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Sakai, Kenji; Oi, Motoki; Kai, Tetsuya; Watanabe, Akihiko
JAEA-Technology 2010-001, 35 Pages, 2010/02
JAEA-Technology-2010-001.pdf:12.39MB
A MLF general control system (MLF-GCS) at J-PARC consists of several subsystems of integral control and interlock, network, server, timing distribution systems, and PPS. The design and construction of MLF-GCS has progressed for the first proton beam injection in 2008. After finishing the construction of most of the subsystems, the commissioning on operation and control of the MLF has started step by step in 2007. During short period before the first beam injection, the trial operations, performance tests, and improvements of the MLF-GCS subsystems have been executed under restricted conditions. After the first beam injection in May 2008, the subsystems have been improved according to experience on the beam operations, the administrative structure for the MLF operation shift has been established, and the stable and efficient operations of the MLF-GCS has been realized. This paper reports on the commissioning on the MLF operation and control from April 2007 to March 2009.
Editorial Committee of Refining and Conversion Facility Decommissioning Results
JAEA-Technology 2010-002, 66 Pages, 2010/05
JAEA-Technology-2010-002.pdf:19.73MB
The Refining and Conversion Facility located in the Ningyo-toge Environmental Engineering Center had the natural uranium conversion process and reprocessed uranium conversion process. The construction of this facility was started in 1979 and completed in October 1981. Dismantling of equipments in radiation controlled area of this facility was started from 2008, and all equipments in radiation controlled area will be dismantled by the 2011 fiscal year. This report describes the master plan of this decommissioning and shows as the progress in first half year of 2009FY, the actual time schedule, the method of decommissioning, the decommissioning progress appearance with photographs, work rates of each room/each worker class, and the quantity of dismantled materials and secondary wastes.
Takahashi, Nobuo; Yokoyama, Kaoru; Morimoto, Yasuyuki; Shimaike, Masamitsu; Ikegami, Sohei; Sugitsue, Noritake
JAEA-Technology 2010-003, 92 Pages, 2010/06
JAEA-Technology-2010-003.pdf:10.76MB
At the reprocessed uranium conversion facilities, Hydration and Conversion room-1,2,3, Dehydration and Conversion room-1,2, Dry process filter room have been dismantled according to the schedule, in 2009 fiscal year. The 
-ray measurement had been carried out before dismantlement to evaluate the radioactivity inventory. As a result, the uranium recovery work was forecasted for reasonable dismantlement. In addition, the feature nuclide affecting the results of the measurement on the air dose was evaluated. Additionally, as the waste data, -ray analysis results are shown.
Tamaki, Hitoshi; Yoshida, Kazuo
JAEA-Technology 2010-004, 124 Pages, 2010/07
JAEA-Technology-2010-004.pdf:1.72MB
This document is a procedure guide developed by Japan Atomic Energy Agency for PSA (Probabilistic Safety Assessment) of MOX fuel Fabrication Facilities. The procedure guide consists of two parts. The first part describes the procedure of PSA. The second part shows the practical examples of PSA of a typical facility with information applicable to the practical assessment.
Shimizu, Shigeru; Fujii, Katsutoshi; Kawasaki, Tomokatsu
JAEA-Technology 2010-005, 72 Pages, 2010/06
JAEA-Technology-2010-005.pdf:2.44MB
In the Japanese Industrial Standard, JIS Z 4511 sets the condition of X-ray reference fields to be used for the performance test of radiation measuring instruments for radiation protection. With the soft X-ray generator installed in the Facility of Radiation Standard in Nuclear Science Research Institute, we have established four series of soft X-ray reference fields with quality index 0.6, 0.7, 0.8 and 0.9 based on JIS Z 4511. In this process, quality of the X-ray fields, X-ray spectra, conversion coefficients to the dose equivalent from Air-Kerma were evaluated in the soft X-ray fields produced with X-ray tube voltage ranging from 6 kV to 100 kV. As a result, it is found that dose equivalent standard with good precision and wide range of test energy point and dose rates can be provided, this report describes these detailed data.
Suzuki, Hajime; Hanaki, Tatsumi
JAEA-Technology 2010-006, 40 Pages, 2010/06
JAEA-Technology-2010-006.pdf:6.44MB
Research at the Tono Mine was concluded in FY2003. A plan for closure activities of the Tono Mine is being developed in accordance with the Mid-term plan by JAEA (October 1st, 2005 to March 31st, 2010). This report presents a summary of the specific closure activities under review.
Mo production in JRR-3Hirose, Akira; Komeda, Masao; Kinase, Masami; Sorita, Takami; Wada, Shigeru
JAEA-Technology 2010-007, 68 Pages, 2010/06
JAEA-Technology-2010-007.pdf:3.76MB
We investigated the production process of Mo, which is parent nuclide of 
Tc, in JRR-3. Tc is most commonly used as a radiopharmaceutical in the field of nuclear medicine. Currently the supplying of Mo is only dependent on imports from foreign countries, so JAEA is aiming at domestic production of a part of Mo in cooperation with the industrial arena. This report presents the technical study for the production process of Mo by using the neutron radiation method of (n,) reaction in JRR-3.
Tohei, Toshio; Nakashio, Nobuyuki; Osugi, Takeshi; Ishikawa, Joji; Mizoguchi, Takafumi; Hanawa, Ritsu; Someya, Keita*; Takahashi, Kenji*; Iseda, Hirokatsu; Kozawa, Kazushige; et al.
JAEA-Technology 2010-008, 28 Pages, 2010/06
JAEA-Technology-2010-008.pdf:5.0MB
The Waste Volume Reduction Facility (WVRF) was constructed for volume reduction and the chemical stabilization of the low level radioactive waste in the Nuclear Science Research Institute of JAEA. The metal melting system in the WVRF treats radioactive metal waste. From the experience of trial operations, the improvement has conducted on the casting process in the metal melting system. The performance of the improved casting process was verified through the trial operations from Oct. 2008. In this report, we describe the reduction of the processing time, of the utilities consumption, of the load of maintenance on the improved casting process.
Shimizu, Shigeru; Sawahata, Tadahiro; Kajimoto, Yoichi; Shikaze, Yoshiaki; Yoshihara, Yasuaki*; Tatebe, Yosuke
JAEA-Technology 2010-009, 78 Pages, 2010/06
JAEA-Technology-2010-009.pdf:3.06MB
In the Japanese Industrial Standard, JIS Z 4511 sets the condition of X-ray reference fields to be used for the performance test of radiation measuring instruments for radiation protection. We renewed a X-ray tube of the medium-hard X-ray irradiation device that was damaged in the Facility of Radiation Standards in Nuclear Science Research Institute. Therefore, we established four series of medium-hard X-ray reference fields with quality index of 0.6, 0.7, 0.8 and 0.9 based on JIS Z 4511. In this process, quality of the X-ray fields, X-ray spectra, conversion coefficients to the dose equivalents from Air-kerma were evaluated in the medium-hard X-ray fields produced with X-ray tube voltage ranging from 20kV to 300kV. As a result, medium-hard X-ray reference fields were established that can provide the dose equivalent standard with good precision and wide range of test energy points and dose rates. We clarified these detailed data.
Inoue, Shuichi; Omuro, Tadao; Nabeya, Hideaki; Matsui, Yoshinori; Iida, Kazuhiro; Ito, Kazuyuki; Kimura, Akihiro; Kanno, Masaru
JAEA-Technology 2010-010, 27 Pages, 2012/05
JAEA-Technology-2010-010.pdf:1.99MB
In fuel irradiation transient tests using a boiling water capsule, a dilution tube has been installed in the boiling water capsule in order to detect fission products (FP) from an irradiated fuel, in case of the fuel failure during the transient, by a radiation monitor located outside the reactor. When the fuel failure occurs, the released FP flows out from the capsule through the dilution tube. The dilution tube is designed to minimize the released FP that can be detected by the radiation monitor located outside the reactor. This report summarized the measurement results of the dilution tube installed in the boiling water capsule.
Mizukoshi, Yasutaka; Kushida, Naoya
JAEA-Technology 2010-011, 16 Pages, 2010/06
JAEA-Technology-2010-011.pdf:1.21MB
The inside of Metallography cell, which is an alpha-tight hot cell of post irradiation examination facility, is contaminated by radioactive matters and nuclear fuel materials at high levels, because many fuel pins that were irradiated in nuclear reactor were examined in this hot cell over many years. Therefore, for reasons of safety of workers and of the requirements of the act, the devices for negative pressure controlling (e.g. automatic control exhaust valves) must be updated under the condition of maintained negative pressure in hot cell or under the condition of completion of decontamination of radioactive matters in hot cell. Update method of automatic control exhaust valves of Metallography cell at the design-time of this hot cell was that the automatic control exhaust valves were updated under the condition of no ventilation operation after completion of decontamination. However, this method harmed the experiments of fuel pins because the working period of this method needed over one year. Therefore, a safe and efficient update method of deteriorated automatic control exhaust valves that have been perennially used for control of negative pressure in Metallography cell is invented, and this method was carried out.
Sato, Hiroyuki; Ohashi, Hirofumi; Tazawa, Yujiro; Sakaba, Nariaki; Tachibana, Yukio
JAEA-Technology 2010-012, 65 Pages, 2010/06
JAEA-Technology-2010-012.pdf:1.45MB
Japan Atomic Energy Agency is planning to demonstrate hydrogen production by thermochemical water-splitting IS process utilizing heat from the high-temperature gas-cooled reactor HTTR (HTTR-IS system). The previous study identified that the HTTR modification due to the coupling of hydrogen production plant requires an additional safety review since the scenario and quantitative values of the evaluation items would be altered from the original HTTR safety review. Hence, preliminary safety analyses are conducted by using the system analysis code. Calculation results showed that evaluation items such as a coolant pressure, temperatures of heat transfer tubes at the pressure boundary, etc., did not exceed allowable value. Also, the peak fuel temperature also did not exceed allowable value and therefore the reactor core was not damaged and cooled sufficiently.
Kawato, Yoshimi; Tomioka, Osamu; Takahashi, Kuniaki; Meguro, Yoshihiro; Sakamoto, Hiroyuki*; Haga, Kazuko*
JAEA-Technology 2010-013, 38 Pages, 2010/07
JAEA-Technology-2010-013.pdf:1.36MB
It is important to understand fundamental solidification characteristics of incinerated ashes of combustible and poorly combustible wastes generated by JAEA. Simulated solidified substances using incinerator fly ash were prepared under different conditions such as solidified materials, ash filling rates, amount of solidification retarders and so on. The compressive strength of the solidified substances prepared using a normal portland cement (OPC), a blast furnace slag cement (BB), and a low alkalinity cement (LAC) exceeded a standard value, 1.47 N/mm
. The compressive strength made from the BB was lower 1.47 N/mm when the filling rate of the incinerated ash was 40%. For the substances using the LAC, all the strengths were over 1.47 N/mm. Pb and Zn would behave as retardative substances for solidification. All substances showed the compressive strength with the BB or the LAC. As insolubilizers for heavy metals, ferrous sulfate and sodium sulfide prevented Cr from elution.
Nakagawa, Akinori; Sone, Tomoyuki; Sasaki, Toshiki; Nakazawa, Osamu; Tashiro, Kiyoshi
JAEA-Technology 2010-014, 46 Pages, 2010/06
JAEA-Technology-2010-014.pdf:1.76MB
Steam reforming treatment system was developed for volume reduction of Tri-n-butyl phosphate contaminated with uranium, which is difficult to treat with incineration, due to generation of corrosive compounds, a large amount of secondary waste, etc. This system consists of a steam reforming process in which organic waste is decomposed/gasified in steam atmosphere and a submerged combustion process in which vaporized waste is burned in water and has good features such as high volume reduction rate of waste, low secondary waste generation rate, etc. Results obtained this study were as follows: Volume reduction rate of waste was 99.6%. Uranium entrainment to off-gas was suppressed and the concentration of uranium in waste water was under 0.037mg/L. The concentration of CO and NOx in the off-gas were less than 100ppm and 250ppm respectively. Plugging and corrosion control technologies were developed and it was confirmed that the waste treatment system can run for long periods.
Araki, Masaaki; Kato, Tomoaki; Arai, Masaji
JAEA-Technology 2010-015, 35 Pages, 2010/06
JAEA-Technology-2010-015.pdf:1.04MB
Research reactor JRR-3 is a light water moderated and cooled pool type research reactor using low enriched uranium-silicon-aluminum-dispersion-type fuel. French Competent Authority (FCA) required that the criticality safety of the JRF-90Y-950K package is maintained even if it is deformed under oblique drops onto a bar. Criticality analyses of the JRF-90Y-950K package were carried out for the transport of JRR-3, JRR-4 or JMTR fuel. The results show that criticality safety is kept even if it is deformed under oblique drops onto a bar.
Ishimori, Kenichiro; Haraga, Tomoko; Shimada, Asako; Kameo, Yutaka; Takahashi, Kuniaki
JAEA-Technology 2010-016, 54 Pages, 2010/08
JAEA-Technology-2010-016.pdf:2.38MB
Simple and rapid analytical methods for radionuclides in low-level radioactive waste have been developed by the present authors. The methods were applied to simulated solidified products and actual metal wastes to confirm their usefulness. The results were summarized as analytical guide lines. In the present work, cement solidified products and ash wastes were analyzed followed by the analytical guide lines and subjects were picked up and improved for the application of the analytical guide lines to these wastes. Pulverization and homogenization methods for ash wastes were improved to prevent a contamination since the radioactivity concentrations of the ash wastes were relatively high. Pre-treatment method was altered for the ash wastes and cement solidified products taking account for their high composition of Ca. Newly, an analytical method was also developed to measure 
I with a dynamic reaction cell inductively coupled plasma mass spectrometer. In the analytical test based on the guide lines, -ray emitting nuclides, 
CoCo and 
CoCs, were measured to estimate the radioactivity of the other alpha and 
-ray emitting nuclides. The radionuclides assumed detectable, 
H,
C,
Cl,
Ni,
Sr, and 
-ray emitting nuclides, were analyzed with the analytical guide lines and their applicability for ash wastes and cement solidified products were confirmed.
Horiuchi, Yasuharu; Hirano, Toru; Ikeda, Koki; Matsui, Hiroya
JAEA-Technology 2010-017, 122 Pages, 2010/07
JAEA-Technology-2010-017.pdf:35.17MB
JAEA-Technology-2010-017-appendix(CD-ROM).zip:28.63MB
Knowledge of strain variations at an excavation face is important for the prediction of rock bursts and for the application of the appropriate supplementary construction methods for excavation of shafts to great depths. JAEA installed the intelligent type strain meters, at G.L-500m depth in pilot boreholes drilled from the 200m level in the ventilation and main shafts of the Mizunami URL. Strain variations due to several events including the excavation itself were monitored and analyzed. Because of the breakdown of the monitoring system, the data is very short term. Nevertheless, it was possible to do some analysis for the study and important understanding derived from the analysis. Monitoring results indicate that the intelligent type strain meter is able to measure very small fluctuations and detect rock deformation from blasting with 300m vertical separation from the measurement section. The strain meter can detect conditions in the rock mass such as differences in deformability.
Hosokawa, Jinsaku; Iimura, Koichi; Ogawa, Mitsuhiro; Tomita, Kenji; Yamaura, Takayuki
JAEA-Technology 2010-018, 269 Pages, 2010/08
JAEA-Technology-2010-018.pdf:5.75MB
At Oarai Research and Development Center, Japan Atomic Energy Agency (JAEA) advances the plan of refurbishing Japan Materials Testing Reactor (JMTR) to start the operation in fiscal 2011. Fuel Transient Test Facility is scheduled to be set up as neutron irradiation test equipment of the light-water reactor fuel that uses JMTR after it operates again. The abnormal transition examination device is the irradiation facilities where the output sudden rise examination that makes the light-water reactor fuel an irradiation sample is done to use it to develop the safety evaluation technology and the damage influence evaluation technology of the light-water reactor fuel that reaches high burn-up. In this report, as for the system design, it is a summary to JMTR among detailed designs of the abnormal transition examination device of the installation schedule.
Ogawa, Mitsuhiro; Iimura, Koichi; Hosokawa, Jinsaku; Kanno, Masaru
JAEA-Technology 2010-019, 178 Pages, 2010/07
JAEA-Technology-2010-019.pdf:20.16MB
JMTR is making preparations of the irradiation examinations towards the re-operation from the 2011 fiscal year now. Design examination of the high-duty irradiation loop is in one of these irradiation examinations of the irradiation plan. The examination is the plan to carry out the irradiation examination of the light water reactor fuel (uranium fuel and mixed oxide fuel) which reached the high burnup, under the irradiation environment nearer to the light water reactor plant. In the 2009 fiscal year, we carried out (1) System design and (2) Earthquake-proof calculation of in-pile tube of the high-duty irradiation loop. And, for the fuel action between covering pipe and pellets of fuel rod which reached the high burnup, we carried out (3) System design of the lift-off test facility. Moreover, we carried out (4) Examination about detection system of fuel breakage when a fuel sample is damaged, and (5) Examination about system composition of effluent treatment system.
Oba, Toshinobu; Fukushima, Manabu; Takeuchi, Masaki; Uno, Yuki; Owada, Minoru; Terakado, Yoshibumi
JAEA-Technology 2010-020, 31 Pages, 2010/07
JAEA-Technology-2010-020.pdf:1.33MB
Japan research reactor No.3 (JRR-3) has a heavy water tank. The heavy water tank surrounds the reactor core to use thermalize neutrons for experiments. The heavy water cooling system removes the heat generated by ray in the heavy water reflector. The heavy water cooling system is composed of the cooling system and the helium gas system. The helium gas system has an important role of helium gas circulation. The helium gas system also has a role to recombine deuterium gas and oxygen gas. We had overhauled the helium compressor regularly and replaced consumable parts. However, in recent year, the helium compressor had sometimes stopped by the leakage of seal oil. In 2007, we refurbished the helium compressor with new one. This report describes refurbishment of helium compressor.
Sakai, Akihiro; Amazawa, Hiroya; Nakata, Hisakazu; Takahashi, Kuniaki; Kihara, Shinji
JAEA-Technology 2010-021, 152 Pages, 2010/07
JAEA-Technology-2010-021.pdf:7.87MB
Total radioactivity and radioactive concentration limit of nuclides in low level radioactive waste that are expected to cause relatively large dose in near surface disposal are needed to be described in the licensing application form, as so-called "main nuclides", for disposal business of LLW generated from research, industrial and medical facilities. In this report, as an example, the main nuclides were preliminarily selected out of the nuclides contained in LLW generated from main research reactors and PIE facilities in Nuclear Science Research Institute of JAEA, by use of nuclide composition ratios in the wastes and their radioactivity concentration limit of near surface disposal derived by Nuclear Safety Commission in Japan. As results of preliminary selection of main nuclides without fixed radioactive inventory in the wastes, 24, 30 and 33 nuclides were selected as main nuclides for LLW from the reactors, PIE facilities, and both facilities, respectively.
Nakanoya, Takamitsu; Matsuda, Makoto
JAEA-Technology 2010-022, 35 Pages, 2010/07
JAEA-Technology-2010-022.pdf:4.52MB
An ECR ion source has been installed for producing highly charged ion beams of gaseous elements, in the 20 MV high-voltage terminal of the JAEA-Tokai tandem accelerator. The ECR ion source can easily produce intense ion beams for gaseous elements, but not for metal-ion beams. We have developed an oven method in order to produce intense metal-ion beams from the ECR ion source. We have carried out the production test for various metals on a testing stand of the ECR ion source. We have investigated operational parameters for producing 16 different metal-ion beams. In this article, we describe the oven developed in this work, and summarized experimental data of the ionization properties and mass spectrum for each metal element.
gas emissionTayama, Hidekazu; Nakanoya, Takamitsu; Otokawa, Yoshinori; Tsukihashi, Yoshihiro; Seki, Nobuo*; Onodera, Teruo*; Nisugi, Hikaru*
JAEA-Technology 2010-023, 42 Pages, 2010/09
JAEA-Technology-2010-023.pdf:4.81MB
The high-pressure gas facility for the tandem accelerator at nuclear science research institute is the facility to transfer SF gas between the accelerator and gas storage tanks. The SF gas is used to keep high voltage insulation of the tandem accelerator. This facility is one of the largest SF gas handling facilities in research laboratories. This facility has been operated for 31 years. In addition to regular maintenance, we have evaluated the deterioration due to aging. SF gas is regarded as a kind of green house gases that causes global warming and it is strongly required to reduce such gas emission into the atmosphere in recent years. In JAEA, the reduction of gas the emission is also an important problem. We have been continuously taking action for reducing the emission of SF gas. In this article, we report the records of maintenance, evaluation of aging, and activity of reducing SF gas emission.
Kawakami, Takeshi; Yamamoto, Kazuya; Fukumoto, Masahiro
JAEA-Technology 2010-024, 83 Pages, 2010/08
JAEA-Technology-2010-024.pdf:3.88MB
"Drill of evacuation with family car", "Drill of evacuation for the disabled with family car", and "Evacuation drill from the large enclosure" had been conducted in the National Comprehensive Nuclear Disaster Exercise on December 21st and 22nd, 2009 in Ibaraki Prefecture. This work evaluated the dynamic traffic flow of evacuees' cars during the evacuation drill using three kinds of data, i.e. questionnaire for the participants in the evacuation drill, GPS tracking data of vehicles of evacuees, and photographies shot from the air and ground. The fluctuations of traffic volume influenced by traffic controls for the outside of evacuation zone was evaluated using the traffic volume data which were provided by Ibaraki prefecture. The opinion survey was also conducted to participants of evacuation drill for three purposes, to get the data of choice of measures for evacuation, to find out problems of evacuation for the disabled, to find out problems of evacuation from the large enclosure.
Kanamori, Masashi; Suto, Toshiyuki; Tanaka, Kenichi*; Takada, Jun*
JAEA-Technology 2010-025, 11 Pages, 2010/08
JAEA-Technology-2010-025.pdf:1.55MB
Verification of dose control method for Tokaimura JCO criticality accident was performed. Personal dose estimation for Tokaimura criticality accident termination was performed based on measurements of neutron and ray doses taken before the work commenced, but the personal dose for the workers as a result of the termination work was found to be approximately 50 times higher than the previous estimation. For this report, we reevaluated doses based on the results of close range measurements from 40 meters to 100 meters, and the results were found to match personal doses with an accuracy of between 60-80%.
Mikake, Shinichiro; Yamamoto, Masaru; Ikeda, Koki; Sugihara, Kozo; Takeuchi, Shinji; Hayano, Akira; Sato, Toshinori; Takeda, Shinichi; Ishii, Yoji; Ishida, Hideaki; et al.
JAEA-Technology 2010-026, 146 Pages, 2010/08
JAEA-Technology-2010-026.pdf:41.08MBJAEA-Technology-2010-026-appendix(CD-ROM).zip:83.37MB
The Mizunami Underground Research Laboratory (MIU), one of the main facilities in Japan for research and development of the technology for high-level radioactive waste disposal, is under construction in Mizunami City. In planning the construction, it was necessary to get reliable information on the bedrock conditions, specifically the rock mass stability and hydrogeology. Therefore, borehole investigations were conducted before excavations started. The results indicated that large water inflow could be expected during the excavation around the Ventilation Shaft at GL-200m and GL-300m Access/Research Gallery. In order to reduce water inflow, pre-excavation grouting was conducted before excavation of shafts and research tunnels. Grouting is the injection of material such as cement into a rock mass to stabilize and seal the rock. This report describes the knowledge and lessons learned during the planning and conducting of pre-excavation grouting.
Asozu, Takuhiro; Matsuda, Makoto; Kutsukake, Kenichi
JAEA-Technology 2010-027, 21 Pages, 2010/08
JAEA-Technology-2010-027.pdf:4.64MB
The JAEA-Tokai tandem accelerator has two ion injectors, one is the negative ion injector placed on the ground and the other is the positive ion injector in the high voltage terminal. The electrostatic steerers in the high voltage terminal are used for ion beams from the both injectors. Because the beams from the negative ion injector gain high energy at the 20MV terminal, the electrodes of the electrostatic steerers are designed to be supplied several ten kV. The high voltages are supplied by two unipolar DC power supplies and they are controlled as the sum of the voltages keeps constant. The high electric potential between the electrodes affects the beam trajectory as an electrostatic lens. The potential must be too high for the low energy ion beams from the positive ion injector on the 100kV deck. We simulated the beam trajectory by calculation and evaluated the strength of the lens effects. We report the results and the effective reduction for the lens effect.
Fukushima, Manabu; Owada, Minoru; Ota, Kazunori; Takeuchi, Masaki; Goto, Shingo; Imahashi, Masaki; Terakado, Yoshibumi
JAEA-Technology 2010-028, 24 Pages, 2010/09
JAEA-Technology-2010-028.pdf:1.01MB
The cooling tower of the JRR-3's secondary cooling system is used to emit the heat from the core into the atmosphere. The appropriate maintenance of the cooling tower has helped the safe and stable reactor operation. Temperature of the secondary coolant had controlled constantly by changing the number of cooling fans. But, just after the number of fans changed, the temperature changed transiently and consequently the reactor thermal power changed. In order to amend this some weakness, the control system has improved to change the speed of fans constantly. The maintenance and improvement activities with the records of inspection are compiled to be utilized for future work.
Yamamoto, Masanori; Watanabe, Kazuhiro; Yamanaka, Haruhiko; Takemoto, Jumpei; Yamashita, Yasuo*; Inoue, Takashi
JAEA-Technology 2010-029, 60 Pages, 2010/08
JAEA-Technology-2010-029.pdf:10.49MB
A power supply for the ITER Neutral Beam Injector (NBI) is a DC ultra-high voltage (UHV) power supply to accelerate negative ion beams of 40 A up to an energy of 1 MeV. Japan Atomic Energy Agency as the Japan Domestic Agency for ITER contributes procurement of dc -1 MV main components such as step-up -1 MV transformers rectifiers, a high voltage deck 2, a -1 MV insulating transformer, a transmission line, a surge reduction system and equipments for site test. Design of the surge suppression in the NBI power supply is one of the key issues to obtain the stable injector performance. This report describes the design study using EMTDC code on the surge suppression by optimizing the core snubber and additional elements in the -1 MV power supply. The results show that the input energy from the stray capacitance to the accelerator at the breakdown can be reduced to about 25 J that is smaller than the design criteria of 50 J for the ITER NBI.
Yamagishi, Hideshi*; To, Kentaro
JAEA-Technology 2010-030, 16 Pages, 2010/09
JAEA-Technology-2010-030.pdf:1.38MB
In two-dimensional position sensitive (2-D) neutron detectors used for neutron scattering experiments in the J-PARC, it is required that very small pulse signals consisted of several hundred channels should be measured with discriminating form noises and ray signals and converted from analogue to digital signals in real time. To establish performances of neutron detectors such as fast response and a very small spatial resolution, multi-channel small signals should be measured and the signal processing should be carried out with high S/N ratios. For development of multi-channel electronics with fast response and very low noise, manufacture of an application specific integrated circuits (ASICs) with high performances is indispensable for the 2-D neutron detectors. Therefore, MOSFETs with high gm and low noise required for the ASIC were designed and the noise performances were studied and estimated.
Hiranai, Shinichi; Suzuki, Sadaaki; Sato, Fumiaki; Kobayashi, Takayuki; Hasegawa, Koichi; Yokokura, Kenji; Moriyama, Shinichi
JAEA-Technology 2010-031, 24 Pages, 2010/09
JAEA-Technology-2010-031.pdf:1.71MB
The JT-60U electron cyclotron heating (ECH) system injects a millimeter wave at 110 GHz into the JT-60U plasma, and heats the plasma or drives a current locally to enhance the confinement performance of the JT-60U plasma. The ECH system of high power gyrotrons, transmission lines and antenna that launch millimeter wave beams toward the plasma. On the long pulse injection, one of the most important purposes is to prevent arcing in the transmission lines and to transmit millimeter wave beams efficiently. This report describes the problems occurred in a long pulse injection test (0.5 MW, 30 s), e.g., increase in released gas, temperature rise of the transmission line and an arcing at the vacuum window during the conditioning process. It also describes measures for the problems, e.g., improvements in vacuum pumping system, cooling system, and arc detector and introduction of the new dummy road system.
Editorial Committee of Refining and Conversion Facility Decommissioning Results
JAEA-Technology 2010-032, 115 Pages, 2010/09
JAEA-Technology-2010-032.pdf:29.72MB
The Refining and Conversion Facility located in the Ningyo-toge Environmental Engineering Center had the natural uranium conversion process and reprocessed uranium conversion process. The construction of this facility was started in 1979 and completed in October 1981. Dismantling of equipments in radiation controlled area of this facility was started from 2008, and all equipments in radiation controlled area will be dismantled by the 2011 fiscal year. This report describes the master plan of this decommissioning and shows as the progress in latter half year of 2009FY, the actual time schedule, the method of decommissioning, the decommissioning progress appearance with photographs, work rates of each room / each worker class, and the quantity of dismantled materials and secondary wastes.
Shibahara, Yuji; Tachibana, Mitsuo; Ishigami, Tsutomu; Izumi, Masanori; Nanko, Takashi
JAEA-Technology 2010-033, 42 Pages, 2010/10
JAEA-Technology-2010-033.pdf:1.02MB
Manpower needs for the dismantling process in FUGEN 3rd/4th feedwater heater room was calculated with the evaluation system (PRODIA Code), and it was inspected whether the conventional evaluation model had applicability for FUGEN or not. It was confirmed that the conventional evaluation model for feedwater heater had no applicability. In comparison of the calculated value with the actual data, we found two difference: (1) the evaluated manpower were significantly larger than the actual data, (2) the manpower need for the dismantling of 3rd feedwater heater was twice larger than that of 4th feedwater heater, though these equipments were almost same weight. It was found that these were brought (1) by the difference in the work descriptions of dismantling between JPDR and FUGEN, and (2) by that in the cutting number between 3rd feedwater heater and 4th one. The manpower needs for the dismantling of both feedwater heaters were calculated with a new calculation equation reflecting the descriptions of dismantling, and it was found that these results showed the good agreement with the actual data.
Tagami, Susumu; Sano, Naruto; Otobe, Haruyoshi; Akabori, Mitsuo; Kurobane, Shiro
JAEA-Technology 2010-034, 65 Pages, 2010/10
JAEA-Technology-2010-034.pdf:3.56MB
An experimental facility called the Module for TRU High Temperature Chemistry (TRU-HITEC) was installed in the Back-end Cycle Key Elements Research Facility (BECKY) of the Nuclear Fuel Cycle Safety Engineering Research Facility (NUCEF) in February, 2003. The main purpose of this facility is to perform the basic studies of the behavior the transuranium elements (TRU) in pyrochemical reprocessing and oxide fuels. Hot-experiment started in December, 2004. TRU-HITEC consists of three / cells and a glove box. This is the only facility in the country as large-scale facilities maintained a high purity argon gas atmosphere. The experience gained through the maintenance and improvement is useful also for the maintenance of similar designed facility. This report describes the maintenance method and improvement for the purpose of keeping the performance of TRU-HITEC.
Suzuki, Satoshi*; Komatsuzaki, Takashi*; Sukegawa, Yasuhiro*; Oki, Koichi
JAEA-Technology 2010-035, 134 Pages, 2010/09
JAEA-Technology-2010-035.pdf:22.59MB
It is important in the waste management to evaluate the quantity of radioactivity in the wastes. This report summarizes the improvement, examinations in the nondestructive measurement system using the passive method applied to the evaluation of the quantity of uranium in container waste. Results are followings. (1) Evaluation of the quantity of uranium in container waste was about 
50% against true value. (2) Repeatedly accuracy of the evaluation value is about 50%. (3) The validity of the evaluation to container wastes was confirmed by cross-checking with the system for the drum. (4) When the radioactivity is higher than 1 Bq/g, the facing couple method is effective. (5) If the weight of container is 1t, the detection limit by NaI detector is about 20g (U-238) at the center of container, 3g (U-238) at the surface. Detection limit by Ge detector is about 70g (U-238) at the center, 10g (U-238) at the surface. (6) There is a possibility that about 80% of the container wastes become clearance wastes.
Sekita, Kenji; Arakaki, Etsushi; Wakabayashi, Hiroshi
JAEA-Technology 2010-036, 42 Pages, 2010/11
JAEA-Technology-2010-036.pdf:2.9MB
The Liquid Nitrogen (LN
) manufacturing facility in HTTR, is a high-pressure gas manufacturing facility. The facility provides LN to cold charcoal trap (CCT) in primary and secondary helium purification systems, impurities gas trap for gas chromatography mass spectrometer in primary and secondary helium sampling systems. The facility has been performed periodical inspection according to the law and rule, and each inspection item satisfied the judgment value. Thus, it was confirmed that the maintenance of LN manufacturing facility was appropriate. In addition, the effective and efficient LN amount to be consumed was clarified on the basis of the monitoring. Results of the liquid level of the storage tank and the consumption of LN as the reactor was operated or stopped, by considering the filling frequency and amount of the filling of LN to the facility by a tank lorry. This report describes method and result of periodical inspection and equipment management.
Iwai, Yasunori; Yamanishi, Toshihiko
JAEA-Technology 2010-037, 23 Pages, 2010/11
JAEA-Technology-2010-037.pdf:1.61MB
In the fuel cycle of a fusion reactor, palladium diffuser purifies hydrogen isotopes. We have developed the numerical code of hydrogen permeation through palladium alloy membrane in consideration of each elementary reaction step and effect of external gas-film resistance of mass transfer on hydrogen permeation through palladium alloy membrane was quantitatively evaluated using the code. In the absence of external mass transfer resistance, the rate-controlling step of mass transfer through palladium alloy membrane is solid state atomic diffusion in the range of operating temperature and recombinative desorption at low partial pressure side at lower temperature. The thinner membrane thickness is admittedly preferable for increasing in hydrogen permeation flux. However, the effect of external gas-film resistance of mass transfer on hydrogen permeation flux through palladium alloy membrane should be considered when the membrane thickness is less than 10 mm. Especially in case of insufficient hydrogen pressure on high partial pressure side of membrane, hydrogen permeation flux remarkably decreases due to external gas-film resistance.
Tochio, Daisuke; Hamamoto, Shimpei; Inoi, Hiroyuki; Shimazaki, Yosuke; Sekita, Kenji; Kondo, Masaaki; Saikusa, Akio; Kameyama, Yasuhiko; Saito, Kenji; Emori, Koichi; et al.
JAEA-Technology 2010-038, 57 Pages, 2010/12
JAEA-Technology-2010-038.pdf:2.36MB
In HTTR, in-service operation is conducted through the rise-to power operation with rated operation or high-temperature test operation from achievement of first criticality at 1998. To make practical use HTGR system, it must be demonstrated to supply stable heat to heat utilization system for long-term. In HTTR, high-temperature/parallel-loaded long-term operation had been performed from January 2010. As the result, it was demonstrated to supply stable heat to heat utilization system for 50 days with HTTR, moreover, various long-term operation data were gained. This paper reports the characteristics of the high-temperature long-term operation for HTTR obtained from the operation.
Koarashi, Jun; Mikami, Satoshi; Miyauchi, Toru; Kozawa, Tomoyasu*; Yokota, Tomokazu*; Nakada, Akira; Akiyama, Kiyomitsu; Momose, Takumaro
JAEA-Technology 2010-039, 34 Pages, 2010/12
JAEA-Technology-2010-039.pdf:1.13MBJAEA-Technology-2010-039(errata).pdf:0.08MB
The current methodology for monitoring airborne radioiodine at the Tokai reprocessing plant (TRP) was reviewed, and some investigations were made to re-evaluate collection and measurement techniques in the methodology. The investigations focused particularly on: (1) in situ collection efficiency of an iodine sampler for I and its dependence on sampling flow rate; (2) evaluation of I and 
I activities collected in an activated charcoal cartridge; (3) I collection capacity of an activated charcoal cartridge under reprocessing off-gas conditions; and (4) real-time monitoring system for I in airborne effluent. The results obtained gave not only the validity of the TRP's monitoring method, but also technical aspects required for establishing a more reliable and effective monitoring method for radioiodine isotopes.
Yamamoto, Masahiko; Ishibashi, Atsushi; Nagayama, Tetsuya; Surugaya, Naoki; Kurosawa, Akira; Hiyama, Toshiaki
JAEA-Technology 2010-040, 28 Pages, 2010/12
JAEA-Technology-2010-040.pdf:0.97MB
Precise analysis of plutonium is necessary for material control and safeguards in nuclear facility. Thus, controlled-potential coulometry, which yields absolute results and high precision, was applied for the determination of plutonium. The coulometry system and sample pretreatment procedures were optimized following ISO12183:2005. Plutonium sample prepared from NBL CRM-126 Pu metal was measured and agreed well with certified value. For spike preparation of isotope dilution mass spectrometry (IDMS), plutonium solution was prepared from MOX powder. Plutonium content was 15.5995 mgPu/g. The uncertainty was calculated by ISO/BIPM Guide to the Expression of Uncertainties in Measurements. The relative expanded uncertainty was 0.023% with confidence interval of 95%. The results were in good agreement with those obtained by IDMS. Thus the proposed coulometry method was successfully applied for the determination of plutonium at the highest level of precision and accuracy.
Sudo, Tomoyuki; Nakashio, Nobuyuki; Osugi, Takeshi; Mimura, Ryuji; Ishihara, Keisuke; Satomi, Shinichi; Myodo, Masato; Momma, Toshiyuki; Kozawa, Kazushige
JAEA-Technology 2010-041, 38 Pages, 2011/01
JAEA-Technology-2010-041.pdf:4.73MB
The super compactor in the AVRF treats compactible metal wastes mainly generated from research reactors in the Nuclear Science Research Institute of JAEA. Those wastes are compacted with the maximum about 2,000-ton force. The supercompacted wastes are packed into the container and then immobilized with cementitious materials. The solidified wastes (containing supercompacted wastes) become an object for near surface disposal with artificial barrier. For disposal, the solidified wastes must be satisfied the technical criteria. One of the important indicators is the void ratio in the solidified wastes. In this report, we manufactured the supercompacted wastes with the ordinary treatment method for actual wastes treated in the AVRF and immobilized with a mortar grout. The void ratio of the solidified wastes were evaluated in consideration for concrete vault disposal. As a result, We confirmed the integrity of the solidified wastes from a point of view of void ratio.
Kanamori, Masashi; Suto, Toshiyuki; Tanaka, Kenichi*; Takada, Jun*
JAEA-Technology 2010-042, 11 Pages, 2011/01
JAEA-Technology-2010-042.pdf:0.94MB
JAEA-Technology 2009-043 "A Study on dose control for JCO criticality accident termination", the dose we discuss how to manage termination of the criticality accident at work or (we refer as previously report) As a result, based on the measurements from around 40 m to 100 m, we made a re-evaluation of the dose. Reevaluated doses match with the degree of accuracy 60% to 80% compared with the respective individual dose. In this paper, we validate by these doses by using log-log plots and semi-log plots for the distance from the source approximately 100 m and further attenuation. As a result, if the field is under high doses of neutrons, dose constraint assessment should consider some points, by using 10 mSv, half of the annual limit 20 mSv, as dose reference, the work performed could safely be managed. And summaries the valid range of log-log plots for intense neutron dose estimation.
Amazawa, Hiroya; Sakai, Akihiro; Sakamoto, Yoshiaki; Nakata, Hisakazu; Yamamoto, Masayuki*; Kawata, Yosuke*; Kihara, Shinji
JAEA-Technology 2010-043, 153 Pages, 2011/01
JAEA-Technology-2010-043.pdf:9.72MB
The Low-Level Radioactive Waste Disposal Project Center of Japan Atomic Energy Agency will establish a sitting criterion and procedure in a fair and transparent manner to settle on a near surface disposal facility for low level radioactive wastes generated from research, industrial and medical facilities, based on "Plan Concerning the Disposal Business Execution". Therefore, reasonable conceptual design of the disposal facilities will be planned under premise conditions of sitting condition on natural and social environment, waste form condition including radioactive inventory and waste packages, and technical standards based on "Law for the Regulations of Nuclear Source Material, Nuclear Fuel Material and Reactors" and "Law concerning Prevention of Radiation Hazards due to Radioisotopes, etc." and so on. This report summarizes the results of the investigation on the sitting condition in these premise conditions for conceptual designs of the disposal facilities.
Ishii, Yoji; Watanabe, Kazuhiko; Kamiya, Akira; Hayano, Akira; Mikake, Shinichiro; Takeuchi, Shinji; Ikeda, Koki; Yamamoto, Masaru; Sugihara, Kozo
JAEA-Technology 2010-044, 92 Pages, 2011/02
JAEA-Technology-2010-044.pdf:11.73MB
The "Mizunami Underground Research Laboratory" has been carrying out scientific research in granite to establish the technological basis for high-level radioactive waste disposal. To get reliable information on the rock mass geology and hydrogeology and on the bedrock conditions, a pilot borehole investigation was carried out before sinking the ventilation shaft. During this investigation, a zone with high hydraulic head and low hydraulic conductivity was observed at around GL-400m. To reduce water inflow during excavation, pre-excavation grouting with micro-fine cement was done in this region before sinking the Ventilation Shaft. Despite the high hydraulic head and the low hydraulic conductivity, effective reduction of water-inflow was achieved.
Iyatomi, Yosuke; Hoshina, Hiroyuki; Seko, Noriaki; Shimada, Akiomi; Ogata, Nobuhisa; Sugihara, Kozo; Kasai, Noboru; Ueki, Yuji; Tamada, Masao
JAEA-Technology 2010-045, 10 Pages, 2011/02
JAEA-Technology-2010-045.pdf:1.16MB
The concentrations of fluorine (7.2-10 mg/L) and boron (0.8-1.5 mg/L) dissolved in groundwater pumped from the shafts during excavation of the Mizunami Underground Research Laboratory (MIU), Tono Geoscience Centre, must be reduced to the levels below the environmental standards for fluorine: 0.8mg/L and boron: 1 mg/L. As well, collaborative research on groundwater treatment to remove fluorine and boron started in 2006 between the Environmental and Industrial Materials Research Division, Quantum Beam Science Directorate and the Tono Geoscientific Research Unit, Geological Isolation Research and Development Directorate. This is because the Quantum Beam Science Directorate has synthesized fibrous adsorbents with radiation-induced graft polymerization and applied adsorbents to collect rare metals dissolved in hot springs and sea water. The results of previous testing indicate that the adsorbent was able to remove more than 95% of the boron and fluorine and that performance of adsorbent for boron removal was better than the performance using ion-exchange resin. It was also apparent that the pH of groundwater had an influence on the performance of the adsorbent with respect to boron removal. Therefore we reran the recycling test using groundwater from the neutralization tank at the groundwater treatment facility. The results indicated that the performance of the adsorbent using neutral groundwater for boron removal was higher than using uncontrolled groundwater. However the bed volume (BV) with recycled adsorbent decreased compared to first use. It is thought that sulfur added at the groundwater treatment facility was retained by the adsorbent despite elution, and affected the performance such that repeat usage resulted in decreased efficiency. In addition, it is considered that the goals established in the first year compared to the results obtained to date, including the status of waste water treatment at the MIU, and summarized the results in this development.
Zaima, Naoki; Nakashima, Shinichi; Kaneda, Koji; Kado, Kazumi
JAEA-Technology 2010-046, 31 Pages, 2011/02
JAEA-Technology-2010-046.pdf:2.84MBJAEA-Technology-2010-046(errata).pdf:0.05MB
The uranium mass assay systems for 200-litter wastes drums applied neutron and measurements by NDA method had been developed. The measurement systems and trial data are described in this preliminary report. The systems are composed of the 16 pieces of helium-3 proportional counters for neutron detection and a large sized NaI(Tl) scintillation detector for ray detection. The extensive testing trials using the calibrated uranium sources with different enrichment and some kinds of matrices in drums were performed. Through the one year testing the useful experiences of this system concerning neutron and ray measurements for uranium mass were obtained. Almost all instruments and software were so good performance as is designed. As the next step we are scheduled to try measurements for actual wastes that are stored in the Uranium Refining and Conversion Plant at Ningyo-toge, and put practical uses near future. Our research was accomplished with the support of LANL.
Inamura, Yasuhiro; So, J.-Y.*; Nakajima, Kenji; Suzuki, Jiro*; Nakatani, Takeshi; Kajimoto, Ryoichi; Otomo, Toshiya*; Moon, M.-K.*; Lee, C.-H.*; Yasu, Yoshiji*; et al.
JAEA-Technology 2010-047, 74 Pages, 2011/02
JAEA-Technology-2010-047.pdf:15.03MB
This report summarizes the two-year (2007-2009) activities of Korea-Japan collaboration of chopper software development. Here we have described the background of the collaboration and the main part of our work. We also discussed briefly a future plan of our collaboration starting in 2010. Some of detailed description on the management of the collaboration as well as related information is given in appendix.
Suguro, Toshiyasu; Nishikawa, Yoshiaki*; Watahiki, Takashi*; Kagawa, Akio; Iijima, Kazuki
JAEA-Technology 2010-048, 32 Pages, 2011/03
JAEA-Technology-2010-048.pdf:0.89MB
Cementitious materials are considered to be necessary for the construction of TRU waste repository. The cement additives are used for cements and concretes in order to provide their fluidity. Many kinds of cement additives contain organic compounds which may increase radionuclide solubility by complex formation. Therefore, it is important to obtain the solubility data with cement additives for safety assessment of TRU waste disposal. In this work, two types of cement additives, such as sodium formaldehyde acid polymer and poly carboxylic acid polymer which are expected to be applied to the TRU waste disposal system, are selected. Since the chemical condition of the repository is considered to be reducing, the authors carried out batch-type experiments of plutonium solubility under reducing (NaSO
added as reducant) and anoxic condition ([O] 
1 ppm). Other experimental conditions are (1)initial plutonium concentration; 10
M, (2) temperature; 2985 K, (3)experimental period; 7, 14, 28 and 56 days and (4) molecular weight of cement additives; without fractionation 
5,000 and 
5,000. The plutonium concentration in the absence of the cement additives was in the order of 10
mol dm
, while, those in the presence of cement additives were two or three orders of magnitude higher. Additionally, low molecular weight fraction of cement additives brought relatively higher plutonium concentration than high molecular weight fraction.
Ito, Hideaki; Maeda, Shigetaka; Naito, Hiroyuki; Akiyama, Yoichi; Miyamoto, Kazuyuki; Ashida, Takashi; Noguchi, Koichi; Ito, Chikara; Aoyama, Takafumi
JAEA-Technology 2010-049, 129 Pages, 2011/03
JAEA-Technology-2010-049.pdf:6.99MB
The in-vessel gamma dose rate was measured in the experimental fast reactor Joyo to evaluate the activation of reactor structural components and the radiation exposure of the fiber scope used for in-vessel visual inspection. The measurement system, which requires a wide sensitivity range and high durability in a high-temperature environment, was specifically developed for use in the sodium cooled fast reactor. Using this system, the in-vessel gamma dose rate with cooling times of 450 and 720 days after reactor shutdown was measured in Joyo, which has been operated for 71,000 hours over approximately 30 years. The gamma dose rate was calculated using QAD-CGGP2 code with the gamma source intensity obtained by the ORIGEN2 code. The neutron flux used as input to the ORIGEN2 was evaluated by the Joyo dosimetry method. The ratio between the calculated and experimental values ranged from 1.1 to 2.4, confirming the accuracy of gamma dose rate and component activation calculation.
Miyauchi, Hideaki; Yoshitomi, Hiroshi; Sato, Yoshitaka; Tachibana, Haruo; Takahashi, Fumiaki
JAEA-Technology 2010-050, 17 Pages, 2011/03
JAEA-Technology-2010-050.pdf:1.53MB
Regulations on nuclear power state requirements for measurements of personal dose equivalent at the depth of 70 micrometers for exposures, where the maximum dose can be appeared at body parts except the torso. The hands doses have been measured with Thermal Luminescence Dosemeters in the Nuclear Science Research Institute (NSRI) in the Japan Atomic Energy Agency. In this study, we developed a new ring type dosemeter using the optically stimulated luminescence elements. We have inspected the characteristic by irradiation examinations and a Monte Carlo simulation and established dose evaluation method.
Sagawa, Naoki; Yamazaki, Takumi; Kurosawa, Shigeyuki*; Izaki, Kenji; Mizuniwa, Harumi; Takasaki, Koji
JAEA-Technology 2010-051, 35 Pages, 2011/03
JAEA-Technology-2010-051.pdf:1.83MB
The image analysis method using a imaging plate (IP) is recent technique, and this method can get the information of radioactivity distribution by the unit of Photo Simulated Luminescence (PSL). We have investigated the PSL images obtained by measuring some plutonium samples which are radiation protection samples in order to apply imaging plate to the radiation protection at the MOX fuel facility. Plutonium spots were extracted from the PSL image extracted by the threshold, in which about 99% of the back ground was excluded, and identified by the additional requirement that the spot size is more than 40 pixels. The average background is subtracted from PSL strength of the spot area identified as Pu, and the radioactivity of the Pu spot was evaluated by multiplying the conversion calculation that is in consideration of fading.
Jo, Takahisa; Goto, Takehiro; Yabuki, Kentaro; Ikegami, Kazunori; Miyagawa, Takayuki; Mori, Tetsuya; Kubo, Atsuhiko; Kitano, Akihiro; Nakagawa, Hiroki; Kawamura, Yoshiaki; et al.
JAEA-Technology 2010-052, 84 Pages, 2011/03
JAEA-Technology-2010-052.pdf:17.14MB
The prototype fast breeder reactor MONJU resumed the System Startup Test (SST) on May 6th 2010 after five months and fourteen years shutdown since the sodium leakage of the secondary heat transport system on December 1995. Core Confirmation Test (CCT) is the first step of SST, which consists of three steps. CCT was finished on July 22nd after 78 days tests. CCT is composed 20 test items including control rods' worth evaluation, radiation dose measurement etc..