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Journal Articles

None

; ; ; ;

Donen Giho, (90), p.49 - 55, 1994/06

https://jopss.jaea.go.jp/pdfdata/PNC-TN1340-94-002.pdf

Journal Articles

None

;

Donen Giho, (79), p.88 - 94, 1991/09

https://jopss.jaea.go.jp/pdfdata/PNC-TN1340-91-003.pdf

None

JAEA Reports

Measurement of coolant void reactivity in the core fueled with 36-rod clusters

*; *; *; *; *

PNC TN9410 88-135, 39 Pages, 1988/10

PNC-TN9410-88-135.pdf:4.08MB

Behavior of coolant void reactivity due to change in fissile enrichment or composition of 36-rod test fuel cluster has been clarified in the core fueled with the same form fuel assembly as that of Fugen type demonstration reactor. Experimental results will contribute to the investigation of design code WIMS concerning accuracy for the test fuel lattice. The test fuel clusters were loaded in the central (3$$times$$3) channels and/or in those one channel. The test clusters consist of five types in all as shown in the following table; two types of UO$$_{2}$$ and three types of PuO$$_{2}$$-UO$$_{2}$$. Void reactivities were measured by means of the critical level difference method. In the measurement of void reactivities, nine type I clusters were loaded in the (3$$times$$3) channels of the core, and the test cluster of the center channel was replaced with type II, III, IV or V test cluster. Driver fuel (28-rod 1.2 wt% UO$$_{2}$$) channels were made always to be as an air coolant (100%-voided) condition. The void reactivity shifted farther to the negative side as the void fraction increased, if there was no or small distribution of enrichment in the cluster. However, the void reactivity shifted to the positive side compared with the case of no distribution, if the distribution of enrichment was provided in the cluster.

JAEA Reports

Local power distribution in the segment fuel assembly

*; *; *; *; *

PNC TN941 85-155, 102 Pages, 1985/10

PNC-TN941-85-155.pdf:3.7MB

Segment fuel assemblies are planning to load in 10th cycle core of Fugen to confirm a fuel rod soundness in long exposure period. Critical experiment and its analysis for a segment fuel assembly are done to grasp an effect of a connecting part between two segments on local power distribution and to evaluate a calculational accuracy of nuclear design codes. 0.54 wt% PuO$$_{2}$$ enriched MOX (0.54 %MOX) fuel rods are used as the segment fuel rods which are completed by interconnection of a lower and an upper sectional fuel rods being half the normal length. The segment fuel assembly is constructed by replacement four normal rods of eight in the middle disposal layer of 28 rod 0.54 % MOX fuel assembly with the segment fuel rods alternately. Two among four segment fuel rods have several 0.4 mm thickness hafnium sleeves around a plenum of lower section, and those are disposed in 180$$^{circ}$$C rotational symmetry with the two segment fuel rods without hafnium sleeve. The segment fuel assembly is loaded in the central channel of DCA (Deuteriun Critical Assembly) core. Local power distribution in the assembly is obtained from gamma ray scanning of each fuel rod after irradiation. Thermal neutron flux distribution in the coolant and the moderator of the segment fuel cell are measured by activation method using copper wire. In the analysis of the experiment, few energy group constants of each region in the segment fuel lattice are obtained by condensation of 11 energy group lattice calculation by WIMS-D code. Local power distribution and thermal neutron flux distribution corresponding to the measurement points are obtained from two energy group diffusion calculation in (R-$$theta$$-Z) geometry by CITATION code. The following are concluded from the present experiment and analysis. (1)Connecting part (Zry-2) between upper and lower segments makes occur small power peaking in the segment fuel rods itself contiguous to the connecting part and other fuel fods ...

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 %.

JAEA Reports

Measurements and analysises of lattice parametets in 36-rod PuO$$_{2}$$-UO$$_{2}$$ fuel clusters

Fukumura, Nobuo*; *; *; *; *; *; Hachiya, Yuki*

PNC TN941 82-132, 54 Pages, 1982/06

PNC-TN941-82-132.pdf:1.28MB

Measurements and analysises of lattice parameters have been made by use of the 36-rod PuO$$_{2}$$-UO$$_{2}$$ fuel clusters (0.54w/o PuO$$_{2}$$-UO$$_{2}$$) which are composed of the rods with the same diameters as the ones of Fugen type fuel rods. The nine 36-rod fuel clusters were loaded in the central region of the DCA eore with the square lattice of 25.0cm pitch and the surrounding region was occupied with eighty-eight 1.2w/o enriched UO$$_{2}$$ 28-rod fuel clusters. The experiments have been performed with (0% void)and without (100% void) H$$_{2}$$O coolant in the pressure tube. The lattice parameters such as $$^{238}$$U resonance capture ratio ($$rho$$$$^{28}$$), the epicadmium fission ratio of $$^{235}$$U or $$^{239}$$Pu ($$delta$$$$^{25}$$ or $$delta$$$$^{49}$$), the fast fission ratio of $$^{238}$$U ($$delta$$$$^{28}$$) and the fission ratio of $$^{239}$$Pu to $$^{235}$$U ($$delta$$$$^{49}$$$$_{25}$$) were obtained by the foil activation method using foils of plutonium and enriched, natural and depleted uranium. The analysises have been made by use of the sophisticated cell calculation code WIMS which is used for nuclear design of the commercial FUGEN. The results are shown in the table. Here, indices "cell" represent cell averaged values. It is concluded from these results that the code WIMS understimates the fission reaction rates of $$^{238}$$U, $$^{235}$$U and $$^{239}$$Pu, and capture reaction rates of $$^{238}$$U resonanee.

JAEA Reports

Experimental data in DCA (13) Fission reaction rate ratios at 22.5 cm pitch lattice

Fukumura, Nobuo*; *; *; *

PNC TN941 80-53, 63 Pages, 1980/04

PNC-TN941-80-53.pdf:6.58MB

Fission reaction rate ratios have been measured in plutonium fuel loaded in 22.5 cm pitch lattice. The fuels used for the measurements were 0.87 w/o PuO$$_{2}$$ (standard grade) -UO$$_{2}$$[8sPu] and 0.87 w/o PuO$$_{2}$$ (reactor grade) UO$$_{2}$$ [8RPu]. The "coolants" used in the experiment were H$$_{2}$$O [0% void] and Air[100% void]. The uranium fission reaction rate ratios such as $$delta$$$$^{28}$$ and $$delta$$$$^{25}$$ were obtained by use of natural uranium foils, depleted uranium foils and highly enriched uranium foils. The plutonium fission reaction rate ratios such as $$delta$$$$^{49}$$ and $$delta$$$$^{49}$$$$_{25}$$ were obtained by use of highly enriched plutonium foils and highly enriched uranium foils. Fission reaction rate ratios measured in the DCA's lattices are shown in the following table. The results of fission reaction rate ratios measured in 0.54 w/o PuO$$_{2}$$-UO$$_{2}$$ (5s) are also reprinted in the table. The following can be concluded from the present experiment. (1)The reactor-grade 0.87 w/o PuO$$_{2}$$-UO$$_{2}$$ fuel (8R) corresponds to a lower fuel enrichment than that of the standard-grade fuel (8s). (2)The presence of the H$$_{2}$$O coolant weakens change of fuel itself, such as an increase in enrichment or an increase in the resonance part.

JAEA Reports

Experimental data in DCA (15) Micro-parameters at 25.0 cm pitch lattice

*; *; *; *; *

PNC TN941 79-195, 66 Pages, 1979/10

PNC-TN941-79-195.pdf:2.06MB

Micro-parameters have been measured in plutonium fuel loaded in 25.0 cm pitch lattice. The fuels used for the measurements were 0.54 w/o PuO$$_{2}$$ (standard grade)-UO$$_{2}$$[5SPu] and 0.87 w/o PuO$$_{2}$$ (reactor grade)-UO$$_{2}$$[8RPu]. The "coolants" used in the experiment on 5S Pu fuel lattice were H$$_{2}$$O [0% void], mixture of H$$_{2}$$O, D$$_{2}$$O and H3BO$$_{4}$$ [30% void], and Air [100% void]. In the case 8R Pu fuel, H$$_{2}$$O and Air were used as the coolants. The measurements were also done on the lattice of 0% void fraction with 3.9 $$^{10}$$B ppm in D$$_{2}$$O moderator loaded with 5S Pu fuel to investigate the effect of $$^{10}$$B in the moderator. The micro-parameters such as $$rho$$$$^{28}$$, $$delta$$$$^{25}$$, $$delta$$$$^{49}$$, $$delta$$$$^{28}$$ and $$delta$$$$^{49}$$$$_{25}$$ were obtained by the foil activation method in using plutonium-foils, enriched-uranium-foils, natural uranium foils and depleted uranium foils. The micro-parameters measured in the DCA's lattices are shown in the following table.

JAEA Reports

Experimental data in DCA (14); Resonance capture ratio in 22.5 cm pitch lattice

*; Fukumura, Nobuo*; *; *; *

PNC TN941 79-194, 25 Pages, 1979/10

PNC-TN941-79-194.pdf:0.66MB

Resonance capture ratio $$rho$$$$^{28}$$ has been measured in plutonium fuel lattices at 22.5 cm pitch. The fuels used in the experiment were 0.87 w/o PuO$$_{2}$$(standard grade)-UO$$_{2}$$[8sPu] and 0.87 w/o PuO$$_{2}$$ (reactor grade)-UO$$_{2}$$[8RPu]. H$$_{2}$$O[O% void fraction] and air [100% Void fraction] were used as "coolants". The $$rho$$$$^{28}$$ values in fuel rods on each layer of the cluster were obtained from the Cd-ratio of $$^{238}$$U capture with the foil activation method in using depleted uranium. The values of activities in the Cd-covered foils were corrected for the flux perturnation due to the presence of Cd-cover. (Experimental results of $$rho$$$$^{28}$$ in the fuel rods of 0.54 w/o PuO$$_{2}$$-UO$$_{2}$$[5sPu] issued befor, are also corrected and reprinted in this report) The resonance capture ratio $$rho$$$$^{28}$$ are given in the following table.

JAEA Reports

Measurements of intra-cell thermal neutron flux distributions in plutonium fuel lattices; Experiment on 25.0 cm pitch lattice

*; *; *; *; *; Hachiya, Yuki*

PNC TN941 79-149, 76 Pages, 1979/09

PNC-TN941-79-149.pdf:1.5MB

Intra-cell thermal neutron flux distributions have been measured in plutonium fuel lattices at 25.0 cm pitch by means of dysprosium foil activation method. Enrichments of PuO$$_{2}$$ in PuO$$_{2}$$-UO$$_{2}$$ fuels used are 0.54 wt% and 0.87 wt%. The measurements on 0.54 wt% enriched Pu0$$_{2}$$-UO$$_{2}$$ fuel lattices were made using air, light water or D$$_{2}$$O-H$$_{2}$$O-H$$_{3}$$BO$$_{3}$$ mixture containg $$sim$$ 37 wt% of D$$_{2}$$O, as coolants. Those on 0.87 wt% enriched PuO$$_{2}$$-UO$$_{2}$$ fuel lattices were made using air or light water. The effect of $$^{10}$$B in D$$_{2}$$O moderator on the thermal neutron flux distribution was also investigated in 0.54 wt% enriched PuO$$_{2}$$-UO$$_{2}$$ fuel lattice with H$$_{2}$$O coolant and D$$_{2}$$O moderator containg $$^{10}$$B by 3.9 ppm. Measurement uncertainty in the present experiment is $$pm$$2 %, which is almost the same as that in the experiment on plutonium lattices at 22.5 cm pitch. To scrutinize dependence of flux distribution on lattice pitch, the results of the present experiment were compared with those of the experiments on 22.5 cm-pitch lattices which had been already made. The calculations by the code LAMP-DCA agrees with the experiment within $$sim$$ 2 %.

JAEA Reports

Decrease in power peaking in a cluster of different enrichment fuel pins measurement with foil activation method

*; *; *; Hachiya, Yuki*

PNC TN941 75-47, 26 Pages, 1975/05

PNC-TN941-75-47.pdf:0.83MB

In order to study feasibility of the decreasing local power peaking factor, a special type of cluster was assembled by arranging 0.87% enriched PuO$$_{2}$$-UO$$_{2}$$ fuel pins in the inner two layers and 0.54% pins in the outer, among three concentric layers of a cluster. Nine of such clusters with H$$_{2}$$O coolant (0% voidage) were loaded in the central region of DCA core of 22.5 cm lattice pitch and 1.2% enriched UO$$_{2}$$ fuel clusters in the surrounding region. Measurement was made in the central channel (fuel cluster) of the core. In contrast to the usual method of measuring local power peaking factor $$<$$LPF$$>$$ by direct $$gamma$$-ray scanning of fuel pins, power contribution from each nuclei $$^{235}$$U of $$^{239}$$Pu has been specified by present foil activation method using high-enriched uranium and plutonium foils. The resultant factor $$<$$LPF$$>$$ of the different enrichment fuel pins' cluster was obtained as follows. $$<$$LPF$$>$$ = 1.08$$pm$$0.02 This value is favorably less than that of the ordinary uniform arrangement cluster of 0.54% or 0.87% PuO$$_{2}$$-UO$$_{2}$$ fuel pxns. Calculational value by NOAH-II code is 1.11 and the value is overestimated by 2.8% of the experimental one. This discrepancy is explained due to little dependence of $$^{239}$$Pu absorption cross section on thermal neutron spectrum in the NOAH-II calculation, because in the present experiment it was revealed that the cross section (in the form of ratio of $$^{239}$$Pu to $$^{235}$$U fissions) depends largely on thermal neutron energy spectrum.

Journal Articles

None

; ; ; Nagamatsu, Kenji

Symposium on International Safeguards, , 

None

12 (Records 1-12 displayed on this page)
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