Plutonium, element 94, is a synthetic element, meaning it is man-made and not found in meaningful quantities in nature. Its cost is not determined by a public commodity exchange, but rather by the highly specialized context of its intended use and production method. The true cost of plutonium is a complex calculation tied to national security, massive infrastructure, and the physics of its different forms. Estimating its price involves accounting for the immense, multi-layered expenses incurred by the few governments and specialized laboratories that handle it. The final figure depends entirely on whether one is calculating the theoretical fuel value, the cost of production, or the price of a small, certified reference sample.
Estimating the Cost of Plutonium
The estimated cost for a kilogram of plutonium varies widely, reflecting accounting methodology rather than a true market price. Government transfer prices, such as those used by the U.S. Department of Energy (DOE) for internal transactions, provide the closest proxy for a bulk cost estimate. Historically, the value of weapon-grade plutonium (primarily Plutonium-239) has been estimated in a range from a few thousand dollars per gram to over $5,000 per gram, placing a kilogram’s value in the millions of dollars.
The DOE, for instance, once valued defense program plutonium at around $23 per gram in 1982, while new production was valued at over $200 per gram in the same year, illustrating the dramatic difference between existing inventory and new manufacturing costs. More recent estimates for small, certified reference materials of Plutonium-239 metal have been listed at approximately $10,990 per gram, or nearly $11 million per kilogram. These are laboratory-grade samples sold in milligram or gram quantities, and this high figure reflects the purity, certification, and specialized handling required for small-scale, non-bulk transfers. The theoretical fuel value of fissile plutonium, based on the equivalent energy of Uranium-235, was once estimated at around \(5,600 per kilogram, which is much lower than production or transfer costs.
The High Cost of Manufacturing Plutonium
Plutonium cannot be mined; its production is a complex industrial undertaking that begins inside a nuclear reactor. The primary method involves irradiating uranium fuel, specifically the abundant Uranium-238 isotope, with neutrons. This neutron capture process transforms the Uranium-238 into Uranium-239, which then quickly decays through two beta emissions, first into Neptunium-239 and finally into Plutonium-239.
The next and most expensive step is reprocessing, where the spent nuclear fuel rods are chemically separated. The rods contain a trace amount of plutonium mixed with highly radioactive fission products and the remaining uranium. This separation process requires massive, heavily shielded facilities, known as reprocessing plants, to protect personnel from the intense radioactivity. The infrastructure and specialized labor needed for this chemical extraction and purification drive the baseline cost of newly manufactured plutonium into the millions of dollars per kilogram. Reprocessing spent fuel, which yields only a small amount of plutonium, is a significant part of the overall production expense.
Why Different Plutonium Types Have Different Values
Plutonium is not a single product, and the cost difference between its isotopes is staggering, often separated by orders of magnitude. Plutonium-239 (\)\text{Pu-239}\() is the isotope used for nuclear weapons and as fuel in mixed oxide (MOX) reactors. Its value is relatively lower, as it is a byproduct of the conventional nuclear fuel cycle, even though its production is complex.
Plutonium-238 (\)\text{Pu-238}\(), by contrast, is far more expensive and is exclusively used in Radioisotope Thermoelectric Generators (RTGs) for deep space missions and other remote applications. This isotope is produced through a different, dedicated process, typically involving the neutron irradiation of Neptunium-237 (\)\text{Np-237}$) targets. Because \(\text{Pu-238}\) requires specialized facilities and different starting materials, its supply is extremely limited, making its cost significantly higher than \(\text{Pu-239}\).
The Significant Overhead of Handling Plutonium
Once manufactured, the costs associated with safely managing plutonium contribute greatly to its overall effective price. Plutonium’s toxicity and potential for misuse necessitate extreme physical security measures, including layers of safeguards and non-proliferation controls mandated by international bodies. These security costs are a fixed, high overhead that must be applied to every kilogram in inventory.
Storing plutonium requires specialized, environmentally controlled facilities to ensure long-term stability and prevent issues like radiolysis, which can generate hydrogen gas. The regulatory burden and the need for continuous monitoring, surveillance, and specialized transportation also add significantly to the final cost.