Correlated adatom trimer on metal surface: A continuous time quantum Monte Carlo study

The problem of three interacting Kondo impurities is solved within a numerically exact continuous time quantum Monte Carlo scheme. A suppression of the Kondo resonance by interatomic exchange interactions for different cluster geometries is investigated. It is shown that a drastic difference between the Heisenberg and Ising cases appears for antiferromagnetically coupled adatoms. The effects of magnetic frustrations in the adatom trimer are investigated, and possible connections with available experimental data are discussed.Comment: 4 pages, 4 figure

ОБРАЩЕНИЕ С ОСОБЫМИ РАДИОАКТИВНЫМИ ОТХОДАМИ: ПРОГРЕСС ПРАКТИЧЕСКОЙ ДЕЯТЕЛЬНОСТИ И АКТУАЛЬНЫЕ ЗАДАЧИ

The article covers methodological approaches for substantiating the assignment of radioactive wastes (RAO) to special radioactive wastes, as well as the results of its practical application within initial registration of RAO.Обсуждаются методологические подходы к обоснованию отнесения радиоактивных отходов к особым радиоактивным отходам и результаты их практического применения в ходе первичной регистрации РАО

Дозы облучения персонала и населения при нормальной эксплуатации пунктов захоронения радиоактивных отходов

This paper focuses on occupational and public exposure during operation of disposal facilities receiving liquid and solid radioactive waste of various classes and provides a comparative analysis of the relevant doses: actual and calculated at the design stage. Occupational and public exposure study presented in this paper covers normal operations of a radioactive waste disposal facility receiving waste. Results: Analysis of individual and collective occupational doses was performed based on data collected during operation of near-surface disposal facilities for short-lived intermediate-, lowand very low-level waste in France, as well as nearsurface disposal facilities for long-lived waste in Russia. Further analysis of occupational and public doses calculated at the design stage was completed covering a near-surface disposal facility in Belgium and deep disposal facilities in the United Kingdom and the Nizhne-Kansk rock massive (Russia). The results show that engineering and technical solutions enable almost complete elimination of internal occupational exposure, whereas external exposure doses would fall within the range of values typical for a basic nuclear facility. Conclusion: radioactive waste disposal facilities being developed, constructed and operated meet the safety requirements effective in the Russian Federation and consistent with relevant international recommendations. It has been found that individual occupational exposure doses commensurate with those received by personnel of similar facilities abroad. Furthermore, according to the forecasts, mean individual doses for personnel during radioactive waste disposal would be an order of magnitude lower than the dose limit of 20 mSv/year. As for the public exposure, during normal operation, potential impact is virtually impossible by delaminating boundaries of a nuclear facility sanitary protection zone inside which the disposal facility is located and can be solely attributed to the use of public roads during radioactive waste transportation to the disposal facility site. Цель работы – сравнительный анализ фактических и оцениваемых на этапе проектирования доз облучения персонала и населения при захоронении жидких радиоактивных отходов и твердых радиоактивных отходов различных классов. В рамках настоящей статьи рассматривается вариант облучения персонала и населения при нормальной эксплуатации пункта захоронения радиоактивных отходов в режиме размещения отходов. Результаты: выполнен анализ индивидуальных и коллективных доз облучения персонала при приповерхностном захоронении короткоживущих среднеактивных, низкоактивных и очень низкоактивных радиоактивных отходов во Франции, а также при приповерхностном захоронении долгоживущих радиоактивных отходов в России. Проведен анализ проектных оценок доз облучения персонала и населения для объекта приповерхностной изоляции радиоактивных отходов, планируемого к сооружению в Бельгии, а также проектируемых объектов глубинного захоронения в Великобритании и Нижнеканском массиве (Российская Федерация). Техническими и технологическими решениями удается практически полностью исключить внутреннее облучение персонала, а дозы внешнего облучения ограничить диапазоном, характерным и для базовых ядерных технологий. Заключение: планируемые к сооружению, сооружаемые и эксплуатируемые пункты захоронения удаляемых радиоактивных отходов соответствуют действующим в России требованиям безопасности, согласующимся с международными рекомендациями. Оценено, что индивидуальные дозы облучения персонала сопоставимы с данными контроля персонала аналогичных объектов в других странах. Средние индивидуальные дозы облучения персонала при захоронении радиоактивных отходов прогнозируются на порядок ниже установленного предела дозы – 20 мЗв/год. Воздействие на население при нормальной эксплуатации практически исключено установлением санитарно-защитной зоны объекта использования атомной энергии, на которой размещена установка по захоронению отходов, и возможно только при транспортировке радиоактивных отходов по дорогам общего пользования к месту расположения пункта захоронения радиоактивных отходов.

Self-Control of Traffic Lights and Vehicle Flows in Urban Road Networks

Based on fluid-dynamic and many-particle (car-following) simulations of traffic flows in (urban) networks, we study the problem of coordinating incompatible traffic flows at intersections. Inspired by the observation of self-organized oscillations of pedestrian flows at bottlenecks [D. Helbing and P. Moln\'ar, Phys. Eev. E 51 (1995) 4282--4286], we propose a self-organization approach to traffic light control. The problem can be treated as multi-agent problem with interactions between vehicles and traffic lights. Specifically, our approach assumes a priority-based control of traffic lights by the vehicle flows themselves, taking into account short-sighted anticipation of vehicle flows and platoons. The considered local interactions lead to emergent coordination patterns such as ``green waves'' and achieve an efficient, decentralized traffic light control. While the proposed self-control adapts flexibly to local flow conditions and often leads to non-cyclical switching patterns with changing service sequences of different traffic flows, an almost periodic service may evolve under certain conditions and suggests the existence of a spontaneous synchronization of traffic lights despite the varying delays due to variable vehicle queues and travel times. The self-organized traffic light control is based on an optimization and a stabilization rule, each of which performs poorly at high utilizations of the road network, while their proper combination reaches a superior performance. The result is a considerable reduction not only in the average travel times, but also of their variation. Similar control approaches could be applied to the coordination of logistic and production processes

MANAGEMENT OF SPECIAL RADIOACTIVE WASTES: PRACTICAL ADVANCES AND CURRENT CHALLENGES

The article covers methodological approaches for substantiating the assignment of radioactive wastes (RAO) to special radioactive wastes, as well as the results of its practical application within initial registration of RAO

Occupational and Public Exposure During Normal Operation of Radioactive Waste Disposal Facilities

This paper focuses on occupational and public exposure during operation of disposal facilities receiving liquid and solid radioactive waste of various classes and provides a comparative analysis of the relevant doses: actual and calculated at the design stage. Occupational and public exposure study presented in this paper covers normal operations of a radioactive waste disposal facility receiving waste. Results: Analysis of individual and collective occupational doses was performed based on data collected during operation of near-surface disposal facilities for short-lived intermediate-, lowand very low-level waste in France, as well as nearsurface disposal facilities for long-lived waste in Russia. Further analysis of occupational and public doses calculated at the design stage was completed covering a near-surface disposal facility in Belgium and deep disposal facilities in the United Kingdom and the Nizhne-Kansk rock massive (Russia). The results show that engineering and technical solutions enable almost complete elimination of internal occupational exposure, whereas external exposure doses would fall within the range of values typical for a basic nuclear facility. Conclusion: radioactive waste disposal facilities being developed, constructed and operated meet the safety requirements effective in the Russian Federation and consistent with relevant international recommendations. It has been found that individual occupational exposure doses commensurate with those received by personnel of similar facilities abroad. Furthermore, according to the forecasts, mean individual doses for personnel during radioactive waste disposal would be an order of magnitude lower than the dose limit of 20 mSv/year. As for the public exposure, during normal operation, potential impact is virtually impossible by delaminating boundaries of a nuclear facility sanitary protection zone inside which the disposal facility is located and can be solely attributed to the use of public roads during radioactive waste transportation to the disposal facility site