FI117074B - Searching for leaks in nuclear fuel cartridge - involves raising cartridge and sucking water away for analysis of fission prod. content - Google Patents

Abstract

The water is sucked to a grip anchored to the cartridge above the water outlet, the grip forming part of a loading machine for the fuel cartridges. The fuel cartridge is lifted in the water in which it is immersed and maintained in its raised position with a flow of water sustained through it and around the grip. The aspirated water is subjected to analysis with regard to the presence of fission prods. which during the operation of the reactor are formed by the fuel in the cartridge.

Description

11

Method for leakage detection in nuclear fuel cartridges - F utföra läcksökning vid kärnbränslepatroner

Nuclear reactor fuel rods are manufactured with the utmost precision in order to avoid any defects in the fuel enclosure, whereby radioactive products are leaking into the reactor primary circuit. Possibly contamination of the reactor water and thus of different parts of the primary circuit with radio products. When reactor water contamination is detected or suspected, it is most important to locate the leak so that the leaking fuel can be replaced. Generally, individual fuel rods are not investigated for practical purposes, but studies are focused on fuel cartridges that fuel rods. Also when replacing fuel units, replace the cartridges and not the individual fuel rods.

Examination of the suspected fuel cartridge for leaks shall be performed on fission products from gas and / or water tests taken to obtain the highest level of detection of the fuel, which will cause fission products to be removed from the investigated fuel. This can be accomplished by increasing the fuel temperature by external static pressure around the fuel. The temperature may be i; 20 by circulating water through the fuel cartridge, possibly * taking steps to completely drain the water from the fuel cartridge. The present invention relates to a method for detecting leakage from a uun · · uun in a cooker-type nuclear reactor. Soup Reaction * · 25 cartridges comprise a plurality of fuel rods, which are generally so square in cross section. Each of the fuel rods is a set of fuel plates, usually plates, which are superimposed on the capsule tube, usually Zircaloyta. Pc 2

The method of the present invention which is directed at combustion; Submerged in water is ideal for use on roads and can be performed very quickly. It is apparent to the invention that the area is disposed on the fuel cartridge water outlet 5 and surrounded by the t attached to the fuel cartridge above the outlet, the gripper being mounted to the bottom of the fuel cartridges or scoop type lifting suction while suctioning or holding water and while the water flow above 10 through the cartridge and around the gripper, and that was removed in the analysis for the presence of fission products formed from the fuel in the cartridge. The removed water may contain dissolved fission products as well as insoluble in the gas phase. The assay is carried out in a conventional manner, either by continuous recording or by collecting in a vessel for analysis in a different apparatus. Para: The height is obtained at the maximum lifting height, that is, the lifting height from the position of the auger in the reactor core to the highest position of the hoist, however, the lowering heights are achieved. If raised after the fuel cartridge has been lifted in the water and in its 20 position, a lifting height of the fuel cartridge length is preferably used.

• *

According to one embodiment of the invention, the area is protected by combustion; • ·: * ·· Above and around the lift with a hood-like device: V: for the water from the fuel cartridge to spread outside the area! *! <25 containing water containing products will disappear and cannot be analyzed.

• · »* ·

Preferably, leak detection is performed when the reactor is closed for exchange. Once the reactor combustion has reached the minimum acceptable reactivity manganese, partial separation is performed. For partial refueling in a digestion reactor, v <• · Qrt lulls'ο 1 Λ / C λλΙΗλλιπλλο ^ λ wi inoilt / tifl / 4s% i suction ιιμλ 3 may be used to remove the fuel after searching for a leak after searching for a leak. When looking for leaks on a fuel cartridge that will be removed? leakage detection is performed when the fuel cartridge is lifted re 5 and before it is placed in a container next to the reactor vessel.

The invention will now be described in more detail with reference to the accompanying drawing, which schematically shows a device for carrying out the method of the invention.

In the figure, reference numeral 1 shows a loading device for fuel cartridges v 10 for the actor, 2 for the reactor hall floor along which the loading machine is movable, 4 for the reactor core, 5 for the reactor vessel located above the reactor vessel, 6 reactor water in the reactor. Charging the lifting rod 7, which is a telescopic model. The lower part of the lifting rod has an i adapted to engage the nosl 15 9 in the fuel cartridge 10, which in the position shown is just being lifted by the reactor core projection located above the fuel cartridge dewatering 11. - fitted to the top plate of the fuel cartridge. The area 12 around the top of the outlet 8 is protected from the environment by hood-like laws to prevent the water from passing through the fuel cartridge in a range of 1:20 which would cause any leaking fission products to be lost for analysis. The area 12 is not a protected environmental relation in open contact with the environment through the downwardly-facing portion of the hooded device. From area 12 passes a hose 14 or other tube detection apparatus dividing the reactor hall on the floor or on a loading machine. Tube 25 also has a T \ 25 which allows water to be drawn from area 12. When raising the fuel cartridge, the reactor water flows through the fuel cartridge and flushes the contamination! • · »also occurs when the fuel cartridge is lifted in a certain direction of gravity, held in this position, or discharged with fission gas leaked into water *. Water flow through fuel cartridge void M ·! ! size \ / llonityll not ilLAmioii / oAiAn πΙΙ / λμα

Claims (3)

4 4 1. A method for inserting fuel cartridges (1 (for leaks in a cooking type nuclear reactor for leaks in a cooker type nuclear reactor, characterized by: (7) suctioning the water while the cartridge is being lifted in or raised in water and held in its raised position or lowered into the water while being drawn through the fuel cartridge and around the gripper, and that is being investigated for the presence of fission products in the fuel cartridge. Method according to Claim 1, characterized in that i, which is located above the drainage point (11) of the fuel cartridge (10) around the sensing device (8), is protected from the environment by a hood-like device. A method according to claim 1, characterized in that the first step is carried out when the reactor has been shut off to replenish the fuel: (1) the first step is to turn off the fuel (6); y: ovanför et utlopp (11) för vatten frän bränslepatronen och omkring *. Patronen ovanför utloppet förankrad grip (8) anordnad i nederänd Stäng (7) i teleskoputförande account en iaddmaskin (1) för bränslepati vatten under det att bränslepatronen lyftes eller under det • * * 25 tronen efter att ha lyfts i vatt shit lyfta slur och under de av vattnet upprätthälles genom bränslepatronen och omkring g det avsugna vattnet underkast en analys med avseende pä förek fM