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JAEA Reports

Reactivity measurement in the JUPITER experiment and Its accuracy

; Aoyama, Takafumi; ; Shirakata, Keisho

JNC TN9400 2001-032, 57 Pages, 2001/01

JNC-TN9400-2001-032.pdf:1.53MB

This report describes the reactivity measurement method and its accuracy employed in ZPPR (Zero Power Physics Reactor) test facility at Argonne National Laboratory, USA. In ZPPR, reactivity measurements were conducted by means of MSM (Modified Neutron Source Multiplication) method using the fission reaction rates by 64 $^{235}$ U fission chambers which were uniformly located in the core region. The MSM method can evaluate the subcritical reactivity considering the spatial distribution of neutron flux, although its basic equation is the one point approximation reactor dynamic theory. As each detector response varies depending on the core configuration, the uncertainty of the detector response affect directly the accuracy of measured reactivity. Therefore, the average value of many detectors had been conventionally used to reduce the statistical error in the measurerment. In this study, this method was modified to use the linear fitting between measured reaction rates and detector responses. Using this modified method, the uncertainty of each detector response affect the measured reactivity less than the simple averaging method. This new method was verified by applying to the ZPPR control rod worth measurements. It was found that the ratios of neutron source intensities and detector responses could be corrected accurately by the linear fitting in case of reactivity change without or with little fuel movement such as a unit control rod worth measurement.

Journal Articles

Spatial Neutronic Decoupling of Large FastBreeder Reactor Cores:Application to Nuclear Core Design Method

Shirakata, Keisho; ; Nakashima, Fumiaki

Nuclear Science and Engineering, 131, p.137 - 198, 1999/00

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JAEA Reports

Measurements of neutronic coupling of large FBR cores

Shirakata, Keisho

PNC TN9410 96-033, 28 Pages, 1996/02

PNC-TN9410-96-033.pdf:1.15MB

In the U.S.-Japan joint physics large LMFBR core critical experiment program (called JUPITER), neutronic couplings were measured in addition to usual physics characteristics. They were measured particularly in the JUPITER-Io program, whose main purp0se was to study the neutronic decoupling problems. Static, methods such as flux distortions caused by control rod insertion and flux tilt, and dynamic methods such as rod drop, boron oscillator and noise coherence experiments were applied to the measurements of eigenvalue separation, an indicator of the spatial decoupling. Measured results of different methods roughly agreed with each other, and also agreed with calculated results. As a result, it was made clear that the measurement methods were reliable and effective, and that the reactor physics parameter, called eigenvalue separation, could be measured.

Journal Articles

Neutronic Decoupling and Space-Dependent Nuclear Characteristics for Large Liquid-Metal Fast Breeder Reactor Cores

Shirakata, Keisho; ; Nakashima, Fumiaki

Nuclear Science and Engineering, 113(2), p.97 - 108, 1993/02

https://doi.org/10.13182/NSE113-97

Times Cited Count：8 Percentile：63.65(Nuclear Science & Technology)

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Journal Articles

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Sanda, Toshio; Nakashima, Fumiaki; Shirakata, Keisho

Donen Giho, (75), p.20 - 35, 1990/09

https://jopss.jaea.go.jp/pdfdata/PNC-TN1340-90-003.pdf

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Journal Articles

lmprovement af Calculation Method for FBR Control Rod Reactivity

Shirakata, Keisho; Yamamoto, Toshihisa

Donen Giho, (67), p.76 - 78, 1988/09

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Journal Articles

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Shirakata, Keisho; Suzuki, Takeo;

Genshiryoku Kogyo, 34(6), p.48 - 51, 1988/06

http://ci.nii.ac.jp/naid/40001073379

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JAEA Reports

JUPITER-III Experiment Analyses

Shirakata, Keisho; Nakashima, Fumiaki; Sanda, Toshio*; ; Kawashima, Masatoshi*; ;

PNC TN2410 88-004, 359 Pages, 1988/03

PNC-TN2410-88-004.pdf:10.17MB

The JUPITER-III program, which started in Jan. 1987, successfully ended after one year experimental period without any delay from the original schedule. In the study last year, we mainly proceeded the experimental planning checks and data arrangement. This time studies were done putting an emphasis on the analysis of the experimental data and following conlusions were derived from the studies. (1)Pre-analysis for ZPPR-18 was done attempting to check the experimental plan. The result was actually reflected to the experiments for ZPPR-18 successfully. (2)Analysis of criticality for ZPPR-17A, 17B and 17C was done. The C/E value 1.0003 for ZPPR-17A comes to be almost the same value as that for ZPPR-9, which is 0.9995. (3) $_{eff}$ evaluation was made for ZPPR-17A and ZPPR-17B. The value obtained in this study is higher by 3 % than that of ANL, which shows the same tendency as found in the JUPITER-I and II analyses. (4)Control rod calculations were done for ZPPR-17A and 17B. The following C/E values were obtained as a result. Plate type control rod : 0.8710.899. Pin type control rod : 0.8830.890. (5)Experimental data arrangement was done for large zone sodium void experiments and for sodium void drawer oscillating experiments. (6)Criticality analysis for ZPPR-12 was performed for the pin cores and the plate Cores. The C/E value for central and edge pin zone cores agreed with those for the plate cores as shown bellow. Central pin : 1.018. Edge pin : 1.019. Plate cores : 1.020 (7)An attempt was made for building a data base system for the JUPITER programs, using the ZPPR-17A experimental data as an test example. (8)Multidrawer effect was evaluated for ZPPR-17A. The effect on criticality is +0.17k/k.