Safety and security issues at Kashiwazaki-Kariwa nuclear power station

Nuclear Power in Japan: Safety at Kashiwazaki-Kariwa Remains an Issue, Nippon.com Takino Yūsaku 14 May 21

The Fukushima Daiichi accident forced Japan to bolster regulations for its fleet of nuclear reactors. After undergoing significant upgrades, the Kashiwazaki-Kariwa plant in Niigata Prefecture is on track to restart, although recent security issues have come to light that raise new concerns about the safety of nuclear power……..

Over the last several years, utilities looking to restart idled reactors have heavily invested in upgrading facilities to meet rigorous new regulations. So far, though, only a handful of plants have come back online.

Security issues recently uncovered at the Kashiwazaki-Kariwa Nuclear Power Station operated by Tokyo Electric Power Company illustrate the difficulty of passing the Nuclear Regulatory Authority’s stringent safety measures. TEPCO had poured resources into the facility in Niigata Prefecture with the goal of restarting the Unit 6 and 7 reactors at the site, but the NRA has ordered that further improvements be made before authorizing the utility to begin the refueling process. Below I assess the major upgrades made at the Kashiwazaki-Kariwa plant under the new NRA regulations released in July 2013.

Safeguarding Against Tsunami

,,,,,,,,,,,, In the wake of the incident, protecting reactors from tsunami has become a priority. The NRA assessment of the Kashiwazaki-Kariwa plant estimates a tidal wave as high as 6.8 meters could reach the coastline where the facility sits. Learning from Fukushima, TEPCO chose to exceed the regulatory body’s requirement and built a seawall towering 15 meters above the surf. Using existing topography to its advantage, it constructed a 10-meter steel-reinforced concrete barrier for the low-lying Units 1–4 and a 3-meter earth embankment at Units 5–7, which are perched higher above the sea……….

Blackout Response

In an emergency, keeping cooling systems functioning is of utmost importance. To prepare for an event where the seawall and smaller barriers fail or that the power goes out at the Niigata plant, TEPCO installed four sets of mobile gas-fired generators and switchboards on high ground and stationed a fleet of 20 generator cars as backup.

…………… TEPCO faced major challenges in bringing the plant in line with the NRA’s new regulations, considered the strictest in the global nuclear industry. Along with tsunami measures, the utility had to meet stringent antiterrorism guidelines, including developing a response to attackers flying an airplane into the facility. The government completed an inspection of Unit 7 in October 2020 and the bulk of construction was completed in January of this year. TEPCO was confident it had covered all bases, but the discovery that individuals had used an employee ID card to enter the central control room without authorization and that an intruder detection system had not been functioning for an extended period have led the NRA to halt plans for restarting the reactor. The security problems also throw into question whether residents will agree to bringing the plant back online.

Community Considerations

Along with meeting NRA regulations, utilities aiming to restart reactors must win the approval of residents of the towns and cities where plants are located. Debate is often fraught as host communities weigh the economic benefits of nuclear power, including jobs and revenue from government subsidies and local taxes, against safety concerns. Money pouring into construction industries from huge projects to upgrade facilities has only complicated the issue………………..https://www.nippon.com/en/in-depth/d00687/