On capabilities and limitations of current fast neutron-flux monitoring instrumentation for the DEMO LFR ALFRED

Among Gen IV projects for future nuclear power plants, Lead cooled Fast Reactors (LFR) seem to be a very interesting solution due to its benefits in terms of fuel cycle, coolant-safety and waste management. The novelty of the matter causes some open issues about coolant chemical aspect, structural aspects, monitoring instrumentation, etc. Particularly hard neutron flux spectra would make traditional neutron instrumentation unfit to all reactor conditions, i.e. source, intermediate, and power range. Identification of new models of nuclear instrumentation specialized for LFR neutron flux monitoring asks for an accurate evaluation of the environment the sensor will work in. In this study, thermal-hydraulics and chemical conditions for LFR core environment will be assumed, as the neutron flux will be studied extensively by means of the Monte Carlo transport code MCNPX. The core coolant’s high temperature drastically reduces the candidate instrumentation, because only some kind of fission chambers and Self Powered Neutron Detectors can be operated in such an environment. This work aims at evaluating the capabilities of the available instrumentation (usually designed and tailored for Sodium cooled Fast Reactors, SFRs) when exposed to the neutron spectrum derived from ALFRED, a pool-type LFR project to demonstrate the feasibility of this technology into the European framework. This paper shows that such class of instrumentation does follow the power evolution, but is not completely suitable to detect the whole range of reactor power, due to excessive burn-up, damages or gamma interferences. Some improvements are possible in order to increase the signal-to-noise ratio, by optimizing each instrument in the range of reactor power, such to get the best solution. The design of some new detectors are here proposed, together with a possible approach for prototyping and testing them by means of a fast reactor

Considerations on reduction of indoor air pollution from radioactive emissions from building materials and the ground

The goal of this paper is to study the reduction of health risks from indoor radioactive pollutants, as thoron emissions from common building materials, and radon emission from both building materials and the ground. In particular, when dealing with the indoor environment, one of the most important hazard is represented by radon gas, considered by the World Health Organization (WHO) as the second largest cause of lung cancer, cigarette smoke being the first. Such a radioactive gas belongs to the natural radioactive background of radiation, and its presence all over the world is unavoidable. Radon gas density varies due to microclimatic factors such as temperature, air pressure, humidity and changes in ground layers. Radon gas emerges from the ground and penetrates building basements, accumulating itself into the indoor air, and being breathed in by people. Taking care of the airtightness of windows allows the radon concentration to build up, in some cases beyond reference levels, together with other chemical pollutants, i.e. combustion residues and solvents. The EU Basic Safety Standards, stated in the Council Directive 2013/59/Euratom, based on the last recommendations from the International Commission on Radiological Protection (ICRP) and from WHO, are focusing on risks related to radon gas concentration inside dwellings and working places. On considering that Council Directive 2013/59 Euratom has to be transposed into law by each EU Member State by February 2018, it is recommended that radon issues have to be considered during the design phase of the building construction. For NZEB applications a special attention is requested when energy consumption is reduced lower and lower by taking care of airtightness. In such a case, indoor pollutants (chemical, radioactive, particulate, etc.) can significantly accumulate beyond safe levels. This paper describes measurements and remedial actions of study cases, focusing on public and domestic environments

Radiation protection considerations on radon and building materials radioactivity in Near Zero Energy Buildings

Recent updates of the E.U. Basic Safety Standards, stated in the Council Directive 2013/59/EURATOM, are focusing on risks related to radon gas concentration inside dwellings and working places, as well as radioactivity of building materials. In particular, the new E.U. Basic Safety Standards are based on last recommendations from the International Commission on Radiological Protection (ICRP), and from the World Health Organization (WHO), which consider that radon issues, and external irradiation from building material, as topic aspects to population’s health. Further, ICRP Publication 126, by using bio-kinetics models for estimating the effects of radon intakes, has drastically reduced the reference level for radon concentration in dwellings and working places. Radon issues have recently gained particular attention due to current orientations in constructing buildings with energy consumptions lower and lower. Radon gas emerges from the ground, penetrates building’s basements, and accumulates itself into the indoor air, being breathed by people. Taking care of windows’ airtightness allows the radon concentration to build up, in some cases beyond reference levels, together with other chemical pollutants, i.e. combustion residues and solvents. On considering that Council Directive 2013/59 EURATOM has to be transposed into law by each EU Member State by February 2018, it is recommended that radon issues have to be considered during the design phase of the building construction, particularly for NZEB applications. Further, external irradiation from building materials, i.e. tuff, marbles, tiles, pozzolana, coal ashes and so on, may be a reason of concern also. This paper describes radiation protection issues focusing on public and domestic environments, where people are supposed to spend a considerable amount of time. About radon, real measurements are shown, both in domestic and working scenarios. Dealing with external irradiation due to building materials, calculations and simulations have been performed and results are presented

DISPENSE DEL CORSO DI RADIOPROTEZIONE

DISPONIBILE IN FORMATO ELETTRONICO PER GLI STUDENT

Radon, un problema di sicurezza del lavoro

Dopo aver inserito il radon nella più ampia problematica dei NORM- Naturally Occurring Radioactive Materials, vengono esaminati i meccanismi di interazione delle radiazioni originate dal radon e dai suoi prodotti di decadimento con i tessuti biologici, in particolare quelli del comparto bronco-polmonare. Viene fornita inoltre la distribuzione geografica della concentrazione in aria di radon sul territorio nazionale e vengono descritti gli aspetti radioprotezionistici presi in considerazione dalla Normativa Nazionale. Vengono infine presentate le possibili azioni di rimedio per la riduzione delle concentrazioni

Stato radiologico della piscina del Deposito Avogadro: studio della radioattività attesa nelle strutture di un deposito di elementi di combustibile nucleare irraggiati che in passato ospitava un reattore nucleare di ricerca.

Il progetto ha riguardato l’impianto Sorin “Avogadro”, sito presso Saluggia (VC) e attualmente (2011) adibito a deposito temporaneo di elmenti di combustibile Irraggiato proveniente da impianti del Ciclo del Combustibile Nucleare Irraggiato. L’impianto, nel periodo 1959-1971 aveva ospitato il reattore nucleare di ricerca RS1 e successivamente al 1987, elementi di combustibile irraggiato provenienti dalla centrale nucleare di Trino Vercellese. Scopo del progetto, realizzato da “Sapienza” per conto Sogin, è stato quello di determinare quale frazione della contaminazione radioattiva dell’impianto, all’anno 2005, era attribuibile al funzionamento del reattore RS1 e quanta al deposito degli elementi di combustibile di Trino. L’attività ha richiesto sopralluoghi, misure sperimentali e calcoli neutronici condotti sia con metodi deterministici (codice FISPAN) che Monte Carlo (codice MCNP)

EXPERIMENTAL DESIGN PROCEDURES FOR THE CHARACTERIZATION OF VITRIFIED RADIOACTIVE WASTES

EUREX PLANT, SALUGGI

Applicazioni Industriali delle radiazioni nucleari

Corso Specialisti NR - Ministero dell'Interno - Dipartimento VV

Sistema di datazione degli impulsi per tecniche di correlazione neutronica

Sviluppo e messa a punto di software per una sheda di acquisizione di impulsi neutronici per tecniche di correlazione temporale. Contratto di Ricerca ENEA - Sapienza n. 2089 Tecniche per il controllo non distruttivo di residui radioattiv

Dispense del corso di strumentazione e controllo degli impianti nucleari

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