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JAEA Reports

Development of groundwater management technology report

Iyatomi, Yosuke; Mikake, Shinichiro; Matsui, Hiroya

JAEA-Review 2018-004, 42 Pages, 2018/03

JAEA-Review-2018-004.pdf:4.71MB

The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite) at Mizunami City in Gifu Prefecture, central Japan. The three remaining important issues have been carrying out on the MIU project. This report focuses on "Development of groundwater management technology" for "Development of countermeasure technologies for reducing groundwater inflow", which is one of those important issues. The concentrations of naturally occurring fluorine and boron dissolved in groundwater pumped from shafts and horizontal tunnels at MIU, are reduced to the levels below the environmental standards at a water treatment facility. The development of groundwater management technologies including such groundwater treatment is one key issue for large-scale underground facility construction. With this background, literature survey related to investigations on the latest treatment technologies for removing fluorine and boron from waste water were conducted and applicability of the technologies to MIU were reviewed. Additionally, the countermeasures against rocks, soils and groundwater containing naturally occurring heavy metals were summarized. The literature survey results indicated that the adsorbent was able to remove fluorine and boron, and the coprecipitation was able to remove fluorine to the levels below their respective environmental standards. However, the ground water at MIU contains suspended solids and cement due to excavation, its removal rates of fluorine and boron are different from the ones of general waste water. From this point, it concluded that the present groundwater treatment method performed at MIU: coagulation treatment for removal of fluorine and control of pH primary, and adsorbent treatment for removed boron is appropriated.

JAEA Reports

Analytical study of two-region TCA critical experiments with PWR-type MOX fuel by using Monte Carlo code MVP

Rahman, M.*; Suzaki, Takenori; Mori, Takamasa

JAERI-Research 2003-007, 68 Pages, 2003/03

JAERI-Research-2003-007.pdf:2.48MB

no abstracts in English

JAEA Reports

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PNC TJ9500 98-001, 102 Pages, 1998/03

PNC-TJ9500-98-001.pdf:5.87MB

None

JAEA Reports

Postirradiation examination of JOYO MK-II control rods; Irradiation performance of absorber pins

Maruyama, Tadashi; ; ; Onose, Shoji;

PNC TN9410 97-077, 177 Pages, 1997/07

PNC-TN9410-97-077.pdf:9.84MB

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 $^{26}$ cap/m $^{3}$ , whereas all the cracked pins had burnup of higher than 43 10 $^{26}$ cap/m $^{3}$ with the initial gap between B $_{4}$ C pellet and cladding larger than 0.44 mm. The cracks were found at around positions corresponding to the lowest B $_{4}$ C pellet in the stack. The ceramography analysis indicated that B $_{4}$ C 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 B $_{4}$ C 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 ...

JAEA Reports

Irradiation test of HAFM and tag gas samples at the standard neutron field of "YAYOI"

PNC TJ9602 96-004, 49 Pages, 1996/03

PNC-TJ9602-96-004.pdf:1.53MB

To check the accuracy of helium accumulation neutron fluence monitoring (HAFM) technique and the applicability of tag gas activation analysis to fast reactor failed fuel detection, these samples were irradiated at the standard neutron field of the fast neutron source reactor "YAYOI" (Nuclear Engineering Research Laboratory, University of Tokyo). The HAFM samples of 93% enriched B powder of 1 mg contained in a V capsule were set up in the reactor core center (Glory hole :Gy) and another samples including V encapsulated natural B powder of 10 mg, natural B chips and 96% enriched $^{6}$ LiF thermoluminescence dosimeters were in the leakage neutron field from the reactor core (Fast column :FC). These neutron fields were monitored by the activation foils consisting of Al, Fe, Co, Ni, Cu, Ti, In, Au, $^{235}$ U, $^{237}$ Np etc., which were used to derive the neutron flux and spectrum. At the end of March in 1996, the irradiated neutron fluence in the energy more than 0.1Mev reached up to 1.110 $^{17}$ n/cm $^{2}$ at Gy and 5.410 $^{14}$ n/cm $^{2}$ at FC, respectively. Two kinds of tag gas samples, which are the mixed gases of isotipically adjusted Xe and Kr contained in stainless steel (SUS) capsules, were irradiated twice at Gy; one is up to 9kWh and the other 7kWh, and after the irradiation, -ray spectra were measured for each sample. Through comparison with the -ray spectrum from dummy capsule of no tag gas, the -ray peaks of $^{79}$ Kr, $^{125}$ Xe etc., which would be produced from tag gas activation, were able to be clearly identified.

JAEA Reports

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PNC TJ1638 96-001, 60 Pages, 1996/03

PNC-TJ1638-96-001.pdf:3.59MB

None

JAEA Reports

Report of phase I program (19891993) on nuclear material crossover research

Kano, Shigeki; Tachi, Yoshiaki; ; ; Yoshida, Eiichi; Hirakawa, Yasushi

PNC TN9410 94-113, 70 Pages, 1994/04

PNC-TN9410-94-113.pdf:3.67MB

(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 B $_{4}$ C, (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 ...

JAEA Reports