[en] The AFRRI TRIGA reactor was used to simulate nuclear weapon mixed-field radiation injuries with and without additional tissue trauma. The severity of reactor-produced mixed-field radiations over that of γ-photon irradiation was evaluated in mice. Lethal doses (LDs) to 50% of groups of mice were determined for marrow cell (LD_50/30, the dose required to kill 50% of the subjects within 30 days) and intestinal cell (LD_50/6, the dose required to kill 50% of the subjects within 6 days) injury. As neutron (n) proportions in the total (t) radiation dose (D_n/D_t) increased LD values decreased. Relative biological effectiveness (RBE) values for reactor-generated D_n/D_t used ⁶⁰Co γ photons and 250-kVp x-rays as reference standards. RBEs for irradiated mice increased as D_n/D_t increased and was further increased by wound trauma. Compared to γ-photon irradiation, mixed-field irradiation delayed wound closure times 25% to 50%. WR-151327 (200 mg/kg), a radioprotective chemical, injected i.p. into mice prior to either radiation quality alone or into combined injured mice increased 30-day survival and reduced susceptibility to challenge with Klebsiella pneumoniae. Protection against irradiation and resistance to bacterial challenge afforded by the WR compound was greater for γ-photon irradiation than for mixed-field irradiation. The TRIGA reactor can be used to simulate nuclear radiation-induced situations that include traumas or infections. Countermeasures for increasing survival after mixed-field irradiation may be more difficult than for γ-photon irradiated casualties. (authors)