Short Course Initiative: standard and state-of-the-art instrumentation for fission and fusion reactors

Date: 20/04/2015

Contact/chair: Dr. Ludo Vermeeren (lvermeer@sckcen.be).

Module 1: Prof. Abdallah Lyoussi (CEA/INSTN):
Radiation detection and measurement methods

Starting from the physical principles, the course will discuss the performances and the limitations of various radiation detectors that can be used in nuclear reactors and in the subsequent stages of the nuclear fuel cycle. Two specific applications will illustrate the practical applications of the detection techniques: neutron dosimetry in fission reactors and nuclear monitoring of the fuel cycle (passive and active neutron measurements, sensing via photofission, coupling of measurements and combined interpretation).

The course will be structured as follows:

1. Interaction of radiation with matter
2. Physical principles of radiation detectors
1. Gas-filled detectors
2. Scintillation detectors
3. Solid-state detectors (semiconductor, diamond, TLD)
4. Activation detectors
3. Example of specific measurement methods and their applications: nuclear non-destructive assay in nuclear fuel cycle

Prof. Dr. Abdallah Lyoussi was born in Fes, Morocco in 1965. He received his MSc in nuclear physics from Fes University in 1988 and MSc in Nuclear Engineering from French institute of nuclear sciences and technologies (INSTN) in 1990. In 1994 he got his PhD in nuclear physics from Blaise Pascal University (Clermont-Ferrand, France). He has worked on non destructive measurement methods such as photofission interrogation, neutron interrogation by using different kinds of detectors, electronics, data acquisition systems and advanced particles production machine like LINAC; neutron generators, X tubes. He developed, patented and published various works and innovative and advanced nuclear measurement methodologies. Abdallah Lyoussi is Professor at INSTN and Aix-Marseille University where he cochairs a master on "Instrumentation & Measurements in Harsh Media". He is currently working at CEA (French Atomic & Alternative Energies) Cadarache centre as researcher in physics and expert in nuclear measurement. Finally, since May 2010, Abdallah Lyoussi is scientific chair of a new common instrumentation and measurement Lab. between CEA and University of Provence LIMMEX.

Module 2: Dr. Jan Wagemans (SCK·CEN):
Counting neutrons in a nuclear reactor by reactor dosimetry

The aim of reactor dosimetry is to determine neutron fluences for various types of applications. One of the most commonly used techniques for this purpose is the neutron activation technique. Surveillance capsules present in nuclear power reactors, for example, are typically equipped with a set of activation wires or foils (dosimeters). After irradiation the neutron fluence received by the surveillance capsule can be determined from the measured dosimeter activities. Also many experiments in research reactors (reactor physics experiments, material test irradiations, ...) are equipped with neutron dosimetry in order to provide neutron flux and spectrum information.

This course will first present the example of surveillance dosimetry for power reactors. Then some basic aspects of neutron physics will be shortly described. The main part of the course will focus on the neutron activation technique. This will be complemented with practical examples.

Dr. Jan Wagemans (1974) graduated in Physics at the University of Ghent, Belgium, in 1997 and obtained his PhD at the same university in 2000. He is author or co-author of more than 80 publications in peer-reviewed journals and conference proceedings mainly in the field of neutron physics and (co-)editor of five books. In 2002 he joined the SCK·CEN where he is currently head of the Nuclear Systems Measurements unit. Jan Wagemans is chairman of the European Working Group on Reactor Dosimetry (EWGRD) and he is SCK·CEN Academy Collaborator.

Module 3: Dr. Ludo Vermeeren (SCK·CEN)
Self-powered neutron detectors: principles and specific features

Self-powered neutron detectors (SPNDs) are being used routinely in research reactors and in power reactors for on-line neutron flux monitoring. Very often , only information on the time evolution of the neutron flux or of the reactor power is deduced, on the basis of the relative evolution of the detector current; this is complemented by regular calibration. However it is possible to calculate the SPND neutron sensitivity (the ratio between the detector current and the conventional neutron flux) for any specific SPND design with quite good accuracy. This provides a useful tool for design optimization and for absolute on-line neutron flux monitoring without the need for calibration.

This course addresses the basic principles of the diverse types of SPND and sketches a powerful Monte Carlo based model for sensitivity calculation. Results from dedicated test experiments involving various types of SPND in the BR2 research reactor at SCK·CEN (Belgium) will be presented, including data on the gamma induced signal contribution, other parasitic signal contributions, cable currents, time response characteristics and ways to reduce the response time, spectral dependence of the signal, emitter burn-up effects, relative accuracy of the signal and effects of insulation resistance deterioration in radiation fields.

After following the course, the student should have sufficient insight to be able to select the best SPND for specific applications and to interpret the signals correctly.

Ludo Vermeeren obtained a PhD in Sciences (Nuclear and Atomic Physics) in 1992 at the Catholic University of Leuven (Belgium) with a thesis in the field of laser spectroscopy as a method to determine nuclear properties. He continued working in this field as a post-doc at the same university, with many working visits to CERN-ISOLDE. During this time he was also active in the development of a laser ion source for the selective production of radioactive isotope beams. During one year he was detached to the Atomic Physics Division at GSI Darmstadt (Germany). In 1999, he joined SCK·CEN where he mainly concentrated on in-core nuclear instrumentation, including modelling of sensors and radiation fields, developing and testing new types of sensors and interpreting data from innovative and standard sensors for detailed irradiation monitoring. Since 2010 he leads the unit Instrumentation and Control Research within the expert group Nuclear Systems Research of the institute Advanced Nuclear Systems at SCK·CEN; this unit participates actively in the MYRRHA project (I&C and ultrasound visualization techniques), it has significant activities in fusion research and is involved in international collaborations on nuclear instrumentation. Ludo Vermeeren is also SCK·CEN Academy Collaborator.

Module 4: Prof. George Imel (Idaho State Univ.)
Towards future nuclear systems: fast neutron detection

The current developments in the frameworks of fusion and Gen-IV fission reactors require improved techniques for the monitoring of fast neutrons. This short course will provide a general overview of the methods of fast neutron detection.

We will start with a quick discussion of what constitutes a "fast" neutron and how the reaction mechanisms are different from thermal or epithermal neutron, followed by a brief discussion of the applications of fast neutron detectors (spectroscopy, lead slowing-down assay methods, etc.). The majority of the course will cover the methods of fast neutron detection starting with passive. A presentation of useful foil detectors and spectral unfolding methods from measured reaction rates will be made. Then, active methods will be discussed, including threshold fission chambers and recoil devices.

A discussion of the typical uncertainties (which are generally quite higher than thermal or epithermal measurements) will conclude the course.

The scheme of the course:

1. Introduction
1. Fast neutron reactions of interest
2. Uses of fast neutron detectors
2. Methods
1. Passive
1. Foils of interest
2. Unfolding theory
3. Examples
2. Active
1. Threshold fission chambers
2. Recoil methods (e.g., proton recoil)
3. Indirect recoil methods (He-3, Li-6)
4. Slowing-down (lead, bonner spheres)
3. General discussion of uncertainties

Dr. George Imel holds the rank of Professor of Nuclear Engineering and Physics at Idaho State University. He has a very diverse nuclear engineering and applied physics background, both experimental and analytical, with direct experience at 14 experimental nuclear reactors at national laboratories in the US, France and Italy. Dr. Imel has experience in all phases of experiments from planning, execution, through completion of the analyses. He spent eleven years at the Cadarache center of CEA in France, as a senior foreign collaborator, serving as expert in reactor physics techniques, and has served as mentor to Ph.D. candidates at Cadarache, and member of 5 Ph.D. juries in France, Spain and Switzerland. Previously he was at Argonne National Laboratory, and was the section head of a group involved in research in reactor physics, experiments and computer simulations. He has publications in plasma physics, ionospheric physics, materials science, fusion engineering, neutron radiography, neutron measurements, and system modeling, with teaching experience in graduate schools (Penn State, ISU, Univ. of Idaho) and thesis advisor for M.S. and Ph.D. students.

Module 5: Prof. Jean-Marc Layet (Aix-Marseille University):
Advanced diagnostics concepts for fusion reactors

Development of diagnostics is crucial in fusion devices. They provide the measurements required for machine protection, plasma control and physics studies.

Due to the particular characteristics of fusion plasmas (hot plasma, plasma-wall interactions,..), diagnostics are based on a large variety of physical processes. The complexity of fusion reactors has motivated the development of various kinds of plasma diagnostics using the most advanced technologies. The aim of this conference is to give an introduction into the field of plasma diagnostics (including plasma-wall interaction) taken into account the harsh environment and unexplored "burning plasma" conditions of the next generation of fusion reactors (ITER); we will show that the development and integration of plasma diagnostics in ITER is a major challenge.

Prof. Jean-Marc Layet was born in Marseille in 1952. He is professor at the Aix-Marseille University. He is also vice-president of this University and member of the Scientific Council. He is director of the "Laboratoire de Physique des Interactions Ioniques et Moléculaires" (University - CNRS). He set up a collaboration with CEA Cadarache (Institut de Recherche en Fusion Magnétique, Tore-Supra) to study plasma-wall interactions. His main topics of interest are: Plasma physics, Ion sources, Surface physics, Electrons spectroscopies and Near field microscopy

Module 6: Dr. Andrea Murari (JET)
How to Characterise a Reactor Relevant Fusion Plasma

Fusion plasmas are complex non linear systems, continuously driven away from equilibrium in order to achieve better performances in energetic terms. The need to carefully explore the operational parameter space and to find the best compromise between total energy output and sufficient stability, requires the simultaneous determination of a vast series of quantities, obtained with measuring systems called diagnostics. In magnetic confinement fusion the highest emphasis falls on the determination of the magnetic field topology, essential not only for the physics but also for the real time control of the experiments. To quantify the energetic performances of the plasma, the kinetic properties, density and temperature, of both the ion and electron fluid have to be carefully determined. In this perspective, the level of impurities (particles of non reacting species diluting the main plasma) and the radiation emission have also to be closely monitored, because they strongly affect the power balances of the magnetic configuration. The fusion products, alpha particles and neutrons, which constitute the ultimate indicator of the plasma fusion reactor relevance, have to be detected with high time and energy resolution. To determine all these quantities with the required accuracy, in a Tokamak machine practically all the main measurement techniques of the physical sciences are represented. New methods, based on Bayesian statistics and graph theory, are being developed to improve the data analysis and integrate the results of various measurements. Soft computing approaches, such as fuzzy logic, and non algorithmic methods, such as Cellular Neural Networks and Support Vector Machines, are finding useful applications in various aspects of the signal processing, particularly in the field of real time control.

In this lecture, the basic aspects of all these diagnostic sensors and measurement methods will be shortly explained and illustrated with state-of-the-art examples.

Andrea Murari received his B.A. in Applied Electronics, his M.S. degree in Plasma Engineering and his Ph.D. in Nuclear Power Plants in 1989, 1991 and 1993 respectively. He has mainly worked in measurements and data analysis techniques for high temperature plasmas. Between 1998 and 2002 was leader of the technical group supporting all diagnostics of the RFX experiment. Between 2002 and 2010 he was Task Force Leader for Diagnostics on JET. Since 2011 he is the official interface of JET to the EIROFORUM Thematic Group on Measurements. Since July 2008 he is coordinating the European participation to the ITPA topical group on diagnostics. He is now the Head of JET CSU Group on Diagnostics and CODAS (COntrol and Data Acquisition).

Schedule

The courses will be given at the ANIMMA Conference location (Lisbon Congress Center, Lisbon, Portugal) on Monday, April 20, 2015, the day of the ANIMMA2015 opening session.

08:30 - 10:15	Module 1 (A. Lyoussi )
10:15 - 10:30	Coffee Break
10:30 - 11:00	Module 2 (J. Wagemans)
11:00 - 11:30	Module 3 (L. Vermeeren)
11:30 - 12:30	Module 4 (G. Imel)
12:30 - 13:30	Lunch
13:30 - 14:30	Module 5 (J.-M. Layet)
14:30 - 14:45	Coffee Break
14:45 - 15:45	Module 6 (A. Murari)
16:00 - 17:00	Optional examination
18:00	Proclamation

Optional Examination

For PhD students, the possibility is offered to acquire an ECTS certificate for the ANIMMA short courses as a whole. For that purpose we organize an optional examination consisting of multiple-choice questions covering all courses. This examination is scheduled to take place shortly after the last course. The evaluation will be performed immediately and the certificates will be handed out on the same evening.