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The radial neutron camera (RNC) is a key ITER diagnostic system designed to measure the uncollided 14- and 2.5-MeV neutrons from deuterium-tritium (DT) and deuterium-deuterium (DD) fusion reactions, through an array of detectors covering a full poloidal plasma section along collimated lines of sight (LoS). Its main objective is the assessment of the neutron emissivity/alpha source profile and the total neutron source strength, providing spatially resolved measurements of several parameters needed for fusion power estimation, plasma control, and plasma physics studies. The present RNC layout is composed of two fan-shaped collimating structures viewing the plasma radially through vertical slots in the diagnostic shielding module (DSM) of ITER Equatorial Port 1 (EP01): the ex-port subsystem and the in-port one. The ex-port subsystem, devoted to the plasma core coverage, extends from the Port Interspace to the Bioshield Plug: it consists of a massive shielding unit hosting two sets of collimators lying on different toroidal planes, leading to a total of 16 interleaved LoS. The in-port system consists of a cassette, integrated inside the port plug DSM, containing two detectors per each of the six LoS looking at the plasma edges. The in-port system must guarantee the required measurement performances in critical operating conditions in terms of high radiation levels, given its proximity to the plasma neutron source. This article presents an updated neutronic analysis based on the latest design of the in-port system and port plug. It has been performed by means of the Monte Carlo MCNP code and provides nuclear loads on the in-port RNC during normal operating conditions (NOC) and inputs for the measurement performance analysis.

Portable neutron generators are one of the most widespread sources of fast neutrons for different applications, from activation analysis to quantitative estimation of fissile and fertile materials in radioactive waste packages. New techniques based on these devices have been developed for homeland security, e.g. neutron interrogations of packages suspected of containing substances such as explosives. When using portable generators determination of radiation protection quantities is affected by a series of boundary conditions that could differ from an experimental set-up to another, and Radiation Protection Experts cannot assess operator exposure without the aid of time-expensive Monte Carlo simulations. As it is impossible to foresee all kind of scenarios involving such applications, and time is often a critical variable, safety assessment requires faster, even if less accurate, tools for exposure evaluation. In this article experimental measurements of dose rates in a real scenario involving a D-T neutron generator are considered, to validate the Monte Carlo model developed. Consequently, it was possible to demonstrate that the calibration factor at 14 MeV for a neutron dosimeter provides conservative dose estimates and to propose a stand-alone, fast, and easy-to-use calculation tool which is usable on field by the Radiation Protection Expert without full Monte Carlo calculations.

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.

In the frame of the MICADO H2020 project, a passive and active neutron measurement system is being developed to estimate the nuclear material mass inside legacy waste drums of low and intermediate radioactivity levels. Monte-Carlo simulations have been performed to design a new modular and transportable neutron system, with the main objective to reach a good tradeoff between the performances in passive mode, i.e. neutron coincidence counting, and in active interrogation mode with the Differential Die-away Technique. Different designs are compared, which mainly differ in their moderation materials, graphite and polyethylene . This parametric study allowed us to define a prototype taking into account practical constraints in view of its final implementation in a wide range of in-situ locations and nuclear facilities. The total neutron detection efficiency of the prototype is 6.75%, as calculated for an empty drum, i.e. without waste matrix. The detection limit in terms of nuclear material equivalent mass have also been estimated based on assumptions for a homogeneous distribution of nuclear materials inside the drum, filled with four types of matrices covering the range of nuclear waste drums defined in the frame of the project. The most favorable matrix is made of stainless steel in passive mode and of polyethylene in active mode, with an apparent density of 0.7 g cm − 3 and 0.1 g cm − 3 , respectively. The calculated mass detection limits are respectively 68 mg of 240 Pu, 62 mg of 235 U and 39 mg of 239 Pu. The most penalizing matrix is made of polyethylene with an apparent density of 0.7 g cm − 3 , which leads to a mass detection limit of 519 mg of 240 Pu in passive mode, and 564 mg of 235 U or 349 mg of 239 Pu in active mode. Measurement time is 30 min for both passive and active modes. Next steps will be a complete investigation of matrix effects based on intensive Monte-Carlo calculations and an experimental design to figure out the appropriate corrections. Experiments will also be conducted at CEA Cadarache Nuclear Measurement Laboratory with the construction and the assembly of the neutron system prototype, and the measurement of mock-up drums filled with different matrices.

The increasing of terror menace in recent years led the international community to enhance the efforts to minimize threats to people in everyday life by developing devices, techniques, and procedures targeted to improve the collective security. In this framework the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) developed a new device to improve CBRNe resilience, the Neutron Active Interrogation system (NAI). It has been conceived and optimized to identify transuranic-based Radioactive Dispersal Devices potentially hidden in packages, envisaging its utilization in field applications. NAI is based on the detection of neutrons from induced fission on small amount, of the order of a few grams, of fissile material. The device exploits a portable neutron generator based on d-t fusion reaction, a polyethylene structure for reducing the neutron energy in order to maximize the fission cross-section, and an array of 3He proportional counters. Fissile material detection is made using the Differential Die-Away time Analysis (DDAA), an active neutron technique based on the difference among the die-away times of fast interrogation neutrons and prompt fission neutrons induced by thermal neutrons in the moderating system. The original experimental setup was tested on the field during the live demo open to the public at the EDEN Project Demonstration occurred in September 2015 at ENEA Frascati Research Centre in Rome. Since then, the setup has been modified to improve the device detection capabilities. NAI performances have been tested within different environmental conditions, e.g. open field geometry vs. bunker-like geometry, to study the effects of scattering phenomena. The optimized configuration here presented is transportable, lightweight, and able to detect 2 grams of 235U contained in a salt of depleted uranium in real time, independently from the measurement environmental conditions.

In the frame of Chemical, Biological, Radiological, and Nuclear defense European activities, the ENEA, the Italian National Agency for New Technologies, Energy and Sustainable Economic Development, is proposing the Neutron Active Interrogation system (NAI), a device designed to find transuranic-based Radioactive Dispersal Devices hidden inside suspected packages. It is based on Differential Die-Away time Analysis, an active neutron technique targeted in revealing the presence of fissile material through detection of induced fission neutrons. Several Monte Carlo simulations, carried out by MCNPX code, and the development of ad-hoc design methods, have led to the realization of a first prototype based on a 14 MeV d–t neutron generator coupled with a tailored moderating structure, and an array of helium-3 neutron detectors. The complete system is characterized by easy transportability, light weight, and real-time response. First results have shown device's capability to detect gram quantities of fissile materials. © 2017 Elsevier B.V.