The damaged reactors and melted nuclear fuel of the Fukushima Daiichi nuclear power plant present an extremely intense radiation environment. Decommissioning project members are estimating that the maximum radiation intensity around the melted reactors and melted nuclear fuel is 1000 Sv/h. Since humans cannot approach the region, robots must take the lead in decommissioning operations. Such robots need semiconductor devices for operations. However, such devices are exceptionally vulnerable to radiation. Therefore, a radiation-hardened optically reconfigurable gate array (ORGA) has under development Although the ORGA is also constructed using the same radiation-vulnerable semiconductor technology as that used in currently available radiation-hardened devices, ORGAs use a holographic memory technology to increase the radiation tolerance of semiconductor device components. The soft-error tolerance has been confirmed using an americium alpha particle radiation source (Am-241) as 181 times higher than Artix-7 FPGAs using a high-speed optical scrubbing operation.