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The ReCore-Reactor is the nuclear-island part of an integrated engineering concept (not a commercial plant design ready for procurement). The reference unit is sized around 720 MWth, ~300 MWe class when coupled to ReCore-Power at a ~45% net cycle target.
The design is deliberately conservative in materials and physics but more ambitious in plant arrangement: modular multi-loop layout, metallic fuel suited to recycle, heat rejection to nitrogen rather than water. For the broader rationale — supply chains, construction, and what is still open — see Why?.
TRL figures below are estimates for building blocks (NASA/EU-style 1–9 scale), not regulator-certified scores.
| Technology | Est. TRL | Notes / heritage |
|---|---|---|
| SFR sodium primary systems | 8–9 | Decades of operation and R&D: EBR-II (US), Phénix / Superphénix (France), BN-600 / BN-800 (Russia); industrial Na chemistry and loop practice |
| Metallic U-Pu-Zr / U-TRU-Zr fuel | 7–8 | EBR-II / IFR metal-fuel campaigns; demonstrated high conductivity and passive feedback behaviour |
| HT9 ferritic–martensitic cladding | 7–8 | Proven SFR metal-fuel cladding path (e.g. FFTF / EBR-II-class experience) |
| ALIP / EM sodium pumps | 7–8 | Used and developed for liquid-metal service; no shaft seals into primary sodium |
| 316LN vessel and primary piping | 8–9 | Standard nuclear/process austenitic steel; plate, pipe, and weld practice at ~600 °C class |
| Alloy 709 HX tubes / tubesheet | 5–7 | Advanced austenitic (Fe-20Cr-25Ni) SFR candidate; ASME III-5 code-case path; helical internally finned coil at this duty is FOAK |
| Helical shell-and-tube HX (process) | 7–8 | Industrial helical / enhanced tube HX practice; gas-side fins and swirl inserts are conventional |
| Acoustic leak detection in Na | 5–7 | High-pressure gas into liquid Na has a distinct cavitation signature; Na–water SG ALD heritage exists; Na–N₂ plant application is FOAK |
| Fast N₂ isolation / blowdown | 4–6 | Millisecond header valves and a dump tank are industrial components; nuclear-grade actuation and fail-safe logic for this plant are open work |
| Na→N₂ primary HX in an SFR plant | 4–6 | Single-wall helical industrial tubes; nuclear Na–N₂ coupling at this plant scale is FOAK engineering |
| Modular prefabricated vessel sectors | 5–7 | Prefabrication and high-integrity welding (e.g. EBW/LVEB candidates) exist industrially; nuclear modular SFR assembly is project-specific |
| Integrated modular SFR FOAK | 4–5 | Full plant integration, licensing, and demonstration remain open work |
Many historical SFRs used an intermediate sodium loop and water/steam generators — partly for sodium–water chemistry risk, partly for radioactivity isolation, thermal buffering, and other plant reasons. Intermediate loops also add inventory, cost, and leak paths.
This concept explores:
Open work is integration, qualification, and licensing — not inventing a new coolant class.
| Parameter | Target |
|---|---|
| Reactor type | Modular sodium fast reactor |
| Thermal power | 720 MWth |
| Electrical class | ~300 MWe (docs pin; screening ~327 MWe if stretch HX/cycle assumptions hold) |
| Net cycle efficiency (target) | ~45% (recuperated, intercooled N₂ Brayton) |
| Net cycle efficiency (screening) | ~45.4% (stretch envelope, not FOAK guarantee) |
| Primary pressure | near atmospheric (~1 bar) |
| Hot sodium (order of) | ~600 °C |
| Fuel | metallic U-(TRU)-Zr; U-Pu-Zr bridge cores |
| Breeding intent | near iso-breeder (conversion ratio ~1) |
| Primary Na inventory | order of 60 m³ (analytical ~62.6 m³; HX + vessel dominate; compact vs large pool SFRs, not “below 50”) |
| Primary heater | External hybrid helical single-wall Alloy 709 Na→N₂; fins + tape on N₂; ALD + isolation / blowdown |
Metallic fuel supports:
Iso-breeder operation is a design goal: produce roughly as much fissile material as is consumed, reducing dependence on continuous external enrichment for equilibrium cores. First cores would still need a fissile start-up inventory (bridge fuel, e.g. U-Pu-Zr from existing civilian Pu and depleted uranium) while pyroprocessing capacity for full U-TRU-Zr multi-recycle is built.
Primary sodium is intended to transfer heat to nitrogen in external Na–N₂ heaters on the starburst loops (ALIP remains on the cold leg). Because nitrogen is chemically inert toward sodium, a circulating intermediate sodium loop is not the FOAK baseline.
Each of the six modules is a hybrid helical coil of single-wall Alloy 709 tubes: N₂ in the internally finned + twisted-tape bore at ~80 bar; primary Na on the shell; one tubesheet. Duty is 120 MWth per module at a ~600 °C sodium inlet. A double-wall helium-watched tube was dropped as too complex to manufacture at this scale and as an extra thermal resistance. The 80 bar tube-rupture case is then a detection / isolation / relief problem — see safety.
That does not remove primary sodium from the heater shell (the HX remains a nuclear-grade component). A pumped secondary-Na loop plus a second HX remains the fallback if licensing will not accept primary Na on the gas heater. Immersing the N₂ bundle in the vessel is not part of this concept.
The concept aims for defense in depth: inherent physics, passive heat removal, and engineered barriers. Reactor physics provide strong inherent negative feedbacks that assist safety; they do not make meltdown “impossible” or remove the need for engineered shutdown, decay-heat removal, and licensing.
A simplified in-vessel handling concept (triangular fuel wedges and a single-axis hoist, rather than complex multi-axis in-sodium robotics) is planned as a way to reduce mechanical risk relative to some historical designs. It remains concept-level until engineered and demonstrated.