US3674636A - Nuclear reactor means for minimizing lateral vibrations - Google Patents

Nuclear reactor means for minimizing lateral vibrations Download PDF

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Publication number
US3674636A
US3674636A US771190A US3674636DA US3674636A US 3674636 A US3674636 A US 3674636A US 771190 A US771190 A US 771190A US 3674636D A US3674636D A US 3674636DA US 3674636 A US3674636 A US 3674636A
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US
United States
Prior art keywords
fuel
stringer
channel
nuclear reactor
bristles
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US771190A
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English (en)
Inventor
Philip Michael Jones
Raymond Herbert Walsh
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UK Atomic Energy Authority
Original Assignee
UK Atomic Energy Authority
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by UK Atomic Energy Authority filed Critical UK Atomic Energy Authority
Application granted granted Critical
Publication of US3674636A publication Critical patent/US3674636A/en
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
    • G21C3/02—Fuel elements
    • G21C3/04—Constructional details
    • G21C3/06—Casings; Jackets
    • G21C3/12—Means forming part of the element for locating it within the reactor core
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
    • G21C3/02—Fuel elements
    • G21C3/04—Constructional details
    • 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

  • This invention relates to nuclear reactors and is particularly concerned with a problem which can arise in operation of a nuclear reactor of the gas cooled graphite moderated type which is designed for on-load refuelling.
  • coolant gas is passed upwardly through channels in the reactor core structure, such channels containing fuel elements or components such as control rods.
  • the fuel elements typically comprise an outer graphite sleeve containing clusters of fuel pins supported within the sleeve by support and spacer grids.
  • Each fuel channel contains a stringer of such fuel elements, each fuel element being jointed to its neighbours in the stringer so that the stringer as a whole is dischargeable from and chargeable into the fuel element channel.
  • Coolant gas is conducted from the fuel element channels through charge pipes which connect with stand pipes at the reactor charge face.
  • the stand pipes are normally blocked by shield plugs and coolant gas passes through outlet ports in the charge pipes and is collected in a common hot gas plenum. From the hot gas plenum the hot coolant gas is circulated through heat exchangers and then back to the fuel element channels. On load refuelling of such a reactor is carried out whilst the reactor is operating at power and coolant gas flow is maintained through the fuel element channels during refuelling.
  • a fuel stringer is discharged from its fuel channel by lifting the fuel stringer from the fuel channel through the associated charge pipe and stand pipe, the fuel stringer being lifted into a charge machine on the reactor charge face.
  • a fuel stringer is recharged into the fuel channel by lowering from the charge machine through the stand pipe and associated charge tube. Whilst the fuel stringer is bein raised or lowered during refuelling the action of coolant flow can cause lateral vibration of the fuel stringer in the fuel channel or charge pipe with likelihood of damage, particularly to the elements of the fuel stringer.
  • components such as control rods can be liable to vibration when subjected to coolant flow in a channel.
  • a nuclear reactor component chargeable into and dischargeable from a channel in the core structure of a nuclear reactor is provided in the region of its lower end with radially projecting spring bristles arranged on a circumferential line with respect to the longitudinal axis of the component.
  • the invention is particularly applicable to a nuclear reactor fuel stringer comprising a number of fuel elements jointed one to another.
  • a nuclear reactor fuel stringer comprising a number of fuel elements jointed one to another.
  • at least one of the lower fuel elements in the stringer is provided with radially projecting spring bristles arranged circumferentially around the fuel element.
  • the spring bristles are fitted to the bottom fuel element in the stringer of fuel elements.
  • FIG. 1 is an elevation of the lower part of a stringer of fuel elements.
  • FIG. 2 is a detail, on a larger scale, of the lower end of the bottom fuel element in the stringer of fuel elements shown in FIG. 1.
  • FIG. 3 is a detail of the part bounded by the circle III in FIG. 2.
  • FIG. 1 of the drawings there is shown a fuel element stringer 1 for a nuclear reactor.
  • the stringer 1 comprises a number of fuel elements 2 joined in an articulated manner by interconnecting links 3.
  • Each of the fuel elements 2 comprises an outer graphite sleeve 4 containing clusters of fuel pins supported within the sleeve 4 by support and spacer grids (not shown).
  • At the bottom of the sleeve 4 of the lowermost fuel element 2 in the stringer there is fitted a set of radially projecting spring bristles 5.
  • the spring bristles 5 project on a circumference beyond the limit of the outer surface of the sleeve 4 of the fuel element 2.
  • the spring bristles 5 are carried by an adaptor 6 fitted to the lower end of the sleeve 4 of the fuel element 2.
  • the adaptor 6 has a tubular body 7.
  • An end flange 8 with a rim 9 on the body 7 fits about a step 10 at the lower end of the sleeve 4.
  • the bristles 5 are in two sets mounted in circular holders 11 which fit on the body 7 of the adaptor 6 and are held on the body 7 of the adaptor 6 between clamping rings 12.
  • the holders 11 for the bristles 5 are held clamped between the rings 12 by a nut 13 screwed on the lower end of the body 7 of the adaptor 6, spacer rings 14 being fitted between the nut 13 and the lower clamping ring 12.
  • the adaptor 6 is carried by a bottom support 15 which comprises an outer ring 16 joined to a central tubular boss 17 by radial webs 18.
  • the fuel element 2 has a central tie rod 19 which extends below the lower end of the fuel element sleeve 4.
  • a tie rod extension 20 having a tubular internally threaded body 21 is screwed onto the lower end of the tie rod 19 and is prevented from unscrewing by a split pin 22.
  • the tie rod extension 20 has an externally threaded lower end part 23 which is screwed into the central tubular boss 17 of the bottom support 15 and is prevented from unscrewing by a split pin 24.
  • the nut 13 of the adaptor 6 is stepped to seat in a step 25 formed in the outer ring 16 of the bottom support 15.
  • the bottom fuel element 2 of the stringer is located by contact of the bristles 5 with the wall of the fuel element channel or with the wall of the charge pipe leading from the channel in the reactor core structure and lateral vibration of the fuel element stringer is minimised by the location provided by the bristles 5.
  • the arrangement can cope with gradual and step-wise changes in charge path diameter (for example a bristle length would suitably be chosen to provide wall contact at the maximum channel diameter).
  • the arrangement only involves the use of very small quantities of additional neutron absorbing material in the fuel element stringer.
  • the bristles may be of springy metal such as stainless steel. Stiff metal bristles would tend to scratch the walls of the fuel channel but this could be avoided as shown in FIG. 3 by forming blobs 26 on the ends of the bristles or by covering the ends of the bristles with a shoe.
  • Means for minimizing lateral vibration of an elongated nuclear reactor component when subject to coolant flow in a vertical channel in a nuclear reactor core structure while the component is being lifted from or lowered into the channel suspended from its upper end said means comprising spring bristles arranged on a circumferential line around a region at an end of the component which is the lower end when the component is being lifted from or lowered into the channel said bristles extending radially outwardly beyond the outer wall of said lower end.
  • Means for minimising lateral vibration of a fuel element stringer as claimed in claim 2 characterised in that the spring bristles are provided at the bottom end of the lowermost fuel element of the stringer.
  • Means for minimising lateral vibration of a fuel element stringer as claimed in claim 3 characterised in that the bristles are of springy metal and are grouped together in brush like form.
  • Means for minimising lateral vibration of a fuel element stringer as claimed in claim 4 characterised that the outer ends of the bristles terminate in rounded blobs.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Vibration Dampers (AREA)
  • Vibration Prevention Devices (AREA)
US771190A 1967-11-23 1968-10-28 Nuclear reactor means for minimizing lateral vibrations Expired - Lifetime US3674636A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5344767 1967-11-23

Publications (1)

Publication Number Publication Date
US3674636A true US3674636A (en) 1972-07-04

Family

ID=10467841

Family Applications (1)

Application Number Title Priority Date Filing Date
US771190A Expired - Lifetime US3674636A (en) 1967-11-23 1968-10-28 Nuclear reactor means for minimizing lateral vibrations

Country Status (4)

Country Link
US (1) US3674636A (enExample)
DE (1) DE1806539A1 (enExample)
FR (1) FR1592175A (enExample)
GB (1) GB1228769A (enExample)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5009837A (en) * 1989-11-03 1991-04-23 Westinghouse Electric Corp. Axially modular fuel assembly and rod for optimal fuel utilization

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8431042D0 (en) * 1984-12-07 1985-02-13 Atomic Energy Authority Uk Gas cooled nuclear reactors

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5009837A (en) * 1989-11-03 1991-04-23 Westinghouse Electric Corp. Axially modular fuel assembly and rod for optimal fuel utilization

Also Published As

Publication number Publication date
FR1592175A (enExample) 1970-05-11
DE1806539A1 (de) 1969-06-19
GB1228769A (enExample) 1971-04-21

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