EP1340939A2 - Method and apparatus for executing mantainance works in the secondary side of a nuclear steam generator - Google Patents

Abstract

Device for carrying out maintenance work on the secondary side of a nuclear steam raising plant comprises a lance moving in a gap between heating tubes (6). The lance supports a maintenance device, especially an inspection unit, on its free end, and is on a vehicle (16) which travels along a guiding track (12) at the periphery of the heating tube bundle. An Independent claim is also included for a process for carrying out maintenance work on the secondary side of a nuclear steam raising plant by using the above device. Preferred Features: The guiding track is flexible in the longitudinal direction and tensioned against the heating tubes by exerting a tensile stress. The lance can pivot on the vehicle.

Description

The invention relates to a method and an apparatus for performing maintenance work on the secondary side of a nuclear steam generator, especially for inspection or recovery of a foreign part that is between the heating pipes of a nuclear steam generator.

In the manufacture of a nuclear steam generator or at Repair and maintenance work on its secondary side can it happens that within the tube bundle in between Columns located in the heating pipes remain foreign parts that through so-called fretting to damage the heating pipes being able to lead. The detection and recovery of such foreign parts, which are usually found with upright steam generators located on the tube sheet is due to the large number and the narrow arrangement of the heating pipes opening into the tube sheet - a nuclear steam generator usually contains about 4000 to 5000 separated from each other only by a narrow gap Heating pipes - problematic. So far, attempts have been made to recover Foreign parts with manually operated tools on the tube sheet to reach and remove. This is problematic in that than this salvage work because of the limited space are relatively difficult and time consuming require due to the high local dose rate inside of a steam generator to a relatively high radiation exposure of the operating personnel.

Around the tube sheet between the heating tubes of such a steam generator To be able to clean it, for example, from the WO09 / 09850 and EP 05 016 48 B1 are known in the relative wide pipe lane of such a steam generator a flexible Introduce lance, which is deflected by 90 ° and from the Rohrgasse be inserted into the gap between the heating pipes can. With these known devices, however, it is only possible, the pipe gaps in a direction perpendicular to the Rohrgasse to approach. Contaminants or foreign parts that are seen from the Rohrgasse behind the heating pipes, are difficult to grasp. In addition, the starting regions on the outer circumference of the heating tube bundle Because of the flexibility of the lance used and that with growing Extension length increasing instability of the lance end problematic.

Alternatively, it is known from DE 38 05 285 A1, a Lance device to be used in the around the outer periphery a trace of the tube bundle on the steam generator base is on which a mobile sled is ridden, from which from a high pressure fluid through windows in the heating tube bundle injected into the heating tube bundle on the outer circumference becomes. The assembly of such a track on the tube sheet however, is time-consuming and due to constructional circumstances (Structural internals) for a variety of steam generators not possible.

An alternative to this is the one disclosed in WO92 / 07263 Maintenance device provided, on a the heating tube bundle surrounding sheath to arrange a rail in its longitudinal direction flexible and rigid in a transverse direction is. A vehicle is tracked onto this rail. The vehicle is arranged on a steel belt that in the Rail is guided and by one outside the steam generator arranged supply roll unwound or wound on this can be so that the sled is on the rail moved in the circumferential direction around the heating tube bundle. The well-known However, the facility does not allow access to the interior of the Pipe column.

It happens during the operation of such a steam generator also in the area of the tube sheet between the heating tubes to deposits that lead to stress corrosion cracking on the Can lead heating pipes and must be removed regularly.

The invention is based on the object of a method for performing maintenance on the secondary side of a nuclear steam generator, especially for inspection or Rescue one between the heating pipes of a nuclear Specify the foreign part located steam generator with the one hand the health risks for the operating personnel are reduced, and on the other hand the quota is more successful Salvages compared to those known in the prior art Procedure is improved. The invention is also the The task is based on a device for carrying out the method specify.

The first object is achieved according to the invention with a method with the features of claim 1. In the method according to the invention is on the circumference of the heating tube bundle arranged a guideway, on which then at least a vehicle rerailed and remotely controlled along the Guideway is moved to a position in which the direction of extension an extendable lance mounted on the vehicle aligned with a gap between the heating pipes. After reaching This is the position of the lance with one at its free End arranged maintenance device, in particular an inspection device or a recovery tool inserted into the gap remotely.

Through these measures, it is possible to remotely control a variety to approach columns from different circumferential positions, making the maintenance work much easier are. On the one hand, the process according to the invention is the The probability of discovering a foreign part is increased and on the other hand also a thorough inspection of the Foreign part possible, the decision about a suitable Recovery strategy made easier. In addition, there is also a salvage possible from different approach positions and thus improves the chance of a salvage being successful perform. Also cleaning work between the columns can be started from different directions a spray nozzle arranged at the free end is considerably more successful be performed.

In a particularly advantageous embodiment of the invention the guideway is flexible and transverse in its longitudinal direction this is rigid and is carried through the circumference of the heating tube bundle Exerting a tensile force acting in the circumferential direction clamped. The use of a braced on the circumference of the heating tube bundle Guideway enables them to be particularly quick and easy Installation because the guideway is only supported on the heating pipes and other support elements are not required.

The second task is solved with the features of Claim 6, the advantages of which are derived from the Advantages of the method according to the invention explained above result.

Further advantageous configurations of the inventions result themselves from the subordinate to the independent patent claims Dependent claims.

Fig. 1

eine schematische Prinzipdarstellung einer Vorrichtung gemäß der Erfindung mit einer Mehrzahl von Fahrzeugen, die auf eine am Umfang des Rohrbündels angeordnete Führungsbahn aufgegleist sind,

Fig. 2 und 3

alternative Anordnungen der Führungsbahn am Umfang des Heizrohrbündels

Fig. 4

ein erfindungsgemäßes Fahrzeug in Arbeitsposition in einer Seitenansicht,

Fig. 5

das Fahrzeug in einem Querschnitt parallel zur Führungsbahn ebenfalls in einem aufgegleisten Zustand,

Fig. 6 und 7

eine alternative Ausgestaltung der erfindungsgemäßen Vorrichtung in einer Draufsicht senkrecht zur Führungsbahn bzw. parallel zur Führungsbahn.

To further explain the invention, reference is made to the embodiment of the drawing. Show it:

Fig. 1

2 shows a schematic basic illustration of a device according to the invention with a plurality of vehicles which are mounted on a guide track arranged on the circumference of the tube bundle,

2 and 3

alternative arrangements of the guideway on the circumference of the heating tube bundle

Fig. 4

a vehicle according to the invention in the working position in a side view,

Fig. 5

the vehicle in a cross section parallel to the guideway also in a raised state,

6 and 7

an alternative embodiment of the device according to the invention in a plan view perpendicular to the guideway or parallel to the guideway.

1, a nuclear steam generator 2 comprises a heating tube bundle 4, which a variety of arranged in parallel rows Includes heating tubes 6. The heating tubes 6 are through one Tube plate 8 passed through the primary side of the Steam generator 2 separates from the secondary side. The heating pipes 6 stand vertically on the tube sheet 8 and in the drawing perpendicular to the plane of the drawing. A pipe lane 10 divides the heating tube bundle 4 in two halves 4a, 4b, being on one half 4a the cooling water of the primary circuit in the heating tube bundle 4 enters and on the other half 4b from the heating tube bundle 4 flows out.

In the exemplary embodiment, the heating tubes 6 are parallel to one another Rows arranged so that the heating tubes 6 each other Adjacent rows by half a distance from each other are offset.

Half 4a of the heating tube bundle 4 is on its outer circumference with a guideway shown only schematically in the figure 12a provided by an outside of the steam generator 2 arranged clamping device 14 on the outer circumference of the heating tube bundle 4 clamped and thus on the heating tube bundle 4 is fixed. In the illustrated embodiment, the guideway is 12a only on the semicircular outer circumference of the inlet side Half 4a braced and over a guide 15 through the Rohrgasse 10 opposite hand holes 13 after led to the outside of the tensioning device 14.

On the guideway 12a is a plurality of identical Vehicles 16-1 to 16-4 rerailed, which have control and Evaluation lines with one arranged outside the steam generator 2 Control and evaluation device 20 are connected, with which the individual vehicles 16-1 to 16-4 are controlled and in different positions on the circumference of the heating tube bundle 4 can be driven.

The flexible guideway 12a is at a height of approximately 250 up to 300 mm above the tube sheet 8 around the outer circumference of the inlet side or outlet-side heating tube bundle 4 and spring-loaded by the tensioning device 14. The Clamping device 14 is designed so that it is on the guideway 12a acting tensile forces evenly on the Outer circumference arranged heating tubes 6 far below the allowable Distribute load limits.

Two other vehicles 16-5 and 16-6 are on another Guideway 12b rerailed, which are identical to the guideway 12a is. The guideway 12b is passed through the Rohrgasse 10 and to the edge of Rohrgasse 10 Heating tubes 6 of the half 4b of the heating tube bundle 4, where in the figure for reasons of clarity Tensioning the guideway 12b required tensioning devices are not shown.

Each vehicle 16-1 through 16-6 can be controlled and controlled Evaluation device 20 can be controlled independently, so that vehicles 16-1 to 16-6 both move independently of one another can be as well as those on the vehicles 16-1 to 16-6 maintenance, inspection or recovery devices separately controlled for each vehicle 16-1 to 16-6 can be operated.

In the figure, a situation is now shown in which a foreign part 30 inside the inlet-side heating tube bundle 4 is located. This foreign part 30 can now proceed from different positions on the outer circumference of the heating tube bundle 4 or in Rohrgasse 10 can be reached. in the These are exemplary embodiments due to the hexagonal arrangement the heating tubes 6 illustrated six by arrows 31 to 36 Directions or column that are at the perimeter of the Open the heating tube bundle 4 in positions 41 to 46. In these Positions 41 to 46 will now be vehicles 16-1 to 16-6 move through the control and evaluation device 20.

There is an extendable on each of the vehicles 16-1 to 16-6 Lance, the direction of which extends to one of the positions 41 to 46 reachable column is aligned.

With the help of the vehicles 16-1 to 16-6, any interior can Position approached from 6 different directions become. This enables a precise inspection of a Foreign part 30 from different directions, so the decision for a suitable recovery strategy, i.e. the Selection of a suitable recovery tool and the direction of the recovery is relieved.

In the alternative arrangement of the guideway 12 according to FIG. 2 this wraps around the entire heating tube bundle 4, d. H. both halves 4a and 4b, on the outer circumference of the bundle.

In the arrangement according to FIG. 3, the guideway 12a wraps around contiguously in one piece half 4a of the heating tube bundle 4 on the outer circumference through the outer semicircle and the straight circumferential part of the Rohrgasse 10 formed is. The other guideway 12b encloses the half of the heating tube bundle 4b only on the outer semicircle.

4, the guideway 12 comprises an approx. 50 to 100 mm wide band 120 extending in its longitudinal direction, i.e. H. perpendicular to the drawing plane, is flexible so that it adapts to the arcuate Periphery of the heating tube bundle 4 can nestle. At right angles to this, ie parallel to the heating pipes 6, is the strip 120 rigid, so this is when the vehicle is on the track 16 can not twist about the longitudinal axis. On the the vehicle 16 facing away from the flat side of the band 120 with which it is puts on the heating pipes 6, is also an anti-slip covering 122 arranged, which prevents vertical slipping. The The mounting height h of the guideway 12 is approximately 250 to 300 mm.

On the belt 120 is a roller chain 124, in the exemplary embodiment a multiple roller chain, arranged, the chain links 156 each provided with an angle bracket 126 on both sides which together form a multi-part rail on which the vehicle 16 with the aid of a tension lever lock 128 is on.

A lance 130 is mounted on the vehicle 16, which is straight can be retracted and extended, as indicated by the double arrow 132 is illustrated. A steel band is used as lance 130 provided that in a deflection unit arranged on the vehicle 16 134 is guided, which deflects the steel band by 90 ° and this by means of a toothed disk drive 136 which in recesses of the tape engages positively, drives. The deflection unit 134 is by means of a first swivel drive 138 arranged pivotably about a first pivot axis 140 with which the lance 130 on one of the in the respective driving position reachable pipe gap (see Fig. 1) are aligned can. The deflection unit can be operated with a second swivel drive 142 134 can be pivoted about a second pivot axis 144. The first pivot axis 140 runs parallel to the heating pipes 6 and the second pivot axis 144 perpendicular thereto, i. H. horizontal (perpendicular to the plane of the drawing). By swinging around second pivot axis 144 can the free end of the lance 130, the a maintenance device, an inspection device or a recovery tool 150 carries, at different altitudes relative to the guideway 12 can be positioned so that every point on the tube sheet 8 can be approached.

At the end of the free lance 130 there is also a microendoscope or arranged a camera that the exact positioning the lance head and thus the recovery tool or of the inspection device 150 enables. One arranged on the vehicle 16 Camera 148 with lighting enables remote control Approach a pipe gap position to insert the To allow lance 130 in the pipe gap.

Alternatively, the lance 130 can also be used as a carrier for a flexible cleaning lance with one or more spray nozzles or used as a carrier for test probes.

The for the inspection probes at the free end of the band or electrical cables required by the camera or the ones required for tool actuation, for example pneumatically operated mechanical shift cables are guided in the band body.

5 are two synchronously running sprocket drives on the vehicle 16 152 arranged, each a sprocket 154 drive that with the chain links 156 of the multiple roller chain 124 is engaged. In the figure, they are also on everyone Chain link on the outside attached angle plates 126 to recognize the a longitudinally flexible rail form on which the vehicle 16 is rerailed. In the Fig. is also the pulley drive 136 for the band-shaped Lance 130 can be seen.

Instead of a roller chain 124 can be used as a guideway according to FIG 12, a flexible toothed belt 160 can also be provided has a central web 162 which is connected to the vehicle 16 arranged drive wheel 164 meshes. In the embodiment are two drive wheels 164 also driven synchronously provided, which are pivotally arranged on the vehicle 16 and spring loaded by a leg spring 165 into engagement with the Toothed belt 160 are brought.

The toothed belt 160 has on both side flanks (long sides) as a guide element 166 a back milling, the one Rail for constructing a toothed belt 160 adapted vehicle 16 forms. L-shaped arranged on the vehicle 16 Tabs 168 engage behind the toothed belt 160 in the Hinterfräsungen 166. Also in this embodiment the vehicle 16 with the aid of a tension lever lock 170 that of the bilateral guide elements 166 Rail secured.

The flexible band forming the lance 130 is attached to the vehicle 16 carried in a spring-loaded return cassette 172 who retracted and extended it with the aid of the toothed disk drive 136 can be.

In Fig. 7, the rear grip of the L-shaped tabs 168 in the milled 166 clearly visible. In this illustration are also the rotary actuators 138 and 142 for the Swivel movement of the lance 130 around the first or second Swivel axis 140 or 144 visible.

LIST OF REFERENCE NUMBERS

2

steam generator

4

Heating tube

6

heating pipe

8th

tube sheet

10

Rohrgasse

12

guideway

13

hand hole

14

jig

15

guide

16

vehicle

20

Control and evaluation device

30

foreign part

31-36

arrow

41-46

position

120

tape

122

Anti-slip covering

124

roller chain

126

angle bracket

128

Tension lever lock

130

lance

132

double arrow

134

Return unit

136

Toothed disk drive

138

first swivel drive

140

first pivot axis

142

second swivel drive

144

second pivot axis

148

camera

150

mountains tool

152

sprocket

154

Sprocket

156

link

160

toothed belt

162

center web

164

drive wheel

165

Leg spring

166

relief milling

168

flap

170

Tension lever lock

172

Rückholkassette

Claims (16)

Procedure for performing maintenance on the secondary side of a nuclear steam generator, in particular for Inspect or recover one between the heating pipes (6) one Nuclear steam generator (2) located foreign part (30), with a guide track on the circumference of the heating tube bundle (4a, 4b) (12) is arranged, on which subsequently at least a vehicle (16; 16-1 to 16-6) with one mounted on it extendable lance (130) on-board and remotely operated Move along the guideway (12) to a position (41-46) in which the direction of extension of the lance (130) to a gap extending into the interior of the tube bundle (4a, 4b) aligned between the heating pipes (6) and with one on their Free end arranged maintenance device, in particular a Inspection device or recovery tool (150), remote controlled in the Gap can be introduced. The method of claim 1, wherein the vehicle (16; 16-1 to 16-6) is self-propelled. The method of claim 1 or 2, wherein the guideway (12) flexible in its longitudinal direction and rigid at right angles to it and against the circumference of the heating tube bundle (4a, 4b) by exercising tensioned in the circumferential direction becomes. The method of claim 1, 2 or 3, wherein the lance (130) by swiveling around a first and a perpendicular one second pivot axis (140 or 142) on the splitting plane or Position of the foreign part (30) is aligned in the gap. The method of claim 2, 3 or 4, wherein a plurality of vehicles (16-1 to 16-6) that are independent be moved from each other and a maintenance, inspection or a plurality of simultaneous ones required for recovery or successive manipulations of the foreign part (30), performed from several directions (31-36) simultaneously becomes. Device for performing maintenance work on the Secondary side of a nuclear steam generator, in particular for Inspect or recover one between the heating pipes (6) one Nuclear steam generator (2) located foreign part (30), with a retractable into a gap between the heating pipes (6) Lance (130), which has a maintenance device at its free end, in particular an inspection device or a recovery tool (150), carries and extendable arranged on a vehicle (16) is that along a on the circumference of the heating tube bundle (4a, 4b) attachable guideway (12) is movable. The apparatus of claim 6, wherein the vehicle (16) is self-driving. Apparatus according to claim 6 or 7, wherein the guideway (12) flexible in its longitudinal direction and rigid at right angles to it and against the circumference of the heating tube bundle (4a, 4b) arranged heating pipes (6) by exerting a tension is braced. Apparatus according to claim 8, wherein the guideway (12) comprises a roller chain (124), the chain links (156) of which their outer side flanks each with a guide element (126) are provided, the pivotable against each other Guide elements (126) a longitudinally flexible rail form. Apparatus according to claim 8, wherein the guideway (12) comprises a flexible toothed belt (160) attached to its outer Each side flank is provided with a guide element (166) is that form a longitudinally flexible rail. Device according to one of claims 6 to 10, wherein the Lance (130) on the vehicle (16) pivotable about a first and a second pivot axis (140 or 144) perpendicular thereto is mounted is. The apparatus of claim 11, wherein the first pivot axis (140) when the vehicle is on the track (12) runs parallel to the transverse axis of the guideway (12). The apparatus of claim 12, wherein the second pivot axis (144) runs parallel to the direction of travel of the vehicle (16). Device according to one of claims 6 to 13, wherein the Lance (130) is a flexible band that is attached to the vehicle (16) arranged toothed disk drive (136) is driven. Device according to one of claims 6 to 14, with a Control and evaluation device (20) for remote operation of a Plurality of vehicles (16-1 to 16-6). Apparatus according to claim 15, wherein the vehicles (16-1 to 16-6) self-propelled and travel independently of each other are operable.

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