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Ishikawa, Koki; Takamatsu, Misao; Kawahara, Hirotaka; Mihara, Takatsugu; Kurisaka, Kenichi; Terano, Toshihiro; Murakami, Takanori; Noritsugi, Akihiro; Iseki, Atsushi; Saito, Takakazu; et al.
JAEA-Technology 2009-004, 140 Pages, 2009/05
JAEA-Technology-2009-004.pdf:2.0MB
Probabilistic safety assessment (PSA) has been applied to nuclear plants as a method to achieve effective safety regulation and safety management. In order to establish the PSA standard for fast breeder reactor (FBR), the FBR-PSA for internal events in rated power operation is studied by Japan Atomic Energy Agency (JAEA). The level1 PSA on the experimental fast reactor Joyo was conducted to investigate core damage probability for internal events with taking human factors effect and dependent failures into account. The result of this study shows that the core damage probability of Joyo is 5.0
10
per reactor year (/ry) and that the core damage probability is smaller than the safety goal for existed plants (10 ry) and future plants (10
/ry) in the IAEA INSAG-12 (International Nuclear Safety Advisory Group) basic safety principle.
Isozaki, Kazunori; Saito, Takakazu; Sumino, Kozo; Yamazaki, Yuji*; Karube, Koji; Terano, Toshihiro; Sakaba, Hideo
JNC TN9410 2004-014, 172 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.
Karube, Koji; Akagi, S.; Terano, Toshihiro; Onuki, Osamu; Ito, Hideaki; Aoki, Hiroshi; Odo, Toshihiro
JNC TN9430 2004-004, 36 Pages, 2004/03
JNC-TN9430-2004-004.pdf:1.03MB
This paper describes the results of primary auxiliary cooling system,which were done as a part of JOYO MK-III function test. The aim of the tests was to confirm the operational performance of primary auxiliary EMP and the protection system including siphon breaker of primary auxiliary cooling ststem. The items of the tests were:(1) Test No.:SKS-117/Test item/EMP start up test (2) Test No.:SKS-118-1/Test item:EMP start up test when pony mortor running (3) Test NO.:SKS-121/Test item:Function test of siphon breaker The results of the tests satisfied the required performance,and demonstrated succeccful operation of primary auxiliary cooling system.
; Terano, Toshihiro; ; ; Okubo, Toshiyuki
JNC TN9410 2000-004, 30 Pages, 2000/03
JNC-TN9410-2000-004.pdf:0.86MB
The Operation and Maintenance Support Systems for JOYO are being developed, with the aim of ensuring the stable and safe operation of JOYO and improving operational reliability of future FBR plants. Plant Operation Management Expert Tool named JOYPET had been developed as one of the Operation and Maintenance Support Systems, which helps plant operation management. The following functions were developed and applied. (1)Papers management (Plant status management) function for maintenance activities (2)Isolation management support function for plant operation (3)Automatically drawing function of plant operation schedule (4)Isolation judgment function for plant operation By use this system, the plant management of JOYO was able to improved reliability and reduced manpower.
; Terano, Toshihiro; ; Onuki, Osamu; ; Okubo, Toshiyuki;
PNC TN9410 96-103, 88 Pages, 1996/03
This paper describes operational experiences of JOYO Secondary Sodium Purification System which were obtained from April 1990 to March 1995. And, the operational problem of Secondary Sodium Purification System with MK-III core conversion were mentioned in this report. The experience results were as follows. (1)The number of cases of the secondary purification system trouble was 12. Those troubles, however, did not affect to the operation of the plant. (2)As the result of investigation about possibility of using secondary cold trap after MK-III core conversion, amount of trapped impurity was estimated 9.4kg as of January, 1994. In addition, 25.2kg was the estimated amount of trapped impurity at sodium initial purification after MK-III core conversion. It was subtantial excess of original design(18kg). (3)The change of heat transfer characteristics of secondary cold trap economizer occurred about two years after the modification of cold trap control tempereture. It seemed to be led by condition change of sticking impurity to heat transfer tubes which was followed by the modification of set up temperature. When set up temperature had been kept low, heat transfer characteristics was better. (4)A large quantity of sodium vapor was identified on the secondary argon gas system pressure control header. The influence of engulfing of argon gas at over flow line of Secondary Sodium Purification System is concerned.
Terano, Toshihiro; ; Okubo, Toshiyuki;
PNC TN9440 94-015, 104 Pages, 1994/07
The electric preheating system of JOYO has been operated without any Serious problems since its functional acceptance test in 1975. Much of operation and maintenance experiences during 18 years sfter start up of the system have been accumulated. This paper describes a summary of operation experience of the electric preheating system.