JPS59163595A - Control rod position detecting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to the control rod drive mechanism of a nuclear reactor, and in particular, to the control rod drive mechanism of a nuclear reactor, in which an ili control rod that is separated from a drive mechanism and dropped during a scram is inserted into a guide tube of a reactor core. '1B for nuclear reactor to confirm that
IJ rod position detection device (2 related)

[Technical background of the invention and its problems]

The control rod drive mechanism of a nuclear reactor is used to start, stop, and control the output of a nuclear reactor, but in the event of an abnormality (the scram function that makes an emergency shutdown of two reactors), it is also a cheap souvenir to ensure the safety of a nuclear reactor. It is functioning.For this reason, it is mandatory to check the scram function of the Ippin Tai Mechanism before starting up the reactor.

There are two methods for such a control rod drive mechanism (the second is a method in which the first detection is integrated with the drive shaft (lowering two units), and a method in which the control rod is separated from the drive shaft and dropped alone. In order to improve the operational reliability of the furnace, it is common to use both methods in combination.

However, in the latter method, 1. It is difficult to detect whether a control rod that has fallen away from the drive shaft has been inserted into the guide tube of the two cores, and this point has traditionally been a problem for masochistic women.

By the way, a conventional method for detecting the position of a detachable drop-type control rod after it has been removed is illustrated in FIG.

The same figure (2, control rod 1 falling inside the upper guide, total 5)
The control rod 1 falls together with the acceleration mechanism 2 to ensure that the control rod 1 falls, and the magnet 4 attached to the large diameter part 3 of the acceleration mechanism 2 is wound around the outer periphery of the inner chamber 5 of the upper system. It is detected by measuring the single predetermined force passing through the detection coil 6.

However, in this conventional position detection method, the size of the detection coil 6 and magnet 4 is limited due to its structure, so it is difficult to obtain a signal of sufficient size, and the acceleration mechanism is limited. The complete insertion position of control rod 1 is
There was a problem with undetectable temples.

, [Object of the Invention] The present invention has been made in order to solve the above-mentioned problems. Provides a control rod position detection device that can confirm complete insertion of control rods and reliably inspect scram Senhoku (1 required).

[Summary of the invention]

The present invention has been made to achieve the above objects (2. A core and a core upper structure disposed in a reactor vessel, and a rotatable control rod position formed by penetrating the core upper structure over the center of the reactor core. This is a control rod position detection device for a nuclear reactor, which is composed of a detector and a reflector disposed around the upper end of the reactor core.
Jil record? The IjlJ position detector has an elongated circular shape with an ultrasonic transducer attached to the bottom.
Unfortunately, the reflector used has a cylindrical shape.

[Embodiments of the invention]

The uninvented joke will be explained with reference to FIGS. 2 and 3.

FIG. 2 is a schematic cross-sectional view of the interior of a reactor vessel in which a control rod position detection device according to the present invention is installed. As shown in the figure, a control rod position detector 10 is installed at the center of the reactor core 16 through a shielding plug 9 that closes the upper end opening of the reactor vessel 8. is an ultrasonic transducer 1 that transmits and receives ultrasound waves horizontally (-
3 is installed. This ultrasonic transducer 1
The ultrasonic waves transmitted from the reactor vessel 8 are reflected by the reflectors 14 so that they surround the reactor core 16 (two are placed on the core attachment mechanism). The drive shaft 12 (-) is inserted into the reactor core 16. In FIG.
The control rod 15a is in the middle of falling, and the city control rod 15b is complete (showing the state after being separated from the drive shaft 12 of the 1g mr ja structure 11). Note that the reference numeral 19 is a solid metal sodium coolant filled in the reactor vessel 8.

FIG. 3 is a schematic cross-sectional view of the upper part of the core in FIG. The lower guide pipe of the fuel assembly is installed at a special interval in the lower part of the fuel assembly, and the control rod 1 is inserted into it. It becomes.

Next (2) Control rod position detection method according to the present invention (two methods will be explained).

First, in the direct reflection method, the ultrasonic oscillation/reception path by the transducer 13 is as shown by reference numeral 17 in FIG.
・Ultrasonic waves emitted from the runnuducer 13 are sent to the control rod 1
It is reflected by the outer surface of the transducer 5a, directly reflected, and received by the transducer 13i. Then, when the control culm 15a is completely inserted into the guide tube of the reactor core 16, this reflected wave is no longer received, so that complete insertion of the first sub-tube can be detected. Therefore, 7 from the start of the scrum! By measuring the time until the reflected wave from the control rod is no longer received, the scram time of the control #1 drive mechanism can be measured.

On the other hand, in the reflector method, the transmission/reception path of the ultrasonic waves by the transducer 13 is a cylindrical reflection path until the detection 15b is completely inserted (21b1), as shown by the reference numeral 18 in FIG. The ultrasonic wave reflected by the body 14 is 1tilJ
# Rod 15b (= obstructed transducer 13 (-
When the detection 15b is completely inserted into the guide tube of the core 16, the reflected wave of the ultrasonic wave from the reflector 14 is received by the transducer 13, and the control rod is fully inserted. Therefore, by measuring the time from the start of the scram to the time when the reflected wave from the reflector is received, the scram time of the control rod discharge can be added.

In addition, in the explanation of the front self-direct reflection type reed or the boman-yaku type, the position of the control operation '1I51 is indicated by the reference numeral 15a or 15b (although there are two in the explanation, the control) l all constant position. The structure of the display (position 13) is to rotate horizontally, so the publication (
By rotating the position detection device 13 in the same direction as the desired control direction, complete insertion of the rod into the detection heart system can be confirmed.

〔Effect of the invention〕

, + Invention (Secondly, it is necessary to accurately detect the scram performance of all control rod drives in the inspection of the control rod 1 drive system before reactor operation. Therefore, (2!ti control) There is no special modification of the detection drive structure.If necessary, the scram performance of the selected control rod can be detected even during operation.

[Brief explanation of the drawing]

The first section is the conventional separation drop type 1tj1. Parts of the control rod 1 driving mechanism [front view, Figure 2 is an uninvented figure (1) The command shown in one embodiment of such a device!
FIG. 8... Nuclear reactor 9... Shiyahei grab 10...
・The control nose position is the detector 11... City 1j control (single drive 1 arm configuration 12
・・・Drive shaft" 13... Ultrasonic transducer
14...Reflector 15a, 15b...Control cleaning
16...Reactor agent Masu filler Noriyuki Chika (
1 other person) Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) Inside the reactor vessel (2) A reactor core and a core upper mechanism arranged, a rotatable control rod position detector that traces the core upper mechanism over the center of the core, and a front 6 cylinder. It consists of a reflector placed around the upper edge of the core, and
LJ Misaki salary rank! The a detector has a long cylindrical shape with a
It is equipped with an ultrasonic transducer that emits and receives two sets of sound waves, and has the following features: 19-1 nuclear reactor system (i111 + fist position i6 detection device). (2) The offending body has a short cylindrical shape (2), and is a control pulse lfi for a nuclear reactor, as described in Section 1 of the Kaisui Post Office, Matade device.