Though water injection into the reactors of Unit 1-3 at Fukushima Daiichi Nuclear Power Station is continuously done by the regular use reactor injection system, a decrease in the reactor injection water amounts at Unit 1-3 was found as below at 3:00 PM on August 30, 2012 at the regular data check.
- Unit 1: Water injection amount decreased from 4.9m3/h (as of 2:00 PM) to 4.0m3/h (Necessary injection amount: 4.3m3/h)
- Unit 2: Water injection amount decreased from 7.0m3/h (as of 2:00 PM) to 5.5m3/h (Necessary injection amount: 6.1m3/h)
- Unit 3: Water injection amount decreased from 7.0m3/h (as of 2:00 PM) to 5.6m3/h (Necessary injection amount: 6.1m3/h)
As the technical specification for the nuclear reactor facility*1 requires the regular use reactor injection system to maintain the necessary water injection amount as "operational requirements"*2, it has been judged by the shift supervisor that the "operational requirements" stipulated in the technical specification for the nuclear reactor facility is not fulfilled at Unit 1 (at 3:07 PM), Unit 2 (at 3:00 PM) and Unit 3 (at 3:05 PM).
As the "required measures to be taken" in the case of unfulfillment of operational requirements, it is required to either increase the water injection amount to fulfill the operational requirements for the regular use reactor injection system or start operation of the reactor injection pump on standby. We are currently preparing for increasing the water injection amounts.
No significant change in the monitoring post data has been confirmed at this point in time. The cause of this matter will be investigated and adequate measures will be implemented.
End
*1 Technical specification for the nuclear reactor facility
Government-approved fundamental rules for nuclear power station operators to follow in order to maintain safe operation and stable condition of nuclear power stations (including operation management, fuel management, radiation management, emergency measures and equipment/facility management based on the "Policy on the Mid-term Security"), which are stipulated by Article 37 Section 1 of the Act on the Regulations of Nuclear Source Material, Nuclear Fuel Material and Reactors.
*2 Operational requirements
In accordance with the technical specification for the nuclear reactor facility, operational requirements are stipulated to ensure safety and stability of power stations (such as the number of available equipments, temperatures and pressures). In the case that an issue arises with equipment subject to the technical specification and the operational requirements cannot be satisfied temporarily, appropriate measures must be implemented.
