Ammonium perchlorate composite propellant (APCP) reload modules and high power rocket motors shall be stored in what type of container?

The correct choice pertains to the specific nature of ammonium perchlorate composite propellant (APCP) and its storage requirements. APCP is considered a composite propellant that includes an oxidizer, ammonium perchlorate, and a fuel binder, which can be hazardous. Thus, it requires careful handling and storage practices that minimize risk.

The focus on "reasonably safe storage for non-explosive flammable material" highlights the fact that while APCP is classified under the category of explosive materials, the storage practices are aligned with keeping it in a state where risks are mitigated, particularly concerning ignition and fire hazards. Containers must be capable of preventing accidental ignition and minimizing risks associated with their volatile components, addressing safety for individuals and the environment.

In contrast, other options would not suitably minimize risks associated with the storage of APCP. For instance, a container meant strictly for explosives offers more than what is necessary given the potential volatility of APCP, whereas the sealed container under pressure might vastly limit safe access and could potentially increase risks associated with pressure buildup. An open container fails to provide any meaningful protection against environmental influences and increases the potential for accidents by giving unrestricted access, which is impractical for hazardous materials like APCP.

Thus, selecting