Purpose of experiment

A nuclear reactor in operation is a source of a mixed neutron and gamma field, a shut-down nuclear reactor is a source of a gamma field. The purpose of the exercise is the measurement of the gamma field intensity in the vicinity of the fuel elements in the reactor core and in locations outside the reactor core, during reactor operation and in shutdown conditions. The fraction of the delayed gamma field magnitude vs. the total (composed of prompt and delayed gamma rays) during reactor operation is estimated by measurements following a rapid reactor shutdown (SCRAM).

Outcome / What you will learn
Students will:

  1. learn about prompt and delayed gamma radiation
  2. become familiar with miniature ionization chambers
  3. characterize gamma field intensity distribution inside the reactor core and in ex-core locations
  4. estimate the fraction of the delayed gamma field magnitude during reactor operation.
Execution
After discussion on the physical background and the experimental setup, students:

  1. measure the ionization chamber leakage current and background
  2. measure the ionization chamber current dependence on the reactor power (0 – 250 kW)
  3. characterize gamma field intensity distribution inside the reactor core and in ex-core locations
  4. measure gamma field intensity after a rapid reactor shutdown (SCRAM) and estimate the delayed gamma field magnitude fraction during reactor operation.
Exercise No. 8: In-core neutron flux mapping
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