State of the Art of Pyroprocessing Technology in Japan

AbstractMinor actinide recycling in a fuel cycle is a potential technology to minimize the environmental radioactivity burden in waste disposal in the fast reactor era after 2050. Pyroprocessing technology with metal electrorefining expects that no additional process is required to separate minor actinides and short- cooled fuels can be treated due to no-use of organic solvent that degrades by radiation. Pyroprocessing has been explored for metal fuel cycle and nitride fuel cycle in Japan. Metal fuel fast reactor, which can achieve a high breeding ratio over 1.3, and its fuel cycle is a compact system by integrating pyroprocessing. Oxide fuel can be also treated by converting to metals by reduction. Separation of transuranium elements from high level liquid waste originating from aqueous reprocessing has been challenged. Verification of the process and development of an engineering scale device are the current interests for study. In addition, irradiation study of metal fuel with minor actinides currently much advances from the point of fundamental investigation. Accelerator-driven system (ADS) for transmutation of minor actinides is integrated with pyroprocessing for recycling system. The denitriding at anode and azotizing at cathode together with electrorefining have been fundamentally studied by use of plutonium

Development of Transport Technologies for High-temperature Fluid in Pyrometallurgical Reprocessing

AbstractThe development of the engineering technology necessary for pyrometallurgical reprocessing is a key issue for industrial realization. The development of high-temperature transport technologies for molten salt and liquid cadmium is crucial for pyrometallurgical processing; however, there have been very few transport studies on high- temperature fluids. In CRIEPI, the transport technologies of molten salt and liquid cadmium have been developed for several types of transports methods. Based on the results of transport tests, engineering scale process equipments connected each other with the transport technology have been developed, and installed in the Ar atmosphere glove box for integrated tests

A Shock-Induced Pair of Superbubbles in the High-Redshift Powerful Radio Galaxy MRC 0406-244

We present new optical spectroscopy of the high-redshift powerful radio galaxy MRC 0406$-$244 at redshift of 2.429. We find that the two extensions toward NW and SE probed in the rest-frame ultraviolet image are heated mainly by the nonthermal continuum of the active galactic nucleus. However, each extension shows a shell-like morphology, suggesting that they are a pair of superbubbles induced by the superwind activity rather than by the interaction between the radio jet and the ambient gas clouds. If this is the case, the intense starburst responsible for the formation of superbubbles could occur $\sim 1 \times 10^9$ yr ago. On the other hand, the age of the radio jets may be of the order of $\sim 10^6$ yr, being much shorter than the starburst age. Therefore, the two events, i.e., the starburst and the radio-jet activities, are independent phenomena. However, their directions of the expanding motions could be governed by the rotational motion of the gaseous component in the host galaxy. This idea appears to explain the alignment effect of MRC 0406$-$244.Comment: 4 pages (emulateapj.sty), Fig. 1 (jpeg) + Fig.2 (eps). Accepted for publications in ApJ (Letters

Discovery of the First Low-Luminosity Quasar at z > 7

We report the discovery of a quasar at z = 7.07, which was selected from the deep multi-band imaging data collected by the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. This quasar, HSC J124353.93+010038.5, has an order of magnitude lower luminosity than do the other known quasars at z > 7. The rest-frame ultraviolet absolute magnitude is M1450 = -24.13 +/- 0.08 mag and the bolometric luminosity is Lbol = (1.4 +/- 0.1) x 10^{46} erg/s. Its spectrum in the optical to near-infrared shows strong emission lines, and shows evidence for a fast gas outflow, as the C IV line is blueshifted and there is indication of broad absorption lines. The Mg II-based black hole mass is Mbh = (3.3 +/- 2.0) x 10^8 Msun, thus indicating a moderate mass accretion rate with an Eddington ratio 0.34 +/- 0.20. It is the first z > 7 quasar with sub-Eddington accretion, besides being the third most distant quasar, known to date. The luminosity and black hole mass are comparable to, or even lower than, those measured for the majority of low-z quasars discovered by the Sloan Digital Sky Survey, and thus this quasar likely represents a z > 7 counterpart to quasars commonly observed in the low-z universe.Comment: Accepted for publication in ApJ Letter

The Hyper Suprime-Cam SSP survey: Overview and survey design

Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2-m Subaru telescope on the summit of Mauna Kea in Hawaii. A team of scientists from Japan, Taiwan, and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg2 in five broad bands (grizy), with a 5 σ point-source depth of r ≈ 26. The Deep layer covers a total of 26 deg2 in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg2). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey

Relationship between XBP1 genotype and personality traits assessed by TCI and NEO-FFI

There have been several researches on the role of personality in the pathophysiology of bipolar disorder. Recently, a polymorphism of XBP1, a pivotal gene in the endoplasmic reticulum (ER) stress response, was shown to contribute to the genetic risk factor for bipolar disorder. Therefore, in this study, we examined the relationship between the XBP1 gene polymorphism and the personality traits assessed by two self-rating scales, a shortened version of Temperament and Character Inventory (TCI) and NEO-Five Factor Inventory (NEO-FFI) in healthy subjects. The present results suggested that the XBP1 gene polymorphism was associated with the NEO-FFI score of neuroticism in female subjects. However, no significant differences in the other personality scale scores of both assessments were observed among normal subjects with -116C/C, C/G and G/G genotypes. Further investigations are necessary to examine the relationship in patients with bipolar disorder, or use full version of various self-rating personality assessments

Development of Pyro-processing Fuel Cycle Technology for Closing Actinide Cycle

Pyro-processing fuel cycle technology is a promising technological candidate to realize advanced fuel cycle with reduced burdens of proliferation risk and long life radioactive waste. CRIEPI have been studying pyro-processing and metal fuel technology since 1986 for obtaining basic properties, process chemistry and engineering technologies. In this century, CRIEPI and JRC-ITU have jointly demonstrated the recovery of MAs from both irradiated metal fuels and spent MOX fuels. Since 2009, accumulation of the design basics through tests with engineering-scale pyroprocessing equipment is carried out by CRIEPI. According to the results obtained in these studies, feasibility of pyroprocessing fuel cycle technology was evaluated through estimation of Technology Readiness Level and cycle cost based on the design study of fuel cycle facility of 40 tonHM/y throughput.JRC.E.5-Nuclear chemistr

Study of Molten Salt Electrorefining of U-Pu-Zr Alloy Fuel.

Abstract not availableJRC.E-Institute for Transuranium Elements (Karlsruhe

Airborne particle characterization during mechanical cutting operations of prototypic fuel debris simulants

International audienceThe general context of this article concerns the assessment of radioactive aerosols release risk during fuel debris (FD) retrieval operations at Fukushima Daiichi Nuclear Power Plant (1F). This assessment is crucial for ensuring the safety of workers and the wider public throughout the decommissioning efforts at the 1F facility.The Dust Acquisition (DA) project, led by CRIEPI and carried out as a subsidized project of Decommissioning, Contaminated Water and Treated Water Management, funded by METI, in collaboration with ONET, CEA, and IRSN, aims to evaluate the airborne release fraction (ARF) coefficient, a key metric reflecting the amount of radioactive material suspended in the air, particularly during the mechanical cutting of prototypic FD-simulants containing depleted uranium oxide.The experiments were undertaken by ONET/CEA/IRSN on a dedicated facility named FUJISAN2 located at CEA Cadarache. The generated particles underwent comprehensive sampling and characterization, including size distribution, morphology as well as mass and number concentration, using dedicated aerosol metrology devices.This article will present the experimental facility, including its aerosol instrumentation, the cutting sequences, and the methodology implemented to characterize aerosol physical properties and determine ARF coefficients, using gathered aerosol data measured by the different instruments.Comparative analyses are then presented in terms of particles mass concentration between the cutting trials on the different FD simulants, to understand the influence of the sample properties on particle generation