Gamma irradiation-induced defects in borosilicate glasses for high-level radioactive waste immobilisation

Gamma irradiation-induced defects at doses of 0.5 and 5 MGy were studied in lithium sodium-borosilicate (LiNaBSi) and sodium barium-borosilicate (NaBaBSi) glasses, used for high-level radioactive waste immobilisation in the UK and India, respectively. X-band electron paramagnetic resonance (EPR), Raman and UV-Vis-nIR spectroscopies were used to characterise the glasses before and after irradiation. EPR and UV-Vis-nIR absorption spectroscopies revealed the formation of boron-oxygen hole centres (BOHC), electrons trapped at alkali cations or ET centres and peroxy-radicals (PORs) as defects common to both glasses. In addition, E− or polaron centres were observed in NaBaBSi glasses, possibly related to formation of elemental sodium colloids. Time-dependent thermal annealing at a range of temperatures, including those relevant to canister centreline cooling (CCC), which may be of relevance to geological disposal in future technical assessments, was carried out to study thermal stability of these radiation-induced defects. It was observed that PORs are the most thermally-stable defects in both glasses. The influence of glass composition on the segregation of sodium; possible formation of metal colloids upon irradiation has been discussed

The TRANSCEND University Consortium : integrated waste management

TRANSCEND (Transformative Science and Engineering for Nuclear Decommissioning) is a collaborative research consortium comprising 11 universities and 8 industry partners. The £9.4 million research program, funded primarily by the Engineering and Physical Sciences (EPSRC) Research Council of the UK, incorporates >40 projects in total, which will address some of the key challenges within the areas of nuclear decommissioning and waste management; including mobilization, processing, packaging, storage, transport and final disposal. This paper will outline a summary of the current progress and impact of Theme 1 - Integrated Waste Management. This theme focuses on underpinning science and engineering in areas of relevance to hazard reduction and decommissioning, where the three key work package objectives are: (1) New materials and methods for effluent decontamination; (2) Modelling and experiments for understanding pond and silo sludge/slurry behavior; (3) Innovative wasteform materials. In total, this theme has 15 different projects, delivered through both postdoctoral and PhD researchers, all with specific industry supervision from our partners, led by the NNL. The following provides a review of the project summaries to date, and their critical impact

Resurgence of a Nation’s Radiation Science Driven by Its Nuclear Industry Needs

From MDPI via Jisc Publications RouterHistory: accepted 2021-10-26, pub-electronic 2021-11-23Publication status: PublishedThis article describes the radiation facilities and associated sample preparation, management, and analysis equipment currently in place at the Dalton Cumbrian Facility, a facility which opened in 2011 to support the UK’s nuclear industry. Examples of measurements performed using these facilities are presented to illustrate their versatility and the breadth of research they make possible. Results are presented from research which furthers our understanding of radiation damage to polymeric materials, radiolytic yield of gaseous products in situations relevant to nuclear materials, radiation chemistry in light water reactor cooling systems, material chemistry relevant to immobilization of nuclear waste, and radiation-induced corrosion of fuel cladding elements. Applications of radiation chemistry relevant to health care are also described. Research concerning the mechanisms of radioprotection by dietary carotenoids is reported. An ongoing open-labware project to develop a suite of modular sample handling components suited to radiation research is described, as is the development of a new neutron source able to provide directional beams of neutrons

Geopolymers from fly ash and their gamma irradiation

In order to assess the suitability of geopolymers produced from fly ash for use in nuclear waste encapsulation, their behaviour when exposed to gamma radiation has been examined. Irradiation (400 KGy at 4 kGy/h) was found to have had minimal effect on the porosity of bulk samples. Radiolytic hydrogen production from the pore water exhibited a dose rate effect (9 kGy/h up to 280 kGy and 24 kGy/h up to 700 kGy). An effect of surface area was observed with a decrease in hydrogen production corresponding to a decrease in surface area; the effect of pore chemistry was not ruled out.</p