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Oyama, Kazuhiro; Kawahara, Hirotaka; Ishida, Koichi; Ariyoshi, Masahiko; Isozaki, Kazunori; Sugaya, Kazushi*; Fukami, Akihiro*
JNC TN9410 2005-006, 121 Pages, 2005/03
JNC-TN9410-2005-006.pdf:10.81MB
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
JNC-TN9410-2005-005.pdf:14.56MB
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.
Oyama, Kazuhiro; Kawahara, Hirotaka; Ariyoshi, Masahiko; Sugaya, Kazushi*; Fukami, Akihiro*
JNC TN9410 2005-004, 74 Pages, 2005/03
JNC-TN9410-2005-004.pdf:14.44MB
In the MK-III performance test, the experimental fast reactor JOYO measured the reactor thermal power in each step from a low power to a full power, and calibrated the intermediate range neutron monitors and power range neutron monitors of core instrumentation equipment. This report summarized the result of thermal power calibration.The outline is as follows. (1) We measured the reactor thermal power in each step from a low power to a full power, and calibrated the intermediate range neutron monitors and power range neutron monitors of core instrumentation equipment. Between the power range neutron monitors and the reactor thermal power, it has confirmed from this that there was good linearity. (2) From transition of November 20 [November 14 to] reactor thermal power, and the graphite temperature, although the graphite temperature (83-5,6,7) is rising to about 97 degree, it is mostly saturated in the 6th day after the full power attainment. In addition, thermal power calibration was carried out 4 times within this period. (November 14th, 15th, 16th, 18th) (3) All the errors of the full power measurement at the time of rating are 
3.42% (=4.8 MWt). It is in the reactor thermal power error used by the thermal design of a MK-III reactor core (3.6%). (4) The compensation coefficient in
Ishida, Koichi; Ariyoshi, Masahiko; Fukami, Akihiro*; Sugaya, Kazushi*; Kuroha, Takaya*
JNC TN9410 2004-018, 91 Pages, 2004/05
JNC-TN9410-2004-018.pdf:4.31MB
This paper describes the results of following 2 tests, which were examined as a part of JOYO MK-III function test.1) In-Vessel Coolant Flow Distribution Measurement Test2) Primary System Pressure Drop Measurement Test
Sumino, Kozo; Ichige, Satoshi; Fukami, Akihiro*; Maeda, Yukimoto; Suzuki, Soju
PNC TN9430 98-008, 40 Pages, 1998/09
The Raman Distributed Temperature Sensor (RDTS) based on the Raman Scattering Phenomena in the optical fiber is a system, which can easily measure the accurate temperature distribution. In order to evaluate the applicability of RDTS for FBR plant instrumentation, a temperature distribution measurement using RDTS was performed in the primary cooling system of JOYO. By using two optical fiber sensors, which were installed spirally around the primary piping, the temperature distribution on the primary piping was measured from the 30th through the 32nd duty cycle. In addition, the same test was carried out in the secondary cooling system of JOYO in order to test the measurement data from the primary cooling system. The main results were as follows; (1) The temperature data in the primary cooling system was acquired over 180EFPDs of operation at JOYO (accumulated dose : 3 
10
R). (2) The chracteristics of FTR in the high dose rate nuclear plant environment was confirmed. (3) The radiation induced temperature errors were calibrated succesfully by using thermocouple readings. The accuracy of the temperature after calibration was approximately 3
C. (4) It was confirmed that diffent fiber and insulator settings on the piping cause temperature changes.
*; ; ; ; Fukami, Akihiro*; *; Igawa, Kenichi*
PNC TN9410 91-175, 52 Pages, 1991/05
An acoustic detection method is one of the FBR reactor core malfunction detection methods, and is regarded as being promising. In this study, the preliminary experiment of boiling detection by acoustic method was conducted at JOYO to measure the acoustic signal level and to investigate the applicability of the acoustic method. The experiment was performed on June 13 and 14, 1990 during the 8th periodic inspection of JOYO. The results obtained though the experiment are as follows: (1)Sodium bubbling (boiling) induced by the electric heater was detected as the fluctuation of temperature single of the thermocouple attached to surface of the electric heater. (2)Bubbling single of the acoustic detector could not be identified cleary because of the high background noise caused by the primary main pump vibration, sodium flow in the reacter vessel and the electric supply in the containment vessel. (3)The correlation between the signal of the acoustic detector or the fluctuation of temperature signal of the thermocouple and the flow rate of the primary loops was not ascertained. It became clear through this study that the validity of the reactor core malfunction detction by acoustic method depend on the peculiar noise level in the reactor vessel, and the reduction of noise is the subject for a future study.
*; *; Fukami, Akihiro*; *; Igawa, Kenichi*
PNC TN9440 89-006, 49 Pages, 1989/09
In Experimental Fast Reactor "JOYO", "Development of operation Support System" is continued as the enhancement, of opration support by using computer, in order to improve the availability and reliability of "JOYO" and future fast reactors. Plant State Prediction is one of these systems, and its function is to predict important parameters with respect to the security of safety and to figure them as valid data on CRT. This report deals with the examinations to put this function into JOYDAS (JOYO Data Acqisition System). Main results are as follows. (1) Objective phenomena and signals were selected from Emergency Procedure-Operation (EPO) and so on. (2)From these signls, sodium level in R/V and decay heat were selected and these prediction models were produced. (3)AS for sodium level in R/V, its prediction model was compared with the data at Primary Main Pump Trip (1987-9-7) and this reasonability was confirmed.
*; *; *; Fukami, Akihiro*
PNC TN9410 88-032, 159 Pages, 1988/03
It was necessary that the neutron monitors of the Experimental Fast Reactor "JOYO" must be adjusted peculiarly because of its special circumstances of the location. The graphite temperature feedback system, which is named GAPS (Graphite temperature Automatic Precise compensation System), of the neutron detection signal compensates the pecuriarity of the location circumstance by electric circuit, and it is analog electric instrument of which major functions are the graphite temperature compensation and the reactor outlet temperature compensation to the output voltage of the power range neutron monitors. It was designed and developed using new compensation concept from 1986, and started formal application to the "JOYO" from its 15th duty cycle operation on February 1988. It is concluded that the system can compensate within 1.0 MW error to the reference reactor thermal power by analysis and application test to "JOYO". The precision is fairly jmproved by the system compared with manual calibration. The reliability is also improved because the manual calibration works were decreased by the implementation of the system.
*; *; Fukami, Akihiro*; *; *
PNC TN941 85-154, 101 Pages, 1985/10
In-core flow rate distribution measurement test is conducted after the seventh duty cycle of experimental fast reactor "JOYO" irradiation core (MK-II core). The high flow rate test (90% flow rate) and the low flow rate test (20% flow rate) are conducted, which are the same as previous tests. Furthermore, the very low flow rate test (6% flow rate) and also the test at pump-stop condition are newly conducted. The test results are as followings. (1)It is confirmed that the analysis eode which is used for the core management is verified with satisfactory accuracy. (2)In the case of the test at pump-stop condition, it is measured that the flow rate of the fuel subassembly is proportional to each subassembly's decay heat. (3)It is found that the ratio of center fuel subassembly flow rate to the total fuel flow rate at the 6% flow rate test is smaller than the ratio at the 90% flow rate test. (4)The fuel subassembly flow rate slightly decreased by the lapse of time after loading in the core. The decreasing ratio to the burn-up is -8.53 10
/MW D/T and the ratio to the lapse day in the core is -2.12 10
/day.