P. D'hondt's research while affiliated with Belgian Nuclear Research Centre and other places

Publications (78)

Book
FLINS, originally an acronym for Fuzzy Logic and Intelligent Technologies in Nuclear Science, is now extended to Computational Intelligence for applied research. The contributions to the eighth in the series of FLINS conferences cover state-of-the-art research, development, and technology for computational intelligence systems in general and for in...
Article
Since 1998, SCK·CEN, Mol, Belgium, - in partnership with many European research laboratories - is designing a multipurpose Accelerator Driven System for R&D applications - MYRRHA. In parallel, an associated R&D support program is being conducted. MYRRHA aims to serve as a basis for the European experimental ADS providing protons and neutrons for va...
Article
Since 1998, SCK•CEN, Mol, Belgium,—in partnership with many European research laboratories—is designing a multipurpose Accelerator Driven System for R&D applications—MYRRHA. In parallel, an associated R&D support program is being conducted. MYRRHA aims to serve as a basis for the European experimental ADS providing protons and neutrons for various...
Article
Since 1998, SCK·CEN, Mol, Belgium, - in partnership with many European research laboratories - is designing a multipurpose Accelerator Driven System for R&D applications - MYRRHA. In parallel, an associated R&D support program is being conducted. MYRRHA aims to serve as a basis for the European experimental ADS providing protons and neutrons for va...
Article
Since 1998, SCK•CEN in partnership with IBA s.a., is designing a multipurpose ADS for R&D applications -MYRRHA - and is conducting an associated R&D support programme. MYRRHA is an Accelerator Driven System (ADS) under development at Mol in Belgium and aiming to serve as a basis for the European experimental ADS to provide protons and neutrons for...
Article
Full-text available
One of the main SCK•CEN research facility, namely BR2, is nowadays arriving at an age of 40 years just like the major materials testing reactors (MTR) in the world and in Europe (i.e. BR2 (B‐Mol), HFR (EU‐Petten), OSIRIS (F‐Saclay), R2 (S‐Studsvik)). The MYRRHA facility in planning has been conceived as potentially replacing BR2 and to be a fast sp...
Article
The results of a systematic study of the mass and energy of fission fragments emitted in the spontaneous fission of 236,238,240,242,244Pu are reported. A comparison of the fragments' mass and energy distributions demonstrates the occurrence of different fission modes with varying relative probability. These results are discussed in terms of the ran...
Article
To replace the ageing nuclear reactors used today for radio- isotope production, research and industrial applications, we propose to use a spallation neutron source, with neutron multiplication by fission. A 150 MeV cyclotron will be used to produce a proton beam hitting a molten Pb-Bi primary target producing about 0.8 primary neutron per incident...
Article
This paper describes the determination of the relative masses or relative areal densities of two new sets of reference deposits, prior to destructive analysis of subsets of these deposits by isotope dilution mass spectrometry and nondestructive analyses by other means. This work is a repeat of a previous effort of about five years ago. The goal of...
Conference Paper
Security, maintenance, monitoring, diagnosis, and environment are all related to humans and their society, and are the most important and difficult problems of nuclear engineering. These problems are so complicated that they can hardly be solved without a global approach. Therefore, fuzzy engineering may be one of the most powerful tools available...
Article
The concept of the MOL cavity fission spectrum standard neutron field is highlighted. Two applications to neutron dosimetry are treated: (1) Neutron flux determination by distinct fission fragment absolute radiometric measurements on fission foils. (2) Neutron flux determination by detection of the delayed neutrons emitted by a fissile sample. For...
Article
We have measured the light charged particle (LCP) emission probabililty for the spontaneous fission of 244Pu. For the LCP emission to binary fission probability ratio a value of (2.96+/-0.31)×10-3 was found. This result is in agreement with the previously observed trends concerning the LCP emission probability.
Article
FLINS, originally an acronym for Fuzzy Logic and Intelligent Technologies in Nuclear Science, is now extended to Applied Artificial Intelligence for Applied Research. The contributions to the seventh in the series of FLINS conferences contained n this volume cover state-of-the-art research and development in applied artificial intelligence for appl...
Article
The 35Cl(n, p) and the 36Cl(n, p) reactions are of great importance for astrophysics. Several silver chloride samples were evaporated on platinum coated aluminium backings. The sample definition has been achieved by combining destructive and non-destructive methods. The isotopic composition of the 36Cl-enriched material was verified. Pulse height s...
Article
Gold is an excellent comparator material for the k0-standardisation of neutron activation analysis because of its convenient and well defined nuclear properties. The most suitable form for a reference material is a dilute aluminium-gold alloy, for which the self-shielding effect for neutrons is small. Castings of composition Al-0.1 wt.% Au were pre...
Article
The fission fragment escape fraction from bare 235U, 10% 239Pu/Al and 10% 237Np/Al foils were measured for four selected fission products, relevant for reactor neutron dosimetry, using the absolute radiometric technique. The escape fraction for the foils studied amounts up to 4% for the light fission fragments measured, a non-negligible correction...
Article
The energy characteristics and the emission probabilities of the tritons and the ..cap alpha.. particles emitted in the thermal-neutron-induced ternary fission of /sup 233/U, /sup 235/U, /sup 239/Pu, and /sup 241/Pu have been studied at a neutron guide of a high flux reactor, using surface barrier ..delta..E-E telescope detectors. Within the experi...
Article
The energy characteristics and the emission probabilities of the tritons and the α particles emitted in the thermal-neutron-induced ternary fission of 233U, 235U, 239Pu, and 241Pu have been studied at a neutron guide of a high flux reactor, using surface barrier ΔE-E telescope detectors. Within the experimental uncertainties, E¯α and E¯t appear to...
Chapter
Two fission reactions, 238U(n,f) and 232Th(n,f) have been identified as ideal fusion plasma neutron yield diagnostics monitors based on detection,within a time span of ~ 10 to 100 s, of their delayed - neutron signals; these responses, entirely decayed between two successive plasma pulses, are induced during exposure of the sensors in the vicinity...
Chapter
The objectives, direction and current achievements of LWR pressure vessel surveillance research and development activities in Belgium are re-visited. This is done in a perspective which accounts for the recent embodiment in Regulation of the concern about overcooling accidents susceptible to cause a pressurized thermal shock to the reactor vessel....
Article
The thermal-neutron-induced fission cross-section of 238U was measured at an intense and very clean thermal-neutron beam of the Grenoble high-flux reactor. The best 238U sample material used contained only 12 ppb of 235U. The fission fragments were detected with surface barrier detectors. Relative to a thermal fission cross-section of 587.6 barn fo...
Article
The (nth,α) reaction spectroscopy was done on64, 65, 67zn and77Se at the 87 m curved thermal neutron guide of the Grenoble high flux reactor. In each of the64Zn(n, α)61Ni and67Ni(n, α) 64Ni reactions, one line showed up corresponding to anα-particle transition to the first excited state in61Ni and64Ni withσ α1=11±3 μb and 159±20 μb respectively. In...
Article
Energy correlation measurements were performed for the spontaneous fission of 242Pu, the thermal-neutron-induced fission of 241Pu, and the photofission of 242Pu with 12-, 15-, 20-, and 30- MeV bremsstrahlung. The photofission cross section for 242Pu was determined up to 30 MeV. For 242Pu(sf) the overall kinetic energy distribution is strongly asymm...
Article
Energy correlation measurements were performed for the spontaneous fission of /sup 242/Pu, the thermal-neutron-induced fission of /sup 241/Pu, and the photofission of /sup 242/Pu with 12-, 15-, 20-, and 30-MeV bremsstrahlung. The photofission cross section for /sup 242/Pu was determined up to 30 MeV. For /sup 242/Pu(sf) the overall kinetic energy d...
Article
Energy correlation measurements were performed for the spontaneous fission of 244Pu and its photofission with 12-, 15-, 20-, and 30-MeV bremsstrahlung. The photofission cross section for 244Pu was deduced from a measured yield curve up to 30 MeV using the photon difference method. A comparison of the 〈Ek*〉(m*) behavior for spontaneous and photon in...
Chapter
Four types of gas producing reactions induced by thermal neutrons have been studied at an intense thermal neutron beam of the Grenoble High Flux Reactor. (i) hydrogen,tritium and helium production during the ternary fission process for several actinides. (ii) hydrogen and helium production via (nth,p) and (nth,α) reactions on structural materials l...
Article
Fission-fragment mass and kinetic energy distributions and their correlations have been studied for the thermal neutron induced fission of 241Pu. The global mass distribution is smooth, apart from a small shoulder at μH ≈ 144 probably due to the deformed shells N ≈ 88 and N ⩾ 60 in the heavy and the light fragment respectively. When low excitation...
Article
Fission fragment mass and kinetic energy distributions and their correlations have been studied for the thermal neutron induced fission of 237Np. The global mass distribution is rather smooth, apart from a weak shoulder at μH = 140–141. When low excitation events are selected, fine structures associated with the charge of the fragments are observed...
Article
Energy correlation measurements were performed for the photofission of 235U with 12-, 15-, 20-, 30-, and 70-MeV bremsstrahlung. Overall fragment mass and kinetic energy distributions are deduced. The behavior of the total fragment kinetic energy as a function of the fragment mass and excitation energy of the compound nucleus is studied. The results...
Article
The thermal neutron induced (n, alpha) reaction cross sections of 233U, 235U and 238U were measured using a highly pure thermal neutron beam from the Grenoble High Flux Reactor. In the case of the 238U(nth, alpha) 235Th reaction, a Qalpha value of 8.70 +/- 0.05 MeV, a 235Th mass of 235.04751 +/- 0.00006 amu and a Qbeta value of 1.92 +/- 0.16 MeV (f...
Article
Energy correlation measurements were performed for 240Pu(s.f.), 239Pu(nth,f), and the photofission of 240Pu with 12-, 15-, 20-, and 30-MeV bremsstrahlung. The photofission cross section for 240Pu was determined up to 30 MeV, which permitted the calculation of the average excitation energy 〈Eexc〉 of the compound nucleus. The average total kinetic en...
Article
The thermal neutron induced fission cross-section of 232Th was measured at an intense and very pure thermal neutron beam of the Grenoble High Flux Reactor, yielding a value of (3 ± 1) μbarn. For control purposes, the same targets were used at the VandeGraaff accelerator of the CBNM (Geel), where a 232Th (n, f) cross-section value of (0.12 ± 0.02) b...
Article
The energy distributions and the yields of the main charged light particles emitted during the thermal neutron induced ternary fission of 235U were studied using a very pure neutron beam of the Grenoble high-flux reactor. All the measured energy distributions except that of the α-particles are compatible with a gaussian shape. Explanations for this...
Article
A program was written which enables the measurement on a PDP 11/10 system, with CA11C CAMAC interface, of 120 successive spectra of 4096 channels each with counting times down to 200 ms and time intervals between two successive measurements less than 150 us. Off-line a number of successive spectra appropriate to the half-life of the considered fiss...
Article
The post-neutron mass distribution for the sub-barrier fission of the odd-odd nucleus 238Np, produced by thermal neutron capture in 237Np, has been measured using the technique of gamma-spectrometry of fission product catcher-foils at the Grenoble high-flux reactor. The values of the average light and heavy fragment masses and the peak widths are i...
Article
Long-range alpha particles emitted in the photofission of /sup 235/U with 20-MeV bremsstrahlung were measured. The binary to long-range alpha particle ratio, , and full width at half maximum (E/sub ..cap alpha../) were deduced.
Article
Long-range alpha particles emitted in the photofission of 235U with 20-MeV bremsstrahlung were measured. The binary to long-range alpha particle ratio, , and full width at half maximum (Ealpha) were deduced. NUCLEAR REACTIONS, FISSION 235U(gamma,F), Egamma=20 MeV, measured: Long-range alpha spectrum.
Article
The 102Mo activity was obtained by photofission of natural U and thermal-neutron induced fission of 235U, with subsequent chemical separation of the molybdenum fraction. In addition, nuclei with mass 102 were separated from fission products of 235U(n th, f) using the mass separator LOHENGRIN. A decay scheme and absolute γ-intensities are deduced fr...
Article
Fractional independent or cumulative chain yields of 35 fission products were determined for the photofission of 238U with 20-MeV bremsstrahlung, using direct γ spectrometry of irradiated uranium samples, γ-ray spectrometry of fission product catcher foils, and chemical sparation techniques. For the mass chains 131-136 the width parameter c of the...
Article
The mass distributions for the photofission of 235U using bremsstrahlung with end-point energy of 12, 15, 20, 30, and 70 MeV were determined by γ spectrometry of fission product catcher foils. Smoothly varying curves without fine structure were obtained. A third hump in the symmetric region is not present. Several fractional independent chain yield...
Article
Energy correlation measurements with semiconductor detectors were performed for the photofission of 238U with 12-, 15-, 20-, 30-, and 70-MeV bremsstrahlung. The behavior of the mass distribution with changing total kinetic energy of the fragments and with changing excitation energy of the compound nucleus is deduced. The distribution of the total f...
Article
Cumulative yields for about 40 mass chains and fractional independent yields of 128Sn, 128Sbg, 131Teg, 131Tem, 132Ig, 132Im, 134I, 134Cs, 135Xe, and 136Cs were determined for the photofission of 238U with 12-, 15-, 20-, 30-, and 70-MeV bremsstrahlung. Changes in the characteristics of the mass distribution are studied. An enhanced yield in the mass...
Article
The thermal neutron-induced fission cross-section of 231Pa was measured at an intense thermal neutron beam of the Grenoble high flux reactor. The 231Pa (nth,f) and 235U(nth,f)-fragments were measured with surface barrier detectors. Relative to a thermal fission cross-section of 587.6 barn for 235U, a value of (20 ± 1) mbarn was obtained for the 231...
Article
The (n th,α) reaction on180Hf,181Ta and209Bi was studied at the thermal neutron guide of the Grenoble high flux reactor. Upper limits ofσ α ≦13μb, ≦μb and ≦0.3μb, respectively, were obtained for the a branches to the ground states in contrast to the values of ≈100μb to ≈500 mb reported in the literature. Possible reasons for these discrepancies are...
Article
The 235U(nth, alpha) reaction and the alpha-particles emitted in the thermal neutron induced fission of 235U were measured using a very pure thermal neutron beam of the Grenoble high flux reactor. An upper limit of 0.66 mb was determined for the 235U(nth, alpha) reaction cross section, which is lower than all the previous results. The energy distri...
Article
The 102Tcg activity has been obtained by chemical separation of the parent nucleus 102Mo from an UO2(NO3)2.6 H2O sample, irradiated with 20-MeV bremsstrahlung. Four successive Ge(Li) spectra were measured. Several new γ rays were found and the energy values and relative intensities of the known γ lines are compared to the existing data. Levels at 0...
Article
Fission fragment mass and kinetic energy distributions and mass-versus-energy correlations have been measured at the Grenoble high-flux reactor for the thermal neutron induced sub-barrier fission and above-the-barrier fission of 237Np and 235U, respectively. Unwanted events were eliminated by careful timing. In the case of 237Np(nth, f), the two od...
Article
Some characteristics of the thermal-neutron-induced fission of 231Pa, 232Th and 237Np were studied using a highly pure thermal-neutron beam of the Grenoble High Flux Reactor. For the thermal-neutron-induced-fission cross section we obtained 20 ± 4 mb for 237Np, 19 ± 4 mb for 231Pa and less than 2.5 μb for 232Th, in agreement with calculations based...
Article
The 118Ing activity has been obtained by chemical separation of the parent nucleus 118Cd from a UO2(NO3)2.6H2O sample, irradiated with 25- and 50-MeV bremsstrahlung. Two successive Ge(Li) γ-ray supectra were measured. Several new γ rays were found and the relative intensities of the known γ lines are compared and discussed with respect to the exist...
Article
The /sup 118/In/sup g/ activity has been obtained by chemical separation of the parent nucleus /sup 118/Cd from a UO/sub 2/(NO/sub 3/)/sub 2/ x 6H/sub 2/O sample, irradiated with 25- and 50-MeV bremsstrahlung. Two successive Ge(Li) ..gamma..-ray spectra were measured. Several new ..gamma.. rays were found and the relative intensities of the known ....
Article
The 118Ing activity has been obtained by chemical separation of the parent nucleus 118Cd from a UO2(NO3)2.6H2O sample, irradiated with 25- and 50-MeV bremsstrahlung. Two successive Ge(Li) γ-ray supectra were measured. Several new γ rays were found and the relative intensities of the known γ lines are compared and discussed with respect to the exist...
Article
The Ing118 activity has been obtained by chemical separation of the parent nucleus Cd118 from a UO2(NO3)2.6H2O sample, irradiated with 25- and 50-MeV bremsstrahlung. Two successive Ge(Li) γ-ray supectra were measured. Several new γ rays were found and the relative intensities of the known γ lines are compared and discussed with respect to the exist...
Article
Starting from measured provisional and post neutron mass distributions, the neutron emission curve, ν(m*), is calculated for the photofission of 235U and 238U with 25-MeV bremsstrahlung, by applying a method similar to the method described by Terrell. As a test of the procedure, the ν(m*) curve for the spontaneous fission of 252Cf and the thermal n...
Article
The photofission of 235U and 238U with 25-MeV bremsstrahlung was studied. For both nuclei cumulative yields for about 40 mass chains were measured. For 235U fractional independent chain yields of 126Sbg, 126Sbm, 128Sn, 128Sb(9 h), 128Sb(10 min), 131Sb, 131Teg, 131Tem, 132I, 134I, 135Xe, 136Cs, and 140La were determined and for 238U those of 128Sn,...
Article
Fragment energy correlation measurements have been made for the photofission of 235U and 238U with 25-MeV bremsstrahlung. The correlated energies of fission fragment pairs were measured with semiconductor detectors. Distributions of kinetic energy as a function of fragment mass were deduced. The results for the isotopes 235U and 238U are compared....
Article
Fragment energy correlation measurements have been made for the photofission of $sup 235$U and $sup 238$U with 25-MeV bremsstrahlung. The correlated energies of fission fragment pairs were measured with semiconductor detectors. Distributions of kinetic energy as a function of fragment mass were deduced. The results for the isotopes $sup 235$U a...
Article
The thermal neutron induced (n, α) reaction cross section of 238U was measured using the highly pure thermal neutron beam from the 87 m curved neutron guide at the High Flux Reactor of the ILL (Grenoble). The energy spectrum showed an α-particle line with Eα = 9.05±0.06 MeV and σ(n, α) = 1.3±0.6 μb. The α-particle energy was used to calculate the 2...
Article
The thermal neutron induced fission cross section of 232Th was measured using the highly pure thermal neutron beam from the 87 m curved neutron guide at the High Flux Reactor of the ILL (Grenoble). An upper limit of 4 mub was obtained for the fission cross section, which is an order of magnitude smaller than previous results. This result is discuss...
Article
The thermal neutron induced (n, alpha) reaction cross section of 238U was measured using the highly pure thermal neutron beam from the 87 m curved neutron guide at the High Flux Reactor of the ILL (Grenoble). The energy spectrum showed an alpha-particle line with Ealpha = 9.05+/-0.06 MeV and sigma(n, alpha) = 1.3+/-0.6 mub. The alpha-particle energ...
Article
Full-text available
The 6th Technical Review Meeting of the MEGAwatt PIlot Experiment (MEGAPIE) will take place on 27-29 june 2005 at SCK•CEN, Mol, Belgium. At this time the fabrication and assembly of the target and ancillary systems will have been finished and are in the process of being commissioned at the test stand. Therefore this edition of the Technical Review...
Article
Energy correlation measurements were performed for the spontaneous fission of 242Pu, the thermal-neutron-induced fission of 241Pu, and the photofission of 242Pu with 12-, 15-, 20-, and 30- MeV bremsstrahlung. The photofission cross section for 242Pu was determined up to 30 MeV. For 242Pu(sf) the overall kinetic energy distribution is strongly asymm...
Article
The 12th International Conference On Emerging Nuclear Energy Systems that was organised in Hotel Metropole, Brussel, August 21-26, 2005 by SCK•CEN, the Belgian Nuclear Research Centre. The main objective of ICENES 2005 was to provide an international scientific and technical forum for scientists, engineers, industry leaders, policy makers, decision...

Citations

... One possibility is to leave PID controllers and look for another controller design [1], [2]. Fuzzy controller has the advantages of human like IF-THEN rules thinking and can take into account the knowledge of the operators for controlling the reactor [3], [4]. The previous results have shown that fuzzy control is more flexible, more robust, and easier to update than the PID control [5]. ...
... In Eq. 6 24], for the prefactor v=2R i , a kinetic energy 1 2 M v 2 = 100MeV can beassumed for the particle with mass M inside the potential barrier. ...
... The other experimental channels do not reach the core but are located at different distances from it, allowing for a large number of different neutron spectra to be available. In the past years a big effort was devoted to the neutron characterization of the TAPIRO reactor and the results are reported in Ref. [3][4][5] and references therein, in the following called "reference calibration". ...
... The activation method using delayed neutrons has been successfully applied in large fusion devices [11,13,[17][18][19]. This variant of the activation method is implemented on JET together with the standard activation method based on gamma-spectrometry. ...
... High power proton accelerators can potentially be used for production a nuclear weapongrade materials (mainly 233U and 239pu) and therefore they should be monitored and safeguarded. At present, commercially available machines (ADONIS, I.B.A. Belgium [7]) with proton energies around 150 MeV and currents of 1.5 mA (power 225kW), are at the limit of the technology threshold (capacity to produce 100g Pu per year) laid down by the I.A.E.A in their 1NFCIRC documents [ 10]. Large powerful accelerators which may be used for power production and waste transmutation will automatically fall under I.A.E.A. safeguards. ...
... It is pointed out in [68] that the single-shell model, such as the single-shell Nilsson model, failed in reproducing the B(E2) values of the some neighboring Xe isotopes. In [69,70] Nd [49] Ce [50] 0.4 0 Exp. [3,11,29,31,42] 0.6 0.8 Xe [47] Nd [49] Ce [50] 0.2 [3,11,29,31,32,42]; theoretical values from [29] are presented in the Note to the table) Ba nuclei is stated to be situated between the pure vibrational and rotational limit. ...
... The MYD of photofission on 232 Th, 235, 238 U and 240 Pu are predicted with the Bohr-substitution F, G, and M models and compared to the experimental data [29,[34][35][36][37]. The benchmarking results against experimental data are shown in Fig. 2 Fig. 2). ...
... It is symmetric about A = 120 and for every heavy fragments there is a corresponding light one, but the fission with two equal mass fragments is less probable by a factor of about 200. It is interesting, that as the energy of incident γ t s increases, the masses of two FF's tend to be more equal [15]. ...
... This is slightly higher than the deformed 86-88n shell and thus the yields are not as high as in the case of the mass numbers of 133-134 and 138-140. Similar observation was made in our earlier work in [54][55][56][57][58][59][60] bremsstrahlung induced fission of 238 U. The above observations support the even-odd effect and confirms the standard I and standard II asymmetric mode of fission based on spherical 82n and deformed 86-88n shell effect as mentioned by Brosa et al. [68]. ...
... The MYD of photofission on 232 Th, 235, 238 U and 240 Pu are predicted with the Bohr-substitution F, G, and M models and compared to the experimental data [29,[34][35][36][37]. The benchmarking results against experimental data are shown in Fig. 2 Fig. 2). ...