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Sato, Isamu; Onishi, Takashi; Tanaka, Kosuke; Iwasaki, Maho; Koyama, Shinichi
Journal of Nuclear Materials, 461, p.22 - 28, 2015/06
We observed one of the simplified processes by conducting primitive experiments. CsI was heated at 1323 K to be vaporized and deposited on sampling parts with a temperature range of 1023 - 423 K and then B
O
was vaporized at 1973 K to be reacted with Cs/I there. After heating tests, each sampling part was soaked into alkali water to dissolve the surface-deposits for ICP-MS analysis. The results showed that CsI deposited at the sampling parts kept above approx. 850 K was striped by BO vapour. This behaviour will be thermodynamically discussed to study the Cs/I/B chemistry in the severe accidents.
; *; *; *; ; *; *
PNC TN9410 98-053, 43 Pages, 1998/04
In the Power Reactor and Nuclear Fuel Development Corporation (PNC), the following are examined as part of an application technology using a high power electron linac : monochromatic gamma ray sources, free electron lasers, and intense positron sources. This report describes an adaptive estimate of a superconducting magnet in order to efficiently converge a positron beam for the development of an intense positron source. By comparing the intensity of a positron beam using a superconducting magnet with a normal conducting magnet, the intensity obtained was more than double. In addition, a small magnet was manufactured in order to examine the characteristics of the superconducting magnet as a solenoid coil. An excitement test was carried out with rated current. As a result of measuring the maximum magnetic field on the central axis, we achieved 5.6 Tesla, which was the designed value. Therefore, it was confirmed to function as a focusing device, when the superconducting magnet was used to converge the positron beam.
Hazama, Taira
PNC TN9410 97-088, 139 Pages, 1997/10
Critical experiments were carried out on Deuterium Critical Assembly (DCA) modification core. DCA modification core has two regions, that is, test region and driver region. The test region consists of various types of fuel and moderator, while the driver region remains the same as the original DCA core (ATR simulated core). Critical characteristics were measured with various types of core patterns and were compared with calculated values based on SCALE code system. Monte calro code KENO was found to be very accurate in the core analysis. The accuracy stays below 0.5 %dk/k in keff even if core configulation is extremely complicated.
Maruyama, Tadashi; ; ; Onose, Shoji;
PNC TN9410 97-077, 177 Pages, 1997/07
Postirradiation examinations of JOYO MK-II control rods have been carried out since 1983, where 16 subassemblies with total 110 absorber pins of initial load to the fifth reload control rods have been subjected to a number of both non-destructive and destructive examinations. In the course of postirradiation examinations, a cracking of cladding tube was found in the total 15 absorber pins in five control assemblies. This paper indicates the results of postirradiation examinations and analysis of absorber pin performance using CORAL code to elucidate the cause of absorber pin cracking in JOYO MK-II control rods. No crack was found in absorber pins whose maximum burnup was lower than 39 
10
cap/m
, whereas all the cracked pins had burnup of higher than 43 10 cap/m with the initial gap between B
C pellet and cladding larger than 0.44 mm. The cracks were found at around positions corresponding to the lowest BC pellet in the stack. The ceramography analysis indicated that BC pellet exhibited extensive cracking and a part of gap between pellet and cladding closed. The cladding deformation had an ovality and the cracks tended to occur at the shorter diameter side. The cracked surface of absorber pin was of a typical grain boundary fracture. The result of He analysis for the cladding material indicated a substantial amount of He accumulation at the inner surface of cladding, but the bulk He content was not anomalously high compared with those in the neutron irradiated stainless steels. TEM observation indicated He bubbles was not clearly found in the as-irradiated cladding material. The cause of cladding failure was attributed to the ACMI where the gap closure due to relocation of BC pellet took place from early times of irradiation. The code analysis by CORAL indicated that the cladding strain due to ACMI was not fully absorbed by the irradiation creep and that the plastic strain became large enough to ...
Kudo, Hisaaki; Sugimoto, Masaki; Seguchi, Tadao; *; *; *
Yuden, Zetsuen Zairyo Kenkyukai Shiryo, p.33 - 40, 1997/00
no abstracts in English
1993) on nuclear material crossover researchKano, Shigeki; Tachi, Yoshiaki; ; ; Yoshida, Eiichi; Hirakawa, Yasushi
PNC TN9410 94-113, 70 Pages, 1994/04
(Purpose) This report describes the outline, research results obtained, interchange activities, etc. of the Phase I Program on the Nuclear Material Crossover Research, which has been conducted by related research institutes including PNC/OEC from 1989 through 1993 fiscal year, and shows the Phase II Program to be started from 1994 fiscal year. (Method) Crossover research programs, research results and interchange methods were decided through discussions at the crossover research comittee (chairman : Prof.M.Okamoto, TIT) in which PNC, JAERI, NRIM, NIRIM and NCLI were participated as main members. Forums, seminars, symposiums and workshops with domestic and foreign experts on materials research were set up as the opportunities for interchange. (Results) (1)As secretary institutes, PNC and JAERl planned eight times of forums, 3 times of seminars, twice of domestic symposiums, once of international symposium, five workshops with research institutes in France, Germany, Italy and the Netherland. The contacts with outside experts, collection of new information on advanced materials, receipt of test samples, achievement of collaborative research, etc. through these interchanges were much valuable for effective performance of PNC research. (2)The following results were obtained on PNC research. The prospects on creation of following advanced materials were obtained through these interchanges: (a)advanced ceramics having excellent corrosion resistance to sodium, (b)longer life neutron absorbing materials having higher resistance to cracking than BC, (c)high performance shielding materials having higher heat resistance than conventional materials. (3)Phase II Program to be started from 1994 fiscal year has been planned by main five institutes and authorized through the evaluation by two evaluation comittees organized separately by the crossover research comittee and PNC. (Conclusion) The prospects on creation of several advanced materials were obtained through ...
; ;
JAERI-M 5648, 110 Pages, 1974/03
no abstracts in English
Maeda, Shigetaka; Itagaki, Wataru; Maeda, Koji; Maki, Ryosuke*; Yoshida, Katsumi*
no journal, ,
Highly microstructure-controlled ceramic neutron absorbers were developed for improving safety of fast reactors. The control rod worth was evaluated using several compositions as parameter. It was confirmed that the effect of additives on control rod worth was negligible.
C absorber material for fast reactor after irradiationShizukawa, Yuta; Sekio, Yoshihiro; Inoue, Toshihiko; Maeda, Koji; Yoshida, Katsumi*
no journal, ,
no abstracts in English
C control materialsShizukawa, Yuta; Sekio, Yoshihiro; Inoue, Toshihiko; Maeda, Koji; Yoshida, Katsumi*
no journal, ,
no abstracts in English
Nakamura, Kinya*; Ota, Hirokazu*; Takano, Masahide
no journal, ,
CRIEPI has pointed out since 2013 that control rods (CRs) and fuel rods should be developed in parallel both to enhance accident tolerance of light water reactors. CRIEPI has been developing accident-tolerant control rod (ATCR) that can be also expected to improve economic efficiency and reduce the number of spent CRs. Assuming the application of coated Zr alloy to fuel and CR cladding, high temperature integrity test of a novel neutron absorber EuO-50mol% HfO clad with Zr alloy was carried out under the beyond DBA condition. The results showed that the ATCR concept clad with Zr alloy cladding had good integrity without deformation to at least 1700
C. To confirm the miscibility of the novel neutron absorber and the molten fuel under severe accident (SA) conditions, the reaction test between the absorber pellet and (U,Zr)O pellet as molten fuel simulant was carried out in Ar atmosphere in the temperature range of 2200 to 2600C. it was clarified that the Zr- based alloy-clad ATCR concept such as rare earth (RE)-Zr mixed oxide or RE-Hf mixed oxide is highly compatible with oxidic melt containing U and is likely to significantly reduce the risk of recriticality during and after SA.
