EP0429445A1 - Dispositif pour centrer des elements d'un reacteur nucleaire - Google Patents

Dispositif pour centrer des elements d'un reacteur nucleaire

Info

Publication number
EP0429445A1
EP0429445A1 EP88909299A EP88909299A EP0429445A1 EP 0429445 A1 EP0429445 A1 EP 0429445A1 EP 88909299 A EP88909299 A EP 88909299A EP 88909299 A EP88909299 A EP 88909299A EP 0429445 A1 EP0429445 A1 EP 0429445A1
Authority
EP
European Patent Office
Prior art keywords
centering
centering pins
fuel
pins
head
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.)
Withdrawn
Application number
EP88909299A
Other languages
German (de)
English (en)
Inventor
Robert Weber
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Publication of EP0429445A1 publication Critical patent/EP0429445A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • G21C5/00—Moderator or core structure; Selection of materials for use as moderator
    • G21C5/02—Details
    • G21C5/06—Means for locating or supporting fuel elements
    • 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

  • the invention relates to an arrangement for centering components of a nuclear reactor and is applicable for fixing the position of fuel elements.
  • the reactor core which is arranged in a reactor pressure vessel, consists of a large number of fuel elements with a square cross section, which are arranged in a core vessel.
  • fuel rods are held in a supporting structure, which is formed from a fuel element head and a fuel element foot and intermediate guide tubes for control rods. Spacers are attached to the guide tubes, which bundle the fuel rods and hold them in such a way that they can expand freely.
  • a coolant flows through the fuel elements from bottom to top.
  • a scaffold insert is arranged in the core container above the fuel elements.
  • centering pins are attached in the grid plate of the scaffold insert in order to keep the fuel elements in the core container as close as possible to one another and to fix them in this position.
  • these centering pins are threaded into openings in the heads of the fuel assemblies.
  • the centering pins are located in an area where there is a very high neutron flux, which leads to changes in the material properties, in particular embrittlement.
  • the centering pins With horizontal loading, in particular with vibrations, the centering pins can loosen or break, which can lead to a washing away of the loose pin or a part of the centering pin, which then gets into the coolant circuits, which has a disadvantageous effect.
  • the centering pins are therefore checked for their condition during breaks in operation of the reactor and - if necessary - replaced. The review and exchange in the event However, a defect in the known designs is difficult and only possible with great effort.
  • the invention is based on the object of specifying an arrangement which offers a simple test option and easy interchangeability of the centering pins and ensures greater security.
  • This object is divided by an arrangement for centering ' ⁇ au- a nuclear reactor dissolved, fuel assemblies are arranged in which in a core container, the heads of which use by a Gerüst ⁇ are fixable, wherein trier pins at the top of the fuel assemblies centering are arranged on the frame insertion holes are brought into which the centering pins can be inserted.
  • centering pins are easily accessible each time the fuel element is changed and can be easily checked from above using a test device.
  • the stability is no longer primarily decisive for the material selection of the centering pins, since these are exchanged with the spent fuel elements after a relatively short dwell time in the nesutron flow.
  • the choice of material can therefore be made essentially without being influenced by the neutron radiation or by the wear resistance,
  • the centering pins can have a conical neck with a threaded end and can be inserted into a corresponding conical opening in the frame and screwed tight by a nut.
  • centering pins resiliently in the fuel assembly heads.
  • the resilient arrangement only two instead of four diagonally opposite openings need to be provided in the lower lattice plate of the scaffold insert for each fuel element if the structural conditions make this necessary.
  • the resilient arrangement of the centering pins also causes damage to the fuel assemblies when threading the Use of scaffolding avoided.
  • FIG. 1 shows a plan view of a lower grid plate of a core insert of a nuclear reactor arranged above the fuel elements
  • FIG. 2 shows a plan view of the fuel elements arranged within a core enclosure
  • FIG. 3 shows a longitudinal section through a reactor core which is arranged in a reactor pressure vessel
  • FIG. 4 shows a fastening possibility for a centering pin in a frame of the head of a fuel assembly
  • FIG. 5 shows a fastening of a centering pin, which is provided with a conical neck, on a fuel assembly
  • FIG. 6 shows a fastening of a centering pin by a weld seam
  • 7 shows a fastening of a stepped centering pin in the lower head region of a fuel assembly
  • FIG. 8 shows a centering pin spring-mounted in the head of a fuel assembly
  • FIG. 9 shows a plan view of FIG. 8.
  • each fuel assembly 1 contains fuel rods, which are held in a support structure, which has a head 2 and a foot. In between are arranged guide tubes for control rods, to which spacers are attached, which bundle the fuel rods.
  • a large number of fuel elements 1 closely arranged in a row form the reactor core, which is accommodated in the reactor pressure vessel.
  • a scaffold insert 5 is arranged above the fuel element 1, on the lower grid plate 4 of which four openings 7 of a fictitious square are provided (FIG. 1). Centering pins 3 each protrude into two diagonally opposite openings 7.
  • holes 4 are provided in the frame 6 according to FIG. 4, into which the centering pins 3 provided with a stepped neck 3a are inserted and held by a centering pin 10 inserted into a transverse bore 11.
  • the seat of the centering pin 3 in the cylinder opening 7 of the grid plate 4 of the scaffold insert 5 can be seen from FIG. It protrudes from the opening 7 with its tip 3b.
  • the cylinder pin is secured by a caulking edge 12.
  • 5 shows a fastening of a cylindrical pin 3, which has a conical neck 3c with a threaded end 3d and is inserted into a corresponding conical opening 13 in the frame 6 and is screwed tight by a nut 14.
  • a spreading notch 15 serves to secure it.
  • FIG. 7 shows a fastening of a centering pin 3 on a base plate 17 of the head 2 of a fuel assembly.
  • a threaded bore 19 is provided in this base plate 17, into which centering pin 3 is screwed and fixed by a locking screw 20a.
  • the centering pin 3 is offset in diameter in a predetermined centering area, the thinner end 3e provided with an insertion tip 3b penetrating a corresponding bore 18a in structures 18 of the grid plate 4.
  • FIGS. 4 ' to 7 show designs in which the centering pins 3 are inserted rigidly and interchangeably into the head 2 of the fuel elements 1.
  • FIG. 8 shows a spring-loaded interchangeable arrangement of the centering pins 3. While the rigid centering pins 3 require four openings 7 in the base plate 4 when there are two centering pins in the head 2, in the spring-loaded version of the centering pins 3 four centering pins - each one in the four corner areas of the head of a fuel assembly - which then only need two openings in the grid plate. The two centering pins, which are not in engagement, are in the pressed-in position during operation and participate in the spring-loaded floating protection of the fuel assemblies through the framework insert 5.
  • FIG. 8 A design which is shown in FIG. 8 is particularly advantageous, in which the centering pin has a conical centering region 3f which must not have a self-locking effect (ie the angle of inclination c of the conical surface to the central axis must be greater than the friction angle o) essentially depends on the material).
  • the opening 7 in the grid plate 4 of the scaffold insert 5 is correspondingly conical. This results in a play-free engagement of the centering pin in the opening 7, whereby it does not protrude from the top 4a of the grid plate 4 or only slightly so that any structures 18 present on the grid plate 4 do not interfere.
  • two pins can thus be arranged at the head of the fuel assemblies 1 and four openings in the grid plate 4 of the scaffold structure, as well as four pins at the head of the fuel assemblies and two centering openings 7 in the grid plate 4 of the scaffold insert 5.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

Un réacteur nucléaire contient des éléments de combustible (1) dont les têtes (2) peuvent être fixées par un insert en forme de cadre (5). Un dispositif de centrage avec des chevilles de centrage (3) sert à tenir serrées les uns contre les autres les éléments de combustible (1) dans le réacteur nucléaire et à les immobiliser dans cette position. Pour pouvoir facilement vérifier et changer les chevilles de centrage (3) tout en améliorant la sécurité du dispositif, lesdites chevilles de centrage (3) sont agencées au niveau de la tête (2) des éléments de combustible (1) et des ouvertures (7) dans lesquelles s'insèrent les chevilles de centrage (3) sont agencées sur l'insert en forme de cadre (5).
EP88909299A 1988-09-30 1988-09-30 Dispositif pour centrer des elements d'un reacteur nucleaire Withdrawn EP0429445A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/DE1988/000604 WO1990003647A1 (fr) 1988-09-30 1988-09-30 Dispositif pour centrer des elements d'un reacteur nucleaire

Publications (1)

Publication Number Publication Date
EP0429445A1 true EP0429445A1 (fr) 1991-06-05

Family

ID=6819734

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88909299A Withdrawn EP0429445A1 (fr) 1988-09-30 1988-09-30 Dispositif pour centrer des elements d'un reacteur nucleaire

Country Status (2)

Country Link
EP (1) EP0429445A1 (fr)
WO (1) WO1990003647A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013113523B3 (de) * 2013-10-29 2015-04-30 Areva Gmbh Verfahren zur Verbindung eines Zentrierstiftes mit einem Kerngitter
ITUA20163713A1 (it) * 2016-05-04 2017-11-04 Luciano Cinotti Reattore nucleare con nocciolo autoportante

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4030975A (en) * 1973-06-25 1977-06-21 Combustion Engineering, Inc. Fuel assembly for a nuclear reactor
SE387766B (sv) * 1974-12-30 1976-09-13 Asea Atom Ab Brenslepatron med lett demonterbara komponenter
US4560532A (en) * 1982-04-15 1985-12-24 Westinghouse Electric Corp. Nuclear fuel assembly

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9003647A1 *

Also Published As

Publication number Publication date
WO1990003647A1 (fr) 1990-04-05

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