[en] The Office for Nuclear Regulation is an independent nuclear regulatory authority in the UK, who regulates nuclear safety, security, safeguard and conventional health and safety at licensed nuclear sites in Great Britain. This includes regulation on the existing fleet of operating reactors, fuel cycle facilities, waste management and decommissioning sites, licensed defense sites, new nuclear facilities as well as the transport of civil nuclear and radioactive materials. This paper elaborates ONR's key regulatory milestones and deliverables during the period from April 1^st of 2018 to March 31^st of 2019, and summarizes its regulatory approach and measures adopted by the British nuclear safety regulatory authorities to carry out all kinds of supervision, so as to further strengthen the nuclear safety cooperation between UK and China and to enlighten the nuclear safety regulation in China. (authors)

[en] Highlights: • Thermal performance of coiled tube type molten salt steam generator was reported. • Coiled tube included three regions as liquid, vapor-liquid and superheat steam region. • Thermal efficiency had maximum at optimal salt temperature or water flow rate. • Thermal efficiency of present system was higher than 90% at optimal conditions. • Molten salt forced convection can reduce thermal efficiency for more heat loss. -- Abstract: Heat transfer performance of coiled tube type molten salt steam generator has been experimentally reported, and the wall temperature distribution, steam generation rate and thermal efficiency were comprehensively investigated. Heat transfer of the system was mainly determined by two phase flow inside coiled tube and molten salt convection outside tube. The coiled tube can be divided into three regions as liquid phase region, vapor-liquid two phase region and superheat steam region, and the wall temperature in two phase region first decreased for nucleate boiling with high heat transfer coefficient and then increased. When molten salt temperature increased, overall heat transfer coefficient and thermal efficiency first increased, and then dropped due to heat transfer deterioration for superheat steam and high heat loss. According to present experimental system, overall heat transfer coefficient had maximum of 290 W/m² K at optimal molten salt temperature of 340 °C, while thermal efficiency approached to its maximum at molten salt temperature of 320 °C. When inlet water flow rate was increased, the superheat gradually decreased with the wall temperature dropping, and the overall heat transfer coefficient, steam generation rate and thermal efficiency first increased and then decreased. Moreover, molten salt forced convection can remarkably improve overall heat transfer coefficient.

[en] Background: The application of gamma ray spectroscopy on the classification for the sedimentary rocks is helpful to solve the problem of small classification and the long cycle for chemical analysis of the sedimentary rocks. Purpose: This study aims to introduce a method of determining the content of natural radionuclides K, U, Th in the well drilling debris with the low background gamma ray spectroscopy for dipartition among dark gray ash mudstone, dark grey calcareous mudstone and grey calcareous mudstone. Methods: Count rates of K, U, Th in the energy ranges of 1.37-1.56 MeV, 1.66-1.86 MeV and 2.41-2.81 MeV were selected to represent the intensity of radioactivity of K, U, Th. The fisher discriminant criterion was applied to measured count rates of various samples for classification of sedimentary rocks using the Statistical Product and Service Solutions (SPSS) software. Results: According to the count rate of K, U, Th and total count rate of the three mudstones carry out the discriminant analysis of rock lithology by using SPSS software, the accuracy rate reached 100%, 76.47% and 60%, respectively. Conclusion: Gamma ray spectrometry method is of great significance for the division of sedimentary rocks in small class. It could be used to completely identify the dark gray mudstone and the identification effect for dark grey calcareous mudstone, and grey calcareous mudstone is good, but not distinguish them completely. (authors)

[en] Possessed with advantageous optoelectronic properties, perovskites have boosted the rapid development of solution-processed solar cells. The performance of perovskite solar cells (PSCs) is significantly weakened by the carrier loss at grain boundary grooves (GBGs); however, it receives limited attention and there lacks effective approach to solve this issue. Herein, for the first time, we constructed the tungstate/perovskite heterointerface via a "two step" in situ reaction approach that provides effective defect passivation and ensures efficient carrier dynamics at the GBGs. The exposed perovskite at grain boundaries is converted to wide-band-gap PbWO${}_4$ via an in-situ reaction between Pb${}^{2+}$ and tungstate ions, which passivate defects due to the strong ionic bonding. Moreover, recombination loss is further suppressed via the heterointerface energetics modification based on an additional transformation from PbWO${}_4$ to CaWO${}_4$. PSCs based on this groove modification strategy showed good universality in both normal and inverted structure, with an improved efficiency of 23.25 % in the n-i-p device and 23.33 % in the p-i-n device. Stable power output of the modified device could maintain 91.7 % after around 1100 h, and the device efficiency could retain 92.5 % after aging in air for around 2110 h, and 93.1 % after aging at 85 °C in N${}_2$ for 972 h. (© 2023 Wiley‐VCH GmbH)

[en] Special attention should be devoted to the thermal stability of hybrid perovskite solar cells (PSCs), because they are often operated at elevated temperatures. However, effective strategies are lacking for manipulation of heat flow in PSCs to improve their thermal stability. Here, a holistic solution is reported for the rapid removal of dissipated heat within the absorber by introducing hexagonal boron nitride (h-BN) inside and radiator fin outside of the device. This strategy significantly improves the thermal conductivity of perovskite and speeds up the heat transfer of device, which effectively reduces the cell temperature under illumination of simulated AM 1.5G standard spectrum by ≈6.5 °C. Regardless of device configurations, the corresponding PSCs exhibit prolonged lifetimes aged at different temperatures, continuously operated under white light-emitting diode (LED) lamp or full-spectrum illumination. Of particular note, the optimized h-BN/Cu device with n-i-p structure keeps 88% and 93% of its initial PCE after 1776 h of 85 °C thermal aging and 2451 h of maximum power point (MPP) tracking, respectively, and the device with p-i-n structure maintains 96% and 92% of its original PCE after 1704 h of 85 °C thermal aging and 2164 h of MPP tracking. (© 2022 Wiley‐VCH GmbH)