Enduring a super typhoon

The massive storm named Vongfong is expected to be near South Korea and Japan some time over the weekend, just days after the Japanese archipelago was struck by another typhoon which claimed the lives of at least six people. The Japan Meteorological Agency was quoted as saying that Vongfong's strength was "very much similar" to that of Haiyan, which ravaged the Philippines last November, leaving nearly 8,000 people dead or missing when gusts of around 300 kilometers (190 miles) per hour tore through the country.

Alongside strong winds and heavy rain capable of causing landslides and flash floods, such super storms can also trigger an abnormal rise of water called a storm surge which is often the greatest threat to life and property. Of particular concern in Japan is the area around the crippled Fukushima Daiichi nuclear power plant which is still recovering from the 2011 quake and tsunami disaster that triggered a meltdown at the plant.

The operator of the battered power plant, TEPCO, has been having trouble with the early stages of an ice wall being built under the broken reactors to prevent radioactive water from leaking into the ocean. But is the plant also braced for the impact of a super typhoon?

Michael Maqua, nuclear expert at GRS, a German-based organization specializing in the fields of nuclear safety and radioactive waste management, says in a DW interview that while it is likely that some rain water will mix with the contaminated water in the basements of the reactor buildings and thus more radioactivity may be washed into the sea, no critical scenarios are expected given that the vital functions of the plant are secured and out of the reach of flood waters.

DW: Is the crippled Fukushima-Daiichi nuclear plant truly prepared to withstand the force of a super typhoon?

The wind of the typhoon will most likely not affect the buildings themselves, but pose a potential threat to equipment like cranes, scaffolds and also foils. However, given that the operator can prepare the site for the arrival of the typhoon, those things can be secured in advance. We assume that the operator TEPCO will prepare the site this time around just as it has done in the past.

Moreover, given that several typhoons like Neoguri or Wipha have already hit the nuclear power plant (NPP), TEPCO has also undertaken precautionary measures regarding heavy rains and flooding. For example, the operator built dams around the water tanks to prevent contaminated water from leaking.

What potential problems could arise if a super-typhoon such as the one forecast hit Fukushima full force?

Apart from physical damages to construction equipment, we could expect radioactive isotopes from contaminated surfaces being washed away and transported into the groundwater or the sea. Over the past days, the concentration of radioactive substances in the groundwater has increased significantly at some of the plant's measuring points and, according to TEPCO, this was caused by the recent heavy rains.

Furthermore, rainwater could seep into the reactor buildings where it might mingle with contaminated water thus increasing the total amount of contaminated water on the site.

What risk do meters-high tidal waves pose for the plant?

If the plant is hit by tidal waves higher than the existing seawalls, this could affect equipment close to the seaside. However, vital functions of the plant are secured for instance by back-up equipment installed in higher areas of the site, out of the reach of flooding. In this context, we do not expect any really severe scenarios taking place.

Would TEPCO be able to prevent tainted groundwater from leaking into the sea?

Contaminated water from the site is in fact constantly reaching sea water. This is being caused, for example, by leakages in building structures. TEPCO has been trying to solve this problem. The latest and maybe most complex project is the underground construction of an ice wall around the reactors 1 - 4. While the technique is used in tunnel construction, no one has ever used it in this particular context, so it is definitely a challenge.

As mentioned before, the main risk of the typhoon is the intrusion of rain water into the buildings, - mainly into the building of reactor 3 as it does not have a real "housing" yet to keep away rainwater - and areas with contaminated soil.

So it seems likely that some rain water will mix with the contaminated water in the basements of the reactor buildings and thus more radioactivity could be washed to the sea in the days after the typhoon. A slight increase of radioactivity in the seawater therefore is to be expected. Nevertheless, the seawater is permanently analyzed by the authorities.

What preventive measures has Japan put in place to prevent further contamination from spreading in the case of natural disasters?

Currently all Japanese NPPs are in permanent shut down. The Japanese Authority NRA has set new safety requirements for the country's NPPs - regardless of whether they remain offline or are applying for a possible restart. These new regulations also include higher safety standards for NPPs, for instance, in terms of emergency planning.

What are currently the biggest hurdles for TEPCO in terms of decommissioning the crippled reactors?

TEPCO faces two main problems: First, the isolation of the reactor buildings from the environment to prevent further radioactive contamination. To solve this problem, an ice wall around the buildings is being constructed, as already explained before.

In addition, intensive efforts are being made to identify the leakage areas within the buildings and to fix them, if possible. The second challenge is the removal of the molten cores in the reactor, a task which may only be finished within the next decades.

Michael Maqua is head of the plant engineering department at GRS, a German-based organization specializing in the fields of nuclear safety and radioactive waste management.