102123

* :

lines via fire extinguishing systems and condensate water makeup systems from the filtrate tanks as the water sourceslines via condensate water makeup systems from the condensate storage tanks as the water sourcesTEPCO has built a switching facility in Unit 3 for injecting seawater into the reactor via the residual heat removal sea water system.Units 1 and 2 are not provided with such the facility because no seawater lines lead into the reactor buildings of Units 1 and 2.3 motor driven pump 1 diesel driven pumpprocedures for coolant injection using these lines during accidents (severe accidents)*

*Due to the total loss of AC power supply, however, difficulties arose in assuring the air pressure for driving the SRV necessary for depressurization and maintaining the excitation of the electromagnetic valves in the air supply line, resulting in time-consuming depressurization operations. in this accident, as an ad hoc applicable operation, water injection into the reactor using a chemical fire engine that was present at the site was attempted.Nevertheless, since the reactor pressure was higher than the pump discharge pressure of the chemical fire engine, injection of freshwater into the reactor was not available in a few cases. SRV

*

RCICRCIC

:()(,)()

100m = 10kgcm2= 0.98 MPa () 62m,90m,51m,116m

1010kgcm212kgcm23000/2000(2)10kgcm21500/10kgcm22050/(6kgcm2)1200/70(7kgcm2)9 3000(3)10kgcm21500(1.5)10kgcm21210kgcm210001000(1)10kgcm2

()SRVLOCA(1)(2)RCICRCICSRVSRVRPV SRV RPVRPV

*

RCICRCICRPVSRVRCIC:RCICRCIC()*

15/2

TAF06/2 ()Question:(SRV)15/2 Answer:(SRV)15/2EOPcontingence 2 RPVADSSRVs7SRVs4SRVs(SRV)EOP

*

RELAP5-3DRCICRCICRPV(15kg/cm2)

(2160gpm)PCT1500800gpm

* RCICFor unit 2, on March 14 around 18:00 due to the problems including the air pressure for driving SRV and the maintaining excitation of the solenoid valve of the air supply line,the SRV was seemed to be closed and the reactor pressure increased.SRV condition was unclear after March 14 around 18:00

--SRV air SRV RCIC4SRVSRV air SRV HPCI4SRV6MPa, 0.5MPaRCIC/ HPCISRV

--SRVRCIC/HPCIHamaoka

Because of the total loss of the AC power supply, motor driven valves had to be opened manually for the PCV venting operations. For operation of pneumatically-actuated valves, the pressurized air required for operating such valves could not be assured, and thus a temporary air compressor had to be mounted to assure the pressurized air. For such reasons, the facilities could not be operated in accordance with the documented operation procedures for severe accidents, which caused the PCV venting operation to be delayed.

RCIC+43.240 12(exhaust stack)?

()()-

2Containment Overpressure Protection System (COPS) which protects the containment by use of rupture disks mounted in a line connecting the wetwell airspace to the COPS vent which is located on top of the Reactor Building.Release from the wetwell airspace takes advantage of the suppression pool scrubbing of radioactive aerosol and particulates. Two isolation valves are also used to re-establish containment integrity.

;()

RCICRCICRCIC

SRV(exhaust stack)

*