistances to flow for the two direc-tions of flow differ in exten-t. The resistance to flow in the desired direction of flow must then be smaller than that for -the opposi-te direction. This can be a-ttained by correspondingly desiyned baffles (20) at the storage shaft orifices (18, 19).
The direction of flow in the outer cooling cycle can also be selected by varying heights of both the supply-air duct (7) and the spent-air duct (6) at the building.
It has been found that an angle of inclination of -the ceiling of < 15 is advantageous. This is a:Lso desirable for constructional reasons so that the heig]lt of the building will not be higher than necessary.
For thermodynamic reasons it is recommended to provide the ceiling (4), designed as a heat exchanger, with cooling ribs ~22). By enlarging the heat-transmitting surface the temperature level in the storage depot is lowered. Furthermore, at a specific cooling performance -the space required for the ceiling (4) is reduced.
The shie]ding of the ceiling by baffles (21) (for example, by a suspended thick concre-te ceiling) prevents a direct irradiation of -the ambient air in the outer cooling cycle. Dust activation and irradiation of other substances, wllich get into -the heat exchallger with the ambient air is thus limited to minimal values.
~ laterials which cause the radiation dosac3e to weaken are used for tIIe baffles (21). Suitable materials are, for i93 example, concrete, iron or ]ead. The radiation-shielding baffles (21) are designed, for example, as suspended concrete ceilings.
This ceiling (21) can be disposed directly above the storage rack (9). In the region of the up-draft chimneys (3) and down-draft chimney (8) said ceiling (21) has ports (24) which permit t}-le cooling air -to flow into and out of the cooling cluct (5).
Up-draft chimney (3) and down-draft chimney (8) are so constructed that scattered radiation effects are avoided, i.e., an unimpeded radiation from the radioactive material into the up-draft chimney (3) and down-draft chimney (8) and propaga-tion of radiation due to scattering on the limiting walls is prevented.
The production of the ceiling (4) from a metallic material (for example, steel) is particularly favourable since metals usually have very good heat-conducting properties and the res;.starlce fo heat transfer between the 1nner and outer cooling cyclcs ls minilnized. For ~he same reason it is recolr~ended to sub~ect the surface of -the meta]lic ceiling (4) to a treatment ~hich promotes heat transport by radiation (for example, by eloxadizing, coat of black paint).
A protection against corrosion (for example, galvaniz-ing, eloxadizing) assures that the ceiling (4) also corresponds to the requirements over a lengthy period.
Circular storage shafts (2) and circular storage con-tainers (1) have been found to be favourable costwise. Other cross sections, as for example, square or hexagonal ones, are of course also suitable.
The lockable charging orifices (13) in the limiting walls (14) are particularly suitable since they permit a local 30 separation between storage cell (15), charging passac3e (10) and removal passage (11). This is of great aclvantage witn rec~.lrd to possible measures of intervention.
3t:;93 Cross f]ow-impeding baffles (16) within the storage racks (9) can favourably prevent the formation of a localization of heat at the highcst point of -the s~orage rack and thus also the possibility of hot-spot formations.
Because of the fact that the storage shaft walls are heated due to heat transport by radiation from the surface of the storage containers the air in the spaces between the storage racks (9) is warmed and rises upwards, where it accumulates in the upper region of the storage racks (9) so that the locali~a-tion of heat is possible in said region.
Therefore, in order to avoid this, there are installedmetal sheets (16) disposed transversely in the spaces between the storage racks (9) so as to prcvent the air from f]owing upwards.
Of course, the apparatus according to the p2-esent invention can also be designed as a multistage heat e~changer system with several heat exchangers arranged in tandem (Fig. IV), the ceiling (4) being of multistage design.
This means that on the ceiling (4) the heat produced in the storage cell (15) is not passed directly to the ambient air but it is passed to a further closed c~cle (23), ~hich then passes the heat to the ambient air.
The cooling air is warmed on passing through the ree flow Cl`OSS sect;olls (17) along ~he heated storage con~aillers an~
storage shaft surfaces. The inside shaft surface is heated i93 secondarily by heat transport due to radiation of heat from the storaye container surfaces. The warmed cooling air flows from the storage shaft (2) into the vertical up-draft chimney (3), whcrein it rises upwards.
The apparatus according to the present invention is an indirectly cooled storage depot, in which the warmed cooling air is passed to the ceiling (4), which preferably is slightly inclined in -the direction of flow and is designed as a cooling surface. Along said cooling surface the cooling air is cooled to the inlet temperature of the storage shaft. On emerging from the cooling duct (5) disposed along the ceiling (4) and formed by the ceiling (4) and the storage block (9) and baffles (21) the cooling air passes via the down-draft chimney (8) back to the storage shafts (2). The ambient air, which sweeps over the ceil,;~ng (4) as the e~texnal cooling air for tll~ coollng surace, passes via a supply-air duct (7) to the ceiling (4), where it is warmed. The ambient air thus warmed is returned to the outside via a spent-air duct (6).
Up-draft chimney (3) and down-draft chimney (8) are separated from the charging passage (10) and, when required, from a removal passage (11), by limiting walls (14) containing charging orifices (13).
If a continuous storage operation is not required, then the removal passage (11) and the charging orifices in said limiting wall are dispensed with.
Howcver, it is also possible to dispense with the local separation between up-draft chimney (3) or down-draft chimney (8) and charging passage (10) and to design the charging pclssage directly as the up-draft chimney (3) or down-draft chim-ncy (8) (Fig. V). The limiting walls (14) with the chargingorifices (13) are then dispensed with in this case as wcll.
3t~3 ~ ecause of the inc1ina-tion of the ceiling (4) and of -the storage shafts (2) a speciEic direction of -the amhient air flow can be a-ttained.
The prerequisite of a spec:ific direction of the ambient air flow can also be attained when the individual storage shaf-ts (2) in the storage rack (~) and the cooling duc-t (5) are so designed that the resistances to flow for the two direc-tions of flow differ in exten-t. The resistance to flow in the desired direction of flow must then be smaller than that for -the opposi-te direction. This can be a-ttained by correspondingly desiyned baffles (20) at the storage shaft orifices (18, 19).
The direction of flow in the outer cooling cycle can also be selected by varying heights of both the supply-air duct (7) and the spent-air duct (6) at the building.
It has been found that an angle of inclination of -the ceiling of < 15 is advantageous. This is a:Lso desirable for constructional reasons so that the heig]lt of the building will not be higher than necessary.
For thermodynamic reasons it is recommended to provide the ceiling (4), designed as a heat exchanger, with cooling ribs ~22). By enlarging the heat-transmitting surface the temperature level in the storage depot is lowered. Furthermore, at a specific cooling performance -the space required for the ceiling (4) is reduced.
The shie]ding of the ceiling by baffles (21) (for example, by a suspended thick concre-te ceiling) prevents a direct irradiation of -the ambient air in the outer cooling cycle. Dust activation and irradiation of other substances, wllich get into -the heat exchallger with the ambient air is thus limited to minimal values.
~ laterials which cause the radiation dosac3e to weaken are used for tIIe baffles (21). Suitable materials are, for i93 example, concrete, iron or ]ead. The radiation-shielding baffles (21) are designed, for example, as suspended concrete ceilings.
This ceiling (21) can be disposed directly above the storage rack (9). In the region of the up-draft chimneys (3) and down-draft chimney (8) said ceiling (21) has ports (24) which permit t}-le cooling air -to flow into and out of the cooling cluct (5).
Up-draft chimney (3) and down-draft chimney (8) are so constructed that scattered radiation effects are avoided, i.e., an unimpeded radiation from the radioactive material into the up-draft chimney (3) and down-draft chimney (8) and propaga-tion of radiation due to scattering on the limiting walls is prevented.
The production of the ceiling (4) from a metallic material (for example, steel) is particularly favourable since metals usually have very good heat-conducting properties and the res;.starlce fo heat transfer between the 1nner and outer cooling cyclcs ls minilnized. For ~he same reason it is recolr~ended to sub~ect the surface of -the meta]lic ceiling (4) to a treatment ~hich promotes heat transport by radiation (for example, by eloxadizing, coat of black paint).
A protection against corrosion (for example, galvaniz-ing, eloxadizing) assures that the ceiling (4) also corresponds to the requirements over a lengthy period.
Circular storage shafts (2) and circular storage con-tainers (1) have been found to be favourable costwise. Other cross sections, as for example, square or hexagonal ones, are of course also suitable.
The lockable charging orifices (13) in the limiting walls (14) are particularly suitable since they permit a local 30 separation between storage cell (15), charging passac3e (10) and removal passage (11). This is of great aclvantage witn rec~.lrd to possible measures of intervention.
3t:;93 Cross f]ow-impeding baffles (16) within the storage racks (9) can favourably prevent the formation of a localization of heat at the highcst point of -the s~orage rack and thus also the possibility of hot-spot formations.
Because of the fact that the storage shaft walls are heated due to heat transport by radiation from the surface of the storage containers the air in the spaces between the storage racks (9) is warmed and rises upwards, where it accumulates in the upper region of the storage racks (9) so that the locali~a-tion of heat is possible in said region.
Therefore, in order to avoid this, there are installedmetal sheets (16) disposed transversely in the spaces between the storage racks (9) so as to prcvent the air from f]owing upwards.
Of course, the apparatus according to the p2-esent invention can also be designed as a multistage heat e~changer system with several heat exchangers arranged in tandem (Fig. IV), the ceiling (4) being of multistage design.
This means that on the ceiling (4) the heat produced in the storage cell (15) is not passed directly to the ambient air but it is passed to a further closed c~cle (23), ~hich then passes the heat to the ambient air.
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for storing heat-releasing radio-nuclide configurations, when required with cooling due to natural convection with ambient air, comprising a housing with supply-air and spent-air orifices, supply-air ducts for supplying cooling air and spent-air ducts for removing the air heated by heat absorption, a charging passage disposed in the housing with closed storage cells arranged on one or both sides thereof, said storage cells being provided with ceilings and having storage racks with storage shafts horizontally disposed or in-clined as storage positions for the radionuclide configurations, cooling air passing through said storage shafts in an axial direction, the ceilings of the storage cells being heat ex-changers via an external circulation of air spatially and func-tionally separated, vertical up-draft chimneys and down-draft chimneys being disposed at the storage shaft orifices within the storage cells, and for enforcing a convective flow within the storage cells, the ceiling or the storage shafts being in-clined in the direction of the down-draft chimneys or the storage shafts being provided with flow-resisting baffles which have a lower resistance to flow in the desired direction of flow than in the opposite direction.
2. An apparatus according to claim 1, in which the up-draft chimneys and the down-draft chimneys are open in the region of the storage racks with respect thereto and provided with lockable charging orifices with respect to the charging passages.
3. An apparatus according to claim 1, in which the charging passage is an up-draft chimney or down-draft chimney.
4. An apparatus according to claim 1 or 2, in which an up-draft chimney and a down-draft chimney is provided for each storage rack.
5. An apparatus according to claim 1, 2 or 3, in which the angle of inclination of the ceiling is ? 15°.
6. An apparatus according to claim 1, 2 or 3, in which the ceiling of the storage cells is provided with cooling ribs.
7. An apparatus according to claim 1, 2 or 3, in which the ceiling is provided with radiation-shielding baffles within the storage cells.
8. An apparatus according to claim 1, 2 or 3, in which the ceiling is made of metallic material.
9. An apparatus according to claim 1, 2 or 3, in which the surface of the metallic ceiling is subjected to a treatment inhibiting corrosion and/or promoting the emission of heat by radiation.
10. An apparatus according to claim 1, 2 or 3, in which the ceiling of the storage cells is of multistage struc-ture.
11. An apparatus according to claim 1, 2 or 3, in which the free space between the superimposed storage shafts contains baffles impeding the cross flow.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19813101540 DE3101540C2 (en) | 1981-01-20 | 1981-01-20 | Device for storing heat-releasing radionuclide configurations |
| DEP3101540.9 | 1981-01-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1169693A true CA1169693A (en) | 1984-06-26 |
Family
ID=6122902
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000394464A Expired CA1169693A (en) | 1981-01-20 | 1982-01-19 | Apparatus for storing heat-releasing radionuclide configurations |
Country Status (5)
| Country | Link |
|---|---|
| CA (1) | CA1169693A (en) |
| CH (1) | CH657471A5 (en) |
| DE (1) | DE3101540C2 (en) |
| ES (1) | ES508823A0 (en) |
| FR (1) | FR2498367B1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4889681A (en) * | 1981-10-19 | 1989-12-26 | U.S. Tool & Die, Inc. | Apparatus for reducing floor and seismic loadings in underwater storage areas used in the storing of spent nuclear fuel rods |
| DE3151310A1 (en) * | 1981-12-24 | 1983-07-07 | Deutsche Gesellschaft für Wiederaufarbeitung von Kernbrennstoffen mbH, 3000 Hannover | DRY BEARINGS FOR COMBINED CORE REACTOR FUEL ELEMENTS |
| DE3918444C2 (en) * | 1989-06-06 | 1997-05-22 | Siemens Ag | Storage facility for radioactive waste |
| US5152958A (en) * | 1991-01-22 | 1992-10-06 | U.S. Tool & Die, Inc. | Spent nuclear fuel storage bridge |
| FR2721430B1 (en) * | 1994-06-17 | 1996-09-13 | Cogema | Device and method for bag storage of materials releasing heat. |
| DE19538008B4 (en) * | 1995-10-12 | 2008-04-17 | Areva Np Gmbh | Storage container for receiving radioactive material and methods for storing spent fuel |
| DE19949297A1 (en) * | 1999-10-13 | 2001-04-26 | Steag Encotec Gmbh | Warehouse has a Z-shaped cooling air channel located in ventilating wall above floor of warehouse to form natural draught cooling system |
| FR2896613B1 (en) | 2006-01-26 | 2010-10-15 | Commissariat Energie Atomique | STACKABLE STACKING DEVICE FOR STACKABLE NUCLEAR FUEL AND STACKING MODULE FORMED BY A STACK OF SUCH ELEMENTS |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL6404826A (en) * | 1964-05-01 | 1965-11-02 | ||
| FR2388380A1 (en) * | 1977-04-22 | 1978-11-17 | Messier Sa | DEVICE ALLOWING THE STORAGE OF RADIOACTIVE WASTE AND THE RECOVERY OF THE PARASITIC HEAT EMITTED BY THE LATTER |
| DE2730729A1 (en) * | 1977-07-07 | 1979-01-25 | Nukem Gmbh | Spent fuel element storage esp. for thorium high temp. reactor - is sealed vessels inside air-cooled chamber |
| DE2837839C2 (en) * | 1978-08-30 | 1984-04-26 | Kraftwerk Union AG, 4330 Mülheim | Facility for the maintenance-free storage of radioactive material |
| DE2906629C2 (en) * | 1979-02-21 | 1986-01-23 | Nukem Gmbh, 6450 Hanau | Device for storing heat-emitting radioactive materials |
| DE2913540C2 (en) * | 1979-04-04 | 1986-01-30 | Nukem Gmbh, 6450 Hanau | Air duct for dry storage with heat-emitting radioactive materials |
| DE2929467C2 (en) * | 1979-07-20 | 1985-04-25 | Kraftwerk Union AG, 4330 Mülheim | Storage building for spent nuclear reactor fuel elements |
-
1981
- 1981-01-20 DE DE19813101540 patent/DE3101540C2/en not_active Expired
-
1982
- 1982-01-15 FR FR8200624A patent/FR2498367B1/en not_active Expired
- 1982-01-18 ES ES508823A patent/ES508823A0/en active Granted
- 1982-01-19 CH CH44982A patent/CH657471A5/en not_active IP Right Cessation
- 1982-01-19 CA CA000394464A patent/CA1169693A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR2498367A1 (en) | 1982-07-23 |
| CH657471A5 (en) | 1986-08-29 |
| ES8302344A1 (en) | 1983-01-01 |
| ES508823A0 (en) | 1983-01-01 |
| DE3101540A1 (en) | 1982-08-05 |
| FR2498367B1 (en) | 1985-12-20 |
| DE3101540C2 (en) | 1985-02-14 |
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| MKEX | Expiry |