Customs and Border Protection Border Patrol Agent (CBP BPA) Practice Exam 2025 – Comprehensive All-in-One Guide for Exam Success

The selection of uranium and plutonium as the materials needed to build a nuclear device is based on their unique properties as fissile materials. Fissile materials are capable of sustaining a nuclear fission reaction, which is the process utilized in nuclear weapons.

Uranium-235, a naturally occurring isotope of uranium, can undergo fission when it absorbs a neutron, releasing a significant amount of energy in the form of an explosion. Similarly, plutonium-239, which is not found in nature but is produced in nuclear reactors from uranium-238, also has the ability to sustain a rapid chain reaction, making it suitable for use in nuclear devices.

The other options do not contain elements that can facilitate a nuclear fission reaction. Gold and silver, lead and copper, as well as iron and nickel are stable elements that do not have the necessary nuclear properties for initiating a fission chain reaction, thereby excluding them from being viable materials for building a nuclear device.