Fission cross-section measurement for the 238U(n,f)89Rb reaction induced by D-T neutrons
Introduction
Neutron-induced reactions play an essential role in nucleosynthesis, advanced nuclear reactor design, and stockpile stewardship. Neutron-induced reaction cross-sections data are crucial, not only for fundamental research on nuclear science [1], [2], but also for practical applications in nuclear technology [3], [4], [5]. Thus, it is necessary to measure the precise cross-section values and update database constantly.
238U constitutes more than 90% of nuclear fuel in power reactors [6], [7], [8] with a relative abundance of 99.27%. Deuterium-tritium fusion reaction produces 14 MeV neutrons, which are 2–5 orders of magnitude lower in flux than a 1 MW TRIGA reactor [9], [10]. Accurate knowledge of neutron induced reaction cross-sections around 14 MeV plays a key role in nuclear engineering designs and safe operation of various reactors. It is important to study the fission cross-sections of 238U and 232Th induced by neutrons besides the (n,γ) and (n,xn) reactions.
Many research groups have studied on the cumulative fission yields and description of the fission fragment mass distribution for the 238U(n,f) and 232Th(n,f) reactions by using time-of-flight [11], [12] and off-line γ-ray spectrometric [13], [14] techniques. Our group has performed a series of measurements [15], [16], [17], [18], [19], [20], [21], [22], [23] on the fission data for 232Th induced by D-T and D-D neutrons. In this work, we focus on the measurement of fission cross-sections of 238U induced by D-T neutron. The half-life of fission product was used to identify the possible radionuclide. Pure/background-less activation targets, monoenergetic neutron beams with high flux, and high-resolution low-background γ-ray spectroscopy helped minimize the uncertainties of the measurements.
Section snippets
Experimental details
The irradiation experiment was performed at the K-400 Intense Neutron Generator at the Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics. Neutrons around 14 MeV were produced from T(d,n)4He reaction, and the details of neutron generator were described in our previous articles [15], [16], [17], [18], [19], [20], [21], [22], [23]. The neutron was monitored by accompanying α-particles to make a correction caused by the flux fluctuation in the neutron activation
Fission cross-section estimation
The fission cross-section (σx) can be deduced as the following with the developed NAA formula [26]:where, the subscripts m and x represent the terms associated with the monitor (m) and measured (x) reaction, respectively. σm is the cross-section of the monitor reaction. ε is the detection efficiency. Iγ is the gamma intensity. η is the isotopic abundance of target nuclide. M is the mass of sample. A is the atomic weight. C is the measured gamma count of
Results
Using the time schedule from Fig. 1, a series of gamma spectra were obtained. As shown in Fig. 2, (a) is a full gamma ray spectrum obtained from the UO2(NO3)2 sample, which was irradiated at the neutron energy of 14.1 MeV; (b) is the partial spectrum of the full gamma spectrum with the interested gamma ray of 89Rb. The half-life helped to determine the gamma spectrum with a certain time schedule of cooling and measuring. Identification of the daughter nuclide in the gamma spectrum was based on
Summary
The fission reactions of 238U induced by D-T neutrons were investigated. The half-life was used to identify the possible fission product. The cumulative fission cross-sections of 238U(n,f)89Rb reaction channel were estimated by the selected characteristic γ-peaks (1031.92 keV and 1248.14 keV) with a simple averaged value, i.e., 33.2 ± 2.1, 32.2 ± 2.0, and 32.6 ± 2.1 mb, related to En = 14.1 ± 0.3, 14.5 ± 0.3, and14.7 ± 0.3 MeV, respectively. The cross-sections of 238U(n,f)89Kr fission channel
CRediT authorship contribution statement
Qiang Wang: Writing - original draft, Writing - review & editing, Methodology. Yafei Han: Investigation, Validation, Methodology. Luocheng Yang: Validation, Data curation. Lixin Qin: Formal analysis, Investigation. Changlin Lan: Funding acquisition. Kaihong Fang: Conceptualization, Project administration, Funding acquisition.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
This work was supported by the Fundamental Research Funds for the Central Universities of China (No. lzujbky-2019-53), and the Lanzhou Talent Innovation and Entrepreneurship Project (2019-1-51), and the National Natural Science Foundation of China (No. 11975113).
References (33)
- et al.
Neutron economy and nuclear data for transmutation of long-lived fission products
Prog. Nucl. Energy
(2002) - et al.
Experimental investigation of radioactivities induced in fusion reactor structural materials by 14-MeV neutrons
Fusion Eng. Des.
(2000) - et al.
Cross sections of (n, x) reactions on cerium isotopes induced by D-T neutrons
Appl. Radiat. Isotopes
(2019) Study on transmutation of minor actinides discharged from high burn-up PWR-MOX spent fuel in the force-free helical reactor
Ann. Nucl. Energy
(2003)- et al.
The RTNS-II fusion materials irradiation facility
J. Nucl. Mater.
(1986) - et al.
Fission product yields from 232Th, 238U, and 235U Using 14 MeV neutrons
Nucl. Data Sheets
(2017) - et al.
Measurement of fission products yields in the quasi-mono-energetic neutron-induced fission of 232Th
Nucl. Phys. A
(2016) - et al.
Measurement of fission cross-section for 232Th(n, x)89Rb reaction induced by neutrons around 14MeV
Appl. Radiat. Isotopes
(2012) - et al.
Fission cross-section of the 232Th(n, f)131Sb reaction induced by neutrons around 14 MeV
Radiat. Phys. Chem.
(2017) - et al.
Measurement of the cross-sections for 238U(n, γ)239U reaction in the energy range of 14.1–14.8 MeV using neutron activation method
Radiat. Phys. Chem.
(2018)
Measurement of cross-sections for 14 MeV neutron interaction with 175Lu
Appl. Radiat. Isotopes
ENDF/B-VII.1 nuclear data for science and technology: cross-sections, covariances, fission product yields and decay data
Nucl. Data Sheets
A transfer standard for d+t neutron fluence and energy
Nucl. Instr. Meth.
Cross-sections for 13.5–14.7 MeV neutron induced reactions on palladium isotopes
Appl. Radiat. Isotopes
Half-lives of some short-lived mass-separated gaseous fission products and their daughters
Nucl. Phys. A
Nuclear data sheets for A=89
Nucl. Data Sheets
Cited by (1)
Artificial neural network spectral light curve template for type Ia supernovae and its cosmological constraints
2021, Modern Physics Letters A