Sumino, Kozo; Kobayashi, Tetsuhiko; Isozaki, Kazunori; Yoshida, Akihiro
Nihon Hozen Gakkai Dai-7-Kai Gakujutsu Koenkai Yoshishu, p.255 - 257, 2010/07
In the experimental fast reactor Joyo, maintenance work was conducted based on the classification of safety importance over thirty years. Through the experience, it was confirmed that particular effort was not necessary for the maintenance of sodium cooling systems by controlling the coolant purity properly. Additionally, as a result of the technical review on aging for whole plant, significant aging phenomenon that is particular with sodium cooled fast reactor was not observed.
Ito, Chikara; Isozaki, Kazunori; Ashida, Takashi; Sumino, Kozo; Kawahara, Hirotaka
IAEA-TECDOC-1633 (Internet), p.45 - 56, 2009/11
Ohara, Norikazu; Suzuki, Toshiaki; Isozaki, Kazunori
UTNL-R-0466, p.6_1 - 6_11, 2008/03
no abstracts in English
Suto, Masayoshi; Ichige, Satoshi; Isozaki, Kazunori
UTNL-R-0459, p.5_1 - 5_9, 2007/03
no abstracts in English
Isozaki, Kazunori; Ogawa, Toru; Nishino, Kazunari; Kaito, Yasuaki; Ichige, Satoshi; Sumino, Kozo; Suto, Masayoshi; Kawahara, Hirotaka; Suzuki, Toshiaki; Takamatsu, Misao; et al.
JNC TN9440 2005-003, 708 Pages, 2005/05
Periodic safety review (Review of the aging management) which consisted of Technical review on aging for the safety related structures, systems and components and Establish a long term maintenance program was carried out up to April 2005.1. Technical review on aging for the safety related structures, systems and components It was technically confirmed to prevent the loss of function of the safety related structures, systems and components due to aging phenomena, which (1) irradiation damage, (2) corrosion, (3) abrasion and erosion, (4) thermal aging, (5) creep and fatigue, (6) Stress Corrosion Cracking, (7) insulation deterioration and (8) general deterioration, under the periodic monitoring or renewal of them 2. Establish a long term maintenance program The long term maintenance program during JPY2005 to 2014 were established based on the technical review on aging for the safety related structures, systems and components. It was evaluated that the inspection or renewal based on the long term maintenance program, in addition to the spontaneous inspection long-term schedule of the long term voluntary inspection plan, could prevent the loss of function of the safety related structures, systems and components in future.
Sumino, Kozo; Isozaki, Kazunori; Ashida, Takashi;
Nuclear Technology, 150(1), p.56 - 66, 2005/04
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Ito, Keisuke; Kawahara, Hirotaka; Mori, Takero; Jo, Takahisa; Ariyoshi, Masahiko; Isozaki, Kazunori
JNC TN9410 2005-008, 267 Pages, 2005/03
Control characteristic tests of reactor coolant temperature control system were carried out to confirm its controlling constant to make MK-III hear transport system control stably, and stability against actual disturbance to the plant. The control characteristic test consists of three kinds of tests. As a result, the optimum PI parameters of the reactor coolant temperature control system was confirmed that the proportional gain is between from 0.36 to 1.12(approximately half of MK-II), the integral time is 80 respectively. The gain margin of the control system was between from 7 to 19dB of through the vane opening range.
Oyama, Kazuhiro; Kawahara, Hirotaka; Ishida, Koichi; Ariyoshi, Masahiko; Isozaki, Kazunori; Sugaya, Kazushi*; Fukami, Akihiro*
JNC TN9410 2005-006, 121 Pages, 2005/03
In the MK-III performance test, the experimental fast reactor JOYO raised the reactor thermal power gradually with about 20%, 50%, 75%, 90%, and 100% (140MWt), and reached 140MWt which are the full power of a MK-III reactor core on October 28, 2003. Then, continuation operation beyond full power 100 hour was attained. This report summarized the result of power-up test , full power continuation operation test, blower start-up test.The outline is as follows.(1)From the standby state (system temperature of 250degree), the usual power-up operation (an power-up rate ;about 5MWt/20min, a power is held for about 10 minutes every 5MWt) attained the reactor thermal full power (140MWt) gradually on October 28,2004. Moreover, it checked that each part temperature and flow were less than alarm setting values on each power level.(2)The reactor thermal power was made into the parameter, a series of operations about the blower start-up, and the influence which it has on coolant temperature was checked. As a result, the optimal reactor thermal power which starts up the blower from a natural ventilation cooling state was set to about 18 MWt, and the starting procedure was made into the method(order of 1A-2A-1B-2B) which starts four sets of the one blower at a time one by one.(3)It checked that reactor shutdown operation by two control-rod simultaneous insertion at 35MWt, and it could carry out with time margin with a series of sufficient operations of resulting from control rod insertion in the blower shutdown. By adopting this reactor shutdown operation method, operation of an operation stuff was mitigated and it checked that plant characteristics also improved.(4)The reactor full power was reached on November 14. Continuation operation beyond full power 100 hour was attained after that till on November 20, 10:30. The data of each part of a plant was acquired at intervals of 24 hours, and it checked that it was less than an alarm setting value.
Oyama, Kazuhiro; Kawahara, Hirotaka; Ariyoshi, Masahiko; Isozaki, Kazunori; Sugaya, Kazushi*; Fukami, Akihiro*
JNC TN9410 2005-005, 56 Pages, 2005/03
The experimental fast reactor JOYO MK-III increased that the reactor thermal power by the factor 1.4. The main intermediate heat exchangers (IHX) and the dump heat exchangers (DHX) were exchanged. And then, the flow rate of the main cooling system, the secondary cooling system were increased. As one of the performance test to confirm that the cooling system which included these switch receptacles has an enough decay heat performance, it did an heat transfer characteristics test and it evaluated a heat balance, the decay heat performance of IHX and DHX.The outline is as follows.(1)It confirmed that the modificated plant had fixed performance by the heat balance of full power.(2)The secondary inlet temperature of B-loop IHX is about 6degree higher out of the cooling system with A-loop. It thinks that this is one because of the difference ( about 2 % ) with the flow rate of the main cooling system in measurement. There was decay heat capacity of the A-loop and the B-loop in the balance, making the flow rate of the main cooling system of the A-loop positive and supposing that the B-loop is a revision flow rate and as for the heat transfer performance of IHX of the A-loop and the B-loop, the approximately equal thing could be confirmed. As a result, as for the overall heat transfer coefficient of IHX, the A-loop was about 125 % of the design value, the B-loop was about 129 % of the design value and it confirmed that two IHX had the performance to be equal and an enough decay heat performance.(3)It made DHX outlet air temperature about 20degree and it calculated DHX outlet air flow from the decay heat capacity from sodium coolant and the DHX outlet air temperature in full power. As a result, DHX could confirm that the decay heat ability to be equivalent to he reactor thermal power in 85 - 90 % of capacities of design value (6,750m/min) and an enough decay heat performance.
Maeda, Yukimoto; Kashimura, Yoichi; Suzuki, Toshiaki; Isozaki, Kazunori; Hoshiba, Hideaki; Kitamura, Ryoichi; Nakano, Tomoyuki; Takamatsu, Misao; Sekine, Takashi
JNC TN9440 2005-001, 540 Pages, 2005/02
Periodic safety review (Review of the activity for safety) which consisted of "Comprehensive evaluation of operation experience" and "Incorporation of the latest technical knowledge" was carried out up to January 2005.
Kawahara, Hirotaka; Rekimoto, Masafumi; Jo, Takahisa; Ishida, Koichi; Ariyoshi, Masahiko; Isozaki, Kazunori
JNC TN9410 2005-002, 135 Pages, 2005/02
The manual shutdown tests and loss of electric power supply tests were carried out as the transient response test on anomaly condition at 70MWt and 140MWt operation. The decay heat removal tests by main cooling system were carried out after each transient response tests. It was confirmed that the plant protection system operates properly and the reactor can be shut down safely. These results confirmed that the thermal transients are less severe than the design conditions.
Sumino, Kozo; Ashida, Takashi; Kawahara, Hirotaka; Ichige, Satoshi; Isozaki, Kazunori; Nakai, Satoru
Proceedings of Operating Nuclear Facility Safety(2004ONFS),p204-216, p.204 - 216, 2004/11
Kawahara, Hirotaka; Isozaki, Kazunori; Ishii, Takayuki; Ichige, Satoshi; Nose, Shoichi; Sakaba, Hideo; Nakai, Satoru
JNC TN9410 2004-016, 106 Pages, 2004/06
A key part of the upgrade of the experimental fast reactor JOYO to the MK-III design was the replacement of the dump heat exchangers. MK-III function tests (SKS-1) of the new dump heat exchangers were carried out from August 27,2001 through September 13,2001. The major results of the function tests of the dump heat exchangers were as follows: (1) Air flow of the main blower with an inlet vane opening of 50% was confirmed to exceed the design rated flow of 7,700m3/min. It was also demonstrated that an inlet vane opening of 100% provides about 130% of the design rated flow. This is because the new DHX flow route has more low pressure loss than the design value. (2) Tests of the air flow of the main blower demonstrated that with a fully opened inlet damper a full opened outlet damper and an inlet vane opening of O% provides about 5% of the design rated flow. (3) Free flow coast down characteristics of the main blower achieved an inlet vane O% opening in an average of 7.9 seconds. Revolutions per minute of the main blower reached zero in an average of 8.7 seconds. The delay time from the opening of the vacuum contact breaker to the air flow decrease was approximately 1 second. This was a more conservative value than the 5 seconds assumed in design thermal transient analyses. (4) The loudest noise occurred with the main blower operating with a 25% inlet vane opening. At that time, the noise around the main blower was approximately 100dB, and in the surrounding monitoring area boundary, the noise was 50dB. This was confirmed to be within the standard of the Ibaraki prefectural ordinance. (5) Although the MK-III inlet vane and inlet damper drive unit was bigger than the MK-II unit, the accumulator tank was confirmed to provide sufficient volume during a compression air loss event.
Isozaki, Kazunori; Saito, Takakazu; Sumino, Kozo; Yamazaki, Yuji*; Karube, Koji; Terano, Toshihiro; Sakaba, Hideo
JNC TN9410 2004-014, 172 Pages, 2004/06
This technical report describes MK-III function tests on the primary main cooling pump. MK-III function tests (SKS-1) before MK-III core configuration completed from October 17, 2001 to October 23, 2001. MK-III function tests (SKS-2) after MK-III core configuration completed from January 27, 2003 to February 13, 2003. The results of function tests were shown as follows; (1) The primary main pump was confirmed to do stable control on both CAS (cascade) mode and MAN (manual) mode in the flow control system. And also this was confirmed no-emanation trend both flow and revolution per minute against flow step response, too. (2) The main motor was shifted run-back operation in about 54 seconds after scram. Run-back operation of the main motor (A) was 167m3/h with 117 rpm. 185 m/h with 118 rpm was the main motor (B). And they were controlled within the limit of run-back operational revolution 122 rpm 8 rpm. The flow was confirmed to maintain in 10 percent and over of the rated flow. (3) Succeeding operation to the pony motor was confirmed to do in about 39 seconds after the primary main pump trip. The pony motor (A) operation was 180m3/h with 124rpm. 190 m/h with 123 rpm was the pony motor (B). They were enough satisfied with the forgiven revolution per minute which was 93 rpm and over. And the flow was confirmed to maintain in 10 percent and over of the rated flow. (4) Free flow coast down characteristic of the primary main pump was confirmed that time constant was 10 seconds at both the trip and run-back operation time of the primary main pump. (5) Over flow column sodium level of the main pump duty operation was NL-1,550 mm Na by column (A), NL-1,468mm Na by column (B). They were smaller than NL-1,581 mm Na by the design value. Pressure loss value of the new IHX had more conservative value than the design value. (6) The primary main pump was confirmed which the rated flow could be restored no-scram by the instantaneous power loss within 0.6 second.
Kawahara, Hirotaka; Isozaki, Kazunori; Tomita, Naoki
JNC TN9410 2004-015, 129 Pages, 2004/04
The MK-III modification to improve the irradiation capability of JOYO was carried out. The increase of fast neutron flux and the enlargement of that field increase the reactor thermal rate from 100 MWt to 140 MWt. The main components in the cooling system such as intermediate heat exchangers (IHXs) and dump heat exchangers (DHXs) were replaced in MK-III modification in order to increase heat removal capability. This report describes the specific characteristic in the design and manufacturing, design data and principle of the design for the new DHX.
Oshima, Jun; Ashida, Takashi; Isozaki, Kazunori; Sumino, Kozo; Yamaguchi, Akira; Sakaba, Hideo; Ozawa, Kenji; Tomita, Naoki
JNC TN9410 2004-011, 279 Pages, 2004/04
The MK-III project to improve the irradiation capability of the experimental fast reactor JOYO have been carried out since 1987.The increase of fast neutron flux and the enlargement of irradiation field increase the reactor thermal power from 100MWt to 140MWt. To accommodate the increased thermal power,the IHXs and the IHX connecting piping were replaced. The IHXs were replaced with securing cooling system boundary in high dose rate surroundings and very limited operation space of the radiation controlled area in the containment vessel. Primary sodium contains radioactive 22Na,24Na and radioactive CPs such as 60Co and 54Mn,and this sodium adhered to the inner surface of IHXs and pipe. Therefore, the renovation procedure and method were carefully examined based on the JOYO operation and maintenance experiences and research and development results on the sodium handling technique.The major results obtained in the primary heat transport mechanical system (IHXs) renovation operation were shown as follows;
Michino, Masanobu; Suzuki, Toshiaki; Aita, Tsuyoshi; Suto, Masayoshi; Saito, Takakazu; Kawahara, Hirotaka; Isozaki, Kazunori; Ito, Hideaki; Inoue, Setsunari; Aoki, Hiroshi; et al.
JNC TN9430 2004-001, 103 Pages, 2004/03
This report describes the results of the primary and secondary cooling system interlock test and the fuel handling system function test, which were done as a part of JOYO MK-3 function test. The items of the test are: (1) Primary and secondary cooling system interlock test (SKS-106,210) (2) Loss of electric power supply test (SKS-116) (3) In-vessel and ex-vessel automatic fuel transportation test (SKS-501,502) As the interlock of the primary and secondary cooling system was changed, the interlock test by the reactor scram and the loss of electric power supply was carried out. The function of the remote automatic fuel handling system was confirmed before the handling of the fuel for MK-3 core configuration. The results of the test satisfied the required performance, and it was confirmed that operation of the primary and secondary cooling system interlock and operation of the fuel handling system in JOYO MK-3 were normal.
Maeda, Yukimoto; Aoyama, Takafumi; Yoshida, Akihiro; Sekine, Takashi; Ariyoshi, Masahiko; Ito, Chikara; Masaaki, Nemoto; Murakami, Takanori; Isozaki, Kazunori; Hoshiba, Hideaki; et al.
JNC TN9410 2003-011, 197 Pages, 2004/03
MK-III performance tests began in June 2003 to fully characterize the upgraded core and heat transfer system. Then, the last pre-use inspection was finished in November 2003.This report summarize the result of each performance test.
Kawahara, Hirotaka; Kawahara, Hirotaka; Ichige, Satoshi; Isozaki, Kazunori; Nakai, Satoru
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 0 Pages, 2004/00
A recently completed major upgrade of the JOYO experimental sodium-cooled fast reactor, to the MK-III design, increased its irradiation capability approximately four times. 0ne major change was a 40% increase in thermal power to 140 MWt, which necessitated the replacement of the heat exchangers. Each of the two coolant loops includes an intermediate heat exchanger (IHX) and sodium pump in the primary system, and two dump heat exchangers (DHXs) and a pump in the secondary system. The heat transfer area of the finned tubes in each (air-cooled) DHX was doubled, compared to the old design, to achieve a 35 MWt rating, Major challenges in the replacement of secondary components, such as piping and DHX, were control of impurity ingress into the sodium system, and integrity assurance of the welding. Damage to existing components and systems was avoided during cutting and welding operations by taking measures to Prevent ingress of air into the sodium systems. The measures included use of seal b
Isozaki, Kazunori; Tomita, Naoki
JNC TN9410 2003-005, 55 Pages, 2003/08
The mechanical and oil snubber type piping supports have been installed and used in the piping system including the primary and secondary cooling system in order to restrain the vibration caused by the earthquake in the experimental fast reactor "JOYO". The piping supports moves with pipe corresponding to slow displacement such as thermal expansion of the pipe. On the contrary, when the earthquake happens, it restrains the rapid vibration mechanically or hydraulically. Manufacture guarantees that the piping support can stand the vibration up to 150% load of design specification.The piping support in JOYO could stand the vibration in excess of design value, but the upper limit of the vibration had not been obtained. In order to grasp the upper limit, vibration tests were carried out using the same type piping support as installed in the primary and secondary cooling system. As a result of the vibration test, it was confirmed that the vibration restraint function of piping support could be maintained up to 6 times higher design value. This result will be used for reasonable review of the earthquake-proof design, evaluation of the components and piping system residual lifetime.