Conceptual Designing of Reduced-Moderation Water Reactor (RMWR)

Ōkubo, Tsutomu; Iwamura, Takamichi; Akimoto, Hajime; Araya, Fumimasa; Ohnuki, Akira; Yamamoto, Kazuhito

doi:10.1299/jsmepes.2000.7.250

Cited by 13 publications

(16 citation statements)

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“…The former is derived by introducing experimental values semifictitiously generated by a linear combination (LC) of weighted experimental values, and the latter by products of exponentiated (PE) experimental values. 1) In the present study, we apply the extended bias factor methods to the prediction accuracy evaluation of neutronic characteristics of a breeding light water reactor 2) with the use of the data of FCA-XXII-1 critical experiments 3) and demonstrate the effectiveness of using the extended bias factor methods with the use of these experimental results in reducing uncertainties of typical neutronic characteristics of the target core such as criticality, reaction rate ratio, and reactivity worth. The main purpose of the present study is to evaluate the features and effectiveness of the extended bias factor methods on the basis of the actual core design and existing experimental results, identifying various errors in different neutronic characteristics.…”

Section: Introductionmentioning

confidence: 91%

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Prediction Accuracy Improvement of Neutronic Characteristics of a Breeding Light Water Reactor Core by Extended Bias Factor Methods with Use of FCA-XXII-1 Critical Experiments

Kugo

Andoh

Kojima

et al. 2008

J. Nucl. Sci. Technol.

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Two extended bias factor methods, the LC and PE methods, were applied to the prediction accuracy evaluation of neutronic characteristics of a breeding light water reactor, using data of FCA-XXII-1 critical experiments, in order to investigate the features and effectiveness of these methods on the basis of an actual core design and existing experimental results. The present study confirms the following features of these methods. Both the LC and PE methods can improve the prediction accuracy the most when all the experimental results are used. The prediction accuracy improvement is achieved mainly by reducing uncertainty due to errors in cross sections. This is done by realizing a profile of sensitivity coefficients closer to that of the target core and suppressing the influence of errors in experiments and experimental analysis methods. The PE method always improves the prediction accuracy with the use of any combination of experimental results. It is always superior to the LC method in the improvement of the prediction accuracy. Concerning the effectiveness of using the extended bias factor methods with the data of FCA XXII-1 critical experiments, it is concluded that the experimental results regarding multiplication factor are more effective than the other experimental results, namely, reaction rate ratios of 238 U capture to 239 Pu fission (C28/F49) and void reactivity, in reducing prediction uncertainties of all the neutronic characteristics of the target core investigated: the multiplication factor, the C28/F49, and the void reactivity of the target core. This is due to the fact that the extended bias factor methods cannot fully utilize the potential that these experimental results have for the reduction of the uncertainties due to the errors in cross sections because of their strong correlations to the target core characteristics. This failure is due to large errors in the experiments and/or the experimental analysis methods.

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Section: Introductionmentioning

confidence: 91%

“…The target core is a breeding light water reactor core 2) designed for a high conversion ratio and a high burn-up to effectively utilize uranium fuel through plutonium multiple recycling with mixed oxide fuel. Another important design target is negative void reactivity, necessary from the safety point of view.…”

Section: A Breeding Light Water Reactor Corementioning

confidence: 99%

Prediction Accuracy Improvement of Neutronic Characteristics of a Breeding Light Water Reactor Core by Extended Bias Factor Methods with Use of FCA-XXII-1 Critical Experiments

Kugo

Andoh

Kojima

et al. 2008

J. Nucl. Sci. Technol.

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“…For the core designing of such a breeding light water reactor (LWR) core, it is important to accurately predict core characteristics such as criticality, a breeding performance and a void reactivity and improve the prediction accuracy of them. Through the conceptual designing, we have constructed a tentative core design concept (1) under a BWR-type concept with relatively high core void fraction.…”

Section: Introductionmentioning

confidence: 99%

Application of Bias Factor Method with Use of Exponentiated Experimental Value to Prediction Uncertainty Reduction in Coolant Void Reactivity of Breeding Light Water Reactor

Kugo

Kojima

Andoh

et al. 2008

JPES

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We have applied the bias factor method to a coolant void reactivity of a breeding light water reactor with use of FCA-XXII-1 experiment with introducing a concept of exponentiated experimental value into the bias factor method. We have formulated the prediction uncertainty reduction by the use of the bias factor method extended by the concept of the exponentiated experimental value. From the numerical results, it is verified that the present method can reduce the prediction uncertainty in the design calculation value while the conventional bias factor method cannot reduce it. The present method overcomes a problem caused by the conventional bias factor method in which the prediction uncertainty increases in the case that the experimental core has the opposite reactivity worth and the consequent opposite sensitivity coefficients to the real core. It is concluded that the introduction of exponentiated experimental value can effectively utilize experimental data and extend applicability of the bias factor method.

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“…Figure 1 shows a representative design of the reactor, core and fuel assembly of the FLWR. 4) The FLWR consists of a flat core with an internal blanket region and a triangular tight-lattice rod bundle, both to reduce the moderation of neutrons and to attain negative void reactivity coefficients. Since the FLWR makes plutonium multirecycling possible, the reactor fills the need for the effective utilization of uranium resources and long-term energy supply.…”

Section: Introductionmentioning

confidence: 99%

Effect of Rod Bowing on Critical Power Based on Tight-Lattice 37-Rod Bundle Experiments

Tamai

Kureta

Wei

et al. 2008

J. Nucl. Sci. Technol.

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The confirmation of thermal-hydraulic performance is one of the most important R&D requirements for the design of the Innovative Water Reactor for FLexible Fuel Cycle (FLWR). Since the effect of rod bowing on critical power has not been determined yet due to the lack of experimental data, a large-scale thermal-hydraulic experiment using a tight-lattice 37-rod bundle test section with a bowed rod was carried out with pressure ranging from 2-9 MPa and mass velocity at 200-1000 kg/(m 2 s). It was confirmed that boiling transition (BT) occurs downstream of the rod contact point, and that the wall temperature trace during the BT follows the typical BT pattern of BWR. The critical power with a bowed rod is about 10% lower than that without rod bowing. The critical power increases monotonically with the increase in mass velocity, with the decrease in inlet water temperature, and with the decrease in exit pressure, and these trends are similar to those of the basic bundle without rod bowing. Thus, there is a negligible effect of rod bowing on the dependence of critical power on the mass velocity, the inlet temperature, and the exit pressure.

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Conceptual Designing of Reduced-Moderation Water Reactor (RMWR)

Cited by 13 publications

References 0 publications

Prediction Accuracy Improvement of Neutronic Characteristics of a Breeding Light Water Reactor Core by Extended Bias Factor Methods with Use of FCA-XXII-1 Critical Experiments

Prediction Accuracy Improvement of Neutronic Characteristics of a Breeding Light Water Reactor Core by Extended Bias Factor Methods with Use of FCA-XXII-1 Critical Experiments

Application of Bias Factor Method with Use of Exponentiated Experimental Value to Prediction Uncertainty Reduction in Coolant Void Reactivity of Breeding Light Water Reactor

Effect of Rod Bowing on Critical Power Based on Tight-Lattice 37-Rod Bundle Experiments

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