Alcohol may in fact make radiation poisoning worse. Though red wine specifically may give a slight boost that can be further improved by removing the alcohol entirely.
according to this study:
Consumption of dealcoholised red wine significantly decreased the gamma radiation-induced DNA damage at 1 and 2 h post-consumption by 20%. In contrast alcohol tended to increase radiation-induced genome damage and complete wine protected against radiation-induced genome damage relative to alcohol. The observed effects were only weakly correlated with the concentration of total plasma catechin (R = −0.23).
This study was extremely small though.
Another study looking at the effects of resveratrol, which is belived to be the compound in red wine responsible for the protective effect.
Our aim was to evaluate the radioprotective efficacy, in vitro, of trans-resveratrol against radiation-induced chromosomal damage and to study the genotoxicity and cytotoxicity of this polyphenol in cell cultures without irradiation. The study was carried out by the pre-treatment of human lymphocytes at concentrations from 0 to 219 μM of trans-resveratrol. The results showed that all concentrations tested reduced radiation-induced chromosomal damage compared with cells with any treatment. Maximum damage protection was observed at the concentration of 2.19 μM.
This study used 2Gy of gamma radiation.