Annals Of Nuclear Energy Research Articles

A A Pilot Review of State-of-the-Art Deep Learning Applications to Nuclear Engineering & Technology

Given the advent of big data (BD), the focus of this “pilot” review of the most recent literature is upon deep learning (DL) implementations/solutions to important, as well as inherently complex, nuclear engineering and technology (NET) problems. The potential advancement from implementing large/real-scale DL-based algorithms is critically detailed, as well as highlighted, by inspecting the relevant body of latest research which appears in two major – overlapping, yet also complementary to each other in terms of scope and audience - nuclear energy (NE)-dedicated scientific research means of publication, namely Elsevier’s “Annals of Nuclear Energy” and “Progress in Nuclear Energy” journals. It is demonstrated that, given their (I) accuracy, robustness-to-noise and resilience to incomplete/erroneous information, as well as (II) competence under non-stationary and transient nuclear reactor (NR) operating conditions, deep and convolutional neural networks (DNNs and CNNs, respectively), as well as their variants, are becoming increasingly important, in their own right, for the swift and reliable solution of NET problems. It will be of great interest for – while also advantageous to - the NE, BD, and computational intelligence (CI)/DL communities, to join forces, follow up, and contribute to future research in – as well as application to - this particularly interesting and fruitful collaboration between disciplines.

FLUKA Simulation of Ac-225 Production with a Medical Cyclotron

Alpha-emitting Ac-225 is a radionuclide being developed and used in the treatment of some cancers [1]. Currently, the Department of Energy (DOE) isotope program’s Tri-Lab Effort (Brookhaven National Laboratory, Oak Ridge National Laboratory, Los Alamos National Laboratory) effort provides Ac-225 from a Thorium target irradiated with a high energy proton beam [2]. We have a plan to make Ac-225 from Ra-226 target using the relatively low energy proton beam from a medical cyclotron. FLUKA is a general-purpose Monte Carlo simulation code used to model the interaction and transport of particles from a few KeV to thousands of TeV in arbitrary materials. It is built and maintained with the aim of including the best possible physical models in terms of completeness and precision [3]. In this study, we are using the RESNUCLEi card to score the residual isotopes and activities from the Ra-226 target irradiated in the EBCO TR19 cyclotron. For the simulation, we used 300 mg of Ra-226 (5.0 g/cm3) which is 8.0E+20 atoms. These atoms can be deposited as a 0.0086 cm thick layer on a 1.58 X 4.45 X 0.234 cm aluminum plate. The Ra-226 target geometry is specially designed to fit the solid target holder for the EBCO TR19 cyclotron. The EBCO TR19 cyclotron proton beam energy range is from 13 to 19 MeV and the beam current is 200 μA (1.248E+15 protons/s). At 19 MeV, the highest proton beam energy, protons can penetrate 0.198 cm of Ra-226 (13 MeV, 0.106 cm) and 0.192 cm of aluminum. Thus, the proton beam penetrates the radium layer and is completely stopped in the aluminum plate. Ra-226 target irradiations were simulated using a 40 hours irradiation time using a varied particle energy from 13 to 19 MeV and 200 μA proton beam currents to find the best conditions for Ac-225 production in the EBCO TR19 cyclotron. The maximum yield for the Ac-225 production was obtained at the beam energy 14.5 MeV. The amount of the produced Ac-225 from Ra-226 target is about 340 mCi at EOB. [1]David A. Scheinberg and Michael R. McDevit. Actinium-225 in targeted alpha-particle therapeutic applications. Curr Radiopharm. 2011 Oct; 4(4): 306–320.[2]The Journey of Actinium-225: How Scientists Discovered a New Way to Produce a Rare Medical Radioisotope. DOE News. https://science.energy.gov/news/featured-articles/2018/06-20-18/[3]Giuseppe Battistoni et al. Overview of the FLULA code. Annals of Nuclear Energy. 2015 Aug. Vol 82, Pages 10-18. This research supported by the Department of Energy Office of Science’s Isotope Program.

Characteristics of the high-temperature water film evaporation with countercurrent turbulent air flow in the duct

Passive containment with high design pressure often has high evaporation temperature. The evaporation mass transfer with high evaporation temperature along with countercurrent turbulent airflow in a long duct was experimentally investigated. The experiments were performed for a wall surface temperature range of 71–90 °C. The experimental data showed that the high evaporation temperature significantly enhanced evaporation. By comparison, it reveals that the significant prediction deviation of the correlation from Kang and Park (Nuclear Engineering and Design, Vol. 204, pp 347–359, 2001) is mainly due to the cubic power modification. HMTA from Huang and Yang (Annals of Nuclear Energy, Vol. 76, pp 237–242, 2015) also underestimates the Sherwood number at high evaporation temperature but it could be applicable when the modification of the wavy interface and the advective mass transfer are included. A modified correlation for falling water film evaporation with high evaporation temperature is finally developed.

Three-dimensional transport theory: Evaluation of analytical expressions of Williams and verification of MCNP

“Three-dimensional transport theory: an analytical solution of an internal beam searchlight problem, I”, Annals of Nuclear Energy, 36(8), 1256–1261 (2009) by Williams extends the range of analytical solutions, and the associated development of techniques, numerical results and analysis near singularities. The final integrals are not easy to evaluate as the integrands are highly oscillatory, singular and also on infinite range. We report here some further numerical evaluations of expressions of Williams, and also compare these with those of Williams and Ganapol and Kornreich. The numerical results compare very well. The disagreements are very rare, and even then in the fifth decimal place. We are also able to explore the nature of the results near singularities in conformity with the results of Williams. We also verify MCNP-5, the widely used Monte Carlo code against these analytical results. We have found that MCNP is easily able to provide results within 0.1% deviation from the “exact” results for most cases, and within 1% for almost all cases. It is challenged near the singularities, however, where the deviations are larger.

On some matters concerning the backward and forward equations of probability balance for neutrons in a medium with randomly time-varying properties

The recent contributions to combined zero-power and at-power neutron noise analysis raises a number of interesting questions which deserve further discussion [Kitamura, Y., Pal, L., Pazsit, I., Yamamoto, A., Yamane, Y., Some properties of zero power neutron noise in a time-varying medium with delayed neutrons. Annals of Nuclear Energy, in press.]. It is shown, for example, by direct calculation, that the forward equation of probability balance is exact when combined with a dichotomic Markov process to describe the random physical behaviour of a medium, whereas the backward equation contains errors. This confirms and corroborates the assertions of Pal L. and Pazsit I. [2006. Neuron fluctuations in a multiplying medium randomly varying in time. Physica Scripta 74, 62.] who first pointed out this anomaly. Extensions to spatially random media are discussed, together with an application to the calculation of the extinction probability. Other methods of solution such as that of polynomial chaos are briefly touched upon. In order to carry out the calculations described we use the stochastic ansatz concept [Williams, M.M.R., 2008a. A stochastic ansatz and its relationship with the dichotomic Markov process. Physica A 387, 4997.].

Collision probabilities in spatially stochastic media II

An improved model for calculating collision probabilities in spatially stochastic media is described based upon a method developed by Cassell and Williams [Cassell, J.S., Williams, M.M.R., in press. An approximate method for solving radiation and neutron transport problems in spatially stochastic media. Annals of Nuclear Energy] and is applicable to three-dimensional problems. We shall show how to evaluate the collision probability in an arbitrarily shaped non-re-entrant lump, consisting of a random dispersal of two phases, for any form of autocorrelation function. Specific examples, with numerical values, are given for a sphere and a slab. In the case of the slab we allow the material to have different stochastic properties in the x, y and z directions.

A letter from Alvin Weinberg: “The development of nuclear reactor theory in the Montreal Laboratory of the National Research Council of Canada (Division of Atomic Energy) 1943–1946” [Progress in Nuclear Energy 36 (3) 2000, 239–322

In Canada, during the autumn of 1942, a group of physicists, chemists and engineers were assembled to work on what was to become the Canadian atomic energy project. The base for this work was Montreal. This paper concentrates on the contributions of a sub-group of those scientists, namely those working on the development of nuclear reactor theory. The members of that group comprised an international mix of Canadians, Britons and Americans. A few already had international reputations as theoretical physicists, but the majority were young men and women, generally under the age of 30, who were very talented but not yet famous. They worked under conditions of the utmost secrecy, initially with little help from the United States, and developed virtually from first principles most of the important aspects of modern reactor theory. The results of their work were issued as Canadian National Research Council reports with the prefix MT (Montreal Theory), and between 1943 and 1946 about 80 such reports were written. The theory described therein was fundamental to the later design and construction of the Canadian NRX reactor, which was a very successful research tool. Soon after the end of World War II, a few of the MT reports were written up and published in either the Physical Review or the Canadian Journal of Research. However, more than 80% of the work was not published and therefore did not receive the formal recognition that it deserved. A few of the reports that went unpublished were so important that one wonders why they never appeared in the learned journals. To be sure, the work they contained was certainly used world-wide and the reports cited. However, human nature being what it is, after some years the original sources were forgotten and only the published papers which cited them were quoted. After a while those classic, early MT reports seem to have faded from memory. Thus it was that, when I recently tried to find one of them to check on a particular matter (in fact it was a paper by George Volkoff on the Wiener–Hopf technique) I found extreme difficulty in locating it. The work presented here describes the problems I met in tracking down, not only the Volkoff paper, but many of the others too. It was this difficulty which persuaded me that the MT reports should, after nearly 60 years, receive their due recognition. I am doing that by reprinting here the abstracts of all of the relevant reports, with some personal comments regarding their importance or historical value. In addition, where possible, I am publishing short biographies of the major players in Montreal during the period 1943–1946, thereby demonstrating how those young people’s careers developed in the post-war years. Many went on to receive high scientific honours and academic prestige. In order to put the articles in context, I have also reproduced the abstracts of some British Ministry of Supply reports which were written in the early part of the war (1940–1942), and which are relevant because several of the British scientists involved subsequently found themselves in Montreal. To give some background to the early Canadian work, I have reprinted part of an article by George Laurence (First Head of the Canadian Atomic Energy Control Board) who was an early contributor to research in neutron chain reactors, and whose enthusiasm and talent undoubtedly contributed to the decision to start the atomic energy project in Canada. Over the next few years, this journal or its companion, Annals of Nuclear Energy, will publish a selection of the more important MT reports so that they will be readily accessible to scholars and to practising nuclear engineers. One of these reports, written in 1944 by Boris Davison and which is of seminal value, is reproduced in this issue with kind permission of Atomic Energy of Canada Ltd.

06/02126 MELCOR 1.8.4 sensitivity analysis of the severe accident evolution during the APR 1400 LOCA: Ahn, K. -1. et al. Annals of Nuclear Energy, 2006, 33, (l), 71–83.

06/02126 MELCOR 1.8.4 sensitivity analysis of the severe accident evolution during the APR 1400 LOCA: Ahn, K. -1. et al. Annals of Nuclear Energy, 2006, 33, (l), 71–83.

06/02127 Optimization of the power ascension path for a boiling water reactor using genetic algorithms: Lee, C. -S. and Lin, C. Annals of Nuclear Energy, 2006, 33, (1), 53–61.

The innovative CANDLE (Constant Axial shape of Neutron flux, nuclide densities and power shape During Life of Energy producing reactor) burnup strategy has been successfully applied to both fast and thermal reactors. In particular for thermal reactor applications, CANDLE block-type high temperature gas-cooled reactors (HTGRs) with either U–Pu or U–Th fuel cycle had been proposed and investigated for their simple and safe reactor operation, and the ease of designing a long life reactor. In this work, we investigated the use of Pa-231 mixed homogeneously in the (Th-232/U-233)O2 fuel kernel of the TRISO particles, that is the U–Th–Pa fuel, to obtain better CANDLE burnup performance. Some consideration on how to supply the required U-233 and Pa-231 was also thoroughly discussed. U–Th–Pa fuel decreases the required amount of natural Gd burnable poison in the fresh fuel for establishing a valid CANDLE HTGR design since Pa-231 has a large thermal absorption cross section. Besides the role as a burnable poison nuclide, Pa-231 also serves as a fertile nuclide during the CANDLE burning since Pa-231 is finally transmuted to a fissile U-233 nuclide. A promising analysis result shows that for U-233 and Pa-231 concentrations of 15 and 7.50 w/o, respectively, the discharged burnup can be increased from 138 (U-Th fuel) to 149 GWd/t. This extends the core life time about 16%, i.e. from 35 (U-Th fuel) to 41 years with CANDLE active core height of 800 cm and reactor thermal power of 30 MWth.

06/02119 BWR core-wide stability analysis with respect to dominant feedback mechanisms and characteristic poles: Morishima, N. et al. Annals of Nuclear Energy, 2006, 33, (1), 43–52.

One of the limiting contributors to the heat load constraint for a long term spent fuel repository is the decay of americium-241. A possible option to reduce the heat load produced by Am-241 is to eliminate it via transmutation in a light water reactor thermal neutron environment, in particular, by taking advantage of the large thermal fission cross section of Am-242 and Am-242m. In this study we employ lattice loading optimization techniques to define the loadings and arrangements of fuel pins with blended americium and uranium oxide in boiling water reactor bundles, specifically, by defining the incineration of pre-loaded americium as an objective function to maximize americium transmutation. Subsequently, the viability of these optimized lattices is tested by assembling them into bundles with Am-spiked fuel pins and by loading these bundles into realistic three-dimensional BWR core-wide simulations that model multiple reload cycles and observe standard operational constraints. These simulations are possible via our collaboration with the Westinghouse Electric Co. which facilitates the use of industrial-caliber design tools such as the PHOENIX-4/POLCA-7 sequence and the Core Master 2© GUI work environment for fuel management.The resulting analysis confirms the ability to axially uniformly eliminating roughly 90% of the pre-loaded inventory of recycled Am-241 in BWR bundles with heterogeneous target pins. This high level of incineration was achieved within three to four 18-month operational cycles, which is equivalent to a typical in-core residence time of a BWR bundle.

06/02382 Investigations on post-dryout heat transfer in bilaterally heated annular channels: Tian, W. X. et al. Annals of Nuclear Energy, 2006, 33, (2), 189–197.

06/02382 Investigations on post-dryout heat transfer in bilaterally heated annular channels: Tian, W. X. et al. Annals of Nuclear Energy, 2006, 33, (2), 189–197.

06/02386 Measurements of activation cross-sections for the 19F(n, α) 16 N reaction for neutrons with energies between 13 and 15 MeV : Durusoy, A. and Reyhancan, I. A. Annals of Nuclear Energy, 2006, 33, (2), 159–162.

06/02386 Measurements of activation cross-sections for the 19F(n, α) 16 N reaction for neutrons with energies between 13 and 15 MeV : Durusoy, A. and Reyhancan, I. A. Annals of Nuclear Energy, 2006, 33, (2), 159–162.

06/02130 Reliability analysis of safety grade decay heat removal system of Indian prototype fast breeder reactor: Arul, A. J. et al. Annals of Nuclear Energy, 2006, 33, (2), 180–188.

06/02130 Reliability analysis of safety grade decay heat removal system of Indian prototype fast breeder reactor: Arul, A. J. et al. Annals of Nuclear Energy, 2006, 33, (2), 180–188.

06/02390 On the accuracy of reactor physics calculations for square HPLWR fuel assemblies: Jatuff, F. et al. Annals of Nuclear Energy, 2006, 33, (2), 198–207.

06/02390 On the accuracy of reactor physics calculations for square HPLWR fuel assemblies: Jatuff, F. et al. Annals of Nuclear Energy, 2006, 33, (2), 198–207.

06/02125 Managing the reactivity excess of the gas turbine-modular helium reactor by burnable poison and control rods: Talamo, A. Annals of Nuclear Energy, 2006, 33, (l), 84–98.

06/02125 Managing the reactivity excess of the gas turbine-modular helium reactor by burnable poison and control rods: Talamo, A. Annals of Nuclear Energy, 2006, 33, (l), 84–98.

06/02388 Neutron kinetics in subcritical cores with application to the source modulation method: Wright, J. and Pazsit, I. Annals of Nuclear Energy, 2006, 33, (2), 149–158.

06/02388 Neutron kinetics in subcritical cores with application to the source modulation method: Wright, J. and Pazsit, I. Annals of Nuclear Energy, 2006, 33, (2), 149–158.

06/02135 A study on the degree of deliberation and meditation of cyber poll respondents for nuclear-related decision making: Park, M. S. et al. Annals of Nuclear Energy, 2006, 33, (2), 163–169.

06/02135 A study on the degree of deliberation and meditation of cyber poll respondents for nuclear-related decision making: Park, M. S. et al. Annals of Nuclear Energy, 2006, 33, (2), 163–169.

06/02141 Effects of accident management strategy on the severe accident environmental conditions: Lee, B. C. et al. Annals of Nuclear Energy, 2006, 33, (1), 13–21.

06/02141 Effects of accident management strategy on the severe accident environmental conditions: Lee, B. C. et al. Annals of Nuclear Energy, 2006, 33, (1), 13–21.

06/02133 Study of the spatial discretization and temperature distribution approximation effects on BWR assembly calculations: Tohjoh, M. et al. Annals of Nuclear Energy, 2006, 33, (2), 170–179.

06/02133 Study of the spatial discretization and temperature distribution approximation effects on BWR assembly calculations: Tohjoh, M. et al. Annals of Nuclear Energy, 2006, 33, (2), 170–179.

06/02371 A practical method for calculation of mass-attenuation coefficients of β particles: Gürler, O. and Yalçin, S. Annals of Nuclear Energy, 2005, 32, (18), 1918–1925.

06/02371 A practical method for calculation of mass-attenuation coefficients of β particles: Gürler, O. and Yalçin, S. Annals of Nuclear Energy, 2005, 32, (18), 1918–1925.