Radioactive Fukushima groundwater rises above barrier – Up to 40 trillion becquerels released into Pacific ocean so far – Storage for radioactive water running outPosted by Jim at Sunday, August 04, 2013
By Nathan Layne
3 August 2013
TOKYO (Reuters) – Radioactive groundwater at the crippled Fukushima nuclear plant has risen to levels above a barrier being built to contain it, highlighting the risk of an increasing amount of contaminated water reaching the sea, Japanese media reported on Saturday.
The Asahi newspaper, citing data from a Friday meeting of a task force working on the Fukushima clean-up at Japan's nuclear regulator, estimated that the contaminated water could swell to the ground surface within three weeks.
The latest revelation underscores the hurdles facing Tokyo Electric Power (TEPCO) 2-1/2 years after a massive earthquake and tsunami destroyed the Fukushima plant, triggering the world's worst nuclear disaster since Chernobyl.
One of Tepco's biggest challenges is trying to contain radioactive water that cools the reactors as it mixes with some 400 tonnes of fresh groundwater pouring into the plant daily.
Tepco has been injecting a chemical into the ground to build barriers to contain the groundwater. But the method is only effective in solidifying the ground from 1.8 meters below the surface, whereas data from test wells shows the contaminated water has risen to one metre below the surface, the Asahi said.
No one at Tepco or the regulator, the Nuclear Regulation Authority (NRA), could be reached for comment.
At Friday's meeting a Tepco official said equipment to pump out the water should be ready in late August, the Asahi said.
The Asahi noted that Tepco would need to pump out about 100 tonnes of water each day to prevent leakage into the ocean but that it was not clear where the water would be stored. More than 85 percent of its 380,000 tonnes of storage capacity is already filled, and Tepco has acknowledged it could run out of space.
Last month Tepco reversed months of denials and acknowledged that radioactive water has been leaking into the ocean.
3 August 2013 (The Asahi Shimbun) – After nearly 30 months of failure, Tokyo Electric Power Co. is still providing little reason for confidence in its ability to deal with the radioactive water leaking at its Fukushima No. 1 nuclear plant.
The utility continues to face criticism for its delay in releasing vital information about conditions at the crippled plant. Fishermen and residents have lost patience over the many setbacks in TEPCO’s preparations to decommission the reactors.
And now, the Nuclear Regulation Authority is raising doubts about the utility’s latest plan: constructing underground walls to prevent the contaminated water from reaching the Pacific Ocean.
The immediate concern is radioactive water seeping along the seaward side of the No. 1 to No. 3 reactors and spilling into the sea.
TEPCO is currently solidifying soil with chemicals near a levee to prepare the ground for the walls.
But as work has progressed, the water level in observation wells has risen sharply to about 1 meter from the ground’s surface, apparently due to the accumulation of groundwater blocked from the ocean.
Due to limitations in construction methods, the walls can only be built with their tops at 1.8 meters beneath the surface. That means the water levels in the observation wells have already risen above the top edges.
If such a situation continues, the completed barriers will be unable to prevent the water from reaching the ocean. In addition, calculations show that if the water levels continue to rise at the current pace, contaminated water will flood the surface in about three weeks.
One huge problem facing TEPCO in dealing with the water is the maze of pits constructed beneath the Fukushima No. 1 plant site for pipes and power cables.
Immediately after the nuclear accident started in March 2011, an estimated 11,000 tons of highly radioactive water spilled into the pits under the No. 2 and No. 3 reactors. Some of that water is believed to have leaked further underground from cracks in the pits caused by the magnitude-9.0 Great East Japan Earthquake.
The reactor buildings are still connected to the pits, making it difficult to shut off the flow of water that becomes contaminated in the cooling process of the melted nuclear fuel that remains in the reactors.
A working group of the NRA held its first meeting on Aug. 2 regarding the leaking of contaminated water at the Fukushima plant.
The nuclear watchdog raised concerns that TEPCO’s plan to construct walls to block the leakage would be insufficient, and proposed pumping up the contaminated groundwater.
However, a TEPCO official said installing a pump would have to wait until late August because of the continuing construction work on the walls.
According to one calculation, about 100 tons of groundwater would have to be pumped up daily to prevent the water from leaking into the ocean. But the plant is running out of storage space for the contaminated water.
TEPCO officials remain confident that the completion of the walls in October will alleviate the water problem.
“There should be considerable improvement once we complete the additional measures,” Masayuki Ono, acting general manager of TEPCO’s Nuclear Power and Plant Siting Division, said at an Aug. 2 news conference.
TEPCO has also floated a plan to pump up groundwater flowing from the mountain before it enters the damaged reactor buildings and becomes contaminated. This “clean” water would be released into the ocean, thereby reducing the volume of contaminated water at the site.
However, local fishermen oppose the move in part because of their anger at the latest leaks of contaminated water into the ocean. They have also steadily lost trust in TEPCO.
Water contaminated with extremely high levels of radiation reached the ocean from the pits in the No. 2 and No. 3 reactors in April and May 2011.
TEPCO implemented measures to stop the leaks, and officials said they believed they had properly dealt with the problem at that time.
But in reality, contaminated water continued to flow into the ocean. TEPCO officials did not admit to that problem until 22 July 2013.
On Aug. 2, TEPCO officials said between 20 trillion and 40 trillion becquerels of radioactive tritium had leaked into the ocean. That is about 10 to 100 times the volume emitted over a one-year period of operating the nuclear plant.
“There is only a minor effect on the environment because it is about the same level as the upper limits of emission standards during operating periods,” a TEPCO official said.
However, TEPCO officials noted an increase in the volume of contaminated groundwater reaching the ocean since May, when concentrations of tritium in the water within the port at the Fukushima No. 1 plant began rising.
The utility estimated that between 20 trillion and 40 trillion becquerels will have entered the ocean by the end of July.
The company will make estimates of the flow of strontium, which has greater effects on the environment and tends to accumulate in human bones. [more]
By Toshihiro Okuyama and Toshio Tada
1 August 2013
(The Asahi Shimbun) – The operator of the crippled Fukushima No. 1 nuclear power plant sat on its hands for more than two years despite having pledged to seal a leaking hole in a turbine building, The Asahi Shimbun has learned.
Tokyo Electric Power Co. said in April 2011, just one month after the Great East Japan Earthquake and tsunami triggered the Fukushima nuclear disaster, that it would block the connection between a turbine building and an underground pit to prevent radioactive water from leaking into the sea. However, the utility only began preparing for shielding tests this summer, after contaminated water was found to be leaking into the sea.
TEPCO's inaction is likely responsible for the spread of radiation.
During the early phases of the nuclear meltdowns, water, used to cool the overheating reactors, filled the reactor and turbine buildings as well as adjacent underground pits.
On March 27, 2011, TEPCO workers found that radioactive water, measuring more than 1,000 millisieverts per hour, lay in an underground pit adjacent to the turbine building for No. 2 reactor. The following day, at a news conference to announce the findings, TEPCO officials explained that the tsunami had likely broken open a barrier between the underground pit and the basement level of the turbine building, thereby creating a water channel.
One TEPCO official, answering a question from an Asahi Shimbun reporter on that occasion, acknowledged the possibility that radioactive water could seep from pit joints out into the ground and eventually reach the sea.
Radioactive water was found leaking into the sea near a water intake for the No. 2 reactor on April 2, 2011. The leak was plugged four days later.
On 17 April 2011, TEPCO released a road map toward bringing the nuclear crisis under control. To illustrate the measures it had "considered" or "taken" to prevent a recurrence of the leak from the No. 2 reactor, the utility released a public announcement that explicitly mentioned "shielding the connection between the pit and the turbine building," alongside two other measures it had already taken.
TEPCO, in fact, had yet to seal that connection, and left it unattended afterward. Officials of the utility apparently believed that stopgap measures, which consisted of using concrete and crushed stone to seal the seaward end of the pit, were sufficient.
TEPCO said in June this year it had detected high levels of radioactive substances in groundwater sampled from a well on the ocean side of the turbine buildings. The utility, which acknowledged July 22 that radioactive water was leaking into the sea, came under fire when it was uncovered that its officials had reached that conclusion on July 19.
Experts believe some of the radioactive water lying in pits likely seeped out into the ground and eventually reached the ocean.
TEPCO officials have said the turbine building remains connected with the pit, which means highly radioactive water may still be leaking.
In response to questions from The Asahi Shimbun, TEPCO officials insisted that the act of sealing the seaward end of the pit constituted "shielding the connection between the pit and the turbine building" as stated in the announcement material.
The utility did consider plugging up the leak hole in the turbine building after it put together a set of "reliability enhancement measures" in May 2012 at the behest of the government, but the sealing work "has not been done to this day because of the (technical) difficulties involved," the officials added.
2 August 2013 (ex-skf.blogspot.com) – Fukushima I Nuke Plant Groundwater Contamination: 20 to 40 Trillion Bq of Tritium May Have Been Released Since May 2011
But even that would still be within the annual regulatory target (22 trillion becquerels of tritium) for Fukushima I Nuclear Power plant.
The information about the amount of tritium released since the accident came from TEPCO during the August 2 meeting of the NRA working group to deal with contaminated water at Fukushima I Nuclear Power Plant.
So far, reports of radioactive materials in water have been focused mostly on I-131 (no longer detected) and radioactive cesium. TEPCO does measure other nuclides including tritium and strontium in seawater and fish, but the total estimates haven't been presented, until yesterday for tritium (2 August 2013).
First, the news from Kyodo (8/2/2013):
Dozens of trillions of becquerels of tritium may have leaked from Fukushima I Nuclear Power Plant
Regarding the problem of contaminated water leaking into the ocean from Fukushima I Nuclear Power Plant, TEPCO disclosed the estimate on August 2 showing the amount of tritium in the contaminated water that leaked since May 2011 to be between 20 to 40 trillion becquerels. The estimate was reported during the meeting of the working group set up within Nuclear Regulatory Authority to deal with the contaminated water [at Fukushima I Nuclear Power Plant]. […]
Before we collectively freak out on the huge number like 40 trillion becquerels, let's take a look at what it was before the accident for Fukushima I Nuke Plant and what it probably continues to be at all the other nuclear power plants in Japan when it comes to releasing tritium. […]
What's more worrisome is strontium, which many suspect has exceeded the target. [more]