Spent-fuel dry storage
A cooling loop
that never stops
and never runs.
Decay heat boils a sealed water charge at the base of the cask. The vapor rises, condenses against a finned collar above grade, and gravity returns it. The fuel cools itself, for as long as it stays warm.
- SEALED & SUB-ATMOSPHERIC
- 3 GRANTED U.S. PATENTS
- NOTHING TO INSPECT
Your canisters, your transfer casks, your crews — our silo.
The system
Everything up to the rim is ordinary practice.
The invention begins where the lid lands.
Loading proceeds exactly as it does today. Nothing about the canister, the transfer cask, or the crew's procedure changes.
Fuel is loaded; the canister is welded shut and backfilled with helium.
The canister travels in a shielded transfer cask.
The transfer cask mates over the silo and the canister is lowered in.
The lid is placed. The loop self-starts as decay heat reaches the water charge — and runs for the life of the fuel.
The circuit
A sealed water charge sits in a plenum at the base of the cask, against the hottest part of the cavity wall. Decay heat boils it. Vapour climbs the inner annular passage under its own buoyancy, crosses at the top, and condenses against the inner face of a finned collar that rises above grade. Gravity returns the condensate down the outer passage, cooled further by the surrounding soil on the way. The loop's operating temperature is set by the coolant and charge selected at fabrication, so the same structure can be tuned to a site's thermal requirements.
Why it stays sealed
The circuit is welded — no gaskets, no fittings, no valves anywhere in the loop. It operates below atmospheric pressure, so a breach in the boundary admits air rather than releasing coolant. There is no airway between the environment and the canister, which means no salt, no debris, and nothing to inspect for the life of the installation.
One architecture, three deployments
Drop-in replacement for a conventional above-grade overpack.
Exit and return passages run the length of the shell — storage modules and transport.
Body buried for shielding; only the finned collar stands above ground.
Screening results — 30 kW, 38 °C ambient
Detail
| Quantity | Value |
|---|---|
| Estimated peak cladding temperature | ≈ 194 °C |
| Normal-storage limit | ≈ 400 °C |
| Loop operating pressure | ≈ 23 kPa |
| Heat load still within limit | to 50 kW |
First-order thermal-network results. Detailed validation with licensed codes is the natural first step for a licensee's engineering organization.
Why now
The industry has wanted a circulating loop since 1962.
The idea is not new. What was never solved is sealing it — a circuit that keeps its coolant for the life of the cask, never touches the fuel, and never exchanges air with the weather outside.
- 1962
A water-and-steam thermosiphon cask is patented. It is filled, vented, and serviced — the coolant wets the fuel and escapes through a relief valve.
- 1963
A finned natural-convection loop cask follows. Also open, also serviced.
- —
The industry settles on passive vented convection: simple, proven, and dependent on ambient air reaching the canister.
- 2013
Decay-heat recovery work revives the loop concept.
- 2016
This family closes the gap the field left open: a permanently sealed circulating circuit, integral to the cask shell.
- 2019
A consumable auxiliary cooling jacket enters service — approved for short-term operations, with duty measured in hours.
Chemistry, not just mechanics
Vented designs inhale ambient air for decades. At coastal sites that means salt on the canister, and chloride-induced stress-corrosion cracking is now a recognized aging-management concern. A sealed shell removes the pathway rather than managing its consequences.
Surveillance at scale
Vent inspection is a recurring cost per cask, per interval, for sixty years or more. Consolidated storage contemplates thousands of units. There is nothing to inspect on a cask with no airways.
Where the staff aren't
Small modular and microreactor deployments — including data-center co-location — put fuel where routine surveillance is a staffing problem rather than a line item.
Evidence
Computed, not asserted.
The architecture has been screened with a suite of models built for the purpose, and cross-checked against an independent method. Every figure quoted on this site is reproducible from them.
Thermal network
A one-dimensional resistance model of the full circuit — thermosiphon momentum balance, film correlations, a parallel conduction and radiation path, and finned-shell rejection to ambient.
Two-phase and below-grade
Extensions covering boiling and condensation, sub-atmospheric operation, buried configurations, and coolant inventory margins.
Independent cross-check
A two-dimensional laminar natural-convection simulation, solved from rest with no input from the network model beyond wall temperatures. It reproduced the network model's loop circulation to within about 16 percent — two unrelated methods, neither tuned to the other.
These are screening-level analyses and are identified as such throughout. They establish feasibility and identify the governing sensitivities; they are not a substitute for validated thermal-hydraulic codes. Model parameterization is available to parties evaluating the family.
Patents & contact
Device, system, and method.
Three granted U.S. patents, sole inventor, unencumbered, maintenance fees current. Priority to August 2016, with protection running into the late 2030s.
The cask — a shell containing the closed cooling circuit, closed by a cooled lid.
The cooling system — inner and outer passages in fluid communication, circulating coolant, vertical and horizontal forms.
The method — performing the cooling, from lid placement through decades of storage operation.
Recognised in examination
The family's published disclosure has been cited as particularly relevant prior art in the European examination of a subsequent passive cask-cooling application, and is acknowledged as prior art in that granted patent's background.
Availability
The family is offered for acquisition or exclusive license. CAD models, the full thermal model suite, and detailed technical materials are available under NDA to parties evaluating it.