System for inspection and mending in a reactor vessel of a nuclear reactor

• US 5,519,741 A
• Filed: 08/10/1994
• Issued: 05/21/1996
• Est. Priority Date: 08/20/1993
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Suzuki, Masanori, Hosoda, Yuji, Kajiyama, Shigeru, Morinaka, Ren
• Primary Examiner(s): Walsh, Donald P.
• Assistant Examiner(s): CHELLIAH, MEENA A
• Application Number:
  US08/288,307
• Time in Patent Office: 650 Days
• Field of Search: 376/260, 376/249, 376/205, 376/252, 376/258, 976/DIG. 212, 976/DIG. 213, 81/65.2, 81/100, 174/15.7
• US Class Current: 376/249
• CPC Class Codes: G21C 17/01 Inspection of the inner surfaces of vessels
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

A system for inspection and mending in a reactor vessel of a nuclear reactor comprises a track mechanism, support mechanisms for supporting the track mechanism, an inspection apparatus traveling on the track mechanism, at least one mending apparatus traveling on the track mechanism, a setting mechanism for lowering all the above-described mechanisms and apparatus in the reactor vessel, each of which is composed so as to pass through a hole of an upper grid of a reactor, and an installing mechanism for positioning the support mechanisms fixed with two of the upper grid, a core support plate and internal structures below the core support plate and the track mechanism at the inside of the reactor vessel by remote control and for attaching the inspection apparatus and the mending apparatus to the same track mechanism by remote control. The position data of places to be mended are obtained by the inspection apparatus and transmitted as the target position data to a mending control apparatus for controlling the mending apparatus.

Claims

1. a system for inspection and mending in a reactor vessel of a nuclear reactor, comprising:

a track mechanism;

support mechanisms for supporting said track mechanism;

an inspection apparatus traveling on said track mechanism;

at least one mending apparatus traveling on said track mechanism;

a setting mechanism for lowering all said above-described mechanisms and apparatuses in said reactor vessel, each of said track mechanism, said support mechanisms, said inspection apparatus and said mending apparatuses being composed so as to pass through a hole of an upper grid of a reactor core; and

an installing mechanism for positioning said support mechanisms and said track mechanism at inside places of said reactor vessel by remote operations and for attaching said inspection apparatus and said mending apparatus to said same track mechanism by remote operations.

2. A system for inspection and mending in a reactor vessel of a nuclear reactor according to claim 1, wherein said track mechanism comprises at least two partial tracks, said partial tracks being connected to each other by a link or links and each of said links having an actuator for rotating said partial tracks connected to each other on each of said links.

3. A system for inspection and mending in a reactor vessel of a nuclear reactor according to claim 1, further comprising:

a control apparatus for calculating target positions of places to be mended by using inspection result data by said inspection apparatus and for positioning said mending apparatus at said calculated target positions of places to be mended; and

wherein each of said support mechanisms is fixed with a hole of an upper grid and a hole of a core support plate.

4. A system for inspection and mending in a reactor vessel of a nuclear reactor according to claim 1, further comprising:

a control apparatus for calculating target positions of places to be mended by using inspection result data by said inspection apparatus and for positioning said mending apparatus at said calculated target positions of places to be mended; and

wherein each of said support mechanisms is fixed with a core support plate and one of a plurality of internal structures below said core support plate.

5. A system for inspection and mending in a reactor vessel of a nuclear reactor according to claim 4, wherein said internal structures are housings for control rod drive mechanisms.

6. A system for inspection and mending in a reactor vessel of a nuclear reactor according to claim 3, wherein an ultrasonic inspection apparatus is used as said inspection apparatus.

7. A system for inspection and mending in a reactor vessel of a nuclear reactor according to claim 4, wherein an ultrasonic inspection apparatus is used as said inspection apparatus.

8. A system for inspection and mending in a reactor vessel of a nuclear reactor according to claim 5, wherein an ultrasonic inspection apparatus is used as said inspection apparatus.

9. A system for inspection and mending in a reactor vessel of a nuclear reactor according to claim 1, wherein said installing mechanism further includes a mechanism for disassembling said track mechanism, said inspection apparatus and said at least one mending apparatus so as to be taken out through said hole of said upper grid.

10. A system for inspection and mending in a reactor vessel of a nuclear reactor according to claim 9, wherein an ultrasonic inspection apparatus is used as said inspection apparatus.

11. A system for inspection and mending in a reactor vessel of a nuclear reactor according to claim 1, wherein the system is used for inspecting and mending a shroud of the reactor vessel.

12. A system for inspecting and mending in a reactor vessel of a nuclear reactor according to claim 9, wherein the system is used for inspecting and mending a shroud of the reactor vessel.