Search

The geopolymer catalyst supports utilized in the nuclear waste containers for the Fukushima Daiichi Nuclear Power Station will be required to have high porosity and durability. This work presents the synthesis of a potassium and metakaolin‐based geopolymer and its performance upon dehydration. During water content measurements of the samples, it was seen that in the demolded samples, the water content quickly decreased to less than 30% within 7 days, while the samples that had the cap removed from the container retained more than 50% of the water after 28 days. The pore size distribution of the samples that were post‐cured at different temperatures up to 28 days did not vary greatly with respect to the average pore size. We can infer that structurally stable pores were formed in the first 4 days and were not affected by the post‐curing rate, which may be related to rheological properties and the drainage path of water or hydrogen gas during post‐curing. [ABSTRACT FROM AUTHOR]

Current fission-based methods of 99Mo production require single use uranium targets which leads to spent uranium waste. This waste could be reduced if a target is developed that does not require dissolution so that it can be reused for multiple production runs. MCNP6.2 was used to model reusable targets of 20% and 1% enrichment for activity produced, target efficiency and burnup. The 1% enriched target was found to be much more efficient but had a lower activity produced compared to the 20% enriched target. The ideal target design for 99Mo production that optimises efficiency and reusability and reduces the self-shielding effect of UO 2 was found to be a target that is made from 1% enriched UO 2 with density as high as allowable for sufficient yields, efficient 99Mo extraction and having an irradiation time of 5 days, with the target able to be re-irradiated and re-processed 2–4 times. • Current fission based manufacturing of 99Mo using uranium targets is based on target destruction. • Target destruction leads to increased radioactive waste volumes. • MCNP6 modelling of uranium targets show that higher density targets have more self-shielding effects and are less efficient. • Low density uranium targets with 5 days irradiation maximise 99Mo output and minimising radioactive waste. [ABSTRACT FROM AUTHOR]