/
ReCore-Power is the energy-conversion part of the ReCore engineering concept: a closed Brayton cycle with pure nitrogen (N₂) as the working fluid, coupled to the 720 MWth reactor class with an electrical class of about 300 MWe at a ~45% net efficiency target.
The main motivation is architectural: explore a power island without a water Rankine steam generator and the Na–H₂O reaction risk that has driven many intermediate-loop SFR layouts. Dry or low-water heat rejection is also of interest. That choice is part of the same first-principles Why? — simpler secondary chemistry where possible, industrial hardware classes, and constructability — while accepting that integrated nuclear Na–N₂ plant maturity is still low (see TRL table). Cycle efficiency is prioritised over minimising primary sodium inventory when the two conflict.
TRL figures are estimates for power-conversion building blocks.
| Technology | Est. TRL | Notes / heritage |
|---|---|---|
| Closed-cycle gas turbines (industrial) | 8–9 | Commercial closed gas plants: Ravensburg air plant (1950s, GHH); Oberhausen-Sterkrade helium cogeneration (1970s) — long operating hours |
| Recuperated / intercooled Brayton architecture | 7–8 | Standard thermodynamic plant practice; effectiveness and ΔP are design choices, not new physics |
| Nitrogen as working fluid | 6–8 | N₂ is abundant and industrially handled; pure closed-N₂ nuclear plants are less common than air/steam, but fluid properties are well known |
| Inventory control for load following | 6–7 | Established idea for closed Brayton plants (vary mass, hold temperatures); needs plant-specific tanks and control design |
| Helical recuperator / precooler (gas duty) | 6–8 | Industrial gas HX practice; high-ε advanced (e.g. AM complex helical) recup/precooler/intercooler is the ambitious goal path |
| Na→N₂ heat source interface | 4–6 | External hybrid helical single-wall Alloy 709 heater: fins + tape on N₂; primary Na shell-side — not AM on the Na boundary |
| ALD + fast N₂ isolation / blowdown | 4–6 | Acoustic detection of gas-into-Na plus millisecond header valves; plant-specific qualification is open work |
| Integrated nuclear Na–N₂ Brayton plant | 3–5 | Full FOAK: turbomachinery + nuclear heat source + control + licensing as one system |
At concept level the cycle is:
Target net efficiency is on the order of 45% (docs plant class → ~300 MWe on 720 MWth). First-principles screening with optimistic but non-fantasy component assumptions currently shows about 45.4% / ~327 MWe — a stretch envelope, not a guaranteed FOAK rating. Real net η depends on turbine inlet temperature, recuperator effectiveness, pressure ratio, gas-side ΔP, and turbomachinery maps. Hitting the target is preferred over cutting primary sodium inventory with unproven Na-side HX concepts.
Heat-exchanger split (concept): advanced 3D-printed / complex helical gas exchangers are intended for the recuperator, precooler, and intercoolers (where high ε and low ΔP dominate cycle η). Gyroids / TPMS are not used on the sodium boundary — gas-side ΔP on a closed Brayton is too expensive. The primary Na→N₂ heater is a nuclear-grade hybrid helical shell-and-tube in single-wall Alloy 709: N₂ in the bore with internal fins + twisted tape; primary sodium on the shell. An 80 bar tube breach is intended to be caught by acoustic leak detection and fast module isolation / blowdown, not a helium-watched second wall. A circulating secondary-Na loop is a fallback, not the baseline.
Closed gas cycles can vary electrical output by changing the inventory (mass) of gas in the loop while holding temperatures relatively steady. That is a known control approach for closed Brayton plants and is potentially well suited to supporting variable renewables — if control, economics, and nuclear coupling are demonstrated.
Rejected heat from precoolers / intercoolers can feed district heating or low-to-medium temperature industrial uses where siting allows. Combined heat-and-power figures sometimes quoted above electrical-only efficiency are site- and demand-dependent, not universal plant ratings.
Closed-cycle gas turbines are not speculative. European industrial examples include closed-cycle plants such as the Ravensburg air plant (1950s) and the Oberhausen-Sterkrade helium cogeneration plant (1970s). ReCore-Power borrows that closed-loop philosophy while selecting nitrogen for sodium compatibility and resource availability.
| Feature | Steam Rankine + intermediate Na | N₂ closed Brayton (concept) |
|---|---|---|
| Working fluid | Water / steam | Nitrogen |
| Intermediate Na loop | Often used | Explored as optional / eliminable — still needs full justification |
| Na–water reaction | Design driver at steam generators | Not applicable on N₂ power side; other Na risks remain |
| Load following | Thermal / steam-side limited | Inventory control option (to be demonstrated) |
| Maturity of full Na–N₂ SFR plant | Steam path is historically common | FOAK integration (see TRL table) |