Patent Law and Nuclear Inventions
Expert Guidance from a Patent Attorney for Nuclear Inventions
The rapid advancement of nuclear physics and nuclear engineering has created groundbreaking opportunities in energy, medicine, and industry. At the same time, it has raised important questions about how such sensitive technologies can be protected under patent law. Innovators in nuclear science face a unique challenge: navigating a legal framework that balances technological progress, public safety, and international regulation.
Both the European Patent Office (EPO) and the United States Patent and Trademark Office (USPTO) recognize the importance of protecting nuclear inventions. However, the patentability of such technologies is shaped by strict legal provisions, particularly concerning public order, morality, and safety. While nuclear reactors, radiation shielding systems, isotope production methods, and diagnostic technologies can be patentable, nuclear explosives and technologies related to atomic weapons are explicitly excluded.
This article provides a comprehensive overview of the legal framework for patenting nuclear inventions in Europe and the U.S., with a focus on:
What makes a nuclear invention patentable under Article 52 EPC and its U.S. equivalents.
Exceptions to patentability under Article 53 EPC and related U.S. laws, including the Atomic Energy Act.
How the classification system (G21 Nuclear Physics; Nuclear Engineering) defines different categories of nuclear inventions.
The role of a patent attorney in guiding innovators through patent prosecution for complex nuclear technologies.
By exploring both the opportunities and limitations of patent law, this article aims to equip innovators, researchers, and businesses in the nuclear field with the knowledge necessary to protect their inventions and ensure compliance with international regulations.
European Patent Law and Nuclear Inventions
Patentable Subject Matter under Article 52 EPC
Article 52(1) EPC establishes the general principle:
European patents shall be granted for any inventions, in all fields of technology, provided that they are new, involve an inventive step and are susceptible of industrial application.
For nuclear inventions, this means that innovations in nuclear physics, nuclear engineering, and reactor design can indeed be patented, provided they meet the three key requirements:
Novelty – the invention must not be disclosed in prior art.
Inventive step – it cannot be obvious to a person skilled in the art.
Industrial applicability – it must be capable of practical use, e.g., energy generation, isotope production, radiation protection.
Article 52(2) EPC lists certain items that are not regarded as inventions (e.g., discoveries, scientific theories, mathematical methods, computer programs “as such”). However, many nuclear inventions that rely on advanced mathematical modeling, radiation simulations, or computer-controlled reactor systems may still be patentable if they provide a technical solution to a technical problem.
Exceptions to Patentability under Article 53 EPC
Nuclear inventions face additional scrutiny under Article 53 EPC, which excludes:
Article 53(a): ordre public and morality – inventions contrary to public safety or morality are not patentable. This directly excludes nuclear explosives, atomic bombs, and related technologies.
Article 53(b): biological exclusions – irrelevant for most nuclear inventions.
Article 53(c): medical methods – excludes methods of surgery, therapy, and diagnosis on the human or animal body. However, products (e.g., radiopharmaceutical isotopes or diagnostic compositions) remain patentable.
💡 Important case law clarification:
According to EPO Boards of Appeal, methods merely obtaining information (X-ray imaging, MRI, blood pressure monitoring) are not excluded under Art. 53(c). This means nuclear-based diagnostic technologies (e.g., PET imaging using radioactive tracers) can still qualify for patent protection.
Classification of Nuclear Inventions – IPC/CPC Codes (G21)
Nuclear inventions are systematically categorized under International Patent Classification (IPC) and Cooperative Patent Classification (CPC).
G21 – Nuclear Physics; Nuclear Engineering
G21C – Nuclear Reactors (fission reactors, hybrid reactors, reactor safety, cooling circuits, core design).
G21B – Fusion Reactors (controlled nuclear fusion, plasma confinement, thermonuclear technologies).
G21D – Nuclear Power Plants (conversion of nuclear heat into energy, control systems, coolant handling).
G21F – Protection Against Radiation (shielding, decontamination, radioactive waste treatment).
G21G – Conversion of Chemical Elements; Radioactive Sources (isotope production, radiopharmaceuticals, transmutation).
G21J – Nuclear Explosives (explicitly excluded from patentability under Art. 53 EPC).
🔎 Other relevant cross-references:
Medical diagnostics using radiation: A61B6/00.
Computer simulations of radiation fields: G06G7/54, G01T (radiation measurement).
Industrial applications of nuclear energy: e.g., E21B43/2403 (oil recovery using nuclear methods), C02F1/16 (water treatment using nuclear waste heat).
Patentable vs. Non-Patentable Nuclear Inventions (Examples)
| Patentable | Excluded |
|---|---|
| Nuclear reactor cooling system innovations | Nuclear explosives (Art. 53(a), G21J) |
| Advanced radiation shielding materials (G21F) | Pure scientific theories in nuclear physics (Art. 52(2)(a)) |
| Isotope separation methods for medical use (G21G) | Methods of surgery/therapy involving radiation (Art. 53(c)) |
| Reactor core monitoring systems (G21C) | Abstract simulations without technical effect (Art. 52(2)(c)) |
| Controlled nuclear fusion reactors (G21B) | Fusion bombs (uncontrolled reactions, G21J) |
Case Law on Nuclear Inventions and Patentability
The European Patent Office (EPO) has developed a rich body of case law that directly impacts the patentability of nuclear inventions and computer-implemented simulations relating to nuclear reactors. These decisions provide clarity on how the general provisions of Articles 52 and 53 EPC are interpreted in practice.
Computer-Implemented Simulations and Technical Character
The Enlarged Board of Appeal in G 1/19 examined whether computer-implemented simulations could be considered to have a technical effect, particularly when linked to the operation of technical systems such as nuclear reactors.
T 1227/05 (Circuit simulation) first established that simulations may constitute a technical purpose if they are functionally limited to a technical application.
T 625/11 (Nuclear reactor simulation) extended this principle to nuclear technology. The case involved a method for calculating limit values for reactor operation parameters (such as global power P). The Board accepted that such parameters, being intimately linked to reactor safety and operation, conferred technical character on the invention.
The Enlarged Board in G 1/19 confirmed that T 1227/05 and T 625/11 were correctly decided but emphasized that these were exceptional cases. According to the COMVIK approach, purely calculated results without clear technical application cannot normally establish patentability.
This means that nuclear reactor simulations may be patentable if the claimed invention produces results that are intrinsically technical and directly relevant to the safe or efficient operation of a reactor.
When Simulations Fail to Confer Technical Effect
Not all nuclear simulations meet the patentability threshold.
In T 2660/18, the invention concerned generating a test rod pattern design (fuel bundle configuration) for a nuclear reactor. Unlike in T 625/11, no parameter was identified that was directly and functionally linked to the reactor’s operation.
The Board found that the method’s output could be used for non-technical purposes (such as academic study), and therefore did not achieve a technical effect across the whole scope of the claim.
The decision clarified that data indicative of violated limits during a simulation does not automatically reflect the physical behaviour of a real system, unless narrowly defined and functionally tied to reactor operation.
This demonstrates the EPO’s strict stance: not all nuclear-related simulations are patentable—only those that contribute to solving a real technical problem in reactor design or safety.
Unpatentable Inventions Contradicting Physics
Case law also shows that inventions contradicting accepted physical laws are excluded for lack of industrial applicability.
In T 541/96, the claimed invention proposed inducing nuclear fusion between light and heavy unstable nuclei at low temperatures using an electric field.
The Board rejected the application, ruling that any invention incompatible with the laws of physics fails to meet Articles 57 (industrial applicability) and 83 EPC (sufficiency of disclosure).
Since such an invention could not be reproduced or used in industry, it was not patentable.
This principle is particularly important in the nuclear field, where many speculative claims (e.g., “cold fusion”) are made but lack verifiable technical basis.
Key Takeaways from EPO Case Law
Simulations can be patentable when the calculated parameters are intimately linked to reactor operation (T 625/11).
Not all simulations qualify—if results lack clear technical application, no technical effect is achieved (T 2660/18, G 1/19).
Inventions contrary to physics are unpatentable due to lack of industrial applicability (T 541/96).
The COMVIK approach applies strictly: only technical features contribute to inventive step, while purely abstract or theoretical aspects are ignored.
Case Law on Article 53(c) EPC: Nuclear Radiation and Medical Methods
Article 53(c) EPC excludes from patentability:
methods for treatment of the human or animal body by surgery or therapy, and
diagnostic methods practiced on the human or animal body.
However, products used in such methods remain patentable. The following cases illustrate how the Boards of Appeal have interpreted these exclusions in contexts involving irradiation, radiation therapy, and protective measures against radiation.
T 699/12 – Verification of Radiotherapy Treatment Devices
In T 699/12, the claimed invention related to a method of verifying a radiotherapy treatment device. The claim implied patient irradiation, but the Board held that the method itself only measured the output dose of the radiation source.
The intention was to verify the dose a patient should receive, but the method did not determine or control the actual treatment steps.
The Board concluded that the method concerned only the technical operation of the device, without a functional link to the treatment of the body.
Therefore, it did not fall under the exclusion of Art. 53(c) EPC.
T 1695/07 – Extracorporeal Blood Manipulation
In T 1695/07, the invention involved removing blood from a patient, circulating it extracorporeally, and reintroducing it into the patient.
The Board found this process constituted a method of treatment by surgery, since it posed substantial health risks (going beyond minor risks like tattooing or cosmetic treatments discussed in G 1/07).
It was therefore excluded from patentability under Art. 53(c) EPC.
T 944/15 – Monitoring Body Position During Radiation Treatment
The invention in T 944/15 described a data processing method for controlling a system that monitored a patient’s body position during radiation therapy.
The applicant argued it was a purely computer-implemented method.
The Board disagreed, holding that the teaching of the invention was not complete without steps of initiating monitoring and using the results in radiation treatment.
Thus, the claim effectively defined a method of treatment and was excluded.
Importantly, the Board ruled that protecting a computer program implementing such a method would amount to indirect protection of a therapeutic method, which is prohibited.
T 1077/93 – UV Radiation Protection for Human Skin
The invention concerned a composition intended to protect the skin against UV radiation and reduce damage such as erythema and “sunburn cells.”
The Board found that since the process included interaction with cellular mechanisms, it had a genuine therapeutic effect.
Attempts to reframe the invention as a “non-therapeutic process” could not avoid the exclusion.
Therefore, the method was excluded under Art. 53(c) EPC.
T 1758/15 – Collagen Filler for Radiation Therapy
In T 1758/15, the patent concerned a biocompatible injectable filler (e.g., collagen) inserted between tissues to reduce radiation exposure to sensitive organs during therapy.
The question was whether the filler was a “substance or composition” under Art. 54(5) EPC.
The Board ruled that the therapeutic effect came from the physical displacement of tissue, not from a chemical effect of the filler.
Thus, the filler was not a “substance or composition” in the legal sense, and its use could not establish novelty.
The commercially available collagen destroyed novelty of the claim.
Key Legal Insights from These Cases
Device verification vs. treatment methods – If a claim relates only to verifying or operating a device (T 699/12), it may be patentable. But if it is functionally linked to patient treatment, it risks exclusion (T 944/15).
Substantial health risk test – Processes involving invasive manipulation of the body (T 1695/07) are considered surgical methods, regardless of technical elegance.
Therapeutic vs. cosmetic effects – Where the process interacts with biological mechanisms to prevent or mitigate disease (T 1077/93), it is excluded as therapeutic.
Substance or composition test – For medical uses, patentability depends on whether the claimed effect is caused by a chemical entity or merely by physical structure (T 1758/15).
