Movable standby hydraulic control unit that is usable during a control rod drive system inspection to temporarily replace any one of several hydraulic control units

Patent metadata

Field	Value
Publication number	US-10957458-B2
Application number	US-201815983307-A
Country	US
Kind code	B2
Filing date	May 18, 2018
Priority date	Jun 8, 2017
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

A control rod drive system and an inspection method of the control rod drive system capable of performing inspection safely and effectively. A control rod drive system controlling operation by supplying a hydraulic pressure to control rod drive mechanisms. A plurality of first hydraulic control units supply the hydraulic pressure to corresponding control rod drive mechanisms and a second hydraulic control unit supplies the hydraulic pressure to corresponding control rod drive mechanisms of the first hydraulic control unit as an inspection target instead of the first hydraulic control unit.

First claim

What is claimed is:

1. A control rod drive system controlling operation by supplying a hydraulic pressure to control rod drive mechanisms, comprising:
a plurality of first hydraulic control units;
a plurality of control rod drive mechanisms respectively corresponding to the plurality of first hydraulic control units;
a second hydraulic control unit, which has a same configuration as the plurality of first hydraulic control units;
first piping connecting each first hydraulic control unit with each respectively corresponding control rod drive mechanism; and
a plurality of valves, each on a flow path of the first piping,
wherein the second hydraulic control unit is connected to each control rod drive mechanism via second piping that is connected to each of the plurality of valves,
wherein water does not flow directly between the second hydraulic control unit and any of the first hydraulic control units, and
wherein a flow path of supplying hydraulic pressure to a control rod drive mechanism is switched from a respective first hydraulic control unit to the second hydraulic control unit via a valve.

2. The control rod drive system according to claim 1 ,
wherein each a three-way selector valve, and
a first inlet of each three-way selector valve is connected to a respective discharge port of a respective first hydraulic control unit, a second inlet of each three-way selector value is connected to a respective discharge port of the second hydraulic control unit, and an outlet of each three-way selector valve is connected to a respective control rod drive mechanism.

3. The control rod drive system according to claim 1 ,
wherein each valve includes a tee and a gate valve, and
a first opening of each tee is connected to a respective discharge port of the first hydraulic control unit, a second opening of each tee is connected to a respective discharge port of the second hydraulic control unit though the gate valve, and a third opening of each tee is connected to a respective given control rod drive mechanism.

4. The control rod drive system according to claim 1 ,
wherein the second hydraulic control unit is detachably connected to each valve.

5. The control rod drive system according to claim 4 ,
wherein the second hydraulic control unit is detachably connected to each valve through flange joints.

6. The control rod drive system according to claim 5 ,
wherein the second hydraulic control unit is mobile upon disconnection from the valves.

7. The control rod drive system according to claim 1 , wherein each first hydraulic control unit and the second hydraulic control unit each comprise:
an air operated scram valve,
a scram pilot valve that opens/closes the scram valve,
downstream-side gate valves positioned on a downstream side of the scram valve,
an upstream-side gate valve positioned on an upstream side of the scram valve,
a pressure device positioned between the scram valve and the upstream-side gate valve and configured to pressurize an internal pipe, and
a solenoid valve positioned between the scram valve and the downstream-side gate valves and configured to supply purge water.

8. The control rod drive system according to claim 2 , wherein each first hydraulic control unit and the second hydraulic control unit each comprise:
an air operated scram valve,
a scram pilot valve that opens/closes the scram valve,
downstream-side gate valves positioned on a downstream side of the scram valve,
an upstream-side gate valve positioned on an upstream side of the scram valve,
a pressure device positioned between the scram valve and the upstream-side gate valve and configured to pressurize an internal pipe, and
a solenoid valve positioned between the scram valve and the downstream-side gate valves and configured to supply purge water.

9. The control rod drive system according to claim 3 , wherein each first hydraulic control unit and the second hydraulic control unit each comprise:
an air operated scram valve,
a scram pilot valve that opens/closes the scram valve,
downstream-side gate valves positioned on a downstream side of the scram valve,
an upstream-side gate valve positioned on an upstream side of the scram valve,
a pressure device positioned between the scram valve and the upstream-side gate valve and configured to pressurize an internal pipe, and
a solenoid valve positioned between the scram valve and the downstream-side gate valves and configured to supply purge water.

10. The control rod drive system according to claim 4 , wherein each first hydraulic control unit and the second hydraulic control unit each comprise:
an air operated scram valve,
a scram pilot valve that opens/closes the scram valve,
downstream-side gate valves positioned on a downstream side of the scram valve,
an upstream-side gate valve positioned on an upstream side of the scram valve,
a pressure device positioned between the scram valve and the upstream-side gate valve and configured to pressurize an internal pipe, and
a solenoid valve positioned between the scram valve and the downstream-side gate valves and configured to supply purge water.

11. The control rod drive system according to claim 5 , wherein each first hydraulic control unit and the second hydraulic control unit each comprise:
an air operated scram valve,
a scram pilot valve that opens/closes the scram valve,
downstream-side gate valves positioned on a downstream side of the scram valve,
an upstream-side gate valve positioned on an upstream side of the scram valve,
a pressure device positioned between the scram valve and the upstream-side gate valve and configured to pressurize an internal pipe, and
a solenoid valve positioned between the scram valve and the downstream-side gate valves and configured to supply purge water.

12. The control rod drive system according to claim 6 , wherein each first hydraulic control unit and the second hydraulic control unit each comprise:
an air operated scram valve,
a scram pilot valve that opens/closes the scram valve,
downstream-side gate valves positioned on a downstream side of the scram valve,
an upstream-side gate valve positioned on an upstream side of the scram valve,
a pressure device positioned between the scram valve and the upstream-side gate valve and configured to pressurize an internal pipe, and
a solenoid valve positioned between the scram valve and the downstream-side gate valves and configured to supply purge water.

Assignees

• Hitachi Ge Nuclear Energy Ltd

Inventors

• Ooka Kento
• Misawa Naoto
• Okazawa Hiroshi

Classifications

• G21C17/10

  Structural combination of fuel element, control rod, reactor core, or moderator structure with sensitive instruments, e.g. for measuring radioactivity, strain · CPC title

• G21C9/02

  Means for effecting very rapid reduction of the reactivity factor under fault conditions, e.g. reactor fuse; {Control elements having arrangements activated in an emergency}(control elements per se G21C7/00) · CPC title

• Y02E30/30

  Nuclear fission reactors · CPC title

• G21C7/16 Primary

  Hydraulic or pneumatic drive · CPC title

• G21C15/18

  Emergency cooling arrangements; Removing shut-down heat · CPC title