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Fukushima – 18 March morning updates, radiation and tsunamis

                   Posted on 18 March 2011 by Barry Brook               

                                        [ATTACH=full]79475[/ATTACH]There have been further developments at Fukushima overnight that have, according to the IAEA, made the situation ‘reasonably stable‘ (although it is still serious). Given the state of play over the last week, I’ll take any positive sign I can get.

 Other points to note, as of the morning of Friday 18 March:

 1. FEPC says the following:

Through visual surveys from the helicopter flying above  the Unit 4 reactor secondary containment building on March 16, it was  observed that water remained in the spent fuel pool. The helicopter was  measuring radiation levels above Unit 4 reactor secondary containment  building in preparation for water drops. This report has not been  officially confirmed.

2. WNN says:

The Ministry of Economy Trade and Industry said at 8.38pm  that a cable was being laid to bring external power from transmission  lines owned by Tohoku Electric Power Company. This was to be connected  when radiation levels had died down after a planned venting operation at  unit 2. In addition, one of the emergency diesel units can now be  operated and will be used to supply unit 5 and 6 alternately to inject  water to their used fuel pools. Later, the power will be used to top up  water in the reactor vessels…

After clearing heavy explosion debris from tsunami and the various  explosions across the site over the last six days, eleven high pressure  fire trucks showered unit 3. World Nuclear News understands that 30  tonnes of water “was delivered” in an attempt to shoot water through the  holes in the side of the building, which appear to be very close to the  fuel ponds themselves…

Despite high levels of radiation close to the units, levels detected  at the edge of the power plant site have been steadily decreasing [the below is given in reverse chronological order].

17 March, 4.00pm: 0.64 millisieverts per hour

17 March, 9.00am: 1.47 millisieverts per hour

16 March, 7.00pm: 1.93 millisieverts per hour

16 March, 12.30pm: 3.39 millisieverts per hour

3. The two statements above are supported by the updates from the NEI:

In Japan, engineers have laid a power line that can  connect reactor 2 of the Daiichi facility to the off-site power grid,  the International Atomic Energy Agency reported. Workers are working to  reconnect the power to reactor 2 after they complete spraying water into  the reactor 3 complex to provide additional cooling to the used fuel  pool. Reconnecting to the power grid is expected to enhance efforts to  prevent further damage at the plant.

Japan’s Nuclear and Industrial Safety Agency reported on Thursday  that the backup diesel generator for reactor 6 is working and supplying  electricity to reactors 5 and 6. TEPCO is preparing to add water to the  storage pools that house used nuclear fuel rods at those two reactors.

Radiation readings at the Fukushima Daiichi site boundary were  measured today at a lower level, between 2 and 3 millirem per hour.

Fukushima Daiichi site status

The reactors at the Fukushima Daiichi plant are in stable condition  and are being cooled with seawater, but workers at the plant continue  efforts to add cooling water to fuel pools at reactors 3 and 4. The  status of the reactors at the site is as follows:

Reactor 1’s primary containment is believed to be intact and the  reactor is in a stable condition. Seawater injection into the reactor is  continuing.

Reactor 2 is in stable condition with seawater injection continuing.  The reactor’s primary containment may not have been breached, Tokyo  Electric Power Co. and World Association of Nuclear Operators officials  said on Thursday. Containment pressure is at 65 psig, an indication that  containment has not been breached.

Access problems at the site have delayed connection of a temporary  cable to restore offsite electricity. The connection will provide power  to the control rod drive pump, instrumentation, batteries, and power to  the control room. Power has not been available at the site since the  earthquake on March 11.

Reactor 3 is in stable condition with seawater injection continuing.  The primary containment is believed to be intact. Pressure in the  containment has fluctuated due to venting of the reactor containment  structure, but has been as high as 83 psig.

TEPCO officials say that although one side of the concrete wall of  the fuel pool structure has collapsed, the steel liner of the pool  remains intact, based on aerial photos of the reactor taken on March 17.  The pool still has water providing some cooling for the fuel, however  helicopters dropped water on the reactor four times during the morning  (Japan time) on March 17. Water also was sprayed at reactor 4 using high  pressure water cannons.

Reactors 5 and 6 were both shut down before the quake occurred.  Primary and secondary containments are intact at both reactors.  Temperature instruments in the spent fuel pools at reactors 5 and 6 are  operational, and temperatures are being maintained at about 62 degrees  Celsius. TEPCO is continuing efforts to restore power at reactor 5.

If all of this is successful, the plant will be able to take over from the workers in cooling the fuel in the reactor.

 I’ll provide a further update at the end of today. Meanwhile, you can track the comments on this post (Note:  I suggest we switch to this thread for the rest of today), which are  once again doing a great job at providing a minute-by-minute feed of the  latest developments.

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 Below I reproduce a short essay by Ted Rockwell. Dr Rockwell is a member of the National Academy of Engineering. His classical 1956 handbook, The Reactor Shielding Design Manual,  was recently made available on-line and as a DVD, by the U.S.  Department of Energy. Back in 2002 he was co-author on an article in Science journal, “Nuclear Power  Plants and Their Fuel as Terrorist  Targets“.  It’s definitely worth reading as it’s highly relevant to the current  situation ”” if you bear in mind that the ‘terrorist’ in this context was  Mother Nature ”” and a brutal one at that.

 Ted’s short essay (Rod Adams has also reproduced this), given below, explains well what I meant by my earlier statement:

What has this earthquake taught us? That it’s much, much  riskier to choose to live next to the ocean than it is to live next to a  nuclear power station.