To establish eligibility for compensation under this subpart, a claimant or eligible surviving beneficiary must establish each of the following:

(a) That the claimant was present onsite at any time during a period of atmospheric nuclear testing;

(b) That the claimant was a participant during that period in the atmospheric detonation of a nuclear device; and

(c) That after such participation, the claimant contracted a specified compensable disease as set forth in § 79.22(b).