Radiation-resistant Wi-Fi chip could enable wireless robots for nuclear decommissioning
2.4 GHz receiver withstands up to 500 kGy of radiation
A newly developed 2.4 GHz Wi-Fi receiver from Science Tokyo can survive radiation levels found inside nuclear reactors. With a radiation tolerance of up to 500 kGy, the chip allows robots used in nuclear plant decommissioning to be controlled wirelessly. Such receivers reduce the need for wired connections and can improve worker protection during decommissioning and cleanup operations at contaminated sites such as the Fukushima Daiichi Nuclear Power Plant.
Designing Wi-Fi for Extreme Radiation Conditions
When a nuclear plant reaches the end of its life or is damaged, it must be decommissioned. This process can take more than 20 years and includes decontamination, dismantling and handling radioactive materials so the site can be reused. According to the International Atomic Energy Agency, almost half of the 423 nuclear power reactors in operation today are expected to enter decommissioning by 2050.
During the cleanup of the Fukushima Daiichi Nuclear Power Plant, the use of robots in inaccessible areas expanded significantly. These robots have improved efficiency while reducing risks to workers. However, most robots are controlled through wired connections such as local area network cables, which limits how many robots can be used simultaneously and creates operational challenges such as cable management and navigating confined spaces.
Now, researchers from Institute of Science Tokyo (Science Tokyo), Japan, have developed a 2.4 GHz wireless fidelity (Wi-Fi) receiver chip that can withstand radiation doses of up to 500 kilograys (kGy), enabling wireless control of robots in the ultra-high-radiation environments encountered during nuclear decommissioning.
The study was led by graduate student Yasuto Narukiyo and Associate Professor Atsushi Shirane from the Institute of Innovative Research, Laboratory for Future Interdisciplinary Research of Science and Technology, Science Tokyo, along with Associate Professor Masaya Miyahara at the High Energy Accelerator Research Organization (KEK), Japan. The results will be presented at the 2026 IEEE International Solid-State Circuits Conference (ISSCC), to be held in San Francisco, USA, between February 15–19, 2026.
"Such tolerance addresses the requirements of nuclear power plant decommissioning, which involves exposure to intense gamma radiation emitted from fuel debris. Introducing such a wireless system eliminates the need for complex cabling and enables efficient and seamless operation of a large number of robots," says Shirane.
The receiver chip includes a low-noise amplifier to boost weak incoming signals, followed by a variable-gain amplifier to adjust signal strength. A radio frequency (RF) amplifier prepares the signal for direct conversion to baseband using a mixer, and a transimpedance amplifier then produces four baseband output channels for digital processing.
When electronic chips are exposed to intense gamma radiation, charges become trapped in insulating layers within transistors, which can cause electrical leakage, weaken signals, and increase noise.
To make the receiver more resistant to radiation, the researchers redesigned the chip to reduce the total number of transistors. Fewer transistors mean fewer areas where radiation can cause charge buildup and damage. In the variable-gain amplifier, a transistor normally used to control gain was replaced with an inductor, a passive component that is much less sensitive to radiation.
A similar change was made in the RF amplifier, where a radiation-sensitive P-type metal–oxide–semiconductor transistor was replaced with an inductor. The team also made the remaining transistors physically larger by increasing their length and width and reducing the number of parallel segments, known as "fingers." Radiation damage often creates leakage paths along the edges of transistors, and larger devices are less affected by these edge-related problems. With these strategies, the researchers successfully limited charge trapping, suppressed unwanted leakage currents, and kept the transistor performance stable under high radiation exposure.
In testing, after cumulative exposure to 500 kGy, the chip's signal gain decreased by only 1.4 decibels, its noise figure increased by at most 1.26 decibels, and its power consumption decreased slightly by about 2 milliwatts. Overall, its communication performance remained comparable to that of standard commercial Wi-Fi receivers.
"By realizing Wi-Fi chips that operate stably even under ultra-high-dose radiation environments, wireless remote operation using robots and drones will be promoted, enabling reductions in worker radiation exposure risk and advances in work sophistication," says Shirane.
Because this chip can handle much higher radiation than electronics usually face in space, it could also be useful for future space missions and other extreme radiation settings.
Reference
- Authors:
- Yasuto Narukiyo1, Sena Kato1, Kotaro Yanaka1, Yuya Takahashi1, Masaya Miyahara2, Jill Mayeda1, and Atsushi Shirane1*
*Corresponding author - Title:
- A 500kGy Radiation-Hardened 2.4GHz Wi-Fi Receiver for Innovative Nuclear Power Plant Decommissioning
- Journal:
- 2026 IEEE International Solid-State Circuits Conference (ISSCC)
- Affiliations:
- 1Institute of Innovative Research, Institute of Science Tokyo, Japan
2High Energy Accelerator Research Organization, Japan
Related articles
Further information
Associate Professor Atsushi Shirane
Institute of Integrated Research, Institute of Science Tokyo
Contact
Public Relations Division, Institute of Science Tokyo
- media@adm.isct.ac.jp
- Tel
- +81-3-5734-2975