Tepco working to cool reactors and spent fuel pools

TEPCO forced to shut down contaminated water processing system at Fukushima Daiichi again

Enformable Nuclear News

2 December, 2013

Workers at the crippled Fukushima Daiichi nuclear power plant are working around the clock to cool reactors and spent fuel pools. They are accumulating massive amounts of highly contaminated water from the cooling operations and running out of space to store it on-site.

The troubled Advanced Liquid Processing System, or ALPS, which TEPCO has placed so much responsibility for helping process highly radioactive water to prepare it for storage, has broken down once again during trial operations.

The ALPS design removes radioactive materials by moving contaminated water through various pretreatment stations and adsorption towers. Once processed, the waste materials are transferred to high integrity containers, which are transported to a temporary storage facility.

The first processing systems used at Fukushima Daiichi only removed cesium. The ALPS system is a multi-nuclide removal system, which does remove multiple radioactive materials, but still leaves some behind (like tritium).

TEPCO workers were forced to shut the ALPS system down on Sunday due to a leak of hydrochloric acid from a pipe joint. The hydrochloric acid is used to neutralize alkaline water.

After shutting down the system, workers wrapped the leaking joint with a vinyl bag, which collected over 1 liter of hydrochloric acid at the time of the press release.

The system which was shut down is one of the two units which were in trial operation and scheduled to go into full operation on Sunday. TEPCO said that the leaking unit has been placed on standby and cannot continue operations until the problem is corrected.

TEPCO has been facing severe criticism for its failed management of contaminated water at the Fukushima Daiichi plant. Katsuhiko Ikeda, the secretary general for the Nuclear Regulation Authority, said in October that many of the problems at the crippled facility are caused by a lack of basic checks.

During test runs in June, TEPCO identified that some of the batch treatment tanks had holes in the welds.

In July, the ALPS system was shut down for inspections after corroded parts and other problems were identified.

The system failed again in September after a rubber sheet left in one of the tanks obstructed the flow of water and clogged a drain.

In October, the system was shut down due to programming errors and mistakes. Last month, the system was shut down once again, after the water which was being processed began to corrode one of the tanks.

Critics are worried that TEPCO is relying too much on the ALPS system and do not have enough contingency options if the system is unable to perform as expected.