Pre-purchase and technical reference for IAS nuclear air purification products. Answers to the most common questions from procurement engineers, facility managers, and project teams worldwide.
A systematic, side-by-side comparison of the two test methods that dominate qualification and surveillance of nuclear-grade activated carbon: the non-radioactive cyclohexane method of DIN 3754, and the radioactive methyl iodide method of ANSI/ASME N509, ANSI N510 and ASTM D3803, referenced by U.S. NRC Regulatory Guide 1.52.
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Version 1.0 · July 2026 · Also archived on Zenodo — DOI 10.5281/zenodo.21119531
Nuclear-grade activated carbon adsorbers are the primary engineered barrier against the release of radioactive organic iodine species — principally methyl iodide labeled with iodine-131 (CH3131I) — from nuclear power plant ventilation systems, hospital nuclear-medicine exhaust, radiochemical laboratory exhaust, and emergency air-cleaning systems.
The paper compares the two methods across test conditions, underlying adsorption chemistry, regulatory acceptance, and the specific failure modes each method can and cannot detect — and concludes that the two methods are complementary rather than interchangeable. A plain-language summary lives on our cyclohexane vs. methyl iodide explainer page.
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