Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Karube, Koji; ; ; ; Kawai, Masashi;
PNC TN9440 93-012, 83 Pages, 1993/04
This report describes the operating experience of the primary main cooling system from January 1982 to March 1992, and of the primary auxiliary cooling system from october 1986 to March 1992. 0ut lines of the operating experience ale followings; There have been no serious troubles in this period. (1)The main system; Operation time of the circulation pumps are about 67675 hours. Accumulated operation time of the pumps are about 105970 hours. The pumps has been started 212 times. (2)The auxiliary system; Operation time of the circulation pump (EMP) is about 4767 hours. Accumulated operation time of the pump is about 8667 hours. The pump has been automatically started 31 times with the scheduled test.
*; *
PNC TN9410 88-055, 111 Pages, 1988/06
In this study, decay heat removal capability of the Maintenance Cooling System (MCS) of Monju has been investigated with respect to protected accidents. The protected accidents of the Liquid Metal Fast Breeder Reactors (LMFBRs), such as Protected Loss-of-Heat-Sink (PLOHS) or Loss-of-Reactor-Level (LORL), are of great importance from the viewpoint of the annual frequency of core damage. The progression of the protected accidents is mild in general because reactor decay heat can be dispersed from the core by natural circulation. The decay heat for Monju is to be removed by the Intermediate Reactor Auxiliary Cooling system (IRACS). It is essential to keep the intactness of coolant flow path from the reactor core to the heat sink and the availability of heat sink itself. If the either of them is degraded, it is taken for granted d that protected slow meltdown follows. However, the reactor core can be prevented from any damage or meltdown if the decay heat can be removed through MCS. The plant thermohydraulics of the procected accidents is analyzed using SSC-L to develop success criteria in the decay heat removal by the MCS. Parametric calculations are performed with respect to: available heat capacity in the heat transport system, cooling time before the loss-of-heat-sink and MCS starting time. It has been found, for example, that (1)MCS can remove the decay heat immediately after the reactor shutdown if heat capacity of more than two main coolant loops is available; (2)after two hours cooling time by natual circulation, MCS can remove the decay heat even if no coolant flow is assumed in all the main heat transport system; (3)LORL caused by the failure in sodium make-up can be recovered by the MCS operation. In the PLOHS condition, the coolant temperature may exceed conservative design limit of the MCS piping. However, the conservativeness of the design limit and the method of qualification make compensation for the deterioration in structural strength. Finally, ...
Sasaki, Makoto
PNC TN941 82-56, 106 Pages, 1982/03
A 3 pcs criterion of the neutron start-up monitor at the reactor start-up is set up in order to protect the reactivity accident at the reactor start-up and confirm the normal motion of the monitor. Fast Experimental Reactor "JOYO" has one external neutron source (Sb-Be) in the core region to meet this criterion. However, the 3 cps criterion is not met after long reactor outage, because the half life time of the external neutron source is about only 2 months. In addition, the external neutron source is irradiated by another reactor before beeing put into use. Therefore, it is very convinient if the reactor can start-up without the external neutron source since in this case various potential troubles are avoided. This report describes the start-up experiment without the external neutron source in "JOYO" MK-I core. The results are as followings: (1)The reactor was able to start-u without the external neutron source. (2)The reactor was start-up due to inner neutron of the driven fuels. (3)The reactor may be able to start-up vithout the external neutron source in "JOYO" MK-II core, too.
