Tokyo Electric Power Company [TEPCO] on Wednesday sent a floating robot into the extremely radioactive environment of the Daiichi unit-1 first level basement - "torus room" - to see if it could locate leaks known to be contaminating the Pacific Ocean in rapidly increasing amounts off the Fukushima facility. Somehow (TEPCO has never been forthcoming on this), water being poured into the bottomless reactor vessels has been leaking from the containment structure and escaping into the ground, where it has been mixing with groundwater from mountains to the northwest and flowing right on into the Pacific Ocean. Where it has been busily contaminating everything from plankton to whales (and everything in between).
This Ty-D-Bol robot and its camera managed to find two significant leaks. One is in a conduit shunting water from the lower level of the drywell [containment] to the pressure suppression pool - a donut-shaped tank also called the torus - in the first level basement of the plant, at the juncture of the conduit and the torus itself. The other is from a pipe leading from the torus to a lower basement level and into the ground. Of course, one might legitimately wonder why a nuclear power plant would have pipes leading from the torus "into the ground," I mean, pipes that don't go anywhere wouldn't appear to be very useful, but we are talking about Daiichi here, which has 6 badly designed nuclear plants on one badly designed reservation. Anyway, utility engineers wouldn't speculate on how much water is getting out, but did say it was "gushing" and the torus level basement is flooded. Radiation levels per the robot's readings were between .9 and 1.8 Sv/hr. Or for those who like their readings the old fashioned way, between 90 and 180 Rem per hour.
The engineers also said they expect that damage to the containment structures at units 2 and 3 - which also suffered total meltdowns/melt-throughs in the March 2011 disaster - will be similar. From Enformable's coverage -
"Part of the containment vessel is damaged, and water leaking from there is likely to be flowing down into the ground via the pipe," one TEPCO official said.There are no plans to do anything about the leaks because the radiation levels are too high in the flooded basements for humans to work, but knowing where the leaks they already knew they had are on a diagram will probably go into somebody's long-term plan for "someday - maybe" projects which will no doubt be obsolete long before someday comes and there's a dozen more leaks (or the torus has just plain fallen apart). So for that eventual someday, I for one hope they'll keep the Ty-D-Bol robot handy.
Meanwhile, the operation to remove spent fuel assemblies from the unit-4 spent fuel pool scheduled to begin this weekend or early next week, has been complicated by old inspection reports that some of the assemblies in the pool are damaged, and appear to have been damaged before the 2011 disaster. A TEPCO spokesperson said the damaged assemblies cannot be removed using the cask system designed to transfer the more than 1,500 assemblies over the course of a year.
One of the assemblies was damaged as far back as 1982, when it was mishandled during a transfer, and is bent out of shape, Tepco said in a brief at the bottom of an 11-page information sheet in August.Two other spent fuel racks in the pool were reported in 2010 to have what appears to be wire trapped in them. Rods in the assemblies secured in those racks have pin-hole cracks and have been leaking radioactive gases all that time.
Each one of the more than 1,500 spent fuel assemblies in the pool contains radiation equivalent to about 10 times that of the atomic bomb dropped on Hiroshima in 1945.
The "interesting times" we live in just keep getting more and more interesting, don't they?