N11: Radiation Shielding

This unit aims to:

Introduce the subject of radiation shielding and illustrate solutions to the particle transport equation in the context of Monte Carlo and deterministic transport codes. Simple shielding methods will be compared with sophisticated complex calculations in order to familiarise students with the essential concepts. As well as the core material, the course has four external lecturers who are experts in their respective fields. The use of Monte Carlo and Deterministic Codes will be presented in the context of industry needs and requirements. Shielding applications and the shielding design process will be discussed. Intensive training into the use of the Monte Carlo code MCNP will be provided.

Brief description of the unit

The unit will have nine lectures, four of which will be presented by key experts from respective parts of the nuclear shielding community. The module has a practical component which allows experimental validation of the initial Monte Carlo simulation codes for neutron and gamma radiation fields. The post course assignment extends the simulation work to look at more advanced problems.

  • Radiological Protection Principles
  • ICRP recommendations. Methods of dose control, limitation, ALARP. Current limits and constraints.
  • The Particle Transport Equation
  • Simple derivation, physical meaning of terms, simple solutions (exponential attenuation, infinite hydrogenous system)
  • An introduction to MCNP & Validation
  • A description of the Monte Carlo code MCNP, how to use it and the choice of cross-section data.
  • Simple Shielding Methods
  • Hand calculations including Point sources, line sources, surface sources, infinite sources etc, solid angle fall-off. Attenuation curves, exponential attenuation, source strengths. Simple Codes, Point kernel, principles, limitations and buildup.
  • Monte Carlo Simulation
  • Review of methods available. Monte Carlo, deterministic.  Understanding of theory behind each. Particular issues with gammas and neutrons, secondary gammas etc. Advantages and disadvantages. Overview of underlying statistics, acceleration techniques, nuclear data, some classic examples illustrating strengths and weaknesses
  • Use of Monte Carlo Codes
  • Example codes e.g. MCBEND, MCNP awareness of strengths and weaknesses.
  • Use of Deterministic Codes
  • 1,2 and 3-D. Modelling techniques , nuclear data, some classic examples illustrating strengths and weaknesses. Attila, EVENT
  • The shielding design process
  • Basics of designing shielding to achieve dose targets and to be ALARP
  • Applications of shielding codes
  • Illustration of shielding in real life. Concrete structures, penetrations, scatter…why ALARP etc.

Intended Learning Outcomes

Understand the particle transport equation and the methodologies used to solve it.  
Understand and be able to evaluate a shielding scenario using simple shielding methods (hand calculations).  
Understand the concept of Monte Carlo and Deterministic methods and how they are applied to radiation shielding calculations  
Understand the systematic process that must be followed to design shielding to adequately protect those working with ionising radiation.  
Understand how the range of shielding solutions is consistent with common principles of radiation physics and radiological protection.  
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