Fukushima news - 11/14/2013

Some Fukushima fuel rods were damaged before 2011 catastrophe

Three of the spent fuel assemblies that will be pulled from the Fukushima nuclear plant during a year-long operation were damaged before the 2011 earthquake and tsunami crippled the Japanese facility.

RT,

15 November, 2013

Tokyo Electric Power Co. (TEPCO), which operates the plant, said the damaged assemblies - 4.5 meter high racks with 50 to 70 rods of highly irradiated used fuel - won’t be lifted from the plant’s Reactor No. 4 when a large steel chamber, or cask, is employed to move over 1,500 assemblies to safe storage, Reuters reports.

In an 11-page information sheet released in August, TEPCO said one of the assemblies was even damaged as long ago as 1982, when it was bent out of shape during a transfer.

In 2010, TEPCO said that another two spent fuel racks in the reactor’s cooling pool possibly contained wire trapped in them. Rods in the assemblies have small cracks and are leaking low-level radioactive gases, TEPCO spokesman Yoshikazu Nagai told Reuters on Thursday.

The damaged racks were first reported by a Fukushima area newspaper on Wednesday, as TEPCO is preparing to decommission the plant and remove the spent fuel assemblies from Reactor No. 4.

"The three fuel assemblies...cannot be transported by cask," TEPCO spokeswoman Mayumi Yoshida told Reuters in an email response on Thursday. "We are currently reviewing how to transport these fuel assemblies to the common spent fuel pool."

TEPCO is set to begin removing 400 tons of the hazardous spent fuel, an unprecedented operation, beginning in mid-November.

The damaged assemblies will only make the job more difficult, and could meddle with the year timeframe that TEPCO has set for removal – which is already an ambitious plan to many.

TEPCO is in the process of decommissioning the entire six-reactor Fukushima Daiichi plant after three reactors suffered core meltdowns in March 2011. Moving the fuel assemblies in Reactor No. 4 is the first priority, as their height above ground - 18 meters - is highly vulnerable to another earthquake.

Former US nuclear regulator Lake Barrett, who is advising TEPCO, visited the plant Wednesday and endorsed the preparations for the No. 4 assemblies.

"While removal of the fuel is usually a routine procedure in operating a power plant, the damage to the reactor building has made the job more complex," he said.

He added that he was "genuinely impressed by the thoroughness of the effort and TEPCO's contingency planning."

The fuel assemblies will be lifted - all while submerged in water to prevent overheating - from storage frames in the pool and placed in the cask. Once the 90-ton cask is filled, it will be lifted from the pool by crane, set on the ground, and transported to a storage pool nearby.

Robot detects locations of radioactive leaks at crippled Fukushima nuclear plant

For the first time, a remote-controlled robot has detected the exact spot of radioactive water leaks from the crippled Fukushima nuclear plant’s Reactor 1, local media reported.

RT,

14 November, 2013

The robot was sent close to the lower part of the Reactor 1 containment vessel at the wrecked Fukushima Daiichi on Wednesday. Its camera captured images of radioactive water leaking from two holes of the vessel into the building housing the reactor, NHK television reported.

The lower section of the vessel contains water that cools the molten nuclear fuel rods, damaged after the March 2011 earthquake that triggered a tsunami which hit the Fukushima nuclear facility.

The radiation levels in the inspected area were reported at 0.9 to 1.8 sieverts an hour, while a typical release of radiation is generally accepted to be 1 millisievert a year.

Tokyo Electric Power Company (TEPCO), the nuclear plant’s operator responsible for the cleanup, has to keep the melted uranium fuel rods of the three damaged reactors cool for them to be relatively stable. Thus, the operator is storing huge amounts of radioactive water at Fukushima nuclear facility.

However, TEPCO engineers said that they cannot estimate the amount of water that leaked through the holes, NHK reported. They also admitted that Reactors 2 and 3 of the Fukushima Daiichi have similar problems.

TEPCO is now planning to use robots to locate other leaks which have been causing concern, as it is important not only in solving water contamination problems but also in carrying out decommissioning of the reactors.

This handout picture taken by Tokyo Electric Power Co (TEPCO) on November 13, 2013 shows US nuclear expert Lake Barrett and TEPCO workers inspecting the spent fuel pool at the unit four reactor building of the crippled TEPCO's Fukushima Dai-ichi nuclear plant at Okuma town in Fukushima prefecture. (AFP Photo/TEPCO)This handout picture taken by Tokyo Electric Power Co (TEPCO) on November 13, 2013 shows US nuclear expert Lake Barrett and TEPCO workers inspecting the spent fuel pool at the unit four reactor building of the crippled TEPCO's Fukushima Dai-ichi nuclear plant at Okuma town in Fukushima prefecture. (AFP Photo/TEPCO)

Earlier in November, TEPCO announced that by the end of the month the company will start extracting more than 1,500 fuel rods from the No 4 reactor of the crippled nuclear plant, which contains 10 times more Cesium-137 than Chernobyl did.

The rods are expected to be placed in the outdoor pool at the station by the end of next year.

However, scientists have urged caution as such an operation has never been undertaken, while a mishap could release a huge amount of radiation into the atmosphere or cause an explosion many times worse than the original disaster.

“If something goes wrong this could be a global catastrophe that dwarfs what has happened in Fukushima Daiichi thus far,” Kevin Kamps, a nuclear waste specialist from the organization Beyond Nuclear told RT.

According to experts, complete elimination of the consequences of the nuclear catastrophe will take from 30 to 40 years.

The crippled reactors of the nuclear facility are located near the coast of the Pacific Ocean. After the tsunami that hit Fukushima, the cores of the three reactors melted and burnt through the concrete basement of the reactor zone. The water used to cool them has been leaking into the soil and contaminating the ground water on the premises of the nuclear facility. This water eventually started seeping into the Pacific. According to estimations from Japan’s Ministry of Industry, around 300 tons of contaminated groundwater has leaked into the ocean daily since the nuclear disaster occurred in 2011.

Fukushima Workers Say Decontamination Not Working! They're Afraid To Even Wash Their Hands!

Risky fuel removal about to start

The decades-long decommissioning process at the crippled Fukushima No. 1 plant is about to take what Tokyo Electric Power Co. says is “an important step,” as the utility starts removing fuel rod assemblies from the spent fuel pool high up in reactor building 4 sometime this month.

Japan Times,

14 November, 2013

Moving the massive amount of radioactive fuel assemblies out of the shattered building is significant because it will allow Tepco to monitor the fuel much more easily at another pool in an undamaged facility, experts say.

Meanwhile, they stress the task must be handled very carefully to avoid dropping and damaging the assemblies.

“Usually, spent fuel rods are safely stored in sturdy reactor buildings, but reactor building 4 experienced a hydrogen explosion, so it has lost its full containment capability,” said Kiyoshi Takasaka, an adviser on nuclear issues to Fukushima Prefecture.

The hydrogen blast occurred March 15, 2011, four days after the earthquake and tsunami, blowing the roof off the building and showering debris into the pool.

The pool has 1,533 fuel rod assemblies, 202 of which are unused. Once removed from the pool, the assemblies will be stored in a common pool in a different building.

Each assembly, a zirconium alloy box, is about 4.5 meters long and contains 60 to 80 fuel rods.

A fuel handling machine, which is like a hoist, set up over the pool will lift the assemblies one by one and place them into special transport casks. The casks will be put into the pool ahead of time, so that this work is done underwater to prevent gamma radiation from spilling to the outside environment.

Each cask can store 22 assemblies. A crane installed above the fuel handling machine will load them onto a trailer for transport to the common pool.

If all goes well, removing all of the assemblies will take about a year. Tepco said it is using nearly the same removal equipment used for regular nuclear operations.

Lake Barrett, a special adviser to Tepco who was in charge of the cleanup work after the Three Mile Island nuclear accident in the U.S., said he visited the plant Wednesday and was impressed with Tepco’s preparations.

Building 4 has been reinforced with steel frames and a cover, the equipment is in place and the workers have been trained well for the operation, Barrett said.

“Now I feel confident that they can complete this job properly,” he said, adding that the level of Tepco’s preparations will make the operation almost like a normal fuel removal.

Still, it will be different than performing this operation in an undamaged building, and extra caution is a must.

For instance, engineers normally program coordinates into the fuel handling hoist and let it run automatically, but they will manually control it for this operation.

Takasaka said it is essential that the people in charge of the task have enough training in handling the manual operations.

He added that although Tepco has been picking debris out of the pool, there are still small pieces that could fall between the assemblies and racks that contain the assemblies, possibly making it harder to lift them or even breaking them.

Barrett, who saw the pool for himself, said the water clarity is good but it is true that the assemblies could get jammed by small debris.

Tepco said it is ready for such eventualities. For instance, it plans to use underwater vacuum cleaners as much as possible.

Also, if the hoist detects extra weight when removing the assemblies, it will stop moving to avoid forcing the assemblies.

Another risk is dropping the assemblies and damaging them.

“It is imperative not to drop the assemblies when removing and after removing them from the racks,” said Hisashi Ninokata, a nuclear expert and professor at Polytechnic University of Milan in Italy.

“In the worst-case scenario, dropping a cask is conceivable. To avoid that, it is important to come up with multiple layers of measures,” said Masayuki Ono, a Tepco spokesman.

For instance, the crane’s control wires have been doubled, and it is designed not to drop the assemblies if the power is cut off, Tepco says.

And if an assembly is dropped and gets damaged enough to release radioactive materials, the radiation level outside Fukushima No. 1 will still not exceed the legal limit, the utility claims. This estimation is based on a scenario in which one assembly falls and strikes others, resulting in damage to all of the fuel rods contained in two assemblies.

Earlier this week, Tepco found three damaged assemblies that will be difficult to remove, but officials said the damage appeared to have occurred before the March 11 disasters.

Ninokata feels that as long as Tepco is sufficiently prepared and proceeds carefully, it is hard to imagine that any assemblies will get damaged, but if this does happen, he agrees with the utility that harmful amounts of radioactive materials won’t escape into the environment.

Asked if it’s possible for the spent fuel to achieve recriticality, Zengo Aizawa, vice president of Tepco overseeing the Fukushima crisis, said this is highly improbable since the removal process basically deals with one assembly at a time, and the utility has confirmed that one assembly alone cannot cause a nuclear chain reaction.

Thyroid cancers up in Fukushima

Experts say link to disaster not yet established

Japan Times,

13 November, 2013

Screening of Fukushima residents who were 18 or younger at the time of the 2011 nuclear disaster had found 26 confirmed and 32 suspected cases of thyroid cancer as of Sept. 30, according to the Fukushima Prefectural Government.

The number of confirmed cases was up by eight from August, while the suspected cases rose by seven, the prefecture-led study found.

About 226,000 people have undergone the screening program since it kicked off in October 2011.

The 26 confirmed cases underwent surgery and are doing well, according to the prefecture.

A panel of experts at the prefecture concluded Tuesday that it is too early to link the cases to the nuclear disaster, given that papillary thyroid cancer — the type found in the 26 people — develops at a very slow pace, according to prefectural officials. Following the 1986 Chernobyl catastrophe, it took about four to five years for thyroid cancers in significant number to be detected.

Thyroid cancer is considered a major health concern for children because radioactive iodine spewed by the crippled nuclear plant tends to accumulate in thyroid glands, especially among young children.

Following the Chernobyl disaster, more than 6,000 children were diagnosed with thyroid cancer, according to the U.N. Scientific Committee, which attributed many of the cases to consumption of contaminated milk.

According to media reports, thyroid cancer normally strikes about 1 to 2 people aged 10 to 14 per million in Japan, far less than about 115 in 1 million cases in Fukushima. However, the figure cannot be simply compared, because the screening in Fukushima targets all children under 18, most of whom are without any symptoms, and no such screening is being done elsewhere in Japan.

To address mounting worries among local residents with children, the prefecture will expand the screening tests next April to include people born after the disaster started.