Application of MCBEND to PBMR shielding analysis

Area of Science:

• Nuclear Engineering
• Radiation Shielding

Background:

• Pebble Bed Modular Reactors (PBMR) represent an advanced nuclear reactor design.
• Shielding analysis is critical for ensuring the safety and integrity of reactor components.

Purpose of the Study:

• To conduct a shielding analysis of an early Pebble Bed Modular Reactor (PBMR) design.
• To evaluate potential damage and activation of the core barrel and reactor pressure vessel (RPV).
• To assess boron burn-up in the control layer beneath the core.

Main Methods:

• Utilized the Monte Carlo code MCBEND for primary shielding calculations.
• Addressed complexities below the core, including the de-fuelling chute, requiring multiplication considerations.
• Employed a combination of MCBEND and the criticality code MONK in depletion mode for boron burn-up analysis.

Main Results:

• Quantified damage and activation levels for the core barrel, RPV, top plate, and bottom plate.
• Investigated the impact of the de-fuelling chute on shielding effectiveness below the core.
• Successfully analyzed boron burn-up, a critical aspect for control layer performance.

Conclusions:

• MCBEND is a suitable tool for PBMR shielding analysis, especially in complex regions.
• The study provides crucial data for the design and safety assessment of PBMRs.
• Boron burn-up analysis using MCBEND and MONK is feasible and essential for reactor operation.