The Yomiuri Shimbun November 21, 2013
Govt must take lead in Fukushima nuclear reactor decommissioning
核燃料取り出し 政府が前面に出て廃炉目指せ(11月20日付・読売社説)

Decommissioning work at Tokyo Electric Power Co.’s Fukushima No. 1 nuclear power plant, which is expected to take 30 to 40 years, is finally under way.

Work has begun to remove nuclear fuel from the plant’s No. 4 reactor, bringing the decommissioning work into a new stage of the timetable drawn up by the government and TEPCO.

There are many unknown aspects to deal with, and work to remove nuclear fuel is difficult, as it will continue to take place in an environment with high radiation levels. TEPCO must give top priority to ensuring safety and tackle this task with utmost seriousness.

The No. 4 reactor was offline for a regular inspection at the time of the outbreak of the nuclear crisis in March 2011. Unlike the Nos. 1 to 3 reactors, a core meltdown did not occur at the No. 4 reactor, as nuclear fuel was kept with unused fuel in a storage pool inside the reactor building.

However, hydrogen believed to have come from the neighboring No. 3 reactor via an exhaust system exploded, blowing off the upper portion of the No. 4 reactor building.

Inside the storage pool, there are 1,331 spent nuclear fuel assemblies and 202 unused fuel assemblies. TEPCO plans to remove all of them by the end of next year.

Although reinforcement work has been carried out at the No. 4 reactor, leaving nuclear fuel in the seriously damaged building brings risks of radiation leaks. Removing nuclear fuel is thus an indispensable part of reactor decommissioning. Nuclear fuel assemblies are to be pulled out of the storage pool one by one with a crane, placed in a shipping container and moved to a shared pool.

During the nuclear fuel removal process, meticulous attention must be given to debris remaining inside the No. 4 reactor’s storage pool. It is necessary to prevent such debris from damaging nuclear fuel assemblies when the assemblies are pulled out of the storage pool.

Thorough NRA checks needed

The Nuclear Regulation Authority will oversee the nuclear fuel removal work under a special system. It is important that the NRA thoroughly check whether its schedule is realistic and ensure that potential sources of trouble have not been overlooked.

As for the Nos. 1 to 3 reactors, damaged areas have yet to be identified and the melted fuel situation is unknown. The amount of water contaminated with radioactive substances apparently leaking from damaged areas has continued to increase.

We urge TEPCO to apply the expertise it gains during the nuclear fuel removal work at the No. 4 reactor to recovering melted fuel and other materials at the Nos. 1 to 3 reactors.

The development of advanced robots that can be used for monitoring the situation inside reactors, as well as technology to repair damaged sections, must be taken full advantage of.

One major challenge is to secure a sustainable workforce for decommissioning the reactors.

The decommissioning work is arduous, since it requires workers to wear a full face mask and protective suit. It remains difficult even now to organize the 2,000 to 3,000 workers believed to be needed for this work.

As the decommissioning work proceeds, workers will face increased levels of exposure to radiation, and some restrictions may be needed to limit access to the sites by experienced technicians.

More than ¥2 trillion is said to be necessary for reactor decommissioning work and measures to deal with contaminated water. The government must move steadily forward with this long-term decommissioning work, by taking the lead in developing the needed technology, securing a sustainable workforce, and providing financial assistance.

(From The Yomiuri Shimbun, Nov. 20, 2013)
(2013年11月20日02時21分  読売新聞)