7/28/2011 Water treatment system running below capacity

Source: NHK World
Date: Thursday, July 28, 2011 11:48 +0900 (JST)



A water decontamination system at the Fukushima Daiichi nuclear power plant has been operating below its target capacity, resulting in delays to the firm's timetable of about 2 months.

Tokyo Electric Power Company started running the decontamination system in late June to remove radioactive substances from water pooled in reactor buildings' basements. Treated water is sent back into the reactors as coolant.

TEPCO says the system operated at 63 percent capacity from June 17th until Tuesday, though it aimed to run it at 70 percent capacity.

The company was planning to decrease the amount of contaminated water to a safe level by early August. But, it now says the timetable is likely to be pushed back until late September.

The failure to reach the target is mainly attributed to the fact the system's working capacity is at about 30 percent below designed levels. The system has also stopped repeatedly due to various operational problems.

TEPCO says problems seen in the early stages of the operation have been solved, and that it will try to increase the system's treatment rate from now.

7/27/2011 TEPCO seeks new ways to reduce contaminated water

Source: NHK World
Date: Wednesday, July 27, 2011 08:27 +0900 (JST)




Read text transcript here

7/26/2011 New decontamination unit to arrive at Fukushima

Source: NHK World
Date: Tuesday, July 26, 2011 07:16 +0900 (JST)



A new system to decontaminate radioactive water will arrive at the troubled Fukushima Daiichi nuclear power plant on Tuesday. The current system, the key to cooling the reactors, has been plagued with problems.

The new equipment, SARRY, consists of 14 cylindrical tanks containing minerals. It is designed to reduce radioactive substances in water, such as cesium, to less than one millionth.

The first shipment of tanks and parts left a port in Iwaki, Fukushima on Monday.

The existing device at the plant was hit with problems from Sunday to Monday. Its operating rate has been reduced to 53 percent, far below the goal of 90 percent.

The plant's operator Tokyo Electric Power Company plans to use the new system, along with the existing one.

The utility will bring the remaining components to the Fukushima plant in 2 more shipments. It then aims to begin operating the new system around early August.

7/25/2011 TEPCO tackles trouble with decontamination units

Source: NHK World
Date:





The Tokyo Electric Power Company is trying to figure out why a system to decontaminate radioactive water at the troubled Fukushima Daiichi plant remains unstable.

The system funnels in radioactive water accumulated in the underground facility and reuses it as a reactor coolant after decontaminating radioactive substances.

TEPCO started the operation late last month.

The system sends 3.8 cubic meters of water per hour to each of the No.1 and No.2 reactors.

However, the operation has been unstable for the last 3 days. On Friday, the amount of water injected suddenly decreased to 3.4 cubic meters per hour at No.2 reactor, and then fell to 3.2 cubic meters on Saturday.

At No.1 reactor, water levels decreased to 3.3 cubic meters on Sunday morning.

The utility is examining the pumps each time the amount of water goes down in order to return the system to its previous volume.

On Sunday, the system was halted for 7 hours due to trouble with a device to remove salt from radioactive water. TEPCO restored operation with a back-up mechanism.

The utility says it will closely watch each system and try to track down the causes of the instability.

Monday, July 25, 2011 06:32 +0900 (JST)

7/25/2011 Contaminated water on increase at Fukushima plant

Source: NHK World
Date: Monday, July 25, 2011 14:12 +0900 (JST)


Tokyo Electric Power Company is injecting fresh water from a nearby dam to make up for the shortage of water in its system for cooling the reactors at the damaged Fukushima Daiichi nuclear plant.

The system decontaminates radioactive water that has accumulated in the plant and circulates it.

TEPCO halted the process of removing salt from contaminated water after an alarm went off around noon on Sunday due to a problem with the installation of the desalination equipment. It resumed the operation in the evening after installing another device.

The new device is only able to treat half the amount of water. The amount of contaminated water has been increasing since the problem occurred.

TEPCO began using the new circulatory water injection system late last month. Last week, the government and the utility announced the completion of the first stage of the plan to stabilize the cooling of the reactors.

NHK's reporter points out that as a result of Sunday's trouble, the amount of contaminated water is increasing. He adds that the recycling of cooling water, a key element of bringing the accident under control, cannot be maintained.

TEPCO is investigating the cause of the problem. The utility says the decontamination system as a whole is not operating stably and it needs to improve its reliability.

7/3/2011 TEPCO makes progress on cooling/water treatment system

Date: 7/3/2011

There does seem to be some progress made on TEPCO's cooling/water treatment system. According to the Daily Yomiuri, on Saturday the system was run and has decontaminated 3,580 tons of radioactive water, enough to provide 10 days worth of cooling.[1] Another sign of progress is that the cooling system is able to work off of decontaminated water in a closed loop, without requiring 2-3 tons of fresh water per hour being pumped in (sourced externally) as was previously required when the cooling system first started operating on June 27, 2011.[1, 2]

Also a broken hose with a large hole has been replaced which allows the resumption of reactor #5's cooling, which had been halted to do the repair.[3] NHK World: TEPCO improves circulation cooling system [2] When examining the right sidebar of the EX-SKF blog, where EX-SKF tracks the millimeters from the top of radioactive water drainage ditches to the water level, the distance from the top of the water to the top of the ditches is increasing, which means the amount of contaminated water pooling at Fukushima Daiichi is getting lower: another good sign. Sources: [1] TEPCO in water purification push, Daily Yomiuri [2] TEPCO improves circulation cooling system, NHK World [3] Cooling resumes at Fukushima No.5 reactor, NHK World

EX-SKF Sidebar

6/29/2011 TEPCO restarts new cooling system

Source: NHK World
Date: Wednesday, June 29, 2011 15:28 +0900 (JST)

The operator of the Fukushima Daiichi nuclear power plant restarted its new reactor cooling system on Wednesday after fixing faults in the hosing.
...
Read full article here

6/26/2011 TEPCO ready to try again with water decontamination system

Source: Japan Today
Date: Jun. 27, 2011 - 05:29AM JST

TOKYO — Tokyo Electric Power Co (TEPCO) said Sunday that it plans to start full-scale operations of its system to decontaminate highly radioactive water at its stricken Fukushima Daiichi nuclear power complex on Monday.

The system has been experiencing a number of glitches since last week. TEPCO said it had replaced the chemicals in the absorption equipment and made the necessary repairs.

Goshi Hosono, director of the government’s nuclear crisis task force, said the system has met operational requirements and had decontaminated nearly 5,000 tons of tainted water in test runs on Saturday.

Workers have cooled the reactors and spent fuel by pumping in fresh water, which becomes contaminated with radiation. About 110,000 tons of tainted water have accumulated, and it could start overflowing in early July unless workers get a trouble-plagued water treatment system working properly. 

The system became fully operational a week ago but shut down after a few hours when one of the radiation absorbing cartridges reached its limit much more quickly than expected.

Hosono told NHK that one problem is that heavy rain due to the rainy season might increase the amount of contaminated water.

6/24/2011 Fukushima Meltdown Mitigation Aims to Prevent Radioactive Flood

Source: Scientific American
Date: June 24, 2011
by: David Biello

Three months after its meltdown, the stricken nuclear power plant continues to struggle to cool its nuclear fuel--and cope with growing amounts of radioactive cooling water

More than three months after a powerful earthquake and 14-meter-high tsunami struck Japan, the Fukushima Daiichi nuclear power plant remains flooded with a salty mix of ocean and fresh water that is contaminated with the radioactive residue of three reactors and four spent fuel pools' worth of nuclear fuel. Every day an additional 500 metric tons of seawater is poured onto the still hot nuclear fuel in the stricken reactors and fuel pools. More than 100,000 metric tons of such water now sits in the basement and trenches of the reactors—or evaporates inside the hot reactor buildings, making for a radioactive onsen (hot bath). ... Read full article here

HOLDING TANKS: Tanks hold some of the radioactive water overflowing from cooling efforts at the stricken Fukushima Daiichi nuclear power plant in Japan. Image: Courtesy of TEPCO

6/24/2011 | Decontamination system meets performance target

Source: NHK World
Date: Friday, June 24, 2011 19:59 +0900 (JST)

The operator of the Fukushima Daiichi nuclear plant says a trouble-hit system for decontaminating highly radioactive water at the facility is working as planned.
...
Read full article here

6/23/2011 | TEPCO radioactive water treatment under-performance blamed on incorrectly set valve

Date: 6/23/2011

The Kurion (U.S. company) subsystem was tested to be only 10% as good at filtering radioactive material as expected during previous testing.  TEPCO thinks it is due to the cesium filtration component which was installed with one valve incorrectly opened. Here is the English handout diagram given to reporters:

TEPCO handout

TEPCO will test the radioactive water treatment system with the valve closed.

Click here for further details and video

6/22/2011 | TEPCO restarts Fukushima Daiichi water treatment but tests show underperformance

TEPCO has continued tested it's radioactive water treatment system at Fukushima Daiichi but discovered that the subsystems were not performing up to expectations. Per the EX-SKF blog expectations were for a 1/1,000,000 reduction in radioactive materials overall after filtering, but only a 1/18,400 decrease was actually achieved. The under-performance was noticed in the Kurion treatment subsystem, as well as the Areva (French) subsystem which both did not perform up to expectations.

The latest estimate for the amount of water pooled at the Fukushima Daiichi complex is estimated at more than 110,000 tons. Per TEPCO spokesman Junichi Matsumoto 1700 tons of water have been treated so far. The processing rate at which TEPCO wants to run the water treatment system is 50 tons/hour. Assuming 24 hour nonstop operation, 1200 tons/day of radioactive water could be theoretically processed at this rate.  Approximately 500 tons a day of water is injected in to Fukushima Daiichi per the JAIF (Japan Atomic Industry Forum, Inc.) Earthquake Report for June 22, 2011.

In order to decrease the rate at which the radioactive water is building up TEPCO has reduced the amount of water being poured in to reactors 1 (-.5 tons/hr), 2 (-.5 tons/hr) and 3 (-1 tons/hour) while carefully monitoring the heat level of the reactors. The #3 reactor did experience a heat rise per TEPCO who are monitoring closely without increasing the water poured in to the reactor. The water flow in the #1 and #2 reactors will be reduced by another -.5 tons/hr.

The right sidebar of the EX-SKF blog shows the number of millimeters left to the top of the water ditches for reactors 2 and 3 if you are interested in imminent overflow.

6/20/2011 | Only a few more days of storage capacity left at Fukushima Daiichi for radioactive water

Date: 6/20/2011
by: Jason Chan

TEPCO is still struggling against time to get their on-site Frankenstein-like radioactive water treatment system up and running. According to NHK World, there are only "a few days" of radioactive water storage capacity left (the NHK article is dated Tuesday, June 21, 2011 05:11 +0900 JST).  It is estimated that more than 100,000 tons of radioactive water is currently pooled at the Fukushima Daiichi complex.  If the radioactive water is not able to be decontaminated at a rate at least equal to the amount of radioactive water produced each day (500 tons/day per JAIF), the overflow would go to the sea.

The ad hoc TEPCO water treatment system has been cobbled together from other systems made by French, American and Japanese companies. Per blogger EX-SKF:

...
To review the whole [radioactive water treatment] process, the water first goes to Toshiba's oil separation system. Then it goes to [America's] Kurion's system for oil/technetium removal, then cesium removal, then iodine removal. Then it goes to [France's] Areva's system for further decontamination, and finally arrives at Hitachi's desalination system. [1]

...

The TEPCO radioactive water treatment system was successfully started on Friday, June 17, 2011 at 8 PM EST and then stopped on Saturday, June 18, 2011 at 12:54 AM EST.  It took only 5 hours before a component in Kurion, Inc.'s (the U.S. company) system, which uses zeolite to filter out radioactive cesium, reached it's radiation saturation limit.  Under normal circumstances, replacements to this component do not need to be made for about 30 days.

According to EX-SKF TEPCO is addressing the issue by re-organizing the filtration process across all of the various components as well as restricting the flow rate of radioactive water coming in to the system to reduce the radiation exposure to the Kurion system component(s). [1]

References:
[1] Contaminated Water Processing at #Fukushima: TEPCO Says Water Is "Hot", But The System Can Handle It, EX-SKF blog