New delayed neutron group constants and covariances for LWR core applications, combining summation calculations and integral experiments

Leconte, Pierre; Archier, P.; Jean, C. De Saint; Diniz, Ricardo; Santos, Adimir dos; Fautrat, L.; Foligno, Daniela; Geslot, B.; Gilad, Erez; Tamagno, Pierre; Truchet, G.; Zoia, Andrea

doi:10.1016/j.anucene.2019.107250

Cited by 9 publications

(4 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Priors were centred on TRIPOLI-4 computed values and their distribution was Gaussian. Their standard deviation, σ, was taken from recent work on nuclear data [5][6]. Note that prior knowledge information is helpful to converge to a physical solution and that 𝜆 𝑖 are fixed in JEFF3.1.1.…”

Section: Computational Toolmentioning

confidence: 99%

Measurement of delayed neutrons in a thermal nuclear reactor by means of a long run pile noise experiment in sub-critical state

Boffy¹,

Truchet²,

Geslot³

et al. 2023

EPJ Web of Conf.

Self Cite

View full text Add to dashboard Cite

The transfer function of a zero-power thermal reactor was successfully measured thanks to neutron noise techniques from 1 mHz to 160 Hz. During a month-long experimental campaign, the fluctuations of the neutron population in critical and subcritical configurations of the core were acquired using excore fission chambers and analysed through Cross-Power Spectral Density (CPSD) methodology. Firstly, the reactor’s kinetic parameters, i.e. prompt decay constant, effective delayed neutron fraction and generation time, were obtained at critical state. It required calibrating the reactor’s power, which was done by metal foil activation and measurement of the 235U fission rate. Secondly, these parameters were used to estimate the groups’ abundances of delayed neutrons from the CPSD measured in a sub-critical state. Fitting data with a point kinetic model was done with Bayesian inference - CONRAD and Stan programs were used. A very good agreement was found between experimental abundances and the ones computed with TRIPOLI-4 Monte-Carlo transport code and JEFF3.1.1 nuclear data library. Uncertainties on prior abundances between 6 % to 101 %, held mainly by nuclear data, were lowered down to 4 % to 54 %, depending on the delayed group.

show abstract

Section: Computational Toolmentioning

confidence: 99%

Measurement of delayed neutrons in a thermal nuclear reactor by means of a long run pile noise experiment in sub-critical state

Boffy¹,

Truchet²,

Geslot³

et al. 2023

EPJ Web of Conf.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Advances in code development for reactor physics simulations may also made the experimental modulation studies less attractive in inferring the core parameters. Starting from 2000, several modulation studies with a focus on the determination of kinetic parameters, especially for delayed neutron parameters, are found in the literature [13][14][15][52][53][54]. The kinetic parameter evaluations in major nuclear data libraries rely essentially on experimental data, and the impact of undocumented uncertainty and experimental conditions of various experiments are difficult to quantify.…”

Section: After 1980mentioning

confidence: 99%

“…Fig.4. ZPTF phase measured in the MINERVE reactor[54] compared with equivalent results with the kinetic parameters from Brady & England (ENDF/B-VIII.0β4[56]), Keepin 6-group (JENDL-4.0[57]) and Keepin 8-group expanded (JEFF-3.3[58]). …”

mentioning

confidence: 99%

Review of kinetic modulation experiments in low power nuclear reactors

Jiang

Geslot

Lamirand

et al. 2020

EPJ Nuclear Sci. Technol.

View full text Add to dashboard Cite

The safety improvement of nuclear reactors requires continuous efforts in understanding the fundamental physical quantities related to the fission process. In neutronic models, the reactor dynamics is covered by the kinetic parameters to characterize the temporal behavior of the neutron population subject to perturbations. The reactor transfer function is a frequency domain analogy of this temporal description. It can be measured experimentally through transfer function analysis via noise analysis or kinetic modulation, for the study of reactor stability and kinetic parameters. This paper summarizes the experimental measurements of reactor transfer function through kinetic modulation. Extensive work have been conducted experimentally, starting from the beginning of reactor physics research. An overview is given regarding various experimental designs and conducted analyses. The concepts of the modulation system are also discussed. The current work is limited to online contents and internal archives of CEA Cadarache due to difficulties in accessing references traced back to 1950s.

show abstract

“…A particular feature of the RTF of low power reactors, namely the Zero-Power reactor Transfer Function (ZPTF), is that it is only dependent on the kinetic behavior of prompt and delayed neutron population produced in the fission chain reaction. While an extensive amount of computational work were conducted to improve the modeling of reactor kinetics, recent studies [2][3][4] have shown the potential of an alternative experimental approach, through in-core reactivity modulation, towards the better understanding of the underlying physical phenomena. In this context, the PISTIL device (Periodic reactivity Injection System Transients Induced Locally) was developed by CEA in the framework of a collaboration between CEA and EPFL.…”

Section: Introductionmentioning

confidence: 99%

PISTIL, a reactivity modulation device to probe the transfer function of the nuclear reactor CROCUS

et al. 2021

View full text Add to dashboard Cite

The present article summarizes the development and testing of a reactivity modulation device developed by the French Atomic and Alternative Energies Commission (CEA). It was installed in the CROCUS reactor of the Swiss Federal Institute of Technology in Lausanne (EPFL). Experimental tests were performed in the framework of a collaboration between CEA and EPFL. The so-called PISTIL device aims at measuring the nuclear reactor transfer function in the frequency range of interest between 1 mHz and 200 Hz, in order to probe the in-core kinetic behavior of prompt and delayed neutrons. The reactivity modulation is obtained from the rotation of cadmium foils. The design of the system was driven with the objective of installing PISTIL at the center of the CROCUS reactor. Neutronic simulations with TRIPOLI-4 Monte Carlo code were performed to select the suitable design parameters and meet the safety requirements of the reactor operation. The total reactivity worth of the device, as estimated by TRIPOLI-4 Monte Carlo calculation, was approximately 0.16 $ and the maximum amplitude of the reactivity modulation was about 0.013 $. In-core reactivity calibration was then performed and were consistent as compared to TRIPOLI-4 estimations.

show abstract

New delayed neutron group constants and covariances for LWR core applications, combining summation calculations and integral experiments

Cited by 9 publications

References 20 publications

Measurement of delayed neutrons in a thermal nuclear reactor by means of a long run pile noise experiment in sub-critical state

Measurement of delayed neutrons in a thermal nuclear reactor by means of a long run pile noise experiment in sub-critical state

Review of kinetic modulation experiments in low power nuclear reactors

PISTIL, a reactivity modulation device to probe the transfer function of the nuclear reactor CROCUS

Contact Info

Product

Resources

About