A non-destructive method to determine the neutron production rate of a sample of spent nuclear fuel under standard controlled area conditions

A method to determine the neutron production rate of a sample of spent nuclear fuel by means of non-destructive analysis conducted under controlled-area conditions is described, validated and demonstrated. A standard neutron well-counter designed for routine nuclear safeguards applications is applied. 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 the SCK CEN. The sample transfer and measurement procedures are described together with results of Monte Carlo simulations. Experiments with radionuclide sources were carried out at the Joint Research Centre to test the procedures and to determine the performance characteristics of the detection device. Finally, measurements of a segment of a spent nuclear fuel rod were carried out at the SCK CEN to validate and demonstrate the method.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

An absolute measurement of the neutron production rate of a spent nuclear fuel sample used for depletion code validation

A 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. A neutron well counter designed for routine nuclear safeguards applications is applied. 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. 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. 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. Results of these measurements were used to study the performance of depletion codes, i.e., ALEPH2, SCALE, and Serpent2. The study includes a code-to-code and code-to-experiment comparison using different nuclear data libraries

PA26 is a candidate gene for heterotaxia in humans: identification of a novel PA26-related gene family in human and mouse

Heterotaxia is an aetiologically heterogeneous condition caused by an abnormal left-right axis formation, resulting in reversed left-right polarity of one or more organ systems. In a patient with heterotaxia and a de novo reciprocal translocation t(6;18)(q21;q21), we found that the PA26 gene was disrupted by the 6q21 breakpoint. Northern blot analysis showed decreased expression of the PA26 gene in an Epstein-Barr virus-transformed cell line of this patient. During early embryogenesis of Xenopus, the orthologue of PA26, XPA26 is exclusively expressed in the notochord, a midline structure. This further supports a possible role of PA26 in human situs determination. Mutation analysis of human PA26 gene in 40 unrelated individuals with unexplained heterotaxia failed to identify mutations, indicating that PA26 mutations are not a frequent cause of heterotaxia in humans. Analysis of the PA26 gene structure resulted in the identification of a novel PA26-related gene family, which we have named the sestrin family, and which comprises three closely related genes in human and in mouse

Author Correction: A human immune dysregulation syndrome characterized by severe hyperinflammation with a homozygous nonsense Roquin-1 mutation (Nature Communications, (2019), 10, 1, (4779), 10.1038/s41467-019-12704-6)

The original version of the Supplementary Information associated with this Article included an incorrect Supplementary Information file, in which only the first page of the file was included. The HTML has been updated to include a corrected and complete version of the Supplementary Information file