DE1229199B - Wrapping for the circulation of a coolant for a nuclear reactor fuel rod - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

G21c

German class: 21g-21/20

Number:
File number:
Registration date:
Display day:

H 38133 VIII c / 21g
December 14, 1959
November 24, 1966

The invention relates to a casing for the circulation of a coolant for a nuclear reactor fuel rod, between the fuel rod and a moderator, e.g. B. heavy water is arranged.

It is known that in nuclear reactors in which heavy water is the moderator, each of the in The heavy water immersing fuel rods are wrapped around each rod around an annular flow channel for a coolant, such as carbon dioxide, forms. Since the coolant heats up as it flows along the fuel rod, there will be some Heat conduction of the coolant is released through the wall of the casing to the heavy water. However, this release of heat is undesirable.

In order to remedy this shortcoming, it has already been proposed to remove the coolant from the heavy Wall separating water, d. H. the envelope to be designed as a double jacket, so that this one the Forms shielding reducing heat flow from the coolant to the moderator.

In this known device, the coolant flows in a constant flow rate in both Formed by the double jacket, open top and bottom flow channels, namely initially in the outer channel from top to bottom and then in opposite directions in the inner channel along the fuel rod from the bottom up. As a result, this rod, which is in the middle, generates far more heat per unit of volume developed than in the area of its ends, from its center to the overhead outlet end of the coolant only inadequately cooled because it circulates, especially when it flows above, increasingly assumes a higher temperature and accordingly dissipates less heat.

The invention therefore leaves the basic idea of the aforementioned known cooling device, the To guide coolant in a constant flow rate in countercurrent, and the task is to by changing the flow rate in two circulation channels the cooling along an elongated one Fuel rod to regulate automatically so that the temperature of the coolant and if possible also the heat exchange during the whole orbit of the coolant along the fuel rod remain approximately constant and the cooling effect for a given total throughput of coolant is improved.

For this purpose, the invention is based on a casing arranged between the fuel rod and the moderator for the coolant circulation, the min casing for the circulation of a coolant for
a nuclear reactor fuel rod

Applicant:
Andre Huet, Paris

Representative:

Dr. W. Schalk, Dipl.-Ing. P. Wirth,

Dipl.-Ing. G. E. M. Dannenberg

and Dr. V. Schmied-Kowarzik, patent attorneys,

Frankfurt / M., Große Eschenheimer Str. 39

Named as inventor:
Andre Huet, Paris

Claimed priority:

France of December 15, 1958 (781 697) - -

at least one annular zone surrounding the fuel rod and through the passage slots for the coolant to pass through.

In a known embodiment of such a casing is a rod on the fuel directly adjacent, helically ribbed shell surrounded by a metal sleeve, which are diametrically opposite one another Has slots. The coolant flows through some of the slots in this sleeve towards the fuel rod, which it revolves along the ribbing a few times, after which it is passed through another Part of the slots flows radially outwards again. This will keep the coolant at the first Circulation around the fuel rod is strongly heated, so that overall the heat exchange in the longitudinal direction of the fuel rod decreases rapidly. Thus, in this known embodiment, too, that of the invention underlying task not solved.

This task is also not achieved with another known cooling device for fuel rods solved, in which the coolant flows through the fuel rods traversing channels, because also here a coolant flow results in which the cooling of the stronger heat development in the middle The area of the fuel rods is not adequately matched and from this area to the top The area of the rods with the coolant that is already strongly heated, i.e. with too little heat dissipation, takes place.

609 72S / 305

Claims (1)

3 4 Based on the use of a ring-bounded by two sheaths O ₁ and b ₂ and forming the shaped zone around the fuel rod - as an inner zone adjacent to the fuel rod and through slots for the coolant - an annular flow channel for a through-pointing Sheath, the problem posed this zone flowing in the direction of arrows A is achieved according to the invention in that the through 5 coolant, for. B. carbonic acid forms. The envelope of a cylindrical or conical shell delimited ring O ₁ , b ₂ is enclosed together with the fuel rod in the shaped zone by a further, outer container of a core-shaped zone containing ring-shaped heavy water c , which is admitted through a practical reactor, and this heavy water running parallel to this shell limited shell forms the moderator of the reactor.
According to the invention, the _{outer annular zone formed by the two sheaths O 1} and b ₂ connected to one another are, in the inner sheath, slots are provided for the sheath of the fuel rod at its lower end and in increasing numbers from bottom to top end at e open; Here, a partial flow of the cooling is distributed, which is dimensioned according to the heating by means of or the carbonic acid gas in the direction of the coolant, and which connects the 15 arrows B into the outer annular zone. Establish at both ring zones, of which the inner is suitably chosen places and in different in a manner known per se at both ends for the high positions are in the inner shell b ₁ slots g passage of the coolant is open and which the attached through the from the outer Ring-shaped coolant flows on their base parallel to the zone of carbonic acid gas, which are supplied to one another at a colder temperature than that of the main one. ao stromes A , enters the inner annular zone In this way, the main flow results from the flow in the areas, especially in one of the coolant in the inner zone, that this cools down towards the middle area, in which the fuel requirement of the heating of the cooling rod flowing in it is greatest Gives off heat. At the upper end by means of the slots in the inner shell, the outer annular zone is automatically closed by a more or less large amount of the fact that here the shells b _t and b ₂ are connected to one another flowing in the outer zone and remained cold. At or near the upper end of the coolant flows in per unit of time and the temperature of the inner shell O ₁ is placed in this slot / device of the each after a contactor in the inner zone, which allows the remainder of the coolant flowing between the shells b _x zone through the mixture and b ₂ flowing carbonic acid gas in the main with colder coolant is reduced as desired 30 stream (arrow A) is crossed in the direction of arrows C; this will let the diminished in front of the slot. Heat exchange with the coolant behind in each case. In FIG a slot increased again, and it is shown on the Fig. 1 similar embodiment, in which the entire path of the coolant along the burning envelope b _v b ₂ in a certain area h Cloth rod almost evenly instead. 35 is frustoconical in such a way that in In particular embodiments of an inventive area, the inner ring-shaped zone is tapered according to the envelope and the flow rate of the coolant has the shape of a simple outer ring-shaped zone. This area lies approximately in the middle of the or double truncated cone in such a way that the length of the fuel rod a. At the downstream end of the envelope b _v b ₂ located in the direction of flow 40, the inner annular zone has a conically tapered or a conical at i an outwardly widening truncated cone and a conical widening shape, such that the flow rate of the area results and in these areas the carbonic acid gas in the inner annular zone flow rate of the coolant accordingly (arrow A) in its expanded area up to the corresponding cross-sectional change is increased or 45 slots are reduced and so overall is reduced. As a result, the desired interaction with the slots g, an almost uniformity of the heat exchange along the constant heat exchange along the length of the fuel rod, can be further improved. Fuel rod α is achieved. In the same sense, according to an embodiment, modified from that shown in FIG form according to the invention on the heat exchange 50 embodiment, the shell b _{x has} the same are acted upon by the fact that the outer ring slots / and g as shown in FIGS. 1 and 2 and is shaped zone in a manner known per se from with the envelope b _v b ₂ approximately in the middle of her Corrugated envelopes is limited. downstream area frustoconical The invention is designed below with reference to the drawing. The envelopes O ₁ and b ₂ are also with openings for example explained in more detail, namely shows 55 corrugations k provided in the annular Fig. 1 in section an embodiment of a flow zone of the coolant (arrows ^ and B) cause according to the invention designed envelope for a cross-sectional changes and consequently Fuel rod of a nuclear reactor, affecting its flow velocity (locally), Fig. 2 shows a further embodiment, in which a conical tapering flow between the fuel rod α and the coolant channel is formed between the fuel rod α and the coolant, and (arrow A) is achieved. Fig. 3 shows a further embodiment in which the Walls of the envelope along a conical patent claims:
tapered part are wavy. 65 As can be seen from the illustration according to FIG. 1 - 1. Sheath for the circulation of a coolant is borrowed, is a fuel rod α of a nuclear reactor for a nuclear reactor fuel rod, which is between surrounded by a double-walled envelope, which see the fuel rod and a moderator, ζ. B. heavy water, which forms at least one annular zone surrounding the fuel rod and pass through the passage slots for the coolant, characterized in that the _{annular zone delimited by a cylindrical or conical shell (O 1} ) is surrounded by a further, outer annular zone Zone is enclosed, which is delimited by a practically parallel to this envelope (O ₁ ) extending envelope (Z> ₂ ), and that the upper ends of these envelopes (b _v b ₂ ) are connected to form a closure, wherein in the inner shell (O ₁ ) slots (g, f) are provided and distributed in increasing numbers from bottom to top, which are measured according to the heating of the coolant, and which establish a connection between the two ring zones, of which the inner one in itself known way is open at both ends for the passage of the coolant and to which the coolant flows are fed parallel to each other on their base. 2. Enclosure according to claim 1, characterized in that the outer annular zone has the shape of a single or double truncated cone. 3. Covering according to claim 1 or 2, characterized in that the outer annular zone is delimited by casings provided with corrugations (k). Considered publications: German publication no. 1041177,
529; British Patent Nos. 789 257, 797 608; "Engineering", November 28, 1958, p. 699; "Nucleonics", Vol. 16, No. 4, April 1958, pp. 106-108. 1 sheet of drawings 609 728ßO5 11.66 © Bundesdruckerei Berlin