Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3882313 A
Publication typeGrant
Publication dateMay 6, 1975
Filing dateNov 7, 1972
Priority dateNov 7, 1972
Also published asDE2350750A1
Publication numberUS 3882313 A, US 3882313A, US-A-3882313, US3882313 A, US3882313A
InventorsSiemens Jr Dan H
Original AssigneeWestinghouse Electric Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Concentric annular tanks
US 3882313 A
Abstract
Concentric annular tanks for the storage of solutions containing fissile materials are disclosed. By placing an appropriate neutron isolator between each of the annular tanks, a critical fissile mass can be avoided and additional annular tanks can be added to achieve a desired total volume and maximum floor space usage. In one embodiment the individual tanks are communicatively coupled at at least one location to equalize the fluid level within the corresponding tanks. The couplings are adaptable for the accession of additional concentric annular tanks to accommodate a larger storage volume.
Images(2)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent Siemens, Jr.

[ 1 May 6,1975

[ CONCENTRIC ANNULAR TANKS [75] Inventor: Dan H. Siemens, Jr., Richland,

Wash.

[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh. Pa.

221 Filed: Nov. 1, 1972 [21] Appl. No.: 304,452

[52] US. Cl 250/507; 250/518; 252/3011 W [51] Int. Cl. G2 1/00 {58] Field of Search 250/506, 507, 518, 526, 250/30l.1 W

[56] References Cited UNITED STATES PATENTS 2,918,717 12/1959 Struxmess et a1 250/3011 W 3,046,403 7/1962 Montgomery 250/507 3,056,028 9/1962 Mattingly 250/518 3,101,258 8/1963 Johnson 252/301.l W

Rogers 250/506 Schlies 250/507 Primary ExaminerHarold A. Dixon Attorney, Agent, or FirrnD. C. Abeles [5 7 1 ABSTRACT Concentric annular tanks for the storage of solutions containing fissile materials are disclosed. By placing an appropriate neutron isolator between each of the annular tanks, a critical fissile mass can be avoided and additional annular tanks can be added to achieve a desired total volume and maximum floor space us age. In one embodiment the individual tanks are communicatively coupled at at least one location to equalize the fluid level within the corresponding tanks. The couplings are adaptable for the accession of additional concentric annular tanks to accommodate a larger storage volume.

8 Claims, 3 Drawing Figures PATENTEUMAY ems SHEU 10$ 2 PATENIEDm e|szs SHEET 2 BF 2 FIG.2.

CONCENTRIC ANNULAR TANKS BACKGROUND OF THE INVENTION This invention pertains in general to annular storage tanks and more particularly. to concentric annular storage tanks with isolation for the storage of solutions containing fissile nuclear material.

In the nuclear processing industry it is often neces sary to provide tanks for large volumes containing reactive nuclear material. If these solutions contain fissile material. a geometrically favorable design is required. One geometrically favorable design is a narrow rectangular tank which is commonly referred to as a slabtank. The slab width is dictated by the amount of fissile material present in the storage solution and is normally less than five inches. The main objective in designing the slab width is to avoid criticality. As a result, the slab-tank configuration is impractical when a volume capacity of more than 1,000 liters is desired, due to the extensive amount of floor space required to accommodate the larger volume. Additionally, a large slab-tank is more costly to construct because it requires massive stiffeners to provide structural strength and prevent distortion under stress which could cause the critical slab dimension to change. Another geometrically favorable design is an annular tank. Here again, the annular width of the storage volume is dictated by the fissile material content of the storage solution and is normally less than five inches. There is no limit to the diameter that an annular tank can be constructed. however, there is a waste of floor space inside the annular opening of the tank. Furthermore, an annular tank easily accommodates moderate changes in internal pressure. or vacuum, without distortion of the critical dimension.

Accordingly, an optimized geometrical structural de sign is desired for such tanks that will provide the desired total volume storage capacity required by the nuclear industry while maximizing floor space usage.

SUMMARY OF THE INVENTION Briefly, this invention provides an optimized structural geometry for containment tanks employed in the storage of solutions containing nuclear material. In accordance with this invention, concentric annular tanks are described with neutron isolators positioned between each of the respective tanks. The isolators are designed to have a sufficient neutron capture crosssection to guard against the formation of a critical mass of nuclear material. Additional annular tanks can be added concentrically to achieve a desired total volume and maximum floor space usage. In one embodiment, the individual tanks are communicatively coupled at at least one location to equalize the fluid level within corresponding tanks. The couplings are adaptable for the accession of additional concentric annular tanks to accommodate larger storage volumes while minimizing floor space usage.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference may be had to the preferred embodiment, exemplary of the invention, shown in the accompanying drawings, in which:

FIG. 1 is a planned view of one embodiment of this invention;

FIG. 2 is an elevational sectional view of the embodiment illustrated in FIG. I; and

FIG. 3 is a sectional view of the embodiment of FIG. I illustrating the accession of additional annular concentric tanks.

DESCRIPTION OF THE PREFERRED EMBODIMENT An optimized structural geometry contemplated by this invention for containment tanks applicable for the storage of solutions containing fissile material is illustrated in FIGS. 1. 2 and 3, which show an annular tank design where two, three, or more tanks are arranged concentrically to achieve a more economical use of floor space. By placing an appropriate neutron isolator between each of the annular tanks, additional annular tanks can be added to achieve a desired total volume and maximum floor space usage.

Referring to FIG. I it can be observed that a planned view is provided of a concentric array of two annular tanks exemplary of this invention. An outer hollow annular tank is shown and generally described by reference character 10. The storage area is defined by the tubular inside and outside walls 14 and I2, respectively, which are concentrically formed with a bottom plate sealably affixed therebetween at one end of the corresponding tubular end terminations. The wall thicknesses of the tanks are desirably chosen to accommodate external pressures without the need for stiffness and to provide sufficient shielding against radioactivity. An exemplary thickness from 0.250 to 0.375 inches will provide adequate strength for external pressures up to one atmosphere where materials such as 304L stainless steel are employed. Type 304L stainless steel is described as an exemplary material for the tank walls due to its compatibility with the elements to be stored.

An annular isolator I6 is closely received within the annular opening formed by the tubular wall 14 and is designed from a material that has a sufficient neutron capture cross section to avoid the formation of a critical nuclear mass. In other words, the annular isolator is designed to absorb a sufficient number of delayed neutrons emitted from the elements being contained within the tank 10 and any number of inner concentric tanks to avoid a chain reaction from being sustained. The isolator I6 can be fabricated from any material exemplifying these desired characteristics such as serpentine concrete that has a 10 percent minimum water content. Each isolator can be desirably jacketed with eighteen gage stainless steel to prevent absorption of plutonium into the concrete (where plutonium is among the materials being stored) and to facilitate de contamination after storage.

A second annular tank is concentrically positioned within the annular opening formed by the outer isolator 16 to achieve a higher density usage of floor space. The storage area of the second hollow annular tank I8 is specifically defined by the inner and outer tubular walls 22 and 20, respectively, with a bottom plate sealably affixed therebetween at one of the corresponding tubular end terminations. The thickness of the tank defined by the difference in radial dimensions between the inner and outer walls is dictated by the fissile material content of the solution being stored and is normally less than five inches.

A second annular isolator is concentrically positioned within the annular opening formed by the inner tubular wall 22 of the second tank 18. This inner isolator 24 is substantially identical to the isolator previously described and defined by reference character [6 and provides a sufficient neutron capture cross section to prevent the delay neutrons emitted from the inner circumference of the tank 18 from sustaining a chain reaction.

Referring now to FIG. 2 it will be observed that an elevational sectional view of the annular tanks of FIG. I is presented. The bottom plates. sealably affixed to the respective side walls of the inner and outer tanks previously described with reference to FIG. 1. are illustrated by reference characters 40 and 38, respectively. In addition. the tanks are provided with cover plates 30 and 32 and fluid vents 34 and 36 which are employed to aid in charging the tanks with the materials to be stored. The tanks can either be filled through inlets similar to those described by the vents 34 and 36 or through conduit means 28 which communicatively couples the interior of tank with the exterior thereof. Optional conduit means 26 can additionally be provided to communicatively couple the respective storage volumes of tanks 10 and 18 to equalize the level of storage material within the corresponding tanks. The fluid coupling conduit 26 is desirably designed to disconnect from the respective tanks so that the individual tanks can be used separately where desired. Furthermore. conduit means 28 is designed for interconnection to a third annular tank which can be circumferentially positioned around tank 10 to form a concentric array of three annular tanks with an increase in storage volume and a maximum usage of floor space. With the third tank connected as described conduit means 28 will perform the same function as fluid conducting means 26. Similarly, additional annular tanks can be added. either circumferentially or concentrically, to achieve any desired storage volume.

In the embodiment illustrated the lower plates 40 and 38. which form the bottom walls of the tanks 18 and 10, respectively. are sloped in a direction to assist gravity feed of the storage material through fluid conduit means 26 to conduit 28. Such a structural configuration is desirable where conduit 28 is designed as an exit port to empty the tanks when the storage period has expired. Furthermore. the respective conduits 26 and 28 can be provided with valve closure means to control or shut off the volume of fluid flow of storage material.

FIG. 3 illustrates a sectional view of an array of concentric annular tanks similar to the array previously described with reference to FIGS. 1 and 2. By the addition of a third annular isolator positioned around the periphery of the tank 10 and a third tank positioned in a similar manner around the periphery of the third annular isolator additional storage volume can be ob mined as previously described.

Thus. this invention provides an optimized structural geometry for containment tanks designed for the storage of solutions containing nuclear material. enabling a maximum usage of floor space; more efficient mixing of the storage material; standardization of fabrication techniques; and added structural support.

l claim as my invention:

1. Concentric annular tanks with isolation for the storage of solutions containing nuclear materials comprising:

a first annular hollow tank having a tubular inside and outside wall concentrically formed with a bottom plate sealably affixed therebetween at one of the corresponding tubular end terminations so as to form the bottom wall thereof;

a second annular hollow tank having a tubular inside and outside wall concentrically formed with a bottom plate sealably affixed therebetween at one of the corresponding tubular end terminations so as to form the bottom wall thereof. said second tank being concentrically positioned within the interior annular opening formed by said inside wall of said first tank; and

isolation means associated with said first and second tanks having a neutron capture cross section sufficient to guard against the formation of a critical mass of nuclear material between the storage contents of said first and second tanks.

2. The concentric annular tanks of claim 1 including fluid coupling means positioned substantially adjacent the corresponding bottom walls of the said first and second tanks and communicatively coupling the interior of said first tank with the interior of said second tank.

3. The concentric annular tanks of claim 2 including conduit means associated with said outside wall of said first tank substantially adjacent the bottom wall thereof for communicatively coupling the interior of said first tank with the exterior thereof.

4. The concentric annular tanks of claim 3 wherein said conduit means and said fluid coupling means are aligned along a common diameter of the common annuli of said first and second tanks.

5. The concentric annular tanks of claim 4 including:

a third annular hollow tank having a tubular inside and outside wall concentrically formed with a bottorn plate sealably affixed therebetween at one of the corresponding tubular end terminations so as to form the bottom wall thereof, said first tank being concentrically positioned within the interior annular opening formed by said inside wall of said third tank;

second fluid coupling means associated with said inner wall of said third tank substantially adjacent the bottom wall thereof and aligned along the common diameter of said conduit means. said second fluid coupling means being adaptable to interconnect with said conduit means so as to communicatively couple the interior of said first tank with the interior of said third tank; and

isolation means associated with said first and third tanks having a neutron capture cross section sufficient to guard against the formation of a critical mass of nuclear material between the storage contents of said first and third tanks.

6. The concentric annular tanks of claim 4 wherein said bottom walls of said first and second tanks are sloped along the diameter of said conduit means in a direction to assist gravity from said second tank to said first tank through said fluid coupling means to said conduit means.

7. The concentric annular tanks of claim 1 wherein said isolation means comprises an annular casing of concrete closely received between the inner wall of said first tank and the outer wall of said second tank.

8. The concentric annular tanks of claim 1 including a neutron isolator closely received within the annular opening formed by the inside wall of said second tank and lining the exterior surface area thereof. said isolator having a neutron capture cross section sufficient to guard against the formation of a critical mass of nuclear material within the storage contents of said second tank.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2918717 *Dec 12, 1956Dec 29, 1959Edward G StruxnessSelf sintering of radioactive wastes
US3046403 *Apr 17, 1959Jul 24, 1962Babcock & Wilcox CoDevice for the storage of a heat evolving material
US3056028 *May 3, 1960Sep 25, 1962James T MattinglyNeutron shielding structure
US3101258 *Jun 14, 1961Aug 20, 1963Benjamin M JohnsonSpray calcination reactor
US3111586 *Aug 25, 1961Nov 19, 1963Baldwin Lima Hamilton CorpAir-cooled shipping container for nuclear fuel elements
US3466445 *Oct 6, 1967Sep 9, 1969Atomic Energy CommissionContainer for radioactive fuel elements
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4010375 *May 27, 1975Mar 1, 1977Wachter William JStorage rack for nuclear fuel assemblies
US4044267 *Mar 26, 1976Aug 23, 1977Combustion Engineering, Inc.Fissionable mass storage device
US4400344 *Nov 14, 1977Aug 23, 1983Wachter William JStorage rack for nuclear fuel assemblies
US4476394 *Mar 27, 1981Oct 9, 1984Transnuklear GmbhInsertion canister for radioactive material transportation and/or storage containers
US4649018 *Mar 9, 1984Mar 10, 1987Strabag Bau-AgContainer for the storage of radioactive elements
US4655996 *Oct 6, 1983Apr 7, 1987Commissariat A L'energie AtomiqueEast neutron reactor having a storage structure independent of the core structure
US4706366 *Apr 24, 1985Nov 17, 1987Establissements Lemer & CieMethod of manufacturing a double-wall container including a neutron-absorbing screen for transporting and storing radio-active material
US4820472 *Jul 14, 1981Apr 11, 1989Westinghouse Electric Corp.Nuclear reactor spent fuel storage rack
US4857263 *Nov 30, 1987Aug 15, 1989Westinghouse Electric Corp.Storage of spent nuclear fuel
US5629963 *Nov 18, 1993May 13, 1997Compagnie Generale Des Matieres NucleairesStorage tank for a radioactive fissile material solution
US5894134 *Sep 13, 1996Apr 13, 1999General AtomicsShipping container for radioactive material
US6770897Dec 18, 2001Aug 3, 2004British Nuclear Fuels PlcContainer for nuclear fuel transportation
US6825483Jul 14, 2003Nov 30, 2004British Nuclear Fuels PlcContainer for nuclear fuel transportation
US7372060Nov 17, 2005May 13, 2008Rolls-Royce PlcContainer for fissile material and a method of making the same
US8049194Aug 31, 2007Nov 1, 2011Uranium Asset Management LimitedContainer for nuclear fuel transportation
US8634514Jun 14, 2007Jan 21, 2014Belgonucleaire SaCriticality prevention devices and methods in nuclear fuel production
CN101467216BJun 14, 2007Jul 17, 2013比利格核股份有限公司Safe case packaging devices and process for nuclear fuel production therein
EP2342719A2 *Sep 25, 2009Jul 13, 2011Columbiana Hi Tech LLCContainer for transporting and storing uranium hexaflouride
WO1994011883A1 *Nov 18, 1993May 26, 1994CogemaStorage tank for a radioactive fissile material solution
WO2004112053A1 *May 17, 2004Dec 23, 2004John Haydn BarnesA container for a fissile material and a method of making the same
WO2007144414A1 *Jun 14, 2007Dec 21, 2007Belgonucleaire SaCriticality prevention devices and methods in nuclear fuel production
WO2010036925A2Sep 25, 2009Apr 1, 2010Columbiana Hi Tech LlcContainer for transporting and storing uranium hexaflouride
Classifications
U.S. Classification250/507.1, 976/DIG.276, 588/16, 376/272, 976/DIG.343
International ClassificationG21F5/005, G21F9/04, G21C19/00, G21C19/40, G21F9/22
Cooperative ClassificationG21F5/005, G21C19/40
European ClassificationG21F5/005, G21C19/40