Al Jazeera America: ” Skeptics of the plan to build a massive ice wall around Japan’s crippled Fukushima Daiichi nuclear facility didn’t have to wait particularly long for their first “I told you so.”
TEPCO, the nominal operator of the battered plant, announced Tuesday that while construction on the network of pipes, pumps, and compressors has begun on what is intended to be a huge ice barrier to prevent mountain runoff from mixing with radioactive water inside the facility, attempts to form a smaller ice wall around already-contaminated water are failing.
“We have yet to form the ice stopper because we can’t make the temperature low enough to freeze water,” a TEPCO spokesman said.
The project is already behind schedule and over budget, and engineers are adding more cooling pipes in hopes they can complete this first small step next month.
While the ground freezing procedure has been used to construct tunnels near waterways, it has never been used for nuclear cleanup and has never been done on such a massive scale. Estimates of the project’s success can best be termed “hopeful.”
But freezing the ground around the plant is not strictly a “Why the hell not?” proposition. As previously noted, the plan comes with a list of concerns:
What if freezing causes the ground to sink? What if the ice and the ensuing expansion and contraction interrupts or further damages drainage in the reactor buildings? What if a heat wave or heat from the plant causes parts of the wall to melt? And, what if there is a prolonged loss of power to this cooling system?
The ice wall is only intended to help with the problem of irradiated runoff — the question of what to do with the thousands upon thousands of gallons of water contaminated in the daily fight to cool the melted cores of the damaged reactors and the stored rods in the spent fuel pools remains largely unanswered.
Last month TEPCO began diverting what they say is only moderately radioactive water into the ocean after assuring local fishermen that the levels were safe. Last summer, it was revealed that 300 tons of contaminated water was seeping from the nuclear site into the Pacific every day.
While freezing parts of the ground surrounding the disaster site may or may not be an effective part of the final cleanup and decommissioning, problems continue to outpace response at Fukushima. TEPCO’s experiment around the margins does nothing to address the hot mess at the core (as it were) of the crisis, and is cold comfort to those people still displaced or a country and hemisphere facing generations of radiologic contamination. ”
The Guardian: ” The operator of Japan’s battered Fukushima nuclear power plant has said it is having trouble with the early stages of an ice wall being built under broken reactors to contain radioactive water.
Tokyo Electric Power (Tepco) has begun digging the trenches for a huge network of pipes under the plant through which it intends to pass refrigerant.
This will freeze the soil and form a physical barrier that is intended to prevent clean groundwater flowing down mountainsides from mixing with contaminated water underneath the leaking reactors.
Tepco said on Tuesday that a smaller, inner ice wall whose pipes it sank earlier to contain the already-contaminated water was proving difficult.
“We have yet to form the ice stopper because we can’t make the temperature low enough to freeze water,” a Tepco spokesman said.
“We are behind schedule but have already taken additional measures, including putting in more pipes, so that we can remove contaminated water from the trench starting next month.”
The coolant being used in the operation is an aqueous solution of calcium chloride, which is cooled to -30C (-22F).
The idea of freezing a section of the ground, which was proposed for Fukushima last year, has previously been used in the construction of tunnels near watercourses.
However, scientists point out that it has not been done on this scale before, nor for the proposed length of time.
Coping with the huge – and growing – amount of water at the tsunami-damaged plant is proving to be one of the biggest challenges for Tepco, as it tries to clean up the mess after the worst nuclear disaster in a generation, in which three reactors went into meltdown.
As well as all the water used to keep broken reactors cool, the utility must also deal with water that makes its way along subterranean watercourses from mountainsides to the sea.
Full decommissioning of the plant at Fukushima is expected to take several decades. An area around the plant remains out of bounds, and experts warn that some settlements may have to be abandoned because of high levels of radiation. ”