Radiation Safety Practice Exam

What is the total activity of thorium-232 in the thermal receiver with NSN 1240-01-074-8947?

1. 1.23E-3

2. 5.55E-3

3. 5.55E+3

4. 2.98E+2

The correct answer is: 5.55E-3

The total activity of thorium-232 in the thermal receiver referred to by its NSN can be calculated based on the decay properties and specific activity of thorium-232, which is a naturally occurring radioactive isotope. Thorium-232 has a specific activity of about 4.08 x 10^-12 Ci/gram, and its half-life is approximately 14 billion years, which makes it one of the most stable isotopes. In this context, the chosen answer indicates an appropriate value for the activity level, reflecting the necessary unit conversions and calculations that would be applied based on the mass of thorium-232 present in the thermal receiver. Answering with 5.55E-3 suggests an understanding of both the physical properties of thorium-232 and the context in which it is measured, such as the correct handling and reporting of radioactive materials to ensure safe practices in radiation safety operations. Understanding radioactive decay and the quantity of the isotope present allows for the determination of its activity in becquerels (Bq) or curies (Ci), critical for compliance with safety regulations and ensuring the monitoring of radiation exposure. The choice of 5.55E-3 reflects a moderate level of activity that aligns with typical values encountered in similar