High-density subterranean storage system for nuclear fuel and radioactive waste

Patent metadata

Field	Value
Publication number	US-10446287-B2
Application number	US-201715838414-A
Country	US
Kind code	B2
Filing date	Dec 12, 2017
Priority date	Jan 10, 2013
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

An underground ventilated system for storing nuclear waste materials. The system includes a storage module having an outer shell defining an internal cavity and an inner shell. A majority of the height of the outer shell may be disposed below grade. The outer shell may include a hermetically sealed bottom. First and second canisters are positioned in lower and upper portions within the cavity respectively in vertically stacked relationship. A centering and spacing ring assembly is interspersed between the first and second canisters to transfer the weight of the upper second canister to the lower first canister. The assembly may include centering lugs which laterally restrain the first and second canisters in case of a seismic event. A natural convection driven ventilated air system cools the canisters to remove residual decay heat to the atmosphere. In one non-limiting embodiment, the shells are made of steel.

First claim

What is claimed is:

1. An underground storage module for vertically-stacked storage of nuclear waste canisters, the storage module comprising:
an elongated vertical outer shell defining vertical axis and an internal cavity, the outer shell having a top and a hermetically sealed bottom, the outer shell being disposed below grade for a majority of its height;
an elongated inner shell disposed inside the outer shell in the cavity of the outer shell;
an annular common inlet air plenum extending circumferentially around a top of the outer shell, the inlet air plenum arranged to draw ambient cooling air through a plurality of air inlets arranged around the outer shell;
an annular-shaped vertical downcomer ventilation shaft between the inner and outer shells, the downcomer ventilation shaft arranged to convey the cooling air from the inlet air plenum downwards along the outer shell to a bottom of the cavity;
a first canister positioned in the cavity in a lower position;
a second canister vertically stacked above the first canister in an upper position;
an annular-shaped vertical riser ventilation shaft formed between the inner shell and the canisters, the riser ventilation shaft being in fluid communication with the downcomer ventilation shaft near the bottom of the cavity in the outer shell and arranged to convey cooling air upwards across outer sidewall surfaces of the canisters for removing decay heat; and
a removable top lid mounted on top of the outer shell covering the cavity, the top lid in fluid communication with the riser ventilation shaft and configured to form an airflow pathway to atmosphere through the lid from the riser ventilation shaft;
wherein the inlet air plenum adjoins an exterior side of the top of the outer shell and extends laterally outwards therefrom;
wherein the outer shell includes a plurality of circumferentially spaced apart airflow openings extending laterally between the inlet air plenum and a top of the downcomer ventilation shaft in the cavity, the cooling air entering the downcomer ventilation shaft through the outer shell airflow openings from the inlet air plenum.

2. The storage module of claim 1 , wherein the outer and inner shells are cylindrically shaped and concentrically aligned with the vertical axis.

3. The storage module of claim 1 , wherein the inner shell includes a plurality of circumferentially spaced apart airflow openings extending between the downcomer ventilation shaft and a bottom of the riser ventilation shaft, the cooling air entering the riser ventilation shaft from the downcomer ventilation shaft through the inner shell airflow openings.

4. The storage module of claim 1 , wherein the top lid includes a plurality of radially extending air passages which are in fluid communication with the riser ventilation shaft and a central airflow passageway in the top lid, the air passages and central airflow passageway forming the airflow pathway to atmosphere through the lid.

5. The storage module of claim 4 , wherein the top lid includes a diametrically enlarged top portion disposed over and extending radially beyond the outer and inner shells, and a downward extending bottom portion position inside a top of the inner shell.

6. The storage module of claim 5 , wherein the top portion of the top lid has a larger diameter than the outer shell and the bottom portion has a smaller diameter than the inner shell forming an annular gap in fluid communication with the riser ventilation shaft and the central airflow passageway in the top lid.

7. The storage module of claim 1 , further comprising a concrete top pad circumferentially surrounding a top of the outer shell and a concrete base pad engaging the bottom of the outer shell, the inlet air plenum being disposed and recessed in the top pad.

8. The storage module of claim 7 , further comprising a metal cover plate covering the inlet air plenum, wherein the air inlets are formed as openings through the cover plate.

9. The storage module of claim 7 , wherein the top pad is square-shaped in top plan view and the inlet air plenum has a rectilinear shape.

10. The storage module of claim 1 , further comprising soil filled adjacent to the outer shell and extending between the top pad and the base pad.

11. A system for vertically-stacked underground storage of nuclear waste canisters comprising:
an elongated outer shell defining a vertical axis and an internal cavity;
a first canister positioned in the cavity in a lower position;
a second canister vertically stacked on top of the first canister in an upper position, the first and second canisters being concentrically aligned with the vertical axis;
a removable top lid mounted on top of the outer shell and covering the cavity;
a bottom plate hermetically sealed to a bottom of the outer shell and covering the cavity;
a top of the outer shell embedded in a concrete top pad surrounding the outer shell and a concrete base pad supporting the bottom plate on the outer shell;
the concrete top pad defining a recessed common inlet air plenum extending circumferentially around the top of the outer shell;
a plurality of air inlets arranged around the top pad and in fluid communication with the inlet air plenum, the inlet air plenum operable to draw ambient cooling air therein through the air inlets;
an annular-shaped vertical downcomer ventilation shaft between the inner and outer shells, the downcomer ventilation shaft arranged to convey the cooling air from the inlet air plenum downwards along the outer shell to a bottom of the cavity.

12. The system of claim 11 , further comprising an annular-shaped vertical riser ventilation shaft formed between the inner shell and the canisters, the riser ventilation shaft being in fluid communication with the downcomer ventilation shaft near the bottom of the outer shell and arranged to convey cooling air upwards across outer sidewall surfaces of the canisters for removing decay heat.

13. The system of claim 11 , further comprising soil filled adjacent to the outer shell and extending vertically between the top pad and the base pad.

14. The system of claim 11 , further comprising a centering and spacing ring assembly interspersed between the first and second canisters configured to form an airflow pathway therebetween in fluid communication with the riser ventilation shaft.

15. The system of claim 11 , further comprising a top lid including a plurality of radially extending air passages which are in fluid communication with the riser ventilation shaft and a central airflow passageway in the top lid, the air passages and central airflow passageway forming the airflow pathway to atmosphere through the lid.

16. The system of claim 15 , wherein the top lid includes a diametrically enlarged upper portion disposed over the outer and inner shells and a downward extending bottom protrusion positioned inside an open top of the inner shell.

17. The system of claim 16 , wherein the upper portion of the top lid has a larger diameter than the outer shell and the bottom protrusion has a smaller diameter than the inner shell.

18. An underground storage module for vertically-stacked storage of nuclear waste canisters, the storage module comprising:
an elongated vertical outer shell defining a vertical axis and an internal cavity, the outer shell having a top and a hermetically sealed bottom, the outer shell being disposed below grade for a majority of its height;
an elongated inner shell disposed inside the outer shell and cavity;
a first canister positioned in the cavity in a lower position;
a second ca

Assignees

• Holtec International

Inventors

• Singh Krishna P

Classifications

• G21F7/06

  Structural combination with remotely-controlled apparatus, e.g. with manipulators · CPC title

• G21F9/36 Primary

  by packaging; by baling · CPC title

• B65D21/0224

  Auxiliary removable stacking elements other than covers · CPC title

• G21F7/015

  Room atmosphere, temperature or pressure control devices · CPC title

• B65D43/02

  Removable lids or covers (with means for piercing, cutting, or tearing a frangible inner closure B65D51/22) · CPC title