Activation Calculations

Supporting the management of nuclear activation

Supporting the management of nuclear activation

Activation products are new isotopes that are generated from elements in materials by radiation that undergoes nuclear interactions within those elements. This process varies the composition of the material and generates heat, as well as generating radioactivity in what may be an otherwise stable material.

What are Activation Calculations?

Activation calculations are simulations of the nuclear interactions of radiation with material, with the aim of calculating the products of the activation process. Activation products can be undesirable, for example, resulting in radioactive waste, producing latent dose or material embrittlement. Or they can be desirable, for example, in the production of radionuclides for medical or industrial use, for transmutation of radioactive waste or for production of short-lived isotopes for research purposes.

Why are Activation Calculations Important?

Residual dose rates from radioactive activation products can be the most significant contributor to worker doses where operations take place in heavily shielded areas, but access is required to those areas during shutdown for configuration and maintenance, such as in an accelerator facility. Furthermore, activation of air within active areas and activation of soluble materials in bedrock beneath a facility can all result in pathways via which radioactive material can travel and internal dose can thus be accrued by members of the public. Activation calculations are therefore required to calculate dose accrual and demonstrate that it will be within legal limits as outlined by the appropriate regulatory framework.

Other negative impacts of activation include waste production; important for estimating the production rate and amounts of radioactive waste produced and developing strategies for dealing with the waste. This can include, amongst other items, structural apparatus, sacrificial shield layers, diagnostic components, concrete and in-cell coolants. Furthermore, items subject to significant amounts of activating radiation can suffer sufficient changes in composition such that their material properties change. Therefore, using activation calculations can help quantify all of these operational issues, outline maintenance schedules for replacement of key items and form a significant input to radioactive waste and decommissioning strategies.

Activation calculations can also be important when producing radioisotopes is intentional. With regards to research concerning transmutation of long-lived nuclear waste into shorter-lived isotopes, the yield and species of daughter isotopes can be estimated. Similarly, when considering intentional production of isotopes for medical or industrial uses, performing detailed calculations in an effort to improve understanding of how isotope yield changes with various parameters and understanding of what by-products are likely to be produced can greatly assist with design feasibility and risk mitigation.

TÜV SÜD's Services

TÜV SÜD can offer a range of serviced to support isotope production research, including:

  • Calculation of residual dose rates and residual isotope inventories – Simulations can also be used to estimate residual dose rates between operations and residual radioactive waste inventories from, for example, activated components and coolant.
  • Yield Optimisation – TÜV SÜD’s radiation physics team can perform calculations to assist with calculating optimal target enrichments and configurations and optimal beam patterns and beam energies.
  • Radioactive Waste Strategy and Decommissioning Planning - TÜV SÜD’s radwaste team can offer expert advice in all aspects of radioactive waste management strategy from minimising the production of waste to the development of waste management strategies.

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