JOYO MK-III performance test

Sekine, Takashi; Maeda, Yukimoto; Aoyama, Takafumi; Ariyoshi, Masahiko

Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(4), p.259 - 275, 2005/04

https://doi.org/10.3327/taesj2002.4.259

The MK-III upgrading project was completed in the experimental fast reactor JOYO to increase irradiation capability for irradiation tests. After modification work of cooling system, the system function tests were carried out between August 2001 and March 2003. As a result of these tests, it was confirmed that the performance of whole plant included the modified components, which were the intermediate heat exchanger (IHX) and the dump heat exchanger (DHX) etc., was satisfied with the design. The performance tests were carried out from June 2003 as the last phase of MK-III modification work. During the performance tests, the reactor power was raised step by step as 20%, 50%, 75%, 90% and 100% (140MWt), while confirming the nuclear and thermal characteristics of MK-III core and the heat removal capability of IHX and DHX. All performance tests was successfully carried out and it was confirmed that the performance of JOYO MK-III plant was satisfied with the design. Certificate of pre-use inspection about JOYO MK-III was conferred from Ministry of Education, Culture, Sports, Science and Technology in 27th November 2003 and the MK-III modification work was completed. This report shows the results of the system function tests and the performance tests of JOYO MK-III.

JOYO MK-III Performance test report; Blower start-up test (PT-303), Power-increase test (PT-301), Rated power operation test (PT-302)

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.

JOYO MK-III Performance Test Report; Thermal Power Calibration (PT-311)

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

MK-III Performance Tests in JOYO; Transient Response Tests

Kawahara, Hirotaka; Rekimoto, Masafumi; Jo, Takahisa; Ishida, Koichi; Ariyoshi, Masahiko; Isozaki, Kazunori

JNC TN9410 2005-002, 135 Pages, 2005/02

JNC-TN9410-2005-002.pdf:17.48MB

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.

Study of an instrumentation system for a nuclear reactor plant based on optical fiber Bragg gratings

Amemiya, Kuniaki*; Nakazawa, Masaharu*; Ariyoshi, Masahiko; Ito, Keisuke

JNC TY9400 2004-008, 52 Pages, 2004/04

JNC-TY9400-2004-008.pdf:2.65MB

A new monitoring system of nuclear reactor plants by means of optical fiber Bragg gratings (FBGs) was developed which have sensitivity in temperature, distortion and vibration. The reflective wavelength of FBGs was not influenced by gamma-ray irradiation up to 1.4MGy and by exposure to fast neutrons in excess of 10 sup14 n/cm sup2. A temperature-insensitive vibration sensing system was constructed and operated with no trouble in gamma-ray environments up to 100kGy. Furthermore, a multiple point vibration sensing system was designed and constructed. The system was successfully demonstrated on a cooling system at the "Yayoi" reactor. Thus, we tried to apply the monitoring system to a primary loop area of JOYO to confirm the applicability of FBG sensors for the commercial power reactors. Although a correlation of sodium flow in side pipes and vibration measured by FBG sensors was found before starting of the reactor, it became impossible after starting operation of the reactor because of a decline of signal amplitude. Investigating the reason, it was mainly caused by significant transmission losses at the splicing point and there were no problems with FBG sensors. Various methods, for example, using a more powerful light source and changing the splicing method, may be used to improve it in the future.

Study on In-vessel ISI for JOYO - Core support plate inspection equipment under sodium -

Ariyoshi, Masahiko; Nakayama, Oukatsu

JNC TN9400 2004-015, 27 Pages, 2004/03

JNC-TN9400-2004-015.pdf:0.8MB

This report describes the feasibility study on the in-vessel inspection technique to be applied for the experimental fast reactor JOYO. Since JOYO is a sodium cooled fast reactor and the core structure components are in high temperature and fast neutron irradiation environment, material strength yields to decrease due to heat fatigue and irradiation induced embrittlement. The present surveillance method of testing structural material mechanical property, monitoring subassembly outlet temperature and sodium leak are not sufficient to detect a small crack. Therefore, the direct inspection method to confirm the core structure integrity needs to be developed considering the recent innovative technology. Since the core structure has a complicated form and components under sodium are not visible, the manipulator technology is essential which has various positioning functions. The core support plate was selected to be an important inspection item, and the method which combines ultrasonic non-destructive inspection technology and manipulator technology was examined. In this study, the core support plate inspection equipment concept was examined on the assumption that the inspection of the core support plate was executed under sodium. The sensor for the nondestructive testing is built into the inspection assembly which is loaded in most outer core area, and can be accessed to a low-pressure plenum sidewall by the manipulator. The linear array sensor which arranges several piezo-electric elements were applied to the sensor for the nondestructive testing, and for scanning the inspection object in non-contact. It was assumed for the concept of the manipulator that the sensor was positioned by moving of the arm and bending the joint. The technology of the Master Slave Manipulator for Laparoscopic Surgery was applied for the manipulator. A detailed examination is necessary for this concept in the future. And, the development of in-vessel inspection equipment is continued and prot

Study on in-vessel ISI for JOYO; Thechnical survey of under sodium non-destructive inspection technique and study of application concept

Ariyoshi, Masahiko; Ishida, Koichi

JNC TN9400 2002-010, 25 Pages, 2002/03

JNC-TN9400-2002-010.pdf:0.67MB

This report is concerning the in-vessel in-service inspection (ISI) technology for the experimental fast reactor JOYO. The present ISI method in JOYO is not able to confirm the integrity of the core structure directly, expecting the visual inspection for the top of core assemblies from above the rotating plug. The purpose of this examination is to progress of the ISI method, and to confirm the integrity of the core structure directly. The core support plate is an important structure and it is selected for the object of in-vessel ISI. From the viewpoint of the influence on the plant, it is regarded impotant the method without all sodium draining, and the remote operation from above of the shielding plug. As a result, following technology is thought promising. (1)Under sodium inspection technique by means of ultrasonic method (it is able to apply in-vessel ISI without all sodium draining). (2)Nondestructive inspection technique by laser based ultrasonic method (it is superior in remote operating) (3)The local sodium discharge mechanism (it makes possible to apply laser based ultra sonic method for under sodium inspection) These technologies were investigated, examined, and the concept applied to ISI in JOYO core support plate was examined. Moreover, the problem when these were applied to in-vessel ISI in JOYO was picked up.