March 11, 2011 to Present
Presentation OverviewPresentation Overview
Reactor Design and Features
Chronology of Events
Current Status of Each Reactor
Recovery Actions
Kashiwazaki-Kariwa spent fuel poolduring the earthquake in 2007
Containment
Reactor
Fuel Pool
Drywell
Drywell Head
Suppression Pool
Reactor and ControlRod DesignReactor and ControlRod Design
•Nuclear reactors were shutdown automatically. Within seconds the control rodswere inserted into core and nuclear chain reaction stopped.
•Cooling systems were placed in operation to remove the residual heat. Theresidual heat load is about 3% of the heat load under normal operating conditions.
•Earthquake resulted in the loss of offsite power which is the normal supply toplant.
•Emergency Diesel Generators started and powered station emergency coolingsystems.
•One hour later, the station was struck by the tsunami. The tsunami was larger thanwhat the plant was designed for. The tsunami took out all multiple sets of thebackup Emergency Diesel generators.
•Reactor operators were able to utilize emergency battery power to provide powerfor cooling the core for 8 hours.
•Operators followed abnormal operating procedures and emergency operatingprocedures.
•Nuclear reactors were shutdown automatically. Within seconds the control rodswere inserted into core and nuclear chain reaction stopped.
•Cooling systems were placed in operation to remove the residual heat. Theresidual heat load is about 3% of the heat load under normal operating conditions.
•Earthquake resulted in the loss of offsite power which is the normal supply toplant.
•Emergency Diesel Generators started and powered station emergency coolingsystems.
•One hour later, the station was struck by the tsunami. The tsunami was larger thanwhat the plant was designed for. The tsunami took out all multiple sets of thebackup Emergency Diesel generators.
•Reactor operators were able to utilize emergency battery power to provide powerfor cooling the core for 8 hours.
•Operators followed abnormal operating procedures and emergency operatingprocedures.
•Offsite power could not be restored and delays occurred obtaining and connectingportable generators.
•After the batteries ran out, residual heat could not be carried away.
•Reactor temperatures increased and water levels in the reactor decreased,eventually uncovering and overheating the core.
•Hydrogen was produced from metal-water reactions in the reactor.
•Operators vented the reactor to relieve steam pressure - energy (and hydrogen)was released into the primary containment (drywell) causing primary containmenttemperatures and pressures to increase.
•Operators took actions to vent the primary containment to control containmentpressure and hydrogen levels. Required to protect the primary containment fromfailure.
•Primary Containment Venting is through a filtered path that travels through ductwork in the secondary containment to an elevated release point on the refuel floor(on top of the reactor building).
•A hydrogen detonation subsequently occurred while venting the secondarycontainment. Occurred shortly after and aftershock at the station. Spark likelyignited hydrogen.
•Offsite power could not be restored and delays occurred obtaining and connectingportable generators.
•After the batteries ran out, residual heat could not be carried away.
•Reactor temperatures increased and water levels in the reactor decreased,eventually uncovering and overheating the core.
•Hydrogen was produced from metal-water reactions in the reactor.
•Operators vented the reactor to relieve steam pressure - energy (and hydrogen)was released into the primary containment (drywell) causing primary containmenttemperatures and pressures to increase.
•Operators took actions to vent the primary containment to control containmentpressure and hydrogen levels. Required to protect the primary containment fromfailure.
•Primary Containment Venting is through a filtered path that travels through ductwork in the secondary containment to an elevated release point on the refuel floor(on top of the reactor building).
•A hydrogen detonation subsequently occurred while venting the secondarycontainment. Occurred shortly after and aftershock at the station. Spark likelyignited hydrogen.
Core Uncovered
Fuel Overheating
Fuel melting - CoreDamaged
Core Damaged but retainedin vessel
Some portions of core meltinto lower RPV head
Containment pressurizes.Leakage possible at drywell head
Releases of hydrogen intosecondary containment
•The station was able to deploy portable generators and utilize a portable pump to inject sea water into thereactor and primary containment.
•Station was successful in flooding the primary containment to cool the reactor vessel and debris that mayhave been released into the primary containment.
•Boric acid was added to the seawater used for injection. Boric acid is “liquid control rod”. The boroncaptures neutrons and speeds up the cooling down of the core. Boron also reduces the release of iodine bybuffering the containment water pH.
•The station was able to deploy portable generators and utilize a portable pump to inject sea water into thereactor and primary containment.
•Station was successful in flooding the primary containment to cool the reactor vessel and debris that mayhave been released into the primary containment.
•Boric acid was added to the seawater used for injection. Boric acid is “liquid control rod”. The boroncaptures neutrons and speeds up the cooling down of the core. Boron also reduces the release of iodine bybuffering the containment water pH.
Containment Flooding Effects Containment Flooding Effects
Containment Flooding Effects Containment Flooding Effects
These are current reports from the website link below which is
to The Japan Atomic Industrial Forum,Inc. (JAIF)
It was incorporated as the comprehensive non-governmental
organization on nuclear energy in Japan on March 1, 1956 (much like WANO)
(To open documents, put cursor over document, double click)
Reactor Status Report for March 21
Status Report for March 21
(To open document, put cursor over document, double click)
The following letter was recently sent to OPG and all other Canadian Power Reactors
