The first subcritical experiment was originally scheduled for June 1996, during the final stages of the CTB Treaty negotiations. DOE postponed it at the last minute, however, claiming that more time was needed to assess the environmental implications of such experiments. (See ACT, July 1996.)
The subcritical experiments remain controversial. Some critics have argued that the experiments will undermine the CTB Treaty because they will be perceived by some as an attempt by the United States to qualitatively improve its nuclear arsenal contrary to the spirit of the treaty. Other critics have argued that because they will be conducted underground at the Nevada Test Site, the experiments will complicate future verification efforts by establishing the precedent for continuing activities at former test sites. DOE has maintained, however, that the experiments are consistent with the CTB Treaty because they are not nuclear explosions and the treaty permits continued activities at former test sites.