Nuclear waste cask with impact protection, impact amelioration system for nuclear fuel storage, unventilated cask for storing nuclear waste, and storage and transport cask for nuclear waste

Patent metadata

Field	Value
Publication number	US-11610696-B2
Application number	US-202117374005-A
Country	US
Kind code	B2
Filing date	Jul 13, 2021
Priority date	Oct 3, 2019
Publication date	Mar 21, 2023
Grant date	Mar 21, 2023

Abstract

A nuclear waste cask with impact protection includes impact limiters comprising deformable energy-absorbing perforated sleeves. An impact amelioration system for nuclear fuel storage components includes impact limiter assemblies at the bottom cask to canister interface including impact limiter plugs frictionally engaging corresponding plug holes formed in the cask closure plate. A nuclear waste fuel storage system includes an unventilated cask including a heavy free-floating radiation shielding lid loosely coupled the top end of the cask in a movable manner via the anchor bosses which provides cask overpressurization protection. A nuclear waste cask includes an axially elongated rectangular cuboid cask body having a cavity for holding nuclear waste materials and cask locking mechanism including first locking protrusions on the lid which are selectively interlockable with mating second locking protrusions on the cask body to lock the lid to the cask body.

First claim

What is claimed is:

1. A nuclear waste cask with impact protection comprising:
a longitudinal axis;
a longitudinally elongated cask body including a top end, a bottom end, and a sidewall extending between the ends, and a cavity configured for holding a nuclear waste canister; and
an impact limiter coupled to the top end of the cask body, the impact limiter comprising an annular perforated sleeve having a body including a central opening and a circumferential array of elongated longitudinal passages formed therethrough around the central opening.

2. The cask according to claim 1 , wherein the longitudinal passages are oriented parallel to each other and extend between a top surface and a bottom surface of the perforated sleeve.

3. The cask according to claim 2 , wherein the longitudinal passages are oriented parallel to the longitudinal axis of the cask.

4. The cask according to claim 2 , wherein the longitudinal passages have a circular transverse cross section.

5. The cask according to claim 4 , wherein the longitudinal passages each have a longitudinal length which is greater than their respective diameter.

6. A method for ameliorating impact between components of a fuel storage system, the method comprising:
partially embedding a plurality of impact limiter plugs in corresponding plug holes formed in a bottom closure plate of a cask;
seating the canister on the plugs, the plugs being positioned at a first depth in the plug holes;
impacting the canister against the plugs with an impact force; and
driving the plugs to a second depth in the plug holes deeper than the first depth.

7. The method according to claim 6 , wherein pact force in the impacting step is a result of dropping the cask against a surface.

8. The method according to claim 6 , wherein the driving step includes frictionally engaging and sliding tapered sides of the plugs along tapered sidewalls of the plug holes.

9. The method according to claim 6 , wherein the seating step includes engaging the plugs with a bottom baseplate of the canister.

10. The method according to claim herein the plugs have a frustoconical shape and at least a portion of the plug holes have a frustoconical shape.

11. A method for protecting an unventilated nuclear waste storage system from internal overpressurization, the method comprising:
providing an unventilated cask comprising a sealable internal cavity and a plurality of threaded anchor bosses;
lowering a canister containing high level nuclear waste into the cavity;
positioning a radiation shielded lid on the cask, the lid being in a downward sealed position engaged with the cask making the cavity gas tight to retain pressures exceeding atmospheric;
aligning a plurality of fastener holes formed in the lid with the anchor bosses;
threadably engaging a threaded stud with each of the anchor bosses through the fastener holes of the lid;
rotatably engaging a threaded limit stop with each of the threaded studs;
positioning the limits stops on the studs such that a vertical travel gap is formed between the lid and the limit stops;
wherein during a cask overpressurization condition, the lid slideably moves upward along the studs to a relief position ajar from the cask to vent excess pressure to atmosphere.

12. The method according to claim 11 , wherein when the cask overpressurization condition abates, the lid automatically returning to the downward sealed position to re-engage the cask body and reseal the cavity.

13. The method according to claim 11 , further comprising pumping air out of the cavity of the cask after positioning the lid on the cask to establish a sub-atmospheric pressure in the cavity.

14. The method according to claim 13 , further comprising filling the cavity of the cask with an inert gas.

15. A method for locking a radioactive waste storage cask comprising:
positioning a closure lid on a cask body over an opening leading into an internal storage cavity;
inserting a peripheral array of first locking protrusions on the lid between and through a peripheral array of second locking protrusions disposed on the cask body around the opening;
slideably moving the first locking protrusions beneath the second locking protrusions; and
frictionally engaging the first locking protrusions with the second locking protrusions;
wherein the lid cannot be removed from the cask body.

16. The method according to claim 15 , wherein when the first locking protrusions are arranged in spaced apart groups on a plurality of locking bars slideably mounted on the lid, the locking bars being slideably movable relative to the lid.

17. The method according to claim 16 , wherein the slideably moving step comprises sliding each of the locking bars from an unlocked position in which the first locking protrusions do not engage the second locking protrusions, to a locked position in which the first locking protrusions are positioned beneath the second locking protrusions.

18. The method according to claim 15 , wherein the frictionally engaging step comprises engaging a tapered locking surface on each of the first locking protrusions with a corresponding tapered locking surface on a respective one of the second locking protrusions which locks the lid to the cask body via a wedging action.

19. The method according to claim 18 , wherein engaging the tapered locking surfaces of the first and second locking protrusions draws the lid against the cask body in tightened engagement.

20. The method according to claim 19 , further comprising compressing a gasket between the lid and the cask body when the lid is drawn against the cask body.

Assignees

• Holtec International

Inventors

• Singh Krishna P
• Bullard Ii Charles W
• Zhai Xuejun
• Griffiths John D

Classifications

• Y02E30/30

  Nuclear fission reactors · CPC title

• G21F5/14

  Devices for handling containers or shipping-casks, e.g. transporting devices {loading and unloading, filling of containers (cranes, load-engaging elements or devices for cranes, capstans, winches or tackles B66C)} · CPC title

• G21F5/012

  Fuel element racks in the containers · CPC title

• G21F5/12 Primary

  Closures for containers; Sealing arrangements · CPC title

• G21F5/10

  Heat-removal systems, e.g. using circulating fluid or cooling fins · CPC title