Characteristics of the simulated workplace neutron fields using a 252Cf source surrounded with cylindrical moderators

Area of Science:

• Nuclear Physics
• Radiation Detection and Measurement
• Applied Health Physics

Background:

• Simulated neutron fields are crucial for calibrating radiation detection equipment and assessing workplace safety.
• Realistic neutron spectra are needed to accurately model radiation exposure in nuclear fuel fabrication environments.

Purpose of the Study:

• To establish simulated workplace neutron fields at the Japan Nuclear Cycle Development Institute (JNC).
• To characterize the neutron energy spectrum of these simulated fields.
• To validate the simulation's accuracy against experimental measurements.

Main Methods:

• Utilized a Californium-252 (252Cf) neutron source surrounded by polymethyl methacrylate and steel moderators.
• Employed MCNP-4B code for neutron transport calculations.
• Performed experimental measurements using a Bonner multisphere spectrometer and hydrogen-filled proportional counters.

Main Results:

• The established neutron fields provided realistic spectra comparable to those near MOX fuel fabrication glove-boxes.
• Calculated neutron spectra using MCNP-4B showed good agreement with experimental measurements.
• The experimental setup successfully characterized the neutron energy spectrum.

Conclusions:

• The developed simulated neutron fields are suitable for calibrating radiation monitoring instruments in nuclear facilities.
• The study validates the use of MCNP-4B simulations for characterizing neutron fields.
• These simulated fields enhance the accuracy of radiation safety assessments in MOX fuel fabrication.