How to file VA radiation exposure (Atomic Veterans) claim — 21 presumptive cancers

5-step Schema.org HowTo for ~250K Atomic Veterans (most 80-95 years old). 38 CFR 3.309(d) framework: PRESUMPTIVE service connection for 21 specific cancers when veteran participated in qualifying radiation-risk activity (Hiroshima/Nagasaki occupation, Pacific atmospheric tests, continental nuclear tests, Eniwetok cleanup, uranium mining/processing, Three Mile Island). DTRA dose reconstruction (free) for non-presumptive cases under 38 CFR 3.311. Surviving spouses + children qualify for DIC + CHAMPVA + DEA. NAAV (National Association of Atomic Veterans) advocacy. Atomic Veterans Service Recognition Act 2022 (Congressional Gold Medal).