US3011961A - Mode of fluid tight assembly for moderator blocks of atomic reactors - Google Patents

Mode of fluid tight assembly for moderator blocks of atomic reactors Download PDF

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Publication number
US3011961A
US3011961A US798619A US79861959A US3011961A US 3011961 A US3011961 A US 3011961A US 798619 A US798619 A US 798619A US 79861959 A US79861959 A US 79861959A US 3011961 A US3011961 A US 3011961A
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US
United States
Prior art keywords
blocks
wigner
moderator
assembly
mode
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Expired - Lifetime
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US798619A
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English (en)
Inventor
Lemesle Georges
Rouge Pierre
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C5/00—Moderator or core structure; Selection of materials for use as moderator
    • G21C5/02—Details
    • G21C5/04—Spatial arrangements allowing for Wigner growth
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • Cooling fluid leaks can occur at the level of the junctions between bars and/ or pavings of moderator.
  • the bars can become slightly tilted and the terminal surfaces of the blocks disjointed, Whichproduces gaps between them at their bases.
  • the present invention proposes a new mode of leakproof assembly for the moderator blocks of a solid moderator atomic reactor, which does away with all leaks of the cooling fluid at the level of the assembly components of the various blocks of the moderator,.by retaining for these components a mortise joint type of disposition.
  • This new mode of assembly is essentially characterized in that, between the blocks of the solid moderator to be assembled, are inserted a part of the same moderator material which has a boring coaxial with that through the channel running through the two blocks to be assembled, and oifering two plane surfaces machined perpendicularly to its direction of least Wigner effect, this part playing with respect to the assembly components of the two blocks, and that, according to a cylindrical surface, a male or female role according to the relative orientation of the main Wigner effect of the blocks to be assembled.
  • rings therefore offer either as rings having an external section sensibly equal to the internal section of a housing at the centre of the assembly components of the two blocks, and having'boring of the same axis and diameter as the channel of the pile of which it insures the imperviousness, as a parallelepiped of low height, section identical to that of the bars or paving of the pile and perforatedby a hole of the same diameter as that of the external projection of the blocks having the components of mechanical assembly.
  • the imperviousness is always ensured by the bearing of the plane faces of the ring, normal to the direction of least Wigner effect (generally mistaken with the direction of extrusion of the original bar) against the corresponding faces of the contiguous blocks.
  • the new mode of assembly, object of the present invention offers as an advantage the suppression of leaks resulting from the interplay of the assembly components of the blocks, and a decrease, as compared to other solutions that have been offered, in the amount of wasted raw material such as spills and cuttings during fabrication.
  • FIGURE 2 is a schematic view of an original bar from l which is fabricated the ring, Wigner effect.
  • FIGURE 3 is a sketch of the centering of the assembly of FIGURE 1 before and after irradiation in an atomic pile.
  • the deformations resulting from the, Wigner effect have been highly exaggerated to render the sketch easier to interpret, but in actual practice these deformations arefound not to exceed 3 or4%.
  • FIGURE 4 is a schematic exploded view of an assembly between a bar and a paving, according to the present invention.
  • FIGURE 5 is a schematic sectional view parallel to the axis of a complete assembly according to the present invention.
  • a pile of solid moderator has parallelepiped shaped pavings such as 1 and 2 traversed by a cylindrical channel 3 or 4inside which are to be found the elements of fissionable material (not shown) and circulates the cooling fluid of the react or.
  • the pavings 1 and 2 are cut from a bar of the moderator material, such as for instance graphite, obtained by ex-' trustion and offering some advantageous directions of Wigner expansion, i.e. expansion under the influence of radiations.
  • the origaxes of minimum Wigner expansion being horizontal and perpendicular to each other.
  • Mach paving has a cylindrical centering projection 8 or 9 on which are machined the tenons 10 and 11 and, perpendicularly to these the mortises 12 and 13 which are parallel to their respective axes of least Wigner expansion.
  • a tightness ring '14 is inserted between the pavings 1 and 2.
  • This ring is fabricated from a parallelepiped of graphite having a section identical to that of the pavings and having a hole 15 of diameter equal to that of the projections 8 and 9.
  • the ring 14 is also manufactured so that its contact surfaces 16 and 17 are perpendicular to the direction of extrusion, therefore to the axis of least Wigner effect.
  • the thickness of the ring 14 is calculated by taking into account the stresses to be transmitted; account also has to be taken of the fact that a part of these stresses is transmitted directly by the tenons and mortises 3 and 9 of the pavings 1 and 2.
  • the various com-' ponents of the assembly which is the object of the invention, are deformed, but the centering of the whole is preserved at all times: in fact, as can be seen from FIG- URE 3, the hole 15 of the ring 14- adopts a circular profile 15' since it expands isotropically, whereas the two centering projections 8 and 9 respectively adopt elliptical 3 profiles 8" and 9' since their axes of least Wigner expansion are perpendicular.
  • a pile of solid moderator for an atomic reactor can also include, as is already known, assemblies of a paving 2t) and a prismatic rod 21.
  • the paving 20 is machined so that its direction of least Wigner effect is parallel to two of its lateral faces 24 and 25, and perpendicular to the axis of its channel 22.
  • the rod 21 is machined so as to have its axis parallel tothe direction of the extrusion and therefore to the axis of least Wigner effect.
  • the two blocks have tenons 26 and 27 and perpendicular mortises 28 and 29 which are parallel to the respective sides.
  • the elements of the assembly extend from the outer faces of each block to a central joggle 30 and 31.
  • the two joggles do not have quite the same diameter; that of joggle 3G, machined on the paving 2t) and being susceptible to ovalization under the influence of the radiations, is slightly larger than that of joggle 31, which is machined in rod 21 and remains perfectly circular at all times.
  • a tightness ring 32 is inserted in the assembly within the two joggles 3t and 31, the said ring being of graphite and having an internal diameter equal to that of channel 22 or 23 and an external diameter equal to that of the joggle 31 machined in rod 21.
  • the ring 32 is machined so its axis is parallel to that of the extrusion, therefore to the axis of least Wigner etfect.
  • the centering of the assembly is ensured permanently by the tenons and mortises, the tightness on the other hand is ensured by the contact between the plane faces 33 and 34 of the ring 32 and the bottoms 35 and 36 of the joggles 30 and 31 respectively.
  • the ring 32 is always tight in the joggle 31 of rod 21 because both have parallel directions of extrusion and therefore expand similarly. On the contrary, the ring 32 is mounted with a play inside of the joggle 30; of paving 20 which can ovalize around it.
  • FIGURE shows schematically a complete assembly of four blocks of solid moderator according to a preferred embodiment of the invention.
  • the layout corresponds exactly to the superposition of those described in connection with FIGURES 1 and 4; there can be observed, from bottom to top, a bar of graphite 37, two pavings 38 and 39' and a bar 40.
  • the blocks are assembled according to the invention by means of rings of the male type 41 and 42 and of the female type 43.
  • the two main axes of Wigner effect for each part being in the plane of the figure, are again indicated by their conversional signs, the third axis (not shown) easily identified by deduction for each part.
  • said elements to be assembled having a passage coaxial to that of the channel extending through the two blocks, said element having two plane surfaces perpendicular to its dimension of least Wigner efifect, said element having some play with respect to the components of mechanical assembly of the two blocks, said blocks to be assembled being parallelopipeds placed one above the other with their respective axes of least Wigner expansion substantially parallel to a horizontal edge and perpendicular to each other, cylindrical projections for the blocks including tenons and mortises, said mortises being substantially perpendicular to said tenons and substantially parallel to the axes of least Wigner expansion, said element being a parallelopiped of section identical to those of the blocks, the passage in said element having the diameter of said projections and having its contacting surfaces substantially perpendicular to the axis of least Wigner effect.
  • means for forming a tight assembly between the blocks of the moderator comprising an element of moderator materialinserted between two blocks to be assembled having a passage coaxial to that of the chan ncl extending through the two blocks, said element having two plane surfaces perpendicular to its dimension of least Wigner effect, said element having some play with respect to the components of mechanicalassembly of the two blocks, the two blocks being parallelopipeds and being assembled vertically one above the other, one of the blocks having its direction of least Wigner eifect substantially parallel to its vertical edges, the other block having its direction of least Wignerefiect substantially parallel to a horizontal edge, mortises and tenons in the adjacent faces of the blocks at right angles to each other and with the mortise in the lower block substantially parallel to the axis of least Wigner expansion and a central joggle in the adjacent faces of the blocks, said

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Particle Accelerators (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
US798619A 1958-03-15 1959-03-11 Mode of fluid tight assembly for moderator blocks of atomic reactors Expired - Lifetime US3011961A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR760609 1958-03-15

Publications (1)

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US3011961A true US3011961A (en) 1961-12-05

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US798619A Expired - Lifetime US3011961A (en) 1958-03-15 1959-03-11 Mode of fluid tight assembly for moderator blocks of atomic reactors

Country Status (8)

Country Link
US (1) US3011961A (xx)
BE (1) BE576423A (xx)
CH (1) CH357477A (xx)
DE (1) DE1102300B (xx)
FR (1) FR1193302A (xx)
GB (1) GB897534A (xx)
LU (1) LU36969A1 (xx)
NL (1) NL112194C (xx)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3259548A (en) * 1962-06-01 1966-07-05 Atomic Energy Authority Uk Moderator structures for nuclear reactors

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE624929A (xx) * 1961-11-20

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2852457A (en) * 1955-06-30 1958-09-16 Long Everett Nuclear reactors

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB784291A (en) * 1954-06-30 1957-10-09 Atomic Energy Authority Uk Improvements in or relating to nuclear reactors

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2852457A (en) * 1955-06-30 1958-09-16 Long Everett Nuclear reactors

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3259548A (en) * 1962-06-01 1966-07-05 Atomic Energy Authority Uk Moderator structures for nuclear reactors

Also Published As

Publication number Publication date
BE576423A (fr) 1959-07-01
NL112194C (xx) 1965-12-15
LU36969A1 (xx) 1959-05-05
GB897534A (en) 1962-05-30
FR1193302A (fr) 1959-11-02
CH357477A (fr) 1961-10-15
DE1102300B (de) 1961-03-16

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