System and method for preparing a container loaded with wet radioactive elements for dry storage

Patent metadata

Field	Value
Publication number	US-11742102-B2
Application number	US-202016950713-A
Country	US
Kind code	B2
Filing date	Nov 17, 2020
Priority date	Dec 21, 2007
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

A system for preparing a container holding radioactive waste for dry storage. In one aspect, the invention can be a system for preparing a container having a cavity loaded with radioactive elements for dry storage, the system comprising: a gas circulation system comprising a condenser module, a desiccant module, and a gas circulator module; the gas circulation system configured to form a hermetically sealed closed-loop path when operably connected to the cavity of the container; and means for adding and removing the desiccant module as part of the hermetically sealed closed-loop path.

First claim

What is claimed is:

1. A method for drying spent nuclear fuel comprising:
loading a canister with moisture-laden spent nuclear fuel;
fluidly coupling the canister to a fluidic drying system to form a closed-loop flow circuit therebetween;
recirculating an inert gas through the canister via the closed-loop flow circuit;
drying the canister a first time to remove a first amount of moisture from the spent nuclear fuel;
fluidly coupling a moisture removal apparatus to the closed-loop flow circuit; and
dehumidifying the canister via the moisture removal apparatus to a vapor pressure of 3 Torr or less;
wherein the moisture removal apparatus comprises a vacuum system, and further comprising drawing a vacuum in the canister to dehumidify the canister;
wherein the step of fluidly coupling the moisture removal apparatus to the closed-loop flow circuit comprises closing a first valve downstream of the canister and closing a second valve upstream of a fluid connection point where the moisture removal apparatus is fluidly coupled to the closed-loop flow circuit to fluidly isolate the canister from other portions of the closed-loop flow circuit;
wherein the first and second valves are automatically closed by a programmable controller operably coupled to the first and second valves; and
further comprising the programmable controller closing the first and second valves when the programmable controller detects that the first amount of moisture has been removed from the spent nuclear fuel;
wherein the programmable controller monitors a moisture accumulator fluidly coupled to the closed-loop flow circuit to determine that the first amount of moisture has been removed before closing the first and second valves.

2. The method according to claim 1 , wherein fluidly isolating the canister allows the vacuum to be drawn only on the canister.

3. The method according to claim 1 , wherein the moisture accumulator is fluidly coupled to a condensing module fluidly coupled to the closed-loop flow circuit.

4. The method according to claim 1 , wherein the programmable controller monitors a hygrometer fluidly coupled to the closed-loop flow circuit to determine that the first amount of moisture has been removed before closing the first and second valves.

5. The method according to claim 1 , wherein the step of drying the canister the first time comprises flowing the inert gas through a condensing module downstream of the canister.

6. The method according to claim 1 , wherein the vacuum is drawn for less than 2 hours.

7. A method for drying spent nuclear fuel comprising:
loading a canister with moisture-laden spent nuclear fuel;
fluidly coupling the canister to a fluidic drying system to form a closed-loop flow circuit therebetween;
recirculating an inert gas through the canister via the closed-loop flow circuit;
drying the canister a first time to remove a first amount of moisture from the spent nuclear fuel;
fluidly coupling a moisture removal apparatus to the closed-loop flow circuit; and
dehumidifying the canister via the moisture removal apparatus;
wherein the moisture removal apparatus comprises a vacuum system, and further comprising drawing a vacuum in the canister to dehumidify the canister;
wherein the step of fluidly coupling the moisture removal apparatus to the closed-loop flow circuit comprises closing a first valve downstream of the canister and closing a second valve upstream of a fluid connection point where the moisture removal apparatus is fluidly coupled to the closed-loop flow circuit to fluidly isolate the canister from other portions of the closed-loop flow circuit; and
wherein the first and second valves are automatically closed by a programmable controller operably coupled to the first and second valves;
the programmable controller closing the first and second valves when the programmable controller detects that the first amount of moisture has been removed from the spent nuclear fuel.

Assignees

• Holtec International

Inventors

• Singh Krishna P
• Griffiths John D

Classifications

• F26B21/40

  using gases other than air · CPC title

• F26B21/33

  Humidity · CPC title

• G21F5/06 Primary

  Details of, or accessories to, the containers · CPC title

• F26B5/04

  by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum {(F26B11/049 and F26B17/128 take precedence)} · CPC title

• F26B5/12

  by suction · CPC title