Method of operating nuclear plant

• US 9,076,559 B2
• Filed: 04/03/2009
• Issued: 07/07/2015
• Est. Priority Date: 08/12/2008
• Status: Active Grant

• Current Assignee: Mitsubishi Heavy Industries, Ltd.
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Nishimura, Takao, Umehara, Ryuji
• Primary Examiner(s): McGue, Frank J
• Application Number:
  US12/995,568
• Publication Number:
  US 20110075785A1
• Time in Patent Office: 2,286 Days
• Field of Search: 376/306
• US Class Current: 1/1
• CPC Class Codes: G21C 17/0225 Chemical surface treatment, e.g. corrosion corrosion prevention in presence of water from scale removal or by modification of the properties of the liquid C02F5/00; inhibiting corrosion by adding corrosion inhibitors C23F11/00
• CPC Class Codes: G21D 1/00 Details of nuclear power plant control G21D3/00
• CPC Class Codes: G21D 3/08 Regulation of any parameters in the plant
• CPC Class Codes: Y02E 30/00 Energy generation of nuclear origin
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

An object is to reduce radiation exposure in a nuclear plant. A nuclear plant 1 is a nuclear power generating plant where steam is generated by thermal energy generated by nuclear fission of a nuclear fuel 2C in a nuclear reactor 2, and a turbine 8 is driven by the steam to generate heat by a power generator 10. After a nuclear plant 1 is newly constructed, when a primary cooling system of the nuclear reactor 2 raises the temperature to around a power operation temperature for the first time, zinc is injected into a primary coolant C1 present in the primary cooling system by a zinc injector 20.

Claims

1. A method of operating a nuclear plant including a pressurized water nuclear reactor, comprising injecting zinc into a coolant present in a primary cooling system of the nuclear reactor to form a oxide film on TT690 material which constitutes an inner surface of a primary cooling-system piping, after construction of the nuclear reactor and during execution of a hot function test, wherein

the zinc is injected when a temperature of the coolant becomes a predetermined temperature which is above the range between 60 and 90 Celsius degrees,

an injection rate of the zinc is decreased when a concentration of the zinc in the coolant exceeds a predetermined value,

an injection amount of the zinc in a second stage, in which a generation speed of the oxide film slows compared with a first stage, is reduced compared with that in the first stage.

2. The method of operating a nuclear plant including a pressurized water nuclear reactor according to claim 1, wherein a reduction rate of an injection rate of the zinc at the second stage of injection of the zinc is larger than a reduction rate of an injection rate of the zinc at the first stage of injection of the zinc, and a maximum zinc concentration in a filling line is set to 40 ppb.