Maintenance experience of experimental fast reactor Joyo, 2; The Maintenance experience on the electromagnetic pumps in Joyo sodium cooling system

Suto, Masayoshi; Sugaya, Takashi; Sumino, Kozo

Nihon Hozen Gakkai Dai-7-Kai Gakujutsu Koenkai Yoshishu, p.258 - 262, 2010/07

no abstracts in English

Maintenance experience of sodium cooling system electromagnetic pump on Joyo

Suto, Masayoshi; Sugaya, Takashi; Sumino, Kozo

UTNL-R-0475, p.7_1 - 7_11, 2010/03

no abstracts in English

Plant life management in JOYO; Replacement of gas coolers in reactor vessel concrete shield cooling system and cold trap system

Tobita, Shigeharu; Nishino, Kazunari; Sumino, Kozo; Ogawa, Toru

UTNL-R-0453, p.2_1 - 2_10, 2006/03

no abstracts in English

Upgrade of cooling system heat removal capacity of the experimental fast reactor JOYO

Sumino, Kozo; Isozaki, Kazunori; Ashida, Takashi;

Nuclear Technology, 150(1), p.56 - 66, 2005/04

https://doi.org/10.13182/NT05-A3605

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.

MK-III Function Tests in JOYO; Primary main Cooling Pump

Isozaki, Kazunori; Saito, Takakazu; Sumino, Kozo; Yamazaki, Yuji*; Karube, Koji; Terano, Toshihiro; Sakaba, Hideo; Nakai, Satoru

JNC TN9410 2004-014, 162 Pages, 2004/06

JNC-TN9410-2004-014.pdf:48.0MB

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.

JOYO MK-III Modification work on heat transport system; Work plan and plant control

Isozaki, Kazunori; ; Oshima, Jun; ; Ashida, Takashi; Saito, Takakazu; Sumino, Kozo

JNC TN9410 2002-007, 142 Pages, 2002/07

JNC-TN9410-2002-007.pdf:10.92MB

The MK-III Project to improve the irradiation capability of the experimental fast reactor JOYO have been in underway since 1987. The increase of fast neutron flux and the enlargement of that field increase the reactor thermal rate from 100MWt To 140MWt. To increase cooling capacity of heat transport system, intermediate heat exchangers (IHXs), dump heat exchangers (DHXs), piping connecting to IHXs and DHXs, main motors on Primary and secondary main circulation pumps were replaced. The replacement of these large components was carried out under following hard conditions. (1)Limitation of work space, (2)Fuel subassembly and melten sodium in the reactor vessel, (3)high radiation circumstances for primary cooling system, (4)treatment of radioactive sodium (radioactive sodium and corrosion product such as CO, Mn). There are little experiences of this kind of work in the world. Therefore the organization, workmg plan and safety management points were carefully examined and established, based on the previous experience of JOYO operation and maintenance, research and development results of safety treatment of sodium, experience of previous work on sodium facilities. Following sresults were obtained and effectiveness was confirmed in the work. (1)Development of most suitable working plan derived from elements and full size mock up experiments, reduction of exposure time by workers training, reduction of radiation dose by installation of temporal radiation shielding were useful to reduce radiation dose. The usage of seal bag was useful to prevent the contamination spreading over. (2)The usage of seal bag, oxygen concentration monitoring in the seal bag, nitrogen concentration monitoring in the cooling system cover gas, low pressure control of cover gas were useful to reduce the inflow of oxygen to cooling system. (3)The bite cutting method for piping in air and press down cuttmg by roller cutter in the seal bag to prevent inflow of cutting piece, ...

Replacement of nitrogen gas evaporator of JOYO

Sumino, Kozo; Oshima, Jun; ; ; ; Ozawa, Kenji

JNC TN9410 2001-008, 47 Pages, 2001/03

JNC-TN9410-2001-008.pdf:2.66MB

The nitrogen gas evaporator using steam heating is a main component of the nitrogen gas supply system of JOYO and had been operated without the maintenance in order to supply nitrogen gas to the plant continuously. However, the necessity of replacing the nitrogen gas evaporator occurred due to the corrosion of the tank which involved water and steam for the heating in the recent years. Therefore, the nitrogen gas evaporator using steam was replaced with a new one that has a tank made of stainless steel, and the nitrogen gas evaporator using air heating was newly installed in order to supply the nitrogen gas during the maintenance of the nitrogen gas evaporator using steam heating. In addition, thermometers were installed at water in a tank and supply nitrogen gas in order to monitor these temperatures from the main control room. The main results of a preoperation function test were as follows; (1)It was confirmed that the performance of the new nitrogen gas evaporator using steam heating was more than it of the old one. (2)The nitrogen gas evaporator using air heating could successfully maintain the nitrogen gas atmosphere (within 4% oxygen concentration) in the lower part of the reactor containment vessel. (3)The correlation between the water temperature in a tank and the supply nitrogen gas temperature were confirmed for the normal and maximum operations.

Applicability test of the raman distributed temperature sensor for FBR plant instrumentation

Sumino, Kozo; Ichige, Satoshi; Fukami, Akihiro*; Maeda, Yukimoto; Suzuki, Soju

PNC TN9430 98-008, 40 Pages, 1998/09

PNC-TN9430-98-008.pdf:1.75MB

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 3C. (4) It was confirmed that diffent fiber and insulator settings on the piping cause temperature changes.

Thermal hydraulic analysis in reactor vessel of JOYO MK-III standard core

; Maeda, Yukimoto; Sumino, Kozo;

PNC TN9430 98-005, 96 Pages, 1998/07

PNC-TN9430-98-005.pdf:3.54MB

A thermal hydraulic analysis in the reactor vessel of the JOYO MK-III standard core was performed by Single-Phase Multi-Dimensional Thermal-Hydraulic Analysis Code "AQUA". The major results are as follows: (1)The hydraulic characteristics in the reactor vessel of the MK-III standard core showed the same tendency as it of the MK-II core. (2)It was confirmed that, the coolant, flow rates in each subassembly were more than the minimum coolant flow rates which were described in a document, "Thermal Hydraulic Analysis of JOYO MK-III Core". (3)The coolant, temperature distribution was evaluated at the top of core, at the outlet of the subassemblies, and in the reactor vessel in detail.

Measurement and evaluation of corrosion products deposition distribution in the experimental fast reactor JOYO

Aoyama, Takafumi; ; Sumino, Kozo; Saikawa, Takuya*

PNC TN9410 98-004, 74 Pages, 1997/12

PNC-TN9410-98-004.pdf:2.36MB

The Corrosion Product (CP) is the major radiation source in the primary cooling system of an LNFBR plant. It is important to characterize and predict the CP behavior to reduce the personnel exposure dose due to CP deposition. The CP measurement was carried out in the Experimental Fast Reactor JOYO during the 11th annual inspection period when the accumulated reactor thermal power reached about l43GWd. The CP deposition density was measured using a pure germanium detector. The plastic scintillation fiber (PSF) was applied for the gamma-ray dose rate distri bution measurement and compared with the thermoluminescence dosimeter (TLD). The major results obtained by the CP measurements in JOYO are the follows: (1)The major CP nuclides deposited in the primary cooling system are Mn and CO. Mn is the dominant isotope and it tends to deposit in the cold leg region. On the other hand, Co deposits mainly in the hot leg region. The deposition density of Mn is about seven times as much as that of Co in the cold leg region and twice in the hot leg region. (2)The deposition densities of Mn and Co, and the gamma-dose rate were decreased from the last data in the previous annual inspection period mainly due to the short operation time and the longer cooling time. (3)The continuous gamma-ray dose rate distribution up to 10m can be measured by using the PSF in a few minutes. The PSF is suitable to measure the gamma-ray dose rate distribution in the maintenance work area where it is narrow and the mixture of gamma-ray sources from primary pipings and components. The data base of detailed gamma-ray dose rate distribution was greatly extended by the PSF.