A strategy was established to minimize the stochastic effects of internal and external exposure to radioactive substances by wearing respiratory protection equipment (RPE) during an emergency evacuation. During the evacuation of residents in the event of a nuclear power plant accident, the stochastic effects of internal exposure caused by the inhalation of radioactive aerosol and external exposure due to accumulated radioactive particles in the filter medium of a mask must be minimized. The radioactivity concentration along an evacuation route considers atmospheric dispersion and the resuspension of particles deposited on surfaces. The effective dose due to internal exposure is evaluated using inhalation dose coefficients for each particle diameter. When the face seal leakage and filter medium penetration ratio for each particle diameter of the RPE (N95) is taken into consideration, the internal dose is reduced by 97.2%. Furthermore, the accumulated radioactivity in the filter medium decreases by 91.4% when the respirator is replaced every 48 h.

Plastic scintillators, as a type of radioactive radiation detectors, have shown great potential in the field of nuclear radiation detection because of their well-studied scintillating property. Although much effort has been dedicated to developing plastic scintillators with high detection efficiency, materials with excellent monitoring performance are still needed. A covalent-integration strategy was implemented in the fabrication of a series of polyvinyltoluene (PVT) scintillators containing a polyfluorene-based conjugated polymer (CP) for the detection of radioactive nuclides of Sr-90 and C-14; the scintillators feature an excellent cascade energy transfer from beta radiation to the CP. To act as an antenna for β-radiation harvesting, the fluorescent dopant 2,5diphenyloxazole (PPO) was covalently introduced to the CP side chain. The PPO-functionalized CP was embedded in PVT to fabricate the polymer-blend scintillator, showing enhanced photomultiplier-detectable signal via efficient energy transfer. The cascade energy transfer, in which the β-radiation energy was absorbed by PVT and PPO and was finally transferred to CP, was successfully demonstrated. The scintillator showed a high detection efficiency of up to 50% under Sr-90 radiation, i.e., 30% higher efficiency than a PVT-containing simple mixture of CP and PPO, and it was also better than a conventional scintillator that contained PVT and PPO.

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