Sandro Sandri - Academia.edu (original) (raw)

Papers by Sandro Sandri

To assess the activated corrosion products (ACP) inventories in the primary cooling loop of the I... more To assess the activated corrosion products (ACP) inventories in the primary cooling loop of the ITER plant two operational scenarios are considered that have been studied in different approaches: the M5a and the BPP acp. Then external dose rates around the hot leg are calculated using the MCNP code and the resulting surface concentrations as source terms. A direct comparison

Symposium On Fusion Technology, 1998

... the ITER Primary Heat Transfer System Erik Kajlert3, Luigi Di Расеь, Sandro Sandrf, Didier Ta... more ... the ITER Primary Heat Transfer System Erik Kajlert3, Luigi Di Расеь, Sandro Sandrf, Didier Tarabellid aThe ... 1, F-13108 Saint Paul-lez-Durance, Cadarache, France Occupational dose assessments for the ITER ... NSSR-1", ENEA FUS TECN S+E TR 20/96 [2] Di Pace, L., Cepraga ...

The European Physical Journal Plus, 2021

Nuclear Fusion, 2019

The ITER Heating Neutral Beam (HNB) injectors, one of the tools necessary both to achieve burning... more The ITER Heating Neutral Beam (HNB) injectors, one of the tools necessary both to achieve burning conditions and to control plasma instabilities, are characterized by such demanding parameters as to require the construction of a Neutral Beam Test Facility (NBTF) dedicated to their development and optimization. The NBTF was realized in Padua (Italy), with the direct contribution of the Italian government, through the Consorzio RFX as the host entity, IO, the in kind contributions of three Domestic Agencies (F4E, JADA, INDA) and the technical and scientific support of various European laboratories and universities. The NBTF hosts two experiments: SPIDER and MITICA. The former is devoted to the optimization of the HNB and DNB ion sources and to the achievement of the required source performances. MITICA is the full size prototype of the ITER HNB, with an ion source identical to the one used in SPIDER.

Fusion Science and Technology, 2011

ABSTRACT PRIMA consists of two experiments which will test at the same time the main components o... more ABSTRACT PRIMA consists of two experiments which will test at the same time the main components of the final system and the whole system. The facilities are named respectively SPIDER (Source for Production of Ion of Deuterium Extracted from RF Plasma - ion source only) and MITICA (Megavolt ITER Injector Concept Advanced - the main system). Both injectors accelerate negative deuterium ions with a maximum energy of 1 MeV for MITICA and 100 keV for SPIDER, and a maximum beam current of 40 A for both experiments. Following D-D and D-T reactions on the calorimeter panels, important neutron and photon fields are generated around the injectors; such secondary radiation fields represent a relevant issue from the radiological safety point of view. Major radiation protection issues are the activation of materials and components around the injectors, among which the vessel itself and the corrosion products formed in the cooling loops (by the chemical reaction between metal and water). Both these radiation sources may contribute to personnel dose during maintenance operation. In addition, radioactive tritium is produced inside the vessel (mainly in the MITICA facility) which is likely to be poured in the environment during operation phases thus representing a possible contamination pathway for workers and for the population living in the area surrounding the facility. Finally, important penetrations for the ventilation, the power supply and the auxiliary systems were arranged inside the facilities. Tunnels in the underground region, with relatively large dimensions, were needed for both MITICA and SPIDER bunkers in order to allow personnel access for inspection and maintenance of cables and ducts. Each of these shielding weaknesses may provide important dose contribution to radiation workers thus requiring specific safety analyses. In the present paper all major safety issues and relevant radiological concerns are analyzed with a detailed assessment of dose contribution to personnel working inside the facility. Specific dose evaluations were performed through Monte Carlo simulations. Radiation shielding and radiation protection criteria were realized in order to meet the Italian regulatory limit for non radiation workers, ie. below 1 mSv/yr. Our analysis and project evaluations confirm that this constraint is never exceeded during operating phases of the injectors.

New Journal of Physics, 2017

The ITER Neutral Beam Test Facility (NBTF), called PRIMA (Padova Research on ITER Megavolt Accele... more The ITER Neutral Beam Test Facility (NBTF), called PRIMA (Padova Research on ITER Megavolt Accelerator), is hosted in Padova, Italy and includes two experiments: MITICA, the full-scale prototype of the ITER heating neutral beam injector, and SPIDER, the full-size radio frequency negative-ions source. The NBTF realization and the exploitation of SPIDER and MITICA have been recognized as necessary to make the future operation of the ITER heating neutral beam injectors efficient and reliable, fundamental to the achievement of thermonuclear-relevant plasma parameters in ITER. This paper reports on design and R&D carried out to construct PRIMA, SPIDER and MITICA, and highlights the huge progress made in just a few years, from the signature of the agreement for the NBTF realization in 2011, up to now-when the buildings and relevant infrastructures have been completed, SPIDER is entering the integrated commissioning phase and the procurements of several MITICA components are at a well advanced stage.

IEEE Transactions on Nuclear Science, 2012

We study the radiation environment in MITICA, the prototype of the ITER neutral beam injector, du... more We study the radiation environment in MITICA, the prototype of the ITER neutral beam injector, during deuterium operation. ITER is a scientific challenge: one of the several critical issues to solve is the compatibility to ionizing radiation of diagnostics components placed near the plasma vessel. In fact, non negligible fluxes of neutrons and photons are expected from deuterium-deuterium reactions, also from a major peripheral component such as the Neutral Beam Injector. After evaluating the results of Monte Carlo simulations on the expected environment, we determine the risk of malfunctions due to ionizing radiation in control and diagnostic electronics placed close to the injector vessel. The risk on different families of electronic devices is assessed, focusing separately on displacement damage, total ionizing dose, and single event effects.

La proposta di progetto DTT, Divertor Tokamak Test facility, rappresenta una proposta innovativa ... more La proposta di progetto DTT, Divertor Tokamak Test facility, rappresenta una proposta innovativa e completa nella roadmap verso l’implementazione dell’energia da fusione termonucleare. Il progetto coinvolge un centinaio di ricercatori provenienti da universita e laboratori italiani e stranieri. Approvato dalle autorita italiane, il progetto potra beneficiare di finanziamenti governativi e regionali e di un ampio sostegno europeo, ottenuto nell’ambito del Piano europeo per gli investimenti in infrastrutture. La pubblicazione intende fornire i dati chiave aggiornati del complesso e articolato progetto.

ABSTRACT The Occupational Radiation Exposure (ORE) evaluation is part of the safety analysis proc... more ABSTRACT The Occupational Radiation Exposure (ORE) evaluation is part of the safety analysis process that has the purpose to permit the optimisation of protection, according to the basic recommendations of ICRP. This paper presents the criteria adopted in order to evaluate the ORE during normal operation and maintenance of NET II/ITER and some results concerning system components located in tokamak and tritium buildings. Prompt radiation, activity concentration and intake situations as well as number of workers, number of events and exposure time are considered. Many systems and components, whose location in the plant can affect radiological protection during maintenance and/or surveillance, are identified together with the operations needed for each activity. Accidental conditions and equipment failures have been considered in the special maintenance activity when they are due to events with high probability of occurrence so that such events might be expected during the life of the plant. Some results are reported showing the ORE figures with reference to the main activities

Complex radiation fields at workplaces at European high-energy accelerators and fusion facilities

Fusion Technology, Nov 1, 1994

In this paper a preliminary evaluation of the Occupational Radiation Exposure (ORE) of the person... more In this paper a preliminary evaluation of the Occupational Radiation Exposure (ORE) of the personnel involved in working activities on sections of the ITER primary cooling systems (PCS) is presented. The analysis has been restricted to the primary cooling circuits of the first wall (FW) and of the shielding blanket (SB). The radioisotopes produced by activation in the pipe's material surfaces are identified using the available works and data, their amount is obtained with suitable computer codes. The calculation is performed using the combination of a 1-D discrete ordinate code and activation codes. The corrosion/erosion problem is faced with two different approaches: a simplified model with steady state conditions and a computer code that evaluates the non-homogeneous distribution of the activated corrosion products (ACP) in the cooling circuit. The ORE is assessed for some working activities considering the direct irradiation from the ACP and the average distance of the workers from the cooling circuit. The results presented in the paper are useful in order to address experiments needed to evaluate the main unknown parameters for the ACP evaluation and then to design the primary cooling circuits. Furthermore the work outlines a methodological procedure and presents some preliminary results for the ORE assessment at the PCS of a fusion plant like ITER.

This report outlines the research needs and research activities within Europe to develop new and ... more This report outlines the research needs and research activities within Europe to develop new and improved methods and techniques for the characterization of complex radiation fields at workplaces around high-energy accelerators and the next generation of thermonuclear fusion facilities under the auspices of the COordinated Network for RAdiation Dosimetry (CONRAD) project funded by the European Commission.

Journal of Fusion Energy, Jun 1, 1993

This paper presents the criteria adopted to evaluate Occupational Radiation Exposure (ORE) during... more This paper presents the criteria adopted to evaluate Occupational Radiation Exposure (ORE) during normal operation and maintenance of NET/ITER and some results concerning the fuel cycle systems located in the tokamak and tritium buildings. Prompt radiation, activity concentration, and intake situations as well as number of workers, number of events, and exposure time are considered. Many systems and components, whose location in the plant can affect radiological protection during maintenance and/or surveillance, are identified together with the operations needed for each activity. Accidental conditions and equipment failures have been considered in the special maintenance activity when they are due to events with a high probability of occurrence so that such events might be expected during the life of the plant. Some results are reported showing the ORE figures with reference to the main activities. The total man-Sv/y for the systems and activities considered is about 0.5. Such a result, even if very preliminary and incomplete, means that ORE for the tritium systems of a machine like NET/ITER is not negligible and has to be continuously controlled during the design phase.

The Occupational Radiation Exposure (ORE) evaluation is part of the safety analysis process whose... more The Occupational Radiation Exposure (ORE) evaluation is part of the safety analysis process whose purpose is to permit the optimization of protection, according to the basic recommandations of ICRP. This paper presents the criteria adopted in order to evaluate the ORE during normal operation and maintenance of NET/ITER and some preliminary results. The analyses perfomed are related to a few systems and components of the tokamak and tritium buildings.

Radiation Measurements, Aug 1, 2009

The European Commission has funded within its 6th Framework Programme a three-year project (2005-... more The European Commission has funded within its 6th Framework Programme a three-year project (2005-2007) called CONRAD, COordinated Network for RAdiation Dosimetry. The organizational framework for this project was provided by the European radiation Dosimetry Group EURADOS. Work Package 6 of CONRAD dealt with ''complex mixed radiation fields at workplaces'' and in this context it organised a benchmark exercise, which included both measurements and calculations, in a stray radiation field at a high-energy particle accelerator at GSI, Germany. The aim was to intercompare the response of several types of active detectors and passive dosemeters in a well-characterised workplace field. The Monte Carlo simulations of the radiation field and the experimental determination of the neutron spectra with various Bonner Sphere Spectrometers are discussed in Rollet et al. (2008) and in Wiegel et al. (2008). This paper focuses on the intercomparison of the response of the dosemeters in terms of ambient dose equivalent. The paper describes in detail the detectors employed in the experiment, followed by a discussion of the results. A comparison is also made with the H * (10) values predicted by the Monte Carlo simulations and those measured by the BSS systems.

Fusion Technology, 1994

L’Istituto di Radioprotezione ENEA (IRP) assicura la sorveglianza fisica di radioprotezione per t... more L’Istituto di Radioprotezione ENEA (IRP) assicura la sorveglianza fisica di radioprotezione per tutte le attività con rischi da radiazioni ionizzanti all’interno dei centri di ricerca ENEA, con lo scopo principale di tutelare la salute dei lavoratori, della popolazione e dell’ambiente. Per garantire il migliore servizio nell’affrontare tutte le problematiche connesse alla misura della radioattività è stato creato, nell’ambito del Coordinamento “Attività di Valutazioni e Sorveglianza di Radioprotezione”, un gruppo di lavoro tra gli Esperti Qualificati ENEA per la stesura di una serie di procedure a supporto delle attività di sorveglianza fisica della radioprotezione di responsabilità dell’EQ. Le procedure prevedono la descrizione delle singole tecniche e metodologie di misura, fanno riferimento a documenti internazionali aggiornati e referenziabili e applicano le norme tecniche nazionali ed internazionali in vigore, facendo tesoro dell’esperienza dei centri ENEA, maturata nel corso d...

Journal of Fusion Energy, 1993