Purple Hydrogen is a nuclear-derived low-carbon hydrogen produced using nuclear radiation or high-temperature nuclear heat rather than conventional electricity-only electrolysis. The most distinctive pathway is radiolysis, where ionizing radiation directly splits water molecules into hydrogen and oxygen.
Because nuclear energy provides continuous, zero-carbon baseload power, Purple Hydrogen offers one of the most stable and lowest-emission hydrogen production routes available. It is especially suited for large industrial clusters requiring uninterrupted hydrogen supply over long operating lifetimes.
Hydrogen Production Pathways
Nuclear Radiolysis (Primary Method)
H₂O + radiation → H₂ + O₂ + radicals
Ionizing radiation (gamma rays or neutrons) directly dissociates water molecules without electricity conversion losses.
Radiolysis can utilize reactor coolant water, spent fuel pools, or dedicated radiation chambers, producing ultra-high-purity hydrogen inside or adjacent to nuclear facilities.
Nuclear Heat-Assisted Thermochemical Cycles
High-temperature reactor heat (700–950°C) is used in advanced cycles such as:
Sulfur–Iodine (S-I) cycle
Copper–Chlorine (Cu-Cl) cycle
Hybrid Nuclear Systems
Radiolysis combined with electrolysis or nuclear heat with electrical input to optimize efficiency and scale.
Key Characteristics
Near-zero lifecycle CO₂ emissions
No fossil fuel feedstock or methane leakage
Ultra-high hydrogen purity
Continuous 24/7 baseload production
High gravimetric energy density (120–142 MJ/kg)
Very long asset lifetime (40–60 years)
Physical & Chemical Properties
| Property | Typical Value | Industrial Impact |
|---|---|---|
| Chemical Formula | H₂ | Clean energy carrier |
| Purity | 99.99–99.999% | Sensitive processes |
| Density (STP) | 0.0899 kg/m³ | Lightweight fuel |
| Boiling Point | −252.9°C | Cryogenic storage |
| Energy Content | 120–142 MJ/kg | High efficiency |
| Flammability Range | 4–75% (air) | Safety systems required |
| Auto-Ignition Temp. | ~585°C | Fire prevention |
Available Supply Forms
Compressed hydrogen gas (350–700 bar)
Liquid hydrogen (−253°C)
Bulk pipeline delivery
On-site nuclear-hydrogen systems co-located with reactors
Applications
Energy & Power: Hydrogen turbines, fuel cells, grid balancing
Heavy Industry: DRI steel, furnaces, cement, glass
Chemicals: Ammonia, methanol, synthetic fuels
Mobility: Heavy trucks, buses, rail, marine, aviation fuels
Aerospace: Rocket fuel, cryogenic propulsion
Research & Defense: Nuclear labs, semiconductor manufacturing
Comparison with Other Hydrogen Types
| Parameter | Grey | Blue | Pink | Purple | Green |
|---|---|---|---|---|---|
| Energy Source | Fossil | Fossil + CCUS | Nuclear electricity | Nuclear radiation/heat | Renewables |
| CO₂ Emissions | High | Low | Near zero | Near zero | Zero |
| Production Stability | High | High | Very high | Very high | Variable |
| Scalability | High | High | High | Very High | Medium–High |
Strategic Importance
Purple Hydrogen maximizes the value of nuclear assets by converting constant reactor output into clean hydrogen. It enables deep industrial decarbonization where renewable intermittency is a constraint, supports national energy security, and forms a strong foundation for hydrogen hubs and export infrastructure.