Enhanced Safety Measures at Hamaoka Nuclear Power Station
July 29, 2016
Chubu Electric Power Co.,Inc.
Chubu Electric Power immediately embarked upon tsunami-resistance measures and steps to secure power supplies and coolants in the aftermath of the Fukushima Daiichi Nuclear Power Station accident, in addition to seismic resistant tolerance enhancement works and other voluntary initiatives that have been ongoing at Hamaoka Nuclear Power Station. Reflecting on new regulatory requirements set forth by the Nuclear Regulation Authority (NRA), Chubu Electric Power accelerated its measures to achieve higher safety. Currently, Units 3 and 4 are undergoing NRA's conformability review on the new requirements.
Provided below is the status quo we compiled concerning these enhanced safety measures.
[Units 3 and 4]
Major works to address earthquake/tsunami and severe accidents, planned after the Fukushima Daiichi accident as countermeasure works for Unit 4, are expected to be completed by around September 2016. Meanwhile, in light of field condition- or review-based work detail revisions and design changes, respectively, some of the works are to be maintained from September and onwards.
Regarding the review for Unit 4's conformability on new regulatory requirements, the geological features around the station site are being reviewed. This is an earthquake/tsunami-related effort made in a lead-up to reviews on standard seismic motion and design basis tsunami (Note1) , in which geological conditions serve as preconditions. We are also receiving reviews at the moment on design basis (Note2) and severe accident measures (Note3) together with boiling water reactor operators.
New knowledge and developments on reviews might result in the need to rearrange or add works. We will accordingly announce the timing in which enhanced safety measure works will complete, after the reviews practically comes to an end and we gain an outlook for the works.
Chubu Electric Power will achieve higher safety for Unit 3 in a similar manner as Unit 4, through such efforts as complying with new regulatory requirements.
Unit 5 has completed its soundness evaluation at equipment level concerning seawater inflow events by December 2015, and some of its components still need repair or replacement. However, at the current stage, Chubu Electric Power sees no challenge in restarting the Unit.
We are now collecting data that complements soundness evaluation results, and at the same time exploring concrete details for an equipment repair/replacement plan. Soundness evaluations at system level and continual post-operation inspection programs for equipment are to be looked into as well.
As efforts in tandem with the above, Chubu Electric Power will maintain its considerations on new regulatory requirement-based measures and gear itself up to apply for conformability review on the new regulatory requirements.
With our strong commitment to preventing any events similar to the Fukushima Daiichi accident, Chubu Electric Power seeks to keep pursuing its on-site responses such as developing Hamaoka Nuclear Power Station's equipment measures and emergency response scheme, and harnessing training initiatives to step up field response capabilities. In a drive to boost the effectiveness of assistance for local resident evacuations and other emergency preparedness fronts, we will also strive to reinforce ties between national and local governments and thereby elaborate on nuclear emergency-geared offsite responses in the Station's neighboring areas.
By illustrating these initiatives to the local area and society at large in a readily understandable and thoroughgoing fashion, Chubu Electric Power will seek for understanding toward our operations.
(Note1) Standard seismic motion and design basis tsunami: These are seismic motions/tsunami heights set forth as a standard in seismic or tsunami resistant designs for nuclear power stations. They serve as representative review items that are of significant influence in both promoting countermeasure works and conformability review on the new regulatory requirements
(Note2) Design basis measures: These are measures against design basis events. Examples include natural phenomena such as earthquakes, tsunamis, tornados, as well as fire, on-site flooding, loss of power, and other equipment function losses
(Note3) Severe accident measures: These are measures for the loss of design basis countermeasure features, geared toward preventing severe accidents (i.e. accidents resulting in significant core damage) from occurring/developing