SCINTILLA A European project for the development of scintillation detectors and new technologies for nuclear security

Europe monitors transits using radiation detectors to prevent illicit trafficking of nuclear materials. The SCINTILLA project aims to develop a toolbox of innovative technologies designed to address different usage cases. This article will review the scope, approach, results of the first benchmark campaign and future plans of the SCINTILLA project.Comment: To appear on the Proceedings of the 13th ICATPP Conference on Astroparticle, Particle, Space Physics and Detectors for Physics Applications, Villa Olmo (Como, Italy), 23--27 October, 2013, to be published by World Scientific (Singapore

Thermal hydraulic analysis of Alfred bayonet tube steam generator

The paper analyzes the performance of ALFRED steam generator from the thermal-hydraulic point of view highlighting the effect of some design features. The parameters object of the study are the regenerative heat transfer, the dimension of the inner tube and the length of the bayonet. The system code RELAP5-3D/2.4.2 has been chosen for the analysis. Sensitivities analysis allowed the determination of the different design parameters influence, here briefly summarized. The increase of regenerative heat transfer affects the efficiency of the steam generator through a degradation of the outlet steam quality: the number of bayonet tubes required to remove the nominal power increases with the increase of the global heat transfer coefficient of the inner tube. A higher inner diameter results in a larger surface area for the regenerative heat transfer and in a higher heat transfer coefficient in the annular region because of the reduction of the cross section. The result is an improvement of the performances of the steam generator thanks to the dimension reduction of the annular gap. Finally, if the height of the bayonet tube is reduced by 1 meter, the number of bayonet tubes required to remove the nominal power increases up to 20%

Sicurezza e sostenibilità dell’energia nucleare da fissione: reattori veloci refrigerati a piombo

L’impiego pacifico di energia nucleare, ad oggi basato sullo sfruttamento di neutroni termici e combustibile arricchito in Uranio-235 refrigerato ad acqua, ha ben risposto alla crescente domanda di energia elettrica cui assistiamo da alcuni decenni. Tuttavia, sebbene gli standard di sicurezza già raggiunti nel settore siano sicuramente i più elevati nel mondo industriale, con i reattori attualmente operanti, le riserve di combustibile attualmente conosciute e la quantità di rifiuti nucleari attualmente prodotta, la sostenibilità a lungo termine di questa fonte di energia, nel modo in cui oggi viene impiegata, è un qualcosa su cui riflettere. I reattori di “quarta generazione” potrebbero rappresentare la valida risposta alla richiesta di un’energia nucleare da fissione che sia più sostenibile. Fra questi, appare particolarmente promettente il reattore a neutroni veloci refrigerato a piombo liquido (LFR). La progettazione di un reattore LFR dimostrativo europeo (denominato “ALFRED”) è la sfida raccolta dal progetto europeo “LEADER”, coordinato da Ansaldo Nucleare S.p.A.. Il presente articolo riassume i vantaggi offerti dai reattori LFR, descrive il reattore ALFRED e mette in evidenza i temi su cui concentrare i futuri sforzi della ricerca internazionale

Status of Generation-IV Lead Fast Reactor Activities

Since 2012 the Lead-cooled Fast Reactor provisional System Steering Committee (LFR-pSSC) of the Generation IV International Forum (GIF) has developed a number of top level strategic activities with the aim to assist and support development of Lead-cooled Fast Reactor technology in member countries and entities. The current full members of the GIF-LFR-pSSC (i.e., signatories of the GIF LFR Memorandum of Understanding /MoU/) are: EURATOM, JAPAN, the RUSSIAN FEDERATION, and the REPUBLIC OF KOREA. The pSSC also benefits from the active participation of its observers: the UNITED STATES and the PEOPLE’S REPUBLIC OF CHINA. The paper highlights some of the main collaborative achievements of LFR-pSSC, including the development of the LFR System Research Plan, the LFR White Paper on Safety, the LFR System Safety Assessment paper as well as the LFR Safety Design Criteria paper. The paper then presents the status of the development of LFRs in the GIF member countries and entities. The collaboration among partners of the GIF-LFR-pSSC has proven its effectiveness in assisting the development of LFRs through an open, interactive and collegial environment, developing important synergies and exchange of both technical and strategic information

AP1000 Recovery Improvement After ADS Inadvertent Actuation

The AP1000® advanced Pressurized Water Reactor (PWR) is designed and developed by Westinghouse Electric Company. The AP1000® safety approach and design are such that the plant is capable to mitigate all the Design Basis Accidents (DBAs) relying only on passive safety systems with no AC power and no or very limited operator action. In addition to the passive features, the active systems within the AP1000 design are classified as non-safety related systems, coherently with the fact that they are not needed in an accident scenario and that the plant is surely safe also postulating their failure following a DBA. The high standard against which these active systems are designed and the margin in the design, make the systems realistically available following a DBA and, hence, they could be used to mitigate the accident and improve plant recovery after the accident. A demonstration on how the Normal Residual Heat Removal System (RNS), an active non-safety related system, could be used to mitigate a DBA is given in this paper. The selected accident is the inadvertent actuation of the Automatic Depressurization System (ADS) initially occurring with the plant operating at full power. Relap5 is a computer code well adapted to analyzing this event. Relap5 simulations of the accident, performed on a suitable detailed model of the AP1000® developed in Ansaldo Nucleare S.p.A., demonstrate that RNS can actually be used to reduce the impact of this accident on the containment, hence improving plant recovery after the accident

Development of Safety Design Criteria for the Lead-cooled Fast Reactor

The Lead-cooled Fast Reactor (LFR) provisional System Steering Committee (pSSC) of the Generation-IV International Forum (GIF) has proposed a set of Safety Design Criteria (SDC) dedicated to LFRs. The objective of the LFR SDC is to prescribe a set of reference criteria for the design of LFR systems, structures, and components with the aim of achieving the safety goals of the Generation-IV reactor system. The LFR SDC has been derived from the already existing Safety Design Criteria for the Sodium-cooled Fast Reactor (SFR), since the GIF LFR and SFR systems share a number of characteristics, design features and some corresponding safety-related phenomenology. For the development of the LFR SDC it was also found useful to use the same structure and methodology of the GIF SFR SDC. A set of reference safety design criteria for LFRs is systematically and comprehensively laid out in the SDC to facilitate the development, safety assessment and licensing of LFRs, including BREST-OD-300, ALFRED, SSTAR, SVBR-100, CLEAR-I, and MYRRHA. The paper summarises results of the steps taken to draft the present set of LFR SDC and provides outlook for further review and development activities, in particular towards individual sets of detailed Safety Design Guidelines. Naval Postgraduate Schoo

Status of Generation-IV Lead Fast Reactor Activities

Since 2012 the Lead-cooled Fast Reactor provisional System Steering Committee (LFR-pSSC) of the Generation IV International Forum (GIF) has developed a number of top level strategic activities with the aim to assist and support development of Lead-cooled Fast Reactor technology in member countries and entities. The current full members of the GIF-LFR-pSSC (i.e., signatories of the GIF LFR Memorandum of Understanding /MoU/) are: EURATOM, JAPAN, the RUSSIAN FEDERATION, and the REPUBLIC OF KOREA. The pSSC also benefits from the active participation of its observers: the UNITED STATES and the PEOPLE’S REPUBLIC OF CHINA. The paper highlights some of the main collaborative achievements of LFR- pSSC, including the development of the LFR System Research Plan, the LFR White Paper on Safety, the LFR System Safety Assessment paper as well as the LFR Safety Design Criteria paper. The paper then presents the status of the development of LFRs in the GIF member countries and entities. The collaboration among partners of the GIF-LFR-pSSC has proven its effectiveness in assisting the development of LFRs through an open, interactive and collegial environment, developing important synergies and exchange of both technical and strategic information

Coarse-mesh thermal-hydraulics and neutronics coupling for the ALFRED reactor

Among the six advanced reactor systems identified by the Generation IV International Forum, the lead fast reactor (LFR) has been considered as one of the most promising future nuclear power plants. Among the LFR designs, Ansaldo Nucleare, as coordinator of the Lead-cooled European Advanced DEmonstration Reactor project, proposes Advanced Lead Fast Reactor European Demonstrator (ALFRED) as LFR demonstrator, which is the study object of the present paper. A multiphysics model for the ALFRED core is developed and presented in this paper, which couples neutronics and thermal hydraulics. The first physics is solved with neutron transport Monte Carlo simulations, while temperatures and the lead density are updated with coarse-mesh-based finite volume method CFD runs. The proposed model focuses on the adoption of spatially non-uniform temperature distributions of materials to compute better on-the-fly estimations of nuclides cross sections and thence a more accurate neutron physics description