Superphénix Reactivity and Feedback Coefficients

Vanier, M.; Bergeonneau, P.; Gauthier, J. C.; Jacob, M.; Antoni, Joan; Gesi, E.; Peerani, P.; Adam, J. P.

doi:10.13182/nse90-a23754

Cited by 15 publications

(26 citation statements)

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“…This implies that the calculation accuracy of K R is reasonable, and the calculation uncertainty can be smaller. It should be noted that the measured values of K R and K in are independent of each other because the temperature change owing to a reactor power increase is clearly separated from the R/V inlet temperature change, as defined in Equations (4)- (6). In contrast, the calculated values of K R and K in are correlated through common components such as the Doppler reactivity.…”

Section: Feedback Reactivity Coefficientsmentioning

confidence: 98%

“…They are classified into the following three systems. The source range monitor is used at the start-up of the reactor, the WRM is used from the start-up to power opera- 6.5/0.47 mm tion, and the power range monitor is used for monitoring during power operation. The WRM signals, which are monitored every 1 s, are used in the feedback reactivity experiment.…”

Section: Introductionmentioning

confidence: 99%

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Measurement and analysis of feedback reactivity in the Monju restart core

Kitano

Takegoshi

Hazama

2015

Journal of Nuclear Science and Technology

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The purpose of this study is to develop a feedback reactivity measurement technique in the Japanese prototype fast breeder reactor Monju and to validate calculation methodology to forecast the nuclear feedback phenomena. A feedback reactivity measurement technique has been developed based on a reactivity model featuring components that depend on the reactivity coefficients, denoted as reactor power (K R ) and reactor vessel inlet temperature (K in ). This technique can precisely measure the two reactivity components simultaneously and was applied to the feedback reactivity experiment conducted in the Monju system start-up test in May 2010. A thorough evaluation considering all possible biases and uncertainties demonstrated that the reactivity coefficients can be evaluated with a measurement uncertainty smaller than 3%. The evaluated reactivity coefficients were simulated considering the temperature distribution in the core. The calculated and measured values of K R agreed within 1%, and the value of K in was consistent with that reported in a previous isothermal temperature coefficient experiment. The measured and calculated fuel subassembly outlet temperatures also agreed well within 0.2 • C, which supports the validity of the temperature calculation.

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Section: Feedback Reactivity Coefficientsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Measurement and analysis of feedback reactivity in the Monju restart core

Kitano

Takegoshi

Hazama

2015

Journal of Nuclear Science and Technology

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“…The Doppler Effect is one of the parameters of the core that concerns its dynamic behavior; knowledge of it is therefore important for safety reasons. In the Superphénix, after successful start-up, a test was performed to determine the Doppler effect of the core [10]. In isothermal conditions, the reactivity variation of a core can be described as function of the temperature, as shown in Equation 2, by considering a logarithmic temperature dependence of the Doppler Effect.…”

Section: Doppler Testmentioning

confidence: 99%

Analysis of the Superphenix Start-Up Tests With Apollo-3: From Zero Power Isothermal Conditions to Dynamic Power Transient Analysis

et al. 2021

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Sodium-cooled Fast Reactors (SFRs) remain a potential candidate to meet future energy needs. In addition, the SFRs experimental feedback is considerable, for instance, the French research program has considered experimental facilities including the Superphénix which has emerged as a transition to commercial deployment. In this paper a set of tests from the Superphénix start-up are reanalyzed with new tools, considering APOLLO-3 and TRIPOLI-4 (respectively deterministic and stochastic codes) for neutron physics evaluation, GERMINAL-V2 for the fuel irradiation behavior and CATHARE-3 for the thermal-hydraulics modelling. Neutron physics evaluations are performed for the main control rod worth and the Doppler Effect, both measured under isothermal conditions at Superphénix start-up. A good agreement is obtained for these tests, which were purely neutronic tests. Next, the core temperature distribution is evaluated at nominal conditions, where larger discrepancies are observed. However, these deviations are related to the measurement of the fuel assemblies, which have a larger than expected uncertainty. Finally a transient, consisting of a negative reactivity insertion, is analyzed to assess the dynamic core behavior. A good agreement is obtained during the reactivity insertion, however the thermal-hydraulic model has to be improved, namely the vessel model, which is considered as a 0-D volume.

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“…If this clarification is understood literally, then the PCR will be equal to zero (Kazansky and Slekenichs 2012). The above formulated definition is accompanied in a number of publications by additions such as "with coolant flow rate being constant" (Ovchinnikov and Semenov 1988), or "under the condition of constant water temperature" (Seleznev 2013), or "with constant coolant temperature at the reactor core inlet" (Nier et al 1990), or "under the condition of constancy of coolant heating and inlet coolant temperature" (FGUP 2004). Two definitions of PCR at constant coolant temperature at the reactor core inlet and PCR at constant coolant temperature in the reactor core are used in the guidance document (FGUP 2004) on the basis of which CR values are measured during VVER-1000 reactor start-up operations.…”

Section: Diversity Of Understanding About Pcrmentioning

confidence: 99%

Power coefficient of reactivity: definition, interconnection with other coefficients of reactivity, evaluation of results of transients in power nuclear reactors

Kazansky¹,

Slekenichs²

2018

NUCET

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It is assumed by the authors of the present paper that with growing contribution of nuclear power in the production of electricity, nuclear power plants will be used to a higher degree in a manoeuvrable mode of operation rather than in the base-load mode. In other words, change of power from the nominal level to that of coverage of auxiliary loads will be becoming quite common and not so rare event as scheduled reactor shutdowns for fuel reloading or preventive works. There exist well-known problems in the use of nuclear reactors in the manoeuvrable operation mode, which include the task shared by all types of nuclear reactors. It is advisable to have a unified indicator weakly power-dependent and fairly easy to measure, which would make it possible to formulate the judgement about the nature of the transient processes within the entire power range and to assess the reactivity required for changing the power level by the preset value. Power reactivity coefficient (PRC) can be used as such indicator. Analysis was made of existing definitions and understanding of PRC in relevant references. It turned out that there is no generally accepted definition of the PRC. Based on the performed study, the following definition was suggested: the PRC is the ratio of the low reactivity introduced into the reactor to the power increment at the end of the transient process. It is assumed here that variation of reactivity is dependent on the energy released in nuclear fission but is not related to the changes of reactivity induced by feedback signals in the automatic reactor power control system. Analysis of the relationship between the PRC and temperature coefficients and technological parameters associated with the steady-state control program was performed taking the above suggested definition into account. PRC calculations were performed using the simplest model of VVER-1000 type power reactor. It was found that PRC is weakly power-dependent. The purpose of the present study is to investigate dependence of PRC on the temperature reactivity effects and on the technological parameters associated with the steady-state control program of the power unit, using the example of VVER-1000. Effects of PRC on the static and dynamic power reactor operation modes are analyzed.

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Superphénix Reactivity and Feedback Coefficients

Cited by 15 publications

References 0 publications

Measurement and analysis of feedback reactivity in the Monju restart core

Measurement and analysis of feedback reactivity in the Monju restart core

Analysis of the Superphenix Start-Up Tests With Apollo-3: From Zero Power Isothermal Conditions to Dynamic Power Transient Analysis

Power coefficient of reactivity: definition, interconnection with other coefficients of reactivity, evaluation of results of transients in power nuclear reactors

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