Simulation of Nuclear Transmutation using
PyNE- Nuclear Engineering Toolkit in Python
Chirag Maheshkumar Sedani PG Student
UPES, Bidholi-Dehradun, Uttarakhand, India
Abstract
Nuclear transmutation is a process in which conversion of one isotope into another isotope takes place as product of nuclear reactions. PyNE is nuclear engineering toolkit for python. In this paper simulation of transmutation is shown using PyNE in python. Initially PyNE was installed in python to access all the library files. PyNE has all the library file within itself, which has been imported and then simulation has been done. In this paper transmutation of Fe-56 is given. All the stages of transmutation are simulated and at the end total time required for transmutation is also given. Transmutation of any material can be performed using this toolkit under defined circumstances.
Keywords: Nuclear Transmutation, PyNE, Python Simulation
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I. INTRODUCTION
Nuclear Transmutation
To transmute means to convert one element in to another and by extension one isotope to another. The main physical process to perform useful transmutation is nuclear fission. One example of transmutation by fission can be:
n + 239Pu (24000 years) 134Cs (2 years) + 104Ru (stable) + 2 n + 200 MeV
In above reaction 239Pu and n (Neutron) interacts with fission process and produces 134Cs, 104Ru and 200 MeV. The nuclear transmutation is a possible concept of the nuclear fuel cycle that aims to transform a large fraction of long term source of radioactivity, radiotoxicity, and heat into stable or short lived (<30 years) materials i.e. plutonium and minor actinides. The final objective of transmutation is reducing the radiotoxicity and the volume of the high level waste of future reactors and fuel cycles to improve their sustainability. Also increasing the capacity of geological repository for the waste already produced and to be produced by the present reactors.
Transmutation is induced by the irradiation of transuranic waste by high neutron fluxes. Transuranic waste will fission producing fission fragments and energy. Industrial transmutation requires intense neutron source and produce large amount of energy. It must be done in nuclear reactor.
PyNE
PyNE is a suite of tools to aid in computational nuclear science & engineering. PyNE seeks to provide native implementations of common nuclear algorithms, as well as Python bindings and I/O support for other industry standard nuclear codes [4].
II. LITERATURE SURVEY
Oyeon kum [1] stated that, the CINDER code has about 60 years of development history, and is thus one of the world's best transmutation computing codes to date. Unfortunately, it is complex and cumbersome to use. Preparing auxiliary input files for activation computation from MCNPX output and executing them using Perl script (activation script) is the first difficulty, and separation of gamma source computing script (gamma script), which analyzes the spectra files produced by CINDER code and creates source definition format for MCNPX code, is the second difficulty. In addition, for highly nonlinear problems, multiple human in-terventions may increase the possibility of errors. Postprocessing such as making plots with large text outputs is also time consuming. One way to improve these limitations is to make a graphical user interface wrapper that includes all codes, such as MCNPX and CINDER, and all scripts (with a visual C#.NET tool). The graphical user interface merges all the codes and provides easy postprocessing of graphics data and Microsoft office tools, such as Excel sheets, which make the CINDER code easy to use.
complex. The obtained data were used for determining starting nuclide composition for different cooling-down times prior to the beginning of transmutation (irradiation in neutron fluxes) to be input in the ORIGEN2 code.
Composition of fission fragments incorporating 830 nuclides obtained as the result of simulation of the burnup for 439GT fuel assembly (TVSA type) for VVER-1000 nuclear reactor [11] during 3 years using MCU-PTR software complex [12] was selected for transmutation. Subsequently, irradiation of the above set of fragments in neutron flux was simulated using ORIGEN2 code [13]. ORIGEN2 code is supported with its own neutron data library of one-group cross-sections for typical spectra of ther-mal and fast reactors. Calculation was performed using homogenous model with spatially uniform neutron flux not taking into account the effects of blocking of cross-sections. Therefore, calculations of transmutation factors ξr are of approximate nature. Calculation was performed for two neutron spectra: fast re-actor spectrum (= 3.65 × 1015 s–1 cm–2) and thermal reactor spectrum (= 3.65 × 1014 s–1 cm–2). Author concluded that, the calculated transmutation factors proved to be notice-able only during residence of fission fragments in the reactor core: their values reach 5–10 and depend only on the duration of cooling down of fission fragments prior to the beginning of transmutation. The longer is the cooling down period the higher value is attained by the transmutation factor. This is most likely in correlation with the fraction of stable fission fragments which amounts for the case of cooling down during 30 years to about 85%, and to only about 15% for zero cooling down time. After extraction of fission fragments from the neutr on flux transmutation factor reduces to unity within several years. After additional hundred years of irradiation in thermal reactor neutron spectrum the value of transmutation factor reduces to 0.5–0.8. The following trend is clearly visible here: the longer is the irradiation time the larger is the gain obtained as the result of transmutation.
Yu. A Kazansky [3] stated that, the closure of uranium-based fuel cycle assumes that Uranium and Plutonium are extracted from the spent fuel. Among remaining heavy nuclides, the most radioactive are minor actinides. One of the concepts to reduce the reprocessed fuel radioactivity is the repeated long-term irradiation of minor actinides (this process is referred to as transmutation). There are works stating the necessity of hard spectrum neutrons for irradiation, for which special reactors-transmuters and accelerator-driven systems are to be included into the fuel cycle. In his work, practicability of minor actinide transmutation in thermal spectrum reactors is considered. The main factor representing the transmutation practicability that is used in this work, is the ratio of radioacitivities with transmutation, and without, ξ (t). This ratio as a function of time can be greater or less than 1, and its values define to the most extent the transmutation practicability. We computed functions ξ (t) for minor actinides. The conclusions are (from the reduction of radioactivity point of view): Neptunium transmutation is hardly necessary, since the order of magnitude reduction in radioactivity is first reached in hundred thousand years; rather small effect (the order of magnitude radioactivity reduction in 500 years) is found for Curium; the Americium radioactivity is reduced by factor of 10–100 in 300 years after irradiation. It is shown that the best values of ξ (t) are reached at 70–08% burnup of minor actinides. The final conclusion about the practicability of Americium and Curium transmutation must be drawn by taking into account in the considered scenarios the difference in probability of the environmental release, the difference of biological effect and the transmutation efficiency of minor actinides continuously fed to spent fuel storages by the operating nuclear energy industry.
Nicholas W. Touran [5] stated that, advanced nuclear reactors offer safe, clean, and reliable energy at the global scale. The development of such devices relies heavily upon computational models, from the pre-conceptual stages through detailed design, licensing, and operation. An integrated reactor modeling framework that enables seamless communication, coupling, automation, and continuous development brings significant new capabilities and efficiencies to the practice of reactor design. In such a system, key performance metrics (e.g., optimal fuel management, peak cladding temperature in design-basis accidents, levelized cost of electricity) can be explicitly linked to design inputs (e.g., assembly duct thickness, tolerances), enabling an exceptional level of design consistency. Coupled with high-performance computing, thousands of integrated cases can be executed simultaneously to analyze the full system, perform complete sensitivity studies, and efficiently and robustly evaluate various design tradeoffs. TerraPower has developed such a tool—the Advanced Reactor Modeling Interface (ARMI) code system and has deployed it to support the TerraPower Traveling Wave Reactor design and other innovative energy products currently under development. The ARMI code system employs pre-existing tools with strong pedigrees alongside many new physics and data management modules necessary for innovative design. Verification and validation against previous and new physical measurements, which remain an essential element of any sound design, are being carried out.
III. SIMULATION
PyNE has all the library files within it. So to run the simulation library files are imported and then the code was run.
Input
import time import sys
import numpy as np from pyne import nucname from pyne.material import Material
from pyne.transmute.chainsolve import Transmuter nucid = nucname.id('FE56')
t_sim = 31536000.0 tol = 1e-7
phi = np.array([ # fluxin1 from ALARA
0.00000E+00, 0.00000E+00, 0.00000E+00, 0.00000E+00, 0.00000E+00, 0.00000E+00, 0.00000E+00, 8.98755E+13, 9.77446E+12, 8.06925E+12, 1.70726E+12, 1.28302E+12, 1.89143E+12, 2.04175E+12, 2.07250E+12, 1.80384E+12, 1.54256E+12, 1.42579E+12, 1.24872E+12, 1.17419E+12, 1.14707E+12, 1.19572E+12, 1.22437E+12, 1.26141E+12, 4.38938E+11, 9.07635E+11, 1.39910E+12, 1.45818E+12, 1.48523E+12, 1.43566E+12, 1.41561E+12, 1.40784E+12, 1.35321E+12, 2.71459E+12, 2.62508E+12, 2.66233E+12, 1.40292E+12, 1.42487E+12, 1.37130E+12, 1.37665E+12, 1.52025E+12, 1.59680E+12, 1.07723E+12, 2.77969E+11, 2.78790E+11, 5.53898E+11, 1.09314E+12, 1.64561E+12, 1.68331E+12, 1.74677E+12, 1.80254E+12, 1.93480E+12, 1.96231E+12, 1.93938E+12, 1.92934E+12, 1.93774E+12, 1.90789E+12, 1.82967E+12, 1.88061E+12, 1.89368E+12, 1.81907E+12, 3.42703E+12, 1.43106E+12, 2.05052E+12, 1.78729E+12, 1.86431E+12, 1.83209E+12, 1.87158E+12, 1.80219E+12, 1.73173E+12, 1.60686E+12, 1.29878E+12, 1.48781E+12, 1.61671E+12, 1.60349E+12, 1.59722E+12, 3.03722E+12, 2.90241E+12, 1.42928E+12, 1.35835E+12, 2.69252E+12, 2.55807E+12, 2.86956E+11, 1.05539E+11, 2.25492E+11, 5.88210E+11, 1.19440E+12, 2.20287E+12, 1.08398E+12, 1.03200E+12, 9.75760E+11, 9.46015E+11, 9.12835E+11, 9.29522E+11, 8.90411E+11, 8.30228E+11, 8.45313E+11, 8.07049E+11, 7.71896E+11, 7.07755E+11, 8.21782E+11, 7.22692E+11, 7.33346E+11, 6.91441E+11, 1.63354E+12, 1.56807E+12, 5.29641E+11, 4.48653E+11, 1.07702E+12, 8.07461E+11, 1.82087E+12, 7.58110E+11, 1.26259E+12, 1.12779E+12, 1.54243E+12, 6.74366E+11, 8.42541E+11, 4.34202E+11, 2.89471E+11, 3.71251E+11, 2.64038E+11, 2.30016E+11, 5.82748E+11, 9.47843E+11, 1.71492E+12, 1.80379E+12, 5.48701E+11, 8.73235E+11, 1.82674E+12, 1.52497E+12, 1.48336E+12, 9.67624E+11, 6.31697E+11, 6.03210E+11, 5.84716E+11, 1.49733E+11, 1.84075E+11, 7.72799E+11, 1.82977E+11, 1.80083E+12, 1.48029E+12, 1.45254E+12, 1.44214E+12, 1.34832E+12, 1.10171E+12, 1.27549E+12, 1.33060E+12, 1.27163E+12, 1.32883E+12, 1.32596E+12, 1.35429E+12, 1.34940E+12, 1.34862E+12, 1.34699E+12, 1.32883E+12, 1.33697E+12, 1.33352E+12, 1.32882E+12, 1.32283E+12, 1.31655E+12, 1.30955E+12, 1.30178E+12, 1.29327E+12, 1.28377E+12, 1.27355E+12, 1.26193E+12, 1.24944E+12, 1.23535E+12, 1.21970E+12, 1.20272E+12, 1.18312E+12, 1.16152E+12, 1.13736E+12, 2.82140E+12, 5.36871E+13])
tm = Transmuter(phi=phi, tol=tol, log=sys.stdout) t1 = time.time()
out = tm.transmute(inp, t=t_sim) dt = time.time() - t1
print 'Transmutation time: {0}'.format(dt)
As the output it shows the chain reaction of the radionuclides and at last it shows the time for transmutation as well.
Output
--> Fe56 1.0
|--> Fe57 [ 0.00438046] |--> Fe57 1.0
| |--> Fe56 [ 8.55972423e-06] | |--> Fe56 1.0
| | |--> Fe57 [ 1.25875636e-08] | | |--> Mn55 [ 4.94094467e-10] | | |--> Cr52 [ 3.87491320e-12] | | |--> Mn54 [ 3.38033850e-14] | | |--> Fe55 [ 3.24252005e-09] | | |--> Mn56 [ 1.59905049e-12] | | |--> Cr53 [ 3.71225677e-10] | |--> Mn57 [ 5.29448233e-12] | |--> Fe58 [ 9.18336666e-06] | |--> Fe58 1.0
| | |--> Mn58 [ 5.50579059e-17] | | |--> Cr55 [ 5.18805000e-15] | | |--> Fe59 [ 2.42666743e-09] | | |--> Mn58M [ 6.01801770e-11] | | |--> Cr54 [ 5.18991130e-12] | | |--> Mn56 [ 8.01386265e-19] | |--> Cr56 [ 1.66874942e-20] | |--> Cr53 [ 1.21595729e-08] | |--> Mn55 [ 7.74655993e-10] | |--> Cr54 [ 2.35240098e-07] | |--> Cr54 1.0
| | |--> V52 [ 6.44852455e-20] | | |--> Ti50 [ 2.69566822e-13] | | |--> V53 [ 5.32034599e-18] | | |--> Cr53 [ 2.81950119e-10] | | |--> V54 [ 2.55387164e-17] | | |--> Ti51 [ 1.79352912e-16] | | |--> Cr55 [ 1.40945438e-15] | |--> Cr55 [ 1.19819151e-17] | |--> Mn56 [ 6.72436461e-11] |--> Mn55 [ 0.00017116] |--> Mn55 1.0
| |--> Mn56 [ 1.74489151e-09] | |--> Cr54 [ 1.20633097e-08] | |--> Cr55 [ 2.39406026e-13] | |--> V52 [ 1.79426349e-13] | |--> V51 [ 3.06438194e-10] | |--> V53 [ 1.75536085e-17] | |--> Mn54 [ 1.68383934e-07] | |--> Mn54 1.0
| | |--> Cr52 [ 4.39773662e-15] | | |--> V51 [ 6.93564656e-12] | | |--> V50 [ 4.80612381e-13] | | |--> V52 [ 1.47767256e-21] | | |--> Fe54 [ 4.51302168e-14] | | |--> V53 [ 3.45313498e-25] | | |--> Mn53 [ 1.61107481e-10] | | |--> Cr54 [ 4.85981083e-08] | | |--> Mn55 [ 1.08024686e-09] | | |--> Cr53 [ 1.28688325e-11] | |--> Cr53 [ 2.41876795e-10] |--> Cr52 [ 1.35040579e-06] |--> Cr52 1.0
| |--> Ti48 [ 2.66741826e-14] | |--> V51 [ 1.51384510e-10] | |--> Ti50 [ 2.07097938e-16] | |--> V52 [ 4.27284275e-15] | |--> Ti49 [ 7.92519715e-11] | |--> Cr51 [ 1.09072537e-10] | |--> Cr53 [ 8.89591993e-10] | |--> Ti51 [ 2.85300050e-23] |--> Mn54 [ 9.72921990e-09] |--> Fe55 [ 0.00105972] |--> Fe55 1.0
| |--> Fe56 [ 6.22048126e-06] | |--> Fe56 1.0
| | |--> Fe55 [ 2.40410966e-09] | | |--> Mn56 [ 1.16209472e-12] | | |--> Cr53 [ 2.75434266e-10] | |--> Cr54 [ 1.70537115e-08] | |--> Mn53 [ 1.95492583e-09] | |--> Cr51 [ 1.01013449e-10] | |--> Mn54 [ 1.07010032e-08] | |--> Cr53 [ 1.51280374e-12] | |--> Fe54 [ 6.21810640e-07] | |--> Fe54 1.0
| | |--> Mn52 [ 3.11634445e-16] | | |--> Cr50 [ 1.79244516e-13] | | |--> Mn53 [ 4.64570346e-10] | | |--> Mn52M [ 7.15530513e-18] | | |--> Cr52 [ 1.96993819e-15] | | |--> Mn54 [ 3.23514650e-10] | | |--> Cr51 [ 1.75120966e-11] | | |--> Fe53 [ 1.68786921e-16] | | |--> Fe55 [ 7.66412987e-10] | | |--> Cr53 [ 1.97548348e-12] | |--> Cr52 [ 1.30221707e-07] | |--> Cr52 1.0
| | |--> Ti48 [ 1.75295891e-15] | | |--> V51 [ 9.94592049e-12] | | |--> Ti50 [ 1.35963708e-17] | | |--> V52 [ 4.12032917e-16] | | |--> Ti49 [ 5.20510264e-12] | | |--> Cr51 [ 9.57762086e-12] | | |--> Cr53 [ 5.85551932e-11] | | |--> Ti51 [ 2.75115238e-24] | |--> Mn55 [ 0.00013905] | |--> Mn55 1.0
| | |--> Mn56 [ 1.41705352e-09] | | |--> Cr54 [ 6.66065700e-09] | | |--> Cr55 [ 1.94499632e-13] | | |--> V52 [ 1.45770504e-13] | | |--> V51 [ 1.69294963e-10] | | |--> V53 [ 1.42610748e-17] | | |--> Mn54 [ 9.87971943e-08] | | |--> Cr53 [ 1.33878231e-10] |--> Mn56 [ 1.85782312e-07] |--> Mn56 1.0
| |--> Fe56 [ 0.00043724] | |--> Fe56 1.0
| | |--> Fe57 [ 9.63708652e-07] | | |--> Fe57 1.0
| | | |--> Fe56 [ 9.31024176e-10] | | | |--> Cr54 [ 2.55199144e-12] | | | |--> Mn53 [ 2.95532308e-13] | | | |--> Cr51 [ 2.08480107e-14] | | | |--> Mn54 [ 1.71084565e-12] | | | |--> Cr53 [ 2.26986158e-16] | | | |--> Fe54 [ 9.30827174e-11] | | | |--> Cr52 [ 1.94843187e-11] | | | |--> Mn55 [ 2.08496906e-08] | | |--> Mn56 [ 8.17149537e-11] | | |--> Cr53 [ 2.83591353e-08] |--> Cr53 [ 0.00012834]
|--> Cr53 1.0
| |--> V52 [ 4.26296948e-14] | |--> Ti50 [ 5.78481821e-09] | |--> Ti49 [ 1.95066140e-11] | |--> V51 [ 1.50342873e-09] | |--> Ti51 [ 6.02570968e-19] | |--> Cr52 [ 2.61458516e-07] | |--> Cr52 1.0
| | |--> Ti48 [ 3.45464382e-15] | | |--> V51 [ 1.96007372e-11] | | |--> Ti50 [ 2.67941074e-17] | | |--> V52 [ 8.27277081e-16] | | |--> Ti49 [ 1.02577389e-11] | | |--> Cr51 [ 1.91077670e-11] | | |--> Cr53 [ 1.15404141e-10] | | |--> Ti51 [ 5.52374408e-24] | |--> V53 [ 8.76560312e-14] | |--> Cr54 [ 1.97194095e-06] | |--> Cr54 1.0
| | |--> V52 [ 5.40558810e-19] | | |--> Ti50 [ 2.26464551e-12] | | |--> V53 [ 4.45987252e-17] | | |--> Cr53 [ 2.36865302e-09] | | |--> V54 [ 2.14082727e-16] | | |--> Ti51 [ 1.50345712e-15] | | |--> Cr55 [ 1.18149969e-14] | |--> Ti52 [ 1.28370431e-23] Transmutation time: 67.0712919235
IV. CONCLUSION
PyNE is the toolkit which provides simplicity to code all the situation in the terms of simulation. Here in this simulation it is very simple to code the transmutation process with lots of data within the toolkit otherwise it is very complicated to simulate such big chain reaction with tons of data. Also it gives very systematic output so that it can be easily understand. It provides not only transmutation data but all other data regarding nuclear engineering.
REFERENCES
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Karpovich, , Nuclear Engineering and Technology (2017).
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