Radiation Safety Practice Exam

Which isotope is found in the thermal receiver with NSN 1240-01-074-8947?

1. Uranium-235

2. Radium-226

3. Thorium-232

4. Cesium-137

The correct answer is: Thorium-232

The correct answer is Thorium-232. In thermal receivers, which are typically employed in various types of nuclear reactors or thermal radiological applications, Thorium-232 is often utilized due to its favorable properties in neutron absorption and its ability to be converted into fissile Uranium-233 under neutron bombardment. This characteristic makes it a key player in certain types of nuclear fuel cycles, particularly in research and some advanced reactor designs. When considering the alternatives, Uranium-235 is primarily used as fuel in nuclear reactors but is not typically associated with thermal receivers in this context. Radium-226 has historical significance in radiation applications but is not employed in modern thermal receiver technology. Cesium-137, while a common isotope in certain medical and industrial applications, does not have the same relevance or functional role in thermal receivers as Thorium-232 does. This distinction underscores the specific use of Thorium-232 in these particular devices.