Reactor in-vessel sensor and core monitoring apparatus

• US 4,622,202 A
• Filed: 08/02/1983
• Issued: 11/11/1986
• Est. Priority Date: 08/25/1982
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamamoto, Hajime, Yamada, Izumi, Tsunashima, Mikiyasu
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US06/519,698
• Time in Patent Office: 1,197 Days
• Field of Search: 376/246, 376/247, 376/252, 374/117, 374/142, 374/176, 73/198, 73/861.11
• US Class Current: 376/246
• CPC Class Codes: G21C 17/025 for monitoring liquid metal coolants molten metal sampling in general G01N1/125
• CPC Class Codes: G21C 17/032 Reactor-coolant flow measuring or monitoring measuring volume or mass flow in general G01F
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

A sensor for monitoring the interior of a sodium-cooled fast breeder reactor comprises a pair of symmetrical magnetic cores, a magnetostrictive or piezoelectric vibrator element bonded to one of the cores, a primary coil and a plurality of secondary coils surrounding the magnetic cores, and a container enclosing the above members. The primary coil applied with an exciting alternating current generates an acoustic signal voltage indicative of sound, if any, originated in the interior of the reactor. The magnetic flux produced by the exciting current is influenced by the temperature and flow velocity of sodium flowing around the sensor, and corresponding voltage signals resulting from the changed magnetic flux are induced in the secondary coils.

Claims

1. A sensor for monitoring the interior of a reactor, comprising a magnetic core member including a magnetostrictive or piezoelectric vibrator element in a portion thereof, a primary coil excited by an alternating current, a plurality of secondary coils electromagnetically coupled to said primary coil, said primary and secondary coils surrounding said magnetic core member, and a casing enclosing therein said magnetic core member and said primary and secondary coils, whereby the temperature and flow velocity of a conductive liquid flowing outside of said casing are sensed, and a sound wave originated in said conductive liquid is received by said primary coil through said vibrator element.

2. A sensor as claimed in claim 1, wherein said magnetic core member is split into a first core brought into engagement with said sensor casing and a second core spaced apart from said first core, and said magnetostrictive or piezoelectric vibrator element is bonded to the surface of said first core opposite to said second core.

3. A sensor as claimed in claim 1, wherein said magnetostrictive or piezoelectric vibrator element is brought into engagement with said sensor casing.

4. A sensor as claimed in claim 2, wherein a first bias magnet and a second bias magnet are provided for establishing an electrostatic bias field, said first bias magnet being interposed between said first core and said vibrator element, said second bias magnet being disposed on the surface of said second core opposite to said first core.

5. An apparatus for monitoring the interior of a fast breeder reactor comprising:

a monitoring sensor comprising a magnetic core member including a magnetostrictive or piezoelectric vibrator element in a portion thereof, a primary coil excited by an alternating current, a plurality of secondary coils electromagnetically coupled to said primary coil, said primary and secondary coils surrounding said magnetic core member, and a casing enclosing therein said magnetic core member and said primary and secondary coils;

filter means for filtering, in response to the application of AC voltages induced in said secondary coils, to reduce frequency components except that having the frequency of said AC voltages;

signal computer means for executing the addition and subtraction of output signals from said filter means; and

second filter means for filtering, in response to the application of a voltage induced in said primary coil, to reduce the frequency component of said AC voltages from said voltage signal applied from said primary coil.

6. A sensor for monitoring the interior of the reactor and for determining temperature and flow velocity of a conductive liquid flowing outside a casing, the sensor comprising a casing enclosing therein at least a primary coil excited by an alternating current, at least a secondary coil inductively coupled to said primary coil, and a magnetic core member disposed within said primary and second coils, said magnetic core member having a magnetostrictive or piezoelectric vibrator element attached thereto for transforming a sound wave originated in the conductive liquid into an electric signal induced in said primary coil.

7. A sensor as claimed in claim 6, wherein said magnetic core member has a first core portion brought into engagement with said sensor casing and a second core portion spaced apart from said first core portion, said magnetostrictive or piezoelectric element being bonded to the surface of said first core portion opposite to and spaced from said second core portion so as to have a freely vibratable end surface.

8. A sensor as claimed in claim 6, wherein said magnetostrictive or piezoelectric vibrator element is brought into engagement with said sensor casing.

9. A sensor as claimed in claim 7, further comprising a first bias magnet and a second bias magnet for establishing an electrostatic bias field, said first bias magnet being interposed between said first core portion and said vibrator element, and said second bias magnet being disposed on the surface of said second core portion opposite to said vibrator element.

10. A sensor as claimed in claim 6, wherein said at least one secondary coil is disposed in symmetrical relation with respect to said primary coil and inductively coupled to said primary coil, said magnetic core member including a first magnetic core disposed within said primary and second coils and brought into engagement with said sensor casing, and a second magnetic core disposed within said primary and secondary coils so as to be spaced from and facing a surface of said first magnetic core, said magnetostrictive or piezoelectric vibrator element being bonded to the surface of said first magnetic core facing said second magnetic core and being spaced from said second magnetic core so as to have a freely vibratable end portion.