Method of refueling a nuclear reactor

Patent metadata

Field	Value
Publication number	US-10014083-B2
Application number	US-201213461821-A
Country	US
Kind code	B2
Filing date	May 2, 2012
Priority date	May 2, 2012
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

A method of refueling a nuclear reactor that includes the steps of removing the reactor vessel head and upper internals to a storage location and installing a cylindrical tank having open upper and lower ends, on the reactor vessel flange. The cylindrical tank is sealed to the reactor vessel and a penetration on the side of the cylindrical tank is sealed to a refueling canal that is connected to a spent fuel pool. The level of reactor coolant within the reactor vessel is then raised to at least partially fill the cylindrical tank to a level equal to that of the spent fuel pool. The refueling canal is then opened and a refueling machine supported on the reactor vessel is employed to transfer fuel assemblies between the core and the spent fuel pool.

First claim

What is claimed is:

1. A method of refueling a nuclear reactor comprising a reactor vessel having an open upper end with a flange, the reactor vessel housing a core including a plurality of fuel assemblies and an upper internals structure supported above the core, and a head with a mating flange for sealing the open upper end of the reactor vessel; the method comprising the steps of:
removing the reactor vessel head;
placing the reactor vessel head in a first storage location outside of a path above the reactor vessel;
lifting the upper internals structure out of the reactor vessel to a second storage location outside of the path above the reactor vessel;
detachably installing a cylindrical tank having an open lower end and an open upper end, on the reactor vessel flange so that the reactor vessel flange substantially supports the cylindrical tank;
detachably sealing the lower end of the cylindrical tank to the reactor vessel and a penetration on a side of the cylindrical tank to a refueling canal that is connected to a spent fuel pool;
raising a level of reactor coolant within the reactor vessel to at least partially fill the cylindrical tank substantially to a level equal to a level of a coolant within the spent fuel pool;
opening the refueling canal; and
employing a refueling machine at least in part supported above the cylindrical tank, to transfer a number of the fuel assemblies within the core, through the penetration and the refueling canal to a storage location in the spent fuel pool.

2. The method of claim 1 wherein the step of lifting the upper internals structure includes the steps of:
supporting a radiation shield in the form of an shielded bell with an open lower end, above the open upper end of the reactor vessel;
lowering the radiation shield substantially to the reactor vessel flange over at least a portion of the upper internals structure;
raising the upper internals structure within the radiation shield; and
lifting the radiation shield with the upper internals structure inside to the second storage location.

3. The method of claim 2 including the step of lowering the upper internals structure from the radiation shield to a shielded stand at the second storage location.

4. The method of claim 3 wherein the shielded stand is located in a pool of coolant.

5. The method of claim 2 including the steps of:
drawing air into the radiation shield;
filtering the air before it is exhausted from the radiation shield; and

exhausting the air in the radiation shield after it has been filtered.

6. The method of claim 2 wherein the step of lifting the upper internals structure is accomplished with a reactor building main crane.

7. The method of claim 1 including the step of supporting the refueling machine from the reactor vessel.

8. The method of claim 7 including the step of supporting the refueling machine from the top of the cylindrical tank.

9. The method of claim 7 including the step of indexing the refueling machine off of the reactor flange to locate the fuel assemblies to be removed.

10. The method of claim 1 wherein the step of raising the level of reactor coolant is accomplished with an existing reactor vessel penetration.

11. The method of claim 1 wherein the step of sealing the lower end of the cylindrical tank is sealed to the reactor vessel flange.

Assignees

• Harkness Alexander W
• Cummins William Edward
• Westinghouse Electric Co Llc

Inventors

• Harkness Alexander W
• Cummins William Edward

Classifications

• G21C19/20 Primary

  Arrangements for introducing objects into the pressure vessel; Arrangements for handling objects within the pressure vessel; Arrangements for removing objects from the pressure vessel · CPC title

• G21C11/022 Primary

  inside the reactor vessel · CPC title

• G21F7/015

  Room atmosphere, temperature or pressure control devices · CPC title

• Y02E30/40

  Cross-Sectional Technologies · mapped topic

• G21C19/00 Primary

  Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel · CPC title