In that work the total emission rate including the contribution of (α,n) neutrons and neutron multiplication by neutron induced fission is determined. (2020).Īn absolute measurement of the neutron emission rate of a SNF segment is desribed by Perret et al. A detailed description of the experimental procedures and conditions is reported in Schillebeeckx et al. The experiments were carried out at the Laboratory for High and Medium level Activity (LHMA) of SCK CEN, the Belgian nuclear research centre. In this work an absolute measurement of the production rate of prompt fission neutrons by a SNF segment is presented. More extensive discussions on the use of these data are given in Romojaro (2023) and Ilas and Burns (2022). Most of the data originate from measurements at the calorimeter installed at Clab, the Swedish Interim Storage Facility ( SKB, 2006 Murphy and Gauld, 2010). Data obtained by NDA are rather scarce and limited to the measurement of the decay power by calorimetry ( McKinnon et al., 1986 Maeda et al., 2004 SKB, 2006 Murphy and Gauld, 2010). At present, such data are primarily based on a combination of destructive chemical and radiochemical analysis methods ( OECD NEA, 2016 Michel-Sendis et al., 2017), involving various steps starting with the dissolution of the sampled material, affecting the final uncertainty of the results ( OECD NEA, 2011). Both the validation and estimation of confidence limits require high quality experimental data. The results of model calculations need to be validated and realistic confidence limits have to be determined ( Rochman et al., 2023 Seidl et al., 2023). Such an inventory, also referred to as source term, and an evaluation of its evolution over the next thousands of years can only be estimated by model calculations combined with results of non-destructive assay (NDA) to verify/validate the calculations. In addition, these quantities are determined by a complex inventory of nuclides with strong varying characteristics ( Žerovnik et al., 2018). Most of these observables are hard to measure directly, in particular in an operational and industrial context. Similar concerns drive the knowledge of the inventory of other nuclides (e.g., 14C, 36Cl, 79Se, 94Nb, 99Tc, 129I, 226Ra, 237Np) for the long-term safety assessment of disposal facilities. From operational safety perspectives, several quantities are to be known ( Broadhead et al., 1995 Gauld and Ryman, 2001 Hu et al., 2016 Govers et al., 2019): the neutron and γ-ray emission rates and spectra are of interest for radiation protection, the decay heat rate is required for SNF thermal performance and ageing assessment and the inventory of fissile nuclides is one of the main drivers for criticality safety considerations and nuclear safeguards. The study includes a code-to-code and code-to-experiment comparison using different nuclear data libraries.Ĭharacterisation of spent nuclear fuel (SNF) is essential for the back-end of the fuel cycle to support a safe, secure, ecologic and economic handling, transport, storage and disposal of SNF. Results of these measurements were used to study the performance of depletion codes, i.e., ALEPH2, SCALE, and Serpent2. Measurements of a segment of a spent nuclear fuel rod were carried out at SCK CEN resulting in an absolute and non-destructive measurement of the neutron production rate avoiding any reference to a representative spent nuclear fuel sample to calibrate the device. Experiments with 252Cf(sf) sources, certified for their neutron emission rate, were carried out at the Joint Research Centre to determine the characteristics of the detection device. The method relies on a transfer procedure that is adapted to the hot cell facilities at the Laboratory for High and Medium level Activity of SCK CEN in Belgium. A neutron well counter designed for routine nuclear safeguards applications is applied. 4European Commission, Joint Research Centre (JRC), Ispra, ItalyĪ method to determine the neutron production rate of a spent nuclear fuel segment sample by means of non-destructive assay conducted under standard controlled-area conditions is described and demonstrated.3Jožef Stefan Institute (JSI), Ljubljana, Slovenia.2Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium.1European Commission, Joint Research Centre (JRC), Geel, Belgium.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |