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Journal Articles

Reliability evaluation of SPEEDI's prediction by comparison with calculated results based on meteorological observation data

Rintsu, Yuko*; Serizawa, Shigeru*; Yamazaki, Tetsuo*; Umeyama, Nobuaki*; Moriuchi, Shigeru*; Handa, Hiroyuki*; Onishi, Ryoichi*; Takemura, Morio*; Chino, Masamichi; Nagai, Haruyasu; et al.

Proceedings of 16th Pacific Basin Nuclear Conference (PBNC-16) (CD-ROM), 6 Pages, 2008/10

no abstracts in English

Journal Articles

My first stay in Provence in the south of France

Takemura, Morio

FAPIG, (175), p.3 - 17, 2007/07

According to the established agreement on construction of International Thermonuclear Experimental Reactor ITER in France, many engineers of the participant countries of ITER project have left for their new assignments to the Cadarache work site since the middle of 2006. This paper reports an overseas life, which has been experienced by the author for the first time, over a long period of time from last November with focus on personal experience and impression. With introduction of the work site of CEA research center of Cadarache, residence place Aix-en-Provence and the region of Provence including them, there are described environments and troubles in dairy life, a wall of foreign language, and pleasures of weekends.

Journal Articles

Accessibility evaluation of the IFMIF liquid lithium loop considering activated erosion/corrosion materials deposition

Nakamura, Hiroo; Takemura, Morio*; Yamauchi, Michinori*; Fischer, U.*; Ida, Mizuho*; Mori, Seiji*; Nishitani, Takeo; Simakov, S.*; Sugimoto, Masayoshi

Fusion Engineering and Design, 75-79, p.1169 - 1172, 2005/11

 Times Cited Count:5 Percentile:37.38(Nuclear Science & Technology)

In the IFMIF, activated erosion/corrosion materials of Li target back wall deposits on a surface of the Li loop. Therefore, accessibility during maintenance of the Li loop pipings will depend on the activation level of the deposition materials. This paper evaluates effect of target activation on the accessibility of the Li loop pipings. Activation level is calculated by the ACT-4 code. High energy cross section above 15 MeV is introduced using IEAF-2001 data. In this calculation, target material is stainless steel 316. Area of the erosion/corrosion in the back wall is 100 cm$$^{2}$$. The erosion/corrosion rate is 1 micron/y. Dose rate around the Li loop after one year IFMIF operation is evaluated assuming 1% deposition of the erosion/corrosion materials and uniform deposition on surface area of 33 m$$^{2}$$. Permissible level for hands-on maintenance is 10 microSv/hr. As the results, after 1 week from shutdown, close maintenance work 8 cm to the Li loop is possible. Also, after 1 month, hands-on maintenance becomes possible.

Journal Articles

Estimation of radioactivities in the IFMIF liquid lithium loop due to the erosion and corrosion of target back-wall

Yamauchi, Michinori*; Takemura, Morio*; Nakamura, Hiroo; Fischer, U.*; Ida, Mizuho*; Mori, Seiji*; Sato, Satoshi; Nishitani, Takeo; Simakov, S. P.*; Sugimoto, Masayoshi

Fusion Science and Technology, 47(4), p.1008 - 1011, 2005/05

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Review of JAERI activities on the IFMIF liquid lithium target in FY2004

Nakamura, Hiroo; Ida, Mizuho*; Matsuhiro, Kenjiro; Fischer, U.*; Hayashi, Takumi; Mori, Seiji*; Nakamura, Hirofumi; Nishitani, Takeo; Shimizu, Katsusuke*; Simakov, S.*; et al.

JAERI-Review 2005-005, 40 Pages, 2005/03

JAERI-Review-2005-005.pdf:3.52MB

The International Fusion Materials Irradiation Facility (IFMIF) is being jointly planned to provide an accelerator-based Deuterium-Lithium (Li) neutron source to produce intense high energy neutrons (2 MW/m$$^{2}$$) up to 200 dpa and a sufficient irradiation volume (500 cm$$^{3}$$) for testing the candidate materials and components up to about a full lifetime of their anticipated use in ITER and DEMO. To realize such a condition, 40 MeV deuteron beam with a current of 250 mA is injected into high speed liquid Li flow with a speed of 20 m/s. In target system, radioactive species such as 7Be, tritium and activated corrosion products are generated. In addition, back wall operates under severe conditions of neutron irradiation damage (about 50 dpa/y). In this paper, the thermal and thermal stress analyses, the accessibility evaluation of the IFMIF Li loop, and the tritium inventory and permeation of the IFMIF Li loop are summarized as JAERI activities on the IFMIF target system performed in FY2004.

JAEA Reports

JASPER Experimental data book (VII); Gap streaming Experiment

Takemura, Morio*

JNC TJ9450 2000-002, 112 Pages, 2000/03

JNC-TJ9450-2000-002.pdf:2.55MB

This report is intended to make it easier to apply the measured data obtained from the Gap Streaming Experiment, which was conducted at the Oak Ridge National Laboratory (ORNL) during about two months beginning at the start of March, 1992 as the sixth one of a series of eight experiments planned for the Japanese-American Shielding Program for Experimental Research (JASPER) which was started in 1986. For this reason. the information presented includes specifications and measurement data for all configurations, compositions of all materials, characteristics of the measurement system. and daily-basis records of measurements. The Gap Streaming Experiment was planned to obtain the data of neutron streaming characteristics in the inclosure system above the core of an advanced fast reactor for verification and improvement of the analysis method to be applied to the shielding design. A iron-lined solid or slit concrete assembly was placed, with or without a spectrum modifier forming soft incident neutron spectrum, behind the TSR-II reactor of Tower Shielding Facility. Inserting central cylinders and cylindrical sleeves gave various gap width and offset in the slit concrete assembly. Neutron flux was measured behind the configurations with various types of detectors. The integral neutron flux in wide energy region was measured on radial traverse and on the axis behind the concrete assembly in almost all configurations. Neutron spectrum and fine radial distribution in high energy region was measured further in case of hard incident neutron spectrum, Information presented in this report is based mainly on a report issued by ORNL (ORNL/TM-12140. "Measurements for the JASPER Program Gap Streaming Experiment"). Additional information reported by the assignee is utilized also.

JAEA Reports

JASPER Experimental data book (VI); Special materials experiment

Mori, Tomoaki*; Takemura, Morio*

JNC TJ9450 2000-001, 96 Pages, 2000/03

JNC-TJ9450-2000-001.pdf:2.04MB

This report is intended to make it easier to apply the measured data obtained from the Special Materials Experiment, which was conducted at the Oak Ridge National Laboratory (ORNL) during about a month beginning at the end of June, 1992 as the last one of a series of eight experiments planned for the Japanese-American Shielding Program for Experimental Research (JASPER) which was started in 1986. For this reason. the information presented includes specifications and measurement data for all configurations, compositions of all materials, characteristics of the measurement system. and daily-basis records of measurements. The Special Materials Experiment was planned to obtain the data of neutron attenuation characteristics of selected shielding materials for use in advanced fast reactors. The material of particular interest for the experiment was zirconium hydride that is rich in hydrogen. The mockup slabs for the special materials were preceded by the spectrum modifier behind the TSR-II reactor of Tower Shielding Facility. The layer of zirconium hydride was simulated with a combination of zirconium and polyethylene slabs. The thick layer of polyethylene with no zirconium was installed in some configurations.Neutron flux was measured behind the configurations with various types of detectors. The integral neutron flux in wide energy region was measured in eight configurations and neutron spectrum in high energy region was measured also in almost all configurations. Information presented in this report is based mainly on a report issued by ORNL (ORNL/TM-12277. "Measurements for the JASPER Program Special Materials Experiment"). Additional information reported by the assignee is utilized also.

JAEA Reports

Revise of a basic data base for shielding design

*; Takemura, Morio*

JNC TJ9440 2000-005, 157 Pages, 2000/03

JNC-TJ9440-2000-005.pdf:3.7MB

With use of the two-dimensional discrete ordinates code DORT and the standard groupwise shielding design library JSSTDL produced from the latest evaluated nuclear data library JENDL-3.2, experimental analyses for the representative configurations in the Radial Shield Attenuation Experiment of the JASPER were performed. The results were compared with those obtained with use of traditional method DOT3.5/JSDJ2 for the previous JASPER experimetal analyses. In general, the change of the cross section library gives higher results and the change of the transport code gives lower results. Finally the new analysis method gives better agreement with the experimental results and also less deviations of calculational errors between various detectors. Experimental analyses for the thick concrete configulation in the Gap Streaming Experiment of the JASPER was also performed with the new analysis method, after solving the poor agreement found in last year with the original JASPER experimental analyses. The same tendency due to the library change was confirmed with the above mentioned analyses of the Radial Shield Attenuation Experiment. Compilation of the input data necessary for future reanalyses of important configurations in JASPER experiments were continued through the above-mentioned experimental analyses and related informations were added for repletion of the database preserved in a computer disk holding previously accumulated data. Input data descriptions were made for auxiliary routines needed for the experimental analyses and their sample data were compiled and stored in the database.

JAEA Reports

Preparation of a basic data base for shielding design (IV)

*; Takemura, Morio*

JNC TJ9440 99-002, 141 Pages, 1999/03

JNC-TJ9440-99-002.pdf:3.13MB

With use of a standard groupwise shielding design library JSSTDL produced from the latest evaluated nuclear data library JENDL-3.2, experimental analyses for the JASPER experiments were performed. In order to verify the new version of JSSTDL, whose cross setions of thermal energy region was updated, the polyethylene transmission experiments of the Special Materials Experiment was analysed again, and also zirconium transmission experiment of the Experiment was newly analysed. JSSTDL was applied to the analysis of neutron multiplicative region of the in-vessel fuel storage mockup configulations in the IVS Experiment. Also it was applied to the analyses of neutron streaming effect through the mockup of sodium window in B$$_{4}$$C shield in the Flux Monitor Experiment and also the mockup of narrow gaps in thick concrete shield in the Gap Streaming Experiment. The results were compared with those obtained by the same analysis method and input data using the JSDJ2 library that had been applied consistently to the JASPER experiment analyses. Although the analysis with the new version of JSSTDL resulted in a little reduction of overestimation in the polyethylene transmission configulation, the results obtained with JSSTDL are, in general, higher than those with JSDJ2 as had been found in analyses in preceding years for the Radial Shield Attenuation Experiment, the Axial Shield Experiment, the Intermediate Heat Exchager Experiment and so on. Compilation of the input data necessary for future reanalyses of important configurations in JASPER experiments, that were selected at the first stage of this study, were continued and new data were added into the computer disk holding previously accumulated data.

JAEA Reports

JASPER Experimental data Book (IX); Axial shield re-measurement experiment

*; Takemura, Morio*

JNC TJ9440 99-001, 104 Pages, 1999/03

JNC-TJ9440-99-001.pdf:2.12MB

This report is intended to make it easier to apply the measured data obtained from the Axial Shield Re-Measurement Experiment, which was conducted at the Oak Ridge National Laboratory(ORNL) during about one month beginning at the start of August, 1992 as the last one of a series of experiments planned for the Japanese-American Shielding Program for Experimental Research (JASPER) which was started in 1986. For this reason, the information presented includes specifications and measurement data for all configurations, compositions of all materials, characteristics of the measurement system, and daily-basis records of measurements. Axial Shield Experiment was performed in 1990, to study the neutron attenuation characteristics of the axial shield of liquid metal fast reactor (LMR) which is designed in the fuel assembly to reduce the neutron fluence in regions above the core. However, the investigation of the experimental results showed the capability of the influence to the streaming characteristics by the scattered neutrons from the concrete region surrounding the mockup of axial shield region. So, the Axial Shield Re-Measurement Experiment was newly planned and performed, in which the concrete region was covered by lithium-paraffin layer at the front surface. A spectrum modifier was placed behind the TSR-II reactor of Tower Shielding Facility to mockup the leakage neutron spectrum typical to LMRs. Neutron flux was measured behind the experimental configurations with various types of detectors. Information presented in this report is based mainly on a report issued by ORNL (ORNL/TM-12276, "Measurements for the JASPER Program Axial Shield Re-Measurement Experiment") Additional information reported by the assignee is utilized also.

JAEA Reports

JASPER Experimental data book (VIII); Flux monitor experiment

Takemura, Morio*

PNC TJ9055 98-003, 89 Pages, 1998/03

PNC-TJ9055-98-003.pdf:1.89MB

This report is intended to make it easier to apply the measured data obtained from the Flux Monitor Experiment, which was conducted at the Oak Ridge National Laboratory (ORNL) during about two months beginning at the start of May, 1992 as the seventh one of a series of eight experiments planned for the Japanese-American Shielding Program for Experimental Research (JASPER) which was started in 1986. For this reason, the information presented includes specifications and measurement data for all configurations, compositions of all materials, characteristics of the measurement system, and daily-basis records of measurements. The Flux Monitor Experiment was planned to examine the shielding concerns and neutron transport characteristics pertaining to the neutron instrumentation systems (NIS) designed to monitor neutron flux within the reactor vessel of an advanced fast reactor, for verification and improvement of the analysis method to be applied to the shielding design. A spectrum modifier and a mockup around NIS was placed, with or without a in-vessel fuel storage region, behind the TSR-II reactor of Tower Shielding Facility. Neutron flux was measured behind the configurations or in situ with various types of detectors. The integral neutron flux in wide energy region was measured with Bonner ball detectors on the axis and on radial traverse in almost all configurations. Fast neutron spectrum was further measured with spectrometors and also radial distribution of low energy neutron with fission chambers. Information presented in this report is based mainly on a report issued by ORNL (ORNL/TM-12171, "Measurements for the JASPER Program Flux Monitor Experiment"). Additional information reported by the assignee is utilized also.

JAEA Reports

Preparation of a basic data base for shielding design (III)

Takemura, Morio*

PNC TJ9055 98-002, 111 Pages, 1998/03

PNC-TJ9055-98-002.pdf:2.21MB

With use of a standard groupwise shielding design library JSSTDL produced from the latest evaluated nuclear data library JENDL-3.2, experimental analyses for the In-vessel Fuel Storage (IVS) Experiment and the Intermediate Heat Exchanger (IHX) Experiment were performed. The results were compared with those obtained by the same analysis method and input data using the JSDJ2 library that had been applied consistently to the JASPER experiment analyses. In general, the results obtained with JSSTDL are higher than those with JSDJ2 as were found in analyses in last two years for the Radial Shield Attenuation Experiment and the Special Materials Experiment and also the Axial Shield Experiment. The calculation-to-experiment ratios of the fast neutron flux just behind deep penetration in sodium were obtained first by these IVS and lHX experimental analyses with the JSSTDL library. However, it was confirmed not to be easy to evaluate the accuracy of sodium cross section because of its dependency on how to model the swelled sodium slabs and tanks. The analyses with the JSSTDL library were verified by comparison with other analyses with another library based on JENDL-3.2. Compilation of the input data necessary for future reanalyses of important configurations in JASPER experiments, that were selected at the first stage of this study, were continued and new data were added into the computer disk holding previously accumulated data.

JAEA Reports

JASPER Experimental data book (VII); Gap streaming experiment

Takemura, Morio*

PNC TJ9055 97-002, 112 Pages, 1997/03

PNC-TJ9055-97-002.pdf:2.51MB

This report is intended to make it easier to apply the measured data obtained from the Gap Streaming Experiment, which was conducted at the Oak Ridge National Laboratory (ORNL) during about two months beginning at the start of March, 1992 as the sixth one of a series of eight experiments planned for the Japanese-American Shielding Program for Experimental Research (JASPER) which was started in 1986. For this reason. the information presented includes specifications and measurement data for all configurations, compositions of all materials, characteristics of the measurement system. and daily-basis records of measurements. The Gap Streaming Experiment was planned to obtain the data of neutron streaming characteristics in the inclosure system above the core of an advanced fast reactor for verification and improvement of the analysis method to be applied to the shielding design. A iron-lined solid or slit concrete assembly was placed, with or without a spectrum modifier forming soft incident neutron spectrum, behind the TSR-II reactor of Tower Shielding Facility. Inserting central cylinders and cylindrical sleeves gave various gap width and offset in the slit concrete assembly. Neutron flux was measured behind the configurations with various types of detectors. The integral neutron flux in wide energy region was measured on radial traverse and on the axis behind the concrete assembly in almost all configurations. Neutron spectrum and fine radial distribution in high energy region was measured further in case of hard incident neutron spectrum, Information presented in this report is based mainly on a report issued by ORNL (ORNL/TM-12140. "Measurements for the JASPER Program Gap Streaming Experiment"). Additional information reported by the assignee is utilized also.

JAEA Reports

Preparation of a basic data base for shielding design (II)

Takemura, Morio*

PNC TJ9055 97-001, 112 Pages, 1997/03

PNC-TJ9055-97-001.pdf:2.63MB

With use of a standard groupwise shielding design library JSSTDL produced from the latest evaluated nuclear data library JENDL-3.2, experimental analyses for the Axial Shield Experiment (homogeneous and central blockage type shield configurations with B$$_{4}$$C or stainless steel shield material) were performed. The results were compared with those obtained by the same analysis method and input data using JSDJ2 library that had been applied consistently to the JASPER experiment analyses. In general, the results with JSSTDL analyses are higher than those by JSDJ2 as were found in analyses in last year for the Radial Shield Attenuation Experiment and the Special Materials Experiment. Consideration was made on the discrepancies between JSSTDL and JSDJ2 analysis results of the Axial Shield Experiment and also those of the sodium configulation in the Radial Shield Attenuation Experiment. The former was done by exchange of macro cross section of each region, and the latter forcused on sodium cross section was done with use of cross section sensitivity analysis method. Compilation of the input data necessary for future reanalyses of important configurations in JASPER experiments, that were selected in previous study in last year, were continued and new data were added into the computer disk holding previous ones.

JAEA Reports

Preparation of a basic data base for shieldind design

Mori, Tomoaki*; Takemura, Morio*

PNC TJ9055 96-002, 142 Pages, 1996/03

PNC-TJ9055-96-002.pdf:3.2MB

With use of a standard groupwise shielding design library JSSTDL produced from the latest evaluated nuclear data library JENDL-3.2, experimental analyses for the Radial Shield Attenuation Experiment (Configuration II; B$$_{4}$$C, configuration V; Na+B$$_{4}$$C) and the Special Materials Experiment (Configuration III; Polyethylene) were performed. The results were compared with those obtained by the same analysis method and input data using JSDJ2 library that had been applied consistently to the JASPER experiment analyses. In general, the results with JSSTDL analyses are higher than those by JSDJ2. In comparison of the analysis for the configuration including fissionable layer, it was made clear that the cross section libraries with only one group structure in the thermal energy region may give inadequate results when the thermal neutron flux level is relatively high in the fissionable layer neighbouring to such material with big slowing-down effect as polyethylene. Also it was confirmed in the thick sodium configuration that the balanced mesh sizes between axial and radial directions are important for accurate analysis. After a brief review of the state of the JASPER experiment analyses up to this time, important configurations for experiment reanalyses were selected and items of such data as input for the reanalyses were also listed up. The data for reanalyses of some of the selected configurations were arranged in computer files.

JAEA Reports

JASPER Experimental Data Book (VI); Special materials experiment

Mori, Tomoaki*; Takemura, Morio*

PNC TJ9055 96-001, 96 Pages, 1996/03

PNC-TJ9055-96-001.pdf:2.01MB

This report is intended to make it easier to apply the measured data obtained from the Special Materials Experiment, which was conducted at the Oak Ridge National Laboratory (ORNL) during about a month beginning at the end of June, 1992 as the last one of a series of eight experiments planned for the Japanese-American Shielding Program for Experimental Research (JASPER) which was started in 1986. For this reason. the information presented includes specifications and measurement data for all configurations, compositions of all materials, characteristics of the measurement system. and daily-basis records of measurements. The Special Materials Experiment was planned to obtain the data of neutron attenuation characteristics of selected shielding materials for use in advanced fast reactors. The material of particular interest for the experiment was zirconium hydride that is rich in hydrogen. The mockup slabs for the special materials were preceded by the spectrum modifier behind the TSR-II reactor of Tower Shielding Facility. The layer of zirconium hydride was simulated with a combination of zirconium and polyethylene slabs. The thick layer of polyethylene with no zirconium was installed in some configurations. Neutron flux was measured behind the configurations with various types of detectors. The integral neutron flux in wide energy region was measured in eight configurations and neutron spectrum in high energy region was measured also in almost all configurations. Information presented in this report is based mainly on a report issued by ORNL (ORNL/TM-12277. "Measurements for the JASPER Program Special Materials Experiment"). Additional information reported by the assignee is utilized also.

JAEA Reports

Summary report on analysis of JASPER experiments

Shono, Akira; Tsunoda, Hirokazu; Takemura, Morio; Handa, Hiroyuki

PNC TN9410 95-171, 280 Pages, 1995/06

PNC-TN9410-95-171.pdf:12.63MB

All experiments planned in the JASPER (Japanese-American Shielding Program for Experimental Research) project have been conducted from '85 to '92. Results obtained from the post-experimental analyses are described in the annual reports ('86$$sim$$'94). This report is intended to review and summarize the enormous information of the annual reports. For the evaluation, the following topics were chosen. (1)Bulk Shielding attenuation characteristics and analysis accuracy (2)Design-dependent shielding characteristics and analysis accuracy (3)Evaluation of the shielding cross section libraries (4)Improvements in shielding analysis methods. Major conclusions are briefly as follows. (a)Both bulk shielding attenuation characteristics and streaming characteristics of configurations consisting of several materials including boron-carbide(B$$_{4}$$C), graphite, stainless steel, sodium and etc. were clarified and the analysis accuracy confirmed. (b)JSDJ2 (based on the JENDL-2) was demonstrated to be a better cross section library for shielding analysis by reviewing experimental analyses results. (c)The shielding analysis system for fast reactors using a 2-dimensional discrete ordinates code as the standard has been improved and verified. (d)Useful experiences have been gained in verifying both a Monte Carlo code and a 3-dimensional discrete ordinates code, as well as in optimizing various parameters including those for mesh spacing techniques. Another objective of this report is to specify key information which will be useful to review JASPER. For this purpose, information on experiment and analysis is presented in a table format by each experimental item. All technical reports related to JASPER are listed.

JAEA Reports

Experimental data on DCA core(27); Critical experiments of the cores with aseismatic plates

*; Takemura, Morio*; *; *; Fukumura, Nobuo*

PNC TN941 83-65, 51 Pages, 1983/05

PNC-TN941-83-65.pdf:1.08MB

Critical experiments on DCA cores with aseismatic plates have been done in order to clarify the value of the reactivity worth of aseismatic plate and the behavior of the detailed power distribution or the thermal neutron flux distribution around the aseismatic plate. The aseismatic plate was arranged in the heavy water moderator of the nine central channel region of the DCA core. The thickness of the plate is 5mm, 20mm, 40mm or 80mm. The axial position of the plate was a half of critical heavy water level. The DCA core has a 25cm square lattice pitch and 97 fuel clusters with 1.2w/o uranium enrichments. The heavy water includes $$^{10}$$B($$sim$$3ppm). The coolant is light water. The reactivity worth of the plate was measured by use of the critical heavy water level between the cores with and without the plate. Axial power distribution was obtained by measuring the $$gamma$$-ray intensity of the typical fission product ($$^{140}$$La) of irradiated fuel rods. Axial thermal neutron flux distribution was obtained by measuring the activities of irradiated copper wires inserted in the central fuel channel or the moderator regions with and without the plate. The followings are found from the present experiments. (1)The reactivity worth of the aseismatic plate is monotonously increasing with the increase of the thickness of the plate. The values obtained by the present experiments change from about 0.1% $$Delta$$K to 1% $$delta$$K. (2)The axial power distribution depression by the plate with a 40mm thickness in the fuel cluster is increasing toward the outer from the inner in the fuel cluster. The value of the ratio of the depression to the maximum power is about 5% in the inner rod and about 10% in the outer rod. (3)The depression of the thermal neutron flux distribution around the plate in the moderator or in the fuel channel is increasing with increase of the plate thickness. The obtained value of the depression for the core with a 40mm thickness plate is ...

JAEA Reports

Critical experiment on half-inserted SUS control-rod measurement of change in power distribution in fuel pin close to control-rod

Takemura, Morio*; *; *; *; *

PNC TN941 83-67, 96 Pages, 1983/04

PNC-TN941-83-67.pdf:1.73MB

Pressure tube type heavy water reactor has an advantage of load following operation compared with light water reactor. It is planned to prove the possibility of load following operation in the Fugen type demonstration reactor using stainless control-rod (SUS control-rod). Changes in local power distribution and thermal flux distribution due to a small withdrawal of SUS control-rod have been measured for the purpose of confirming the soundness of fuel pin from the viewpoint of the load following operation and fuel design. SUS control-rod (74mm$$phi$$) with the same dimension as those of the demonstration reactor was inserted into the D$$_{2}$$O moderator of the central region of 0.54wt% plutonium mixed-oxide fuel lattice in 25-cm pitch DCA core. The lower end height of the control-rod inserted was changed from 505mm to 605mm (about 40$$phi$$ change in reactivity). Experimental results for the local power change were compared with calculations obtained from WIMS-D and CITATION codes. The following were concluded from the present study. (1)The maximum power change in outer layer pins of fuel cluster due to a small withdrawal of the control-rod occurs in the nearest fuel pin at the middle position of the axial displacement of the control-rod. (2)Outer layer fuel pin power after 100mm withdrawal of control-rod is (1.12$$pm$$0.03) times in maximum as large as that before withdrawal. (3)Local pin power change due to withdrawal of the control-rod occurs mainly in the fuel pins of the nearest and the second nearest fuel clusters to the control-rod. Even in the nearest fuel cluster to the control-rod, power change in the back side fuel pin to the control-rod is very small below 2%. (4)Calculated value of maximum ratio for the outer layer fuel pin power due to 100mm withdrawal of the control-rod overestimate experimental one about 4%.

JAEA Reports

Measurements of intra-cell thermal neutron flux distributions in plutonium fuel lattices; Experiments of multi-rod fuel clusters

*; Fukumura, Nobuo*; *; Takemura, Morio*; *; *

PNC TN941 83-49, 57 Pages, 1983/04

PNC-TN941-83-49.pdf:1.06MB

Intra-cell thermal neutron flux distributions have been measured in 36-rod and 54-rod plutonium fuel clusters by mean of dysprosium foil activation method. Enrichments of PuO$$_{2}$$ in PuO$$_{2}$$-UO$$_{2}$$ fuels used are 0.54 wt% for 36-rod cluster and 0.79 wt% for 54-rod cluster. In the central region of the Deuterium Critical Assembly, nine 36-rod or 54-rod fuel clusters were loaded and the surrounding region was occupied with 1.2 wt% UO$$_{2}$$ fuel clusters arranged in square lattice arrays of 25.0 cm pitch. The measurements were made using air or light water as coolant in the pressure tube. The measurement uncertainty in the present experiment was $$pm$$2 % which was almost the same as that in the previous experiments on plutonium lattices. The dependence of thermal neutron distributions on the number of plutonium fuel rods in the cluster were made clear by the results of present experiments. The present experimental resolts were compared with three calculation code ; the METHUSELAH-II code, the WIMS-D code and the LAMP-DCA code system. The results relevant to averaged thermal neutron flux in the fuel cluster of the METHUSELAH-II code agreed with the experimental results to within 7 %. The results calculated by the WIMS-D agreed with the experimental results within 6 %. On the other hand, the calculated values by the LAMP-DCA were in good agreement with the experimental results within 5 %.

23 (Records 1-20 displayed on this page)