GB2054165A - Induction Apparatus Monitoring Structural Strains in Liquid-metal-cooled Nuclear Reactor - Google Patents
Induction Apparatus Monitoring Structural Strains in Liquid-metal-cooled Nuclear Reactor Download PDFInfo
- Publication number
- GB2054165A GB2054165A GB8021041A GB8021041A GB2054165A GB 2054165 A GB2054165 A GB 2054165A GB 8021041 A GB8021041 A GB 8021041A GB 8021041 A GB8021041 A GB 8021041A GB 2054165 A GB2054165 A GB 2054165A
- Authority
- GB
- United Kingdom
- Prior art keywords
- conductor
- nuclear reactor
- solenoid
- ferromagnetic
- hairpin
- 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.)
- Granted
Links
Classifications
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C17/00—Monitoring; Testing ; Maintaining
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
- G01B7/24—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in magnetic properties
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/12—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress
- G01L1/125—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress by using magnetostrictive means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/12—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress
- G01L1/127—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress by using inductive means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/14—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
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- 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
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Monitoring And Testing Of Nuclear Reactors (AREA)
Abstract
The reactor has strain gauges for monitoring the internal structure. Each gauge comprises electrical inductance apparatus wherein the inductance is varied by torsionally straining a ferromagnetic electrical conductor to vary magnetic coupling. The ferromagnetic member is of metal sheathed mineral insulated cable arranged in hairpin form. The hairpin form of the ferromagnetic conductor (1) causes torsion-sensitive signals in the two arms to be additive whilst on undesired signal caused by stray inductive coupling is self-cancelling. Alternatively, the induction apparatus may be a pair of co-axial tubular members of ferromagnetic material with the inner member surrounded by a non-magnetic conductor of solenoid form and having a linear non- magnetic conductor disposed coaxially, the magnetic coupling being created by differential torsional displacement of the tubular members. <IMAGE>
Description
SPECIFICATION
Liquid Metal Cooled Nuclear Reactors
This invention relates to liquid metal cooled nuclear reactors, and it is concerned with the indication of torque and strain in such nuclear reactors.
In a liquid metal cooled nuclear reactor it is desirable to monitor torque and strain induced in structure exposed to a hostile environment. In one kind of liquid metal cooled nuclear reactor, generally known as of the pool kind, a nuclear fuel assembly is submerged in a pool of liquid metal coolant contained in a primary vessel and there is an internal structure for carrying control apparatus supported from a cover for the primary vessel and immersed in the pool of coolant. To ensure safe operation of the reactor it is desirable to monitor strain in the internal structure.
Therefore it is an object of the invention to provide in such a construction of liquid metal cooled nuclear reactor means for monitoring induced torsional and linear strains.
According to the invention, in a liquid metal cooled nuclear reactor there is provided electrical induction apparatus for indicating torsion or linear strain induced in the structure. The apparatus having means for indicating creation of magnetic coupling when a ferromagnetic member of the apparatus is torsionaily strained.
The electrical induction apparatus may comprise a first electrical conductor of linear form surrounded by a second electrical conductor of solenoid form, one of the conductors being of ferromagnetic material and arranged so that a magnetic coupling is created by torsionally straining the ferromagnetic conductor when an alternating current is passed through the first or second conductors.
The torsional strain may be applied by the application of torque to the linear conductor or tensional strain to the solenoid.
A preferred induction apparatus for indicating strain comprises a ferromagnetic electrical conductor of hairpin form having legs adapted for attachment to the strainable structure and for connection through a voltmeter, and a solenoid surrounding the hairpin conductor adapted for connection to an alternating current source, the conductor being of metal-sheathed mineral insulated cable. In use, the instrument is arranged so that strain of the structure applies torsional strain to the hairpin conductor, thereby providing a magnetic coupling and generating an electrical signal.
Alternatively, the apparatus may comprise a first electrical conductor of linear form surrounded by a second electrical conductor of solenoid form, at least one of the conductors being of mineral insulated cable having a sheath cif ferromagnetic material such as stainless iron, an alternating magnetic coupling being created by torsionally straining the sheathing when an alternating current is passed through the first or second conductors.
Liquid metal cooled nuclear reactor constructions embodying the invention are described by way of example, with reference to the accompanying diagrammatic drawings wherein:
Figure 1 is a sectional view,
Figure 2 is a line diagram of a strain gauge, and
Figure 3 is a line diagram of an arrangement of strain gauges.
The nuclear reactor shown in Figure 1 is a construction of liquid metal cooled fast breeder nuclear reactor. In the construction a nuclear fuel assembly 11 is submerged in a pool 12 of liquid metal coolant within a primary vessel 13. The primary vessel is housed in a concrete vault 14 the vessel being suspended at its rim from the roof structure 1 5 of the vault. Heat exchangers 1 6 and coolant pumps 1 7 (one of each only being shown) are suspended from the roof structure of the vault and are immersed in the pool of liquid metal coolant. The roof structure supports a reactor internal structure 18 which carries control apparatus 1 9 for the reactor and provides a baffle 20 for upwardly flowing coolant.Instruments for monitoring strain in the internal structure are attached at strategic points, each comprising electrical induction apparatus wherein magnetic coupling is created by torsionally straining a ferromagnetic member of the apparatus.
In use of the reactor, coolant is pumped from the pool upwardly through the fuel assembly, thence through the heat exchangers in heat exchange with a secondary coolant and is returned to the pool. The temperature of the coolant in contact with the internal structure and the strain monitoring instruments is approximately 600or.
The example of strain monitoring electrical induction apparatus illustrated in Figure 2 comprises a ferromagnetic electrical conductor 1 of hairpin form having the free ends of its legs formed at right-angles to the longitudinal axis of the hairpin conductor so as to provide mechanical levers 2. The legs of the hairpin conductor are electrically interconnected through a voltmeter 3.
A solenoid 4 is wound from a non-magnetic conductor in two layers so that the ends of the conductor are disposed at one end, and the solenoid surrounds the hairpin conductor 1. The solenoid 4 is connected to a source 5 of alternating current the solenoid connections 6 being disposed at the closed end of the hairpin conductor. Although not shown in the drawing the solenoid also has a core of non-magnetic material for example, stainless steel or ceramic which is shaped to allow each hairpin leg to twist whilst preventing relative lateral movement of the legs and the solenoid.
In use the levers 2 of the hairpin conductor are attached to a structure arranged so that straining of the structure causes relative displacement of the levers thereby applying torsional strain to the legs and setting up a magnetic coupling between the hairpin conductor and the solenoid. An ac signal induced in the hairpin conductor 1 varies with the changes in magnetic coupling between the solenoid 4 and the hairpin conductor, these changes being caused by variations in the torsional strain. The output signal is related to the mechanical displacement of the levers 2 and the voltmeter 3 can be calibrated to read in terms of strain of the structure.
The hairpin form of conductor 1 causes desirable (torsion sensitive) signals in each of the two arms to be additive whilst the undesirable signal caused by stray inductive coupling is selfcancelling thereby improving the signal to noise ratio. Because the ac source is connected only at the end of the solenoid which is remote from the hairpin conductor connections, stray inductive coupling near the coil is minimised. A dynamically balanced arrangement of the connections to the conductors enables the conductor assembly to be self-supporting by its connections thereby allowing it the necessary freedom of movement as the attachments are displaced.
In one construction of instrument the hairpin conductor and solenoid are formed from stainless steel sheathed mineral insulated cable such as that used for thermocouples in a hot and hostile environment. The cable of the hairpin conductor has two cores, one each of iron and constantan which are directly connected together at one end and connected through a voltmeter at the other end so that the undesirable signal caused by stray inductive coupling is self-cancelling whilst the desirable (torsion sensitive) signal induced in the iron core is not opposed by any corresponding signal in the constantan core thereby improving the signal to noise ratio. The cable of the solenoid conductor has a single core of copper or nickelchromium alloy.
In one alternative construction of instrument the cable of the hairpin conductor has a single core of iron.
Typically in such instruments having hairpin conductors 5 cm long the sensitivity for 45 ampere turns at 10 KHz has been found to be 1 mv/i 50 angular displacement of the levers.
Conductors comprising stainless steel mineral insulated cable are capable of working at high temperatures which makes such an instrument emminently suitable for use in the liquid sodium environment of a liquid metal cooled fast breeder nuclear reactor.
In a second alternative construction the conductors are metal sheathed mineral insulated cables having non-magnetic cores, but one of the members is sheathed in stainless iron. The instrument is arranged so that strain in the structure torsionally strains the sheathing thereby varying the magnetic coupling between the conductors.
The construction may include a plurality of strain indicating instruments arranged in a grid system the conductors being inter-connected in groups and arranged for frequency or time multiplexing as illustrated in Figure 3 the instruments being designated 'S'.
It should be appreciated that the invention can also reside in other constructions of liquid metal cooled nuclear reactor, for example, the torsional strain may be applied to the conductor of solenoid form by tensional strain on the solenoid. The electrical induction apparatus could comprise a pair of generally co-axial tubular members of ferromagnetic material with the inner member surrounded by a non-magnetic conductor of solenoid form and having a linear electrical conductor of non-magnetic material coaxially disposed, the magnetic coupling being created by differential torsional displacement of the tubular members.
Claims (9)
1. A liquid metal cooled nuclear reactor having electrical induction apparatus for monitoring torsional or linear strain induced in the reactor structure, the apparatus having means for indicating creation of magnetic coupling when a ferromagnetic member of the apparatus is torsionally strained.
2. A nuclear reactor according to claim 1 wherein the electrical induction apparatus comprises a first electrical conductor of linear form surrounded by a second electrical conductor of solenoid form, one of the conductors being of ferromagnetic material and arranged so that magnetic coupling is created by torsionally straining the ferromagnetic conductor when an alternating current is passed through the first or second conductors.
3. A nuclear reactor according to claim 2 wherein the torsional strain is applied by the application of torque to the linear conductor.
4. A nuclear reactor according to claim 2 wherein the torsional strain is applied by the application of tensional strain to the solenoid.
5. A nuclear reactor according to claim 3 wherein the electrical induction apparatus comprises a ferromagnetic electrical conductor of hairpin form having legs adapted for attachment to the strainable structure and for connection through a voltmeter, and the solenoid surrounding the hairpin conductor is adapted for connection to an alternating current source, the conductor being of metal-sheathed mineral insulated cable.
6. A nuclear reactor according to claim 1 wherein the electrical induction apparatus comprises a first electrical conductor of linear form surrounded by a second electrical conductor of solenoid form at least one of the conductors being of mineral insulated cable having a sheath of ferromagnetic material.
7. A nuclear reactor according to claim 5 wherein the hairpin conductor and solenoid are formed from stainless steel sheathed mineral insulated cable.
8. A nuclear reactor according to claim 7 wherein the cable of the hairpin conductor has two electrically conducting cores one each of iron and non-magnetic material which are directly connected together at one end, and a cable of the solenoid conductor has a single core of nonmagnetic material.
9. A liquid metal cooled nuclear reactor substantially as herein before described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8021041A GB2054165B (en) | 1979-06-28 | 1980-06-26 | D-metal cooled nuclear reactor induction apparatus monitoring structural strains in liqui |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7922522 | 1979-06-28 | ||
| GB8021041A GB2054165B (en) | 1979-06-28 | 1980-06-26 | D-metal cooled nuclear reactor induction apparatus monitoring structural strains in liqui |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2054165A true GB2054165A (en) | 1981-02-11 |
| GB2054165B GB2054165B (en) | 1983-06-08 |
Family
ID=26271993
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8021041A Expired GB2054165B (en) | 1979-06-28 | 1980-06-26 | D-metal cooled nuclear reactor induction apparatus monitoring structural strains in liqui |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2054165B (en) |
-
1980
- 1980-06-26 GB GB8021041A patent/GB2054165B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2054165B (en) | 1983-06-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |