Introduction: Coatings for nuclear power plants — “Ordinary coatings — here — are unacceptable — because they mean — a nuclear — accident”
The coating on the inner wall of the nuclear power plant containment (Containment—the final physical barrier preventing radioactive material leakage) must not only withstand temperature/humidity under normal operating conditions, but also pass LOCA (Loss of Coolant Accident) simulation tests: under extreme conditions of >160°C/5 bar saturated steam/chemical spray (boric acid + NaOH)/radiation (>10⁶ Gy cumulative dose), the coating must not crack, peel, or generate debris (debris may clog the containment spray system and filtration system—consequence—catastrophic). At the same time, the coating surface must be “easily decontaminated”—radionuclides (Cs-137/Co-60) can be easily wiped and cleaned off, with residual <5%; it must not let the nuclear power plant become a "radiation source" that cannot be wiped clean.
Nuclear power protective coatings are specialized coatings designed specifically for the inner walls of nuclear power plant containment buildings and other nuclear-grade equipment—meeting two major nuclear-grade special requirements: LOCA accident simulation (>160°C/5bar—coating remains intact without cracking) and easy decontamination (radioactive nuclide residue 10⁶Gy), inorganic zinc (high-temperature resistant/LOCA), or polysiloxane (weather-resistant/decontaminable) systems—and complying with nuclear power coating standards such as ASTM D3911/D4082 and EJ/T 1086-2012.
FAQ
Q1: What exactly does the LOCA test measure—why is it the “life-or-death exam” for nuclear power coatings?LOCA simulation—inside containment—high-temperature steam pipe rupture—(>160°C saturated steam + 5bar pressure + chemical spray—boric acid/NaOH—+—radiation)”Coating—simultaneously—withstands—heat—/—moisture—/—pressure—/—chemical—/—radiation—five-fold—attack”After test—coating—must not:(1) peel—generate debris (clog—spray—system); (2) blister—(blisters—may—hide—radioactive—particles); (3) adhesion drop—(>5—MPa—retained). “LOCA—=—nuclear—power—coating’s—”college—entrance—exam””Fail—=—cannot—be—used—in—nuclear—power—plant”.
Q2: Decontamination performance — why is the decontamination rate of epoxy coatings lower than that of polysiloxane?Epoxy coating — surface contains polar groups (-OH/-NH2) “hydrophilic — water — hydrophilic — oil” radioactive nuclides (Cs⁺/Co²⁺ — ions) easily — adsorbed — embedded — surface — micro — pores “water — wipe — cannot — remove” decontamination — rate — > — 85-90% — (barely — qualified). Polysiloxane — Si-O-Si — surface energy — extremely — low — ( — 95-98% “poly — siloxane — = — preferred — topcoat — for — decontamination — of — nuclear — power — coatings”.
Summary
Nuclear power coatings — LOCA (>160°C/5 bar/chemical/radiation — coating integrity) + decontamination (radionuclide residue <5%) — two major nuclear-grade special requirements. Epoxy (general radiation resistance) / polysiloxane (optimal decontamination) are the main systems. Kexin New Materials provides nuclear power coating selection consultation.