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Unno, Masayoshi*; Ishikawa, Kumiko*; Kusaka, Katsuhiro*; Tamada, Taro; Hagiwara, Yoshinori*; Sugishima, Masakazu*; Wada, Kei*; Yamada, Taro*; Tomoyori, Katsuaki; Hosoya, Takaaki*; et al.
Journal of the American Chemical Society, 137(16), p.5452 - 5460, 2015/04
Times Cited Count：28 Percentile：64.39(Chemistry, Multidisciplinary)Phycocyanobilin, a light-harvesting and photoreceptor pigment in higher plants, algae, and cyanobacteria, is synthesized from biliverdin IX
(BV) by phycocyanobilin:ferredoxin oxidoreductase (PcyA) via two steps of two-proton-coupled two-electron reduction. We determined the neutron structure of PcyA from cyanobacteria complexed with BV, revealing the exact location of the hydrogen atoms involved in catalysis. Notably, approximately half of the BV bound to PcyA was BVH
, a state in which all four pyrrole nitrogen atoms were protonated. The protonation states of BV complemented the protonation of adjacent Asp105. The "axial "water molecule that interacts with the neutral pyrrole nitrogen of the A-ring was identified. His88 N
was protonated to form a hydrogen bond with the lactam O atom of the BV A-ring. His88 and His74 were linked by hydrogen bonds via H
O. These results imply that Asp105, His88, and the axial water molecule contribute to proton transfer during PcyA catalysis.
Maruyama, Tadashi; Kaito, Takeji; ; ; Unno, Ichiro
PNC TN9410 94-293, 88 Pages, 1994/05
Post-irradiation examination (PIE) for "JOYO" MK-II control rods has been carried out with thirteen subassemblies, five of which indicated occurence of absorber pin breach. The present report describes results of the PIE made for the breached pins and studies were made on features on the breached pins and the cause of breach mechanisms. It was observed that the threshold burnup of breached pins was 57
10
cap/m
above which total 15 Pins breached. The pins with wider gap between B
4C pellet and cladding tended to breach at lower burnup. In the breached pins, extensive absorber cladding mechanical interactions (ACMI) due to relocation of BC pellet took place together with accumulation of He in the cladding material to make He embrittlement. It is inferred that these phenomena caused pin breach when they were in the reactor core. However, it is very difficult to clearly specify the time whether the pin breach occured during the reactor operation or at the time when the reactor was shut down. The results of the present investigation did not support the conclusion made in the previous report that the main cause of pin breach was the stress corrosion cracking and pin breach took place when they were removed from the reactor core. It was concluded that reducing the ACMI due to relocation of BC pellet is very important for extension of life of "JOYO" absorber pin.
Shikakura, Sakae; Maruyama, Tadashi; Sato, Yoshinori; Asaka, Takeo; Ukai, Shigeharu; Unno, Ichiro
Donen Giho, (86), p.20 - 33, 1993/06
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Ukai, Shigeharu; *; Unno, Ichiro; *; ; *; Shikakura, Sakae*
PNC TN9410 89-188, 58 Pages, 1989/10
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; Ukai, Shigeharu; Unno, Ichiro; *; *; Shikakura, Sakae*
PNC TN9410 89-185, 69 Pages, 1989/08
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*; Ukai, Shigeharu; Unno, Ichiro; ; Shibahara, Itaru*; Enokido, Yuji*
PNC TN9410 88-206, 71 Pages, 1988/12
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Unno, Ichiro; Ukai, Shigeharu; *; ; Shibahara, Itaru*; Enokido, Yuji*
PNC TN9410 88-186, 62 Pages, 1988/02
None
Ukai, Shigeharu; Unno, Ichiro; *
PNC TN9410 87-193VOL2, 72 Pages, 1987/02
PNC-TN9410-87-193VOL2.pdf:25.05MB
None
Ukai, Shigeharu; Unno, Ichiro; *
PNC TN9410 87-193VOL1, 48 Pages, 1987/02
PNC-TN9410-87-193VOL1.pdf:9.98MB
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*; ; Ukai, Shigeharu; Unno, Ichiro; *; Shibahara, Itaru*; Enokido, Yuji*
PNC TN9410 87-189VOL2, 103 Pages, 1987/02
PNC-TN9410-87-189VOL2.pdf:13.74MB
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*; ; Ukai, Shigeharu; Unno, Ichiro; *; Shibahara, Itaru*; Enokido, Yuji*
PNC TN9410 87-189VOL1, 45 Pages, 1987/02
PNC-TN9410-87-189VOL1.pdf:5.59MB
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Ukai, Shigeharu; Osato, Yukihiro*; Unno, Ichiro
PNC TN9410 86-134VOL2, 105 Pages, 1986/01
PNC-TN9410-86-134VOL2.pdf:25.84MB
None
Ukai, Shigeharu; Osato, Yukihiro*; Unno, Ichiro; *; ; Shibahara, Itaru
PNC TN9410 86-134VOL1, 70 Pages, 1986/01
PNC-TN9410-86-134VOL1.pdf:15.85MB
Rapsodie PNC-4 (2)(3) was irradiated to confirm the performance and integrity of "Monju" type fuel pin. One of test pins, K09 pin, has highest burnup and almost attained the target burnup of "Monju". Metallographic examination of K09 pin had been partially conducted at France and the integrity of this pin was confirmed. In this examination, fuel microstructure observation and elemental analyses of both K09 pin and K07 pin have been carried out in order to evaluate the irradiation behavior of high burnup fuel pin. Peak burnup and peak fluence of K09 pin and K07 pin reached 128,000 MWD/MTM, 1.2610
(E
O.1 Mev) and 79,000 MWD/MTM, 7.2510
(E 0.1 Mev), respectively. Following results were obtained in this examination. (1)No fuel/cladding gap existed at the middle of fuel column of K07 pin, and it was considered that fuel cladding mechanical interaction (FCMI) occurred at entire fuel column during irradiation. On the other hand, gap width of higher burnup K09 pin reopened to 60 
m due to cladding swelling. Pin diameter of this pin increased by 2.3%. (2)Maximum depth of cladding inner corrosion of K09 pin and K07 pin were 53 m and 75 m respectively. It was confirmed that cladding inner corrosion saturated at high burnup. (3)Oxygen analyses by ion microprobe analyzer made clear that Fe-Ni Phase existing on fuel side in fuel-cladding chemical interaction (FCCI) zone was identified as metallic and Cr-Mn-FP (Cs) phase on cladding side was identified as oxide. (4)At the edge of central void, plutonium concentration increased to about 27 wt% from 20 wt% of fabricated content. (5)There were gray phase and metallic inclusion as precipitation phase in the fuel. Gray phase consisted of Ba-Zr compound, Ba-Cs compound, Ba-Ce compound, and metallic inclusion consisted of Mo-Ru-Rh-Tc-Pd compound, Fe-Pd compound. (6)Clear correlation between fuel microstructure and retained xenon profile across the pellot was obtained. ...
*; Ukai, Shigeharu; Unno, Ichiro
PNC TN9410 85-135vol2, 89 Pages, 1985/02
PNC-TN9410-85-135vol2.pdf:21.38MB
None
*; Ukai, Shigeharu; Unno, Ichiro
PNC TN9410 85-135vol1, 53 Pages, 1985/02
PNC-TN9410-85-135vol1.pdf:7.18MB
The driver fuel Subassembly (Fab. No. PFD003) had been irradiated at location of (1B1) up to end of first cycle from startup of 100 MW in "JOYO" MK-II, and its average total burnup reached to 13,800 MWD/MTM. In order to confirm the integrity of the fuel pin and to grasp the irradiation performance during the reactor operation up to first cycle of "JOYO" MK-II, metallographic examination of fuel and cladding was carried out by optical microscope, scanning electron microscope (SEM), electron probe microanalyser (EPMA) and ion microanalyser (IMA). The results are summarized as follows ; (1)Central void of 0.43 mm in diameter and columnar grain were observed near axial midplane of fuel column. Volatile fission product such as Cesium accumulated in the fuel-cladding gap, and mass transfer of cladding constituents was slightly detected by EPMA. However, reduction of cladding thickness cased by fuel-cladding-chemical-interaction was not observed. (2)Redistribution of uranium and Plutonium did not occur. Such actinoid element was observed to be homogeneously mixed at columnar region. However, concentration of such element varied heterogeneously in unrestructured region. (3)Radial profile of Xenon in the fuel measured by EPMA showed that unrestructured fuel retained fission gas and gas release started in the densified region. Characteristic X-ray of Xe-L was not detected in the gas bubble region. (4)Burnup measured by IMA shows good agreement with calculated value. (5)IMA measurement shows the preferential deposition of manganese and preferential leaching of manganese and nickel in the depth of 2 m of cladding outer surface at the temperature region of 380
C and higher than 500C respectively. Concentration change of cladding outer surface was not detected at the temperature of 450C.
Ukai, Shigeharu; *; Unno, Ichiro
PNC TN9410 85-134vol2, 63 Pages, 1985/02
PNC-TN9410-85-134vol2.pdf:13.21MB
None
Ukai, Shigeharu; *; Unno, Ichiro
PNC TN9410 85-134vol1, 49 Pages, 1985/02
PNC-TN9410-85-134vol1.pdf:6.95MB
Core Fuel Subassembly (Fab. No. PPJX12) was irradiated at the first row of reactor core all through the "JOYO" MK-I period, and estimated to be the highest average burnup of 39,000 MWD/MTM next to PPJX13 of 41,000 MWD/MTM in the "JOYO" MK-I Subassembly. This sabassembly had been intentionally kept in the water pool with insufficient removal of Sodium after irradiation. The observation of outer surface of cladding by scanning electron microscope (SEM), morphological observation of fuel and cladding by Optical microscope, and instrumental analyses by electron microprobe analyser (EPMA) and ion microprobe analyser (IMA) were performed in order to confirm the integrity of cladding kept in pool with insufficient removal of sodium, and to supplement the data base of high burnup region on "JOYO" MK-I fuel. The experimental results are summarized as follows: (1)The condition of outer surface of cladding observed by SEM was similar to that of cladding kept in pool after sufficient removal of sodium, and intergranular attack and corrosion of outer surface of cladding were not observed. (2)Central void and Columner grain were not formed. Fuel structure was observed as fission gas bubble region, densified region and unrestructured region. Gap width between fuel and cladding at oxial middplane of fuel column was reduced to 14m in radius. These results supplement the data base of high burup region on "JOYO" MK-I fuel. (3)Redistribution of Uranium and Plutonium was not observed. Volatile fission product such as Cesium accumulated in the fuel-cladding gap, but the corrosion depth of cladding caused by fuel-cladding chemical interaction was 10m in maximum. (4)Burnup measured by IMA showed good agreement with that calculated using "JYHIST" code.
Mizuno, Mino*; Enokido, Yuji; Unno, Ichiro; Kono, Kenichi; Yamanouchi, Sadamu; Itaki, Toshiyuki
Nuclear Technology, 69(1), p.107 - 113, 1985/00
Times Cited Count：0 Percentile：0.02(Nuclear Science & Technology)None
Enokido, Yuji*; *; Unno, Ichiro
PNC TN9410 84-125, 243 Pages, 1984/09
The morphological observation and the instrumental analysis of fuel elements of core fuel subassembly (Fab. No. PPJX13) irradiated in "JOYO" MK-I have been performed. The burnup of the subassembly (40, 100MWD/MTM) was the highest in breeder core (MK-I) of the reactor. It was expected that the subassembly should exhibit almost all irradiation characteristics throughout the irradiation duration of MK-I. For the examination at Metallography Cell of Analysis and Evaluation Section (AES) in Fuel Monitoring Facility (FMF), samples from two pins selected in the subassembly were prepared. One was the pin with the highest cladding temperature history, and another was a sibling of the center pin. The samples were prepared in the cell, in order to carry out the morphological observation of fuel and cladding by optical microscope and scanning electron microscope, and the instrumental analyses by electron microprobe analyser and ion micro-probe mass analyser. The experimental results are summarized as follows: (1)Central void of about 200 m was formed. From the void toward the outer surface of the fuel, fuel restructuring was observed as an elongated grain zone, a porous equiaxed grain zone and a densified zone. The structure resembles to the typical high burnup fuel structure. (2)Fission products Cs, Te, I, Ag, Pd etc. accumulated in the fuel-cladding gap, but the corrosion caused by fuel-cladding chemical interaction was 12m in maximum. (3)Extraodinal precipitations and grain bundary attack in cladding were not observed. (4)At the outer surface of the cladding, fine particles were found. Reduction of Ni and Mn content in the cladding within 4m from the surface at high cladding temperature position resulted in the enrichment of Cr, Fe and Mo. On the contrary, Ni and Mn deposited on the surface of cladding at low temperature region. (5)The maximum local burnup of the core fuel was 5.08 at.%. (6)The behaviour of fission products in fuels of "JOYO" MK-I was ...
