Nuclear radiation environments widely exist in nuclear power plants, nuclear fuel cycle facilities, radioactive waste repositories, nuclear technology application devices, nuclear emergency sites, space radiation zones and high-energy physics laboratories. Primary ionizing radiation includes gamma rays, X-rays, neutrons and charged particles, inducing Total Ionizing Dose (TID), Displacement Damage (DD) and Single Event Effects (SEE). These cause semiconductor parameter drift, functional failure, insulation aging and dielectric degradation, leading to permanent circuit damage. High‑voltage power supplies serve as core power units for nuclear monitoring instruments, robotic systems, control platforms and detection equipment, delivering stable high‑voltage power to radiation detectors, servo mechanisms, communication terminals and emergency safety systems. Their TID resistance, long-term stability and environmental adaptability directly determine nuclear facility operational safety, emergency response effectiveness, experimental reliability and personnel protection. Nuclear radiation imposes extreme technical challenges beyond conventional industrial standards: 1. Long-term operation under extreme total ionizing dose. Normal nuclear plant environments feature dose rates of 10 rad(Si)/h to 1,000 rad(Si)/h, accumulating 1 Mrad(Si) to 10 Mrad(Si) over service life. Emergency and high-energy physics scenarios exceed 10 krad(Si)/h with short-term total doses reaching tens of Mrad(Si). Commercial components suffer severe drift above 10 krad(Si) and failure beyond 50 krad(Si). Power supplies must withstand up to 10 Mrad(Si) with negligible performance drift and no permanent degradation. 2. Full-spectrum radiation damage mitigation. Gamma rays, neutrons and charged particles induce TID (threshold shift, leakage increase, gain reduction), DD (lattice damage, carrier lifetime decay) and SEE (logic upset, latch-up, burnout). Designs must counter all three mechanisms simultaneously. 3. Radiation insulation aging protection under high voltage. Operating voltages range from hundreds to tens of kilovolts. Ionizing radiation decomposes dielectric molecular structures, increases leakage current and accelerates aging via ozone and free radicals, risking partial discharge, arcing and breakdown. Insulation must maintain stability under maximum accumulated dose. 4. Ultra-high reliability with multi-layer redundancy. Nuclear safety systems require uninterrupted operation with MTBF ≥ 1×10⁵ hours and design life ≥ 20 years. Full redundancy and autonomous recovery are mandatory for unattended radiation-exposed facilities. 5. Combined extreme environmental adaptability. Radiation zones often feature elevated temperatures up to 100 ℃+, high humidity, corrosive hydrogen/sulfide gases and strong vibration. Power supplies must support wide-temperature stability, corrosion resistance, explosion-proof construction and mechanical ruggedness. 6. Ultra-low noise and high-precision output. Nuclear detectors measure nano‑ to micro‑volt weak signals; switching noise degrades signal-to-noise ratio and measurement accuracy. Output stability must exceed ±0.5% with ripple below 0.1%. 7. Nuclear safety compliant protection. Non-bypassable safety interlocks for overvoltage, overcurrent, short circuit, overtemperature, insulation degradation and arcing must integrate seamlessly with nuclear facility safety protocols. This methodology establishes a comprehensive framework covering radiation-hardened topology design, component-level radiation tolerance, circuit-level effect suppression, system shielding, radiation-resistant insulation and long-term reliability optimization. It supports up to 10 Mrad(Si) environments and provides standardized guidelines for nuclear-grade high‑voltage power supply development. Adopting all-solid soft-switch topology + full radiation hardening + graded fault-tolerant redundancy, supplemented by radiation-compatible insulation and nuclear safety protection, the framework eliminates traditional weaknesses such as rapid drift, frequent failure and short service life under heavy radiation. Eight core design principles are defined: 1. Radiation-optimized power topology. Prefer simple low-component soft-switch architectures: flyback/forward for medium power, full-bridge LLC resonant for high power. Soft-switch operation minimizes sensitivity to MOSFET threshold drift and on-resistance shift under TID. Modular construction enables isolated radiation-hardened power stages with N+1 redundancy. Mixed analog-digital control places critical regulation and protection in radiation-tolerant analog circuits; digital sections handle only monitoring and configuration to reduce SEE exposure. Symmetrical voltage-doubling rectifiers reduce transformer stress with SiC diodes and radiation-hardened high-voltage film capacitors. 2. Component-level radiation hardness assurance. All semiconductors adopt radiation-qualified parts with ≥2× dose derating. Wide-bandgap SiC/GaN devices provide superior TID and DD immunity over silicon. Select MOSFETs/JFETs resistant to neutron displacement damage; avoid vulnerable bipolar devices unless specially hardened. Digital ICs feature high SEE immunity with latch-up LET threshold ≥80 MeV·cm²/mg and inherent latch-up reset capability. Passive components eliminate electrolytic/tantalum capacitors; employ ceramic, polyester film and mica capacitors with ≤10% capacity drift under full dose. Resistors use metal-film or wirewound types; magnetic cores adopt radiation-stable nanocrystalline alloys. Insulation materials include polyimide, PTFE, ceramic and radiation-hardened epoxy. All components undergo radiation screening, thermal cycling and burn-in to eliminate early failure. 3. Circuit-level radiation effect suppression and compensation. Implement adaptive bias compensation to counter TID-induced threshold drift, leakage increase and gain decay. Triple Modular Redundancy (TMR) and ECC correct single-event upsets in critical logic and memory. Fast current-limiting and auto-reset circuits eliminate destructive latch-up within 1 μs. High-impedance differential designs suppress radiation-induced leakage; aggressive component derating reduces operational stress. Dual redundant critical control, drive and protection circuits ensure fail-safe operation even with partial radiation failure. Redundant radiation-hardened auxiliary power supplies maintain stable internal biasing. 4. System-level radiation shielding architecture. Multi-layer shielding integrates high-Z materials (lead/tungsten alloy) for gamma attenuation and hydrogen-rich boron-doped composites for neutron moderation/absorption. Monte Carlo simulation optimizes shielding thickness to reduce internal dose below 50% of component limits. Three-tier shielding: overall enclosure → module shielding → localized component shielding eliminates radiation penetration through seams via tongue-and-groove construction, shielded feedthrough connectors and labyrinth ventilation. Internal layout positions sensitive control circuits behind high-voltage metal structures for additional shadow shielding. 5. Radiation-resistant high-voltage insulation design. Insulation systems exclusively employ long-term radiation-stable dielectrics with ≥3× breakdown margin. Fully voidless solid insulation via vacuum epoxy potting eliminates partial discharge caused by radiation-ionized air gaps in transformers and high-voltage modules. Electric field optimization using grading electrodes and functionally graded insulation suppresses localized stress and corona discharge. Real-time insulation monitoring tracks insulation resistance, leakage current and partial discharge with predictive aging diagnostics and automatic safety shutdown. 6. Long-term reliability with full-layer redundancy. Four-tier redundancy covers component, circuit, module and system levels: parallel critical devices, dual control paths, N+1 power modules and full active/standby system hot swap with 1 ms seamless switchover. Autonomous recovery corrects SEU logic errors via watchdog/ECC and resumes normal operation after transient electrical faults. AI-powered health management continuously monitors dose accumulation, thermal parameters, insulation status and aging trends for lifetime prediction and early maintenance alerts. Full radiation and thermal aging validation ensures ≥20-year service life. 7. Extreme environmental compatibility and nuclear safety protection. Wide-temperature construction supports −40 ℃ to +125 ℃ with fully sealed IP67 housing using corrosion-resistant stainless steel/titanium. Explosion-proof Ex d/Ex ia design complies with GB 3836 for combustible gas environments. Non-bypassable hardware safety interlocks with<1 μs response integrate with nuclear safety emergency systems. Full EMI suppression via soft-switch resonance and multi-stage filtering ensures ultra-low interference for precision radiation detectors with output stability ±0.5% and ripple <0.1%. 8. Hierarchical radiation qualification verification. Component-level TID, neutron and SEE characterization establishes radiation parameter databases. Circuit-level simulation and irradiation testing validate drift tolerance and hardening effectiveness. System-level cobalt source and neutron chamber full-dose irradiation verifies total dose survivability alongside thermal cycling and long-term aging durability. This framework fundamentally solves excessive drift, premature failure and short lifespan under heavy nuclear radiation. It achieves full tolerance up to 10 Mrad(Si) with comprehensive TID/DD/SEE mitigation, radiation-stable high-voltage insulation and multi-layer redundancy supporting over 20 years of safe unattended operation. Widely applicable to nuclear power facilities, radioactive waste management, emergency response equipment, high-energy physics experiments and space nuclear power systems, it delivers core technical support for nuclear safety and advanced nuclear technology applications.