APR: your source for nuclear news and analysis since April 16, 2010

Tuesday, April 12, 2011

Fukushima Daiichi: Water in motion.

Japanese media are reporting that TEPCO has begun pumping the water from the No. 2 plant pipe tunnel, outside, into the plant's main condenser. This condenser can hold about 3000 tons of water. Once the tunnel is clear, the turbine building will have to be cleared and then TEPCO can examine restoration of recirculating cooling for this reactor plant.

It is very interesting that the various agencies have noted that the spikes in atmospheric releases are correlative with various events at No. 2 plant, including the "explosive sound" in the lower part of the reactor building that seems to correspond with the failure of the suppression pool's integrity. So, although this plant's reactor core is said to be less fully damaged than, say, No. 1's and although this plant's reactor building is essentially the only one left nearly intact the total contribution to aerially spread contamination for this plant seems to be said to be high.

Another major event not yet fully explained, by the way, is the discovery of neutron-emitting sources at some locations up to a mile away from the site. This is probably from the fuel storage pool accident at No. 4 plant, although TEPCO and NISA do point out that it's possibly from No. 3 plant as well. In the final analysis, it probably does not matter from the standpoint of future actions to be taken because this is theoretically possible from either event.

Some plant and system diagrams to come today on this site.

10:10 AM Eastern Tuesday 4/12


  1. It seems that the plan is to try to keep the site more or less stable over the next several months, before actually starting on any real D&D.
    Presumably the expectation is that the decay process will have muted the emissions enough by then to allow work.
    Is this a sensible strategy in light of the parlous state of the SFPs and the ongoing airborne emissions, or is this in fact the only option that TEPCO has?

  2. @netudiant: There will probably be competing plans, and in fact it's good if there are. I have seen at least one ORNL report, done years back, for post-accident scenarios that described temporary entombment for the plants by basically sealing everything from the drywell in, even with the core still in place. Other studies have been done to essentially wall up the reactor buildings... but since they're structurally ruined at Fukushima (except No. 2) that's not possible. The smartest thing to do is move very very slowly, and have every single step thought out carefully... and DON'T make a plan all the out to six, eight months or a year and try to force anyone to stick to it. This will not be a chain of events that the public will be able to get a plan for and then hold TEPCO, JAIF, GE, Toshiba or Hitachi or anyone else to firmly because new developments and discoveries at and inside the plants at every step might change plans. The industry learned these lessons all the way back at SL-1.. and I'm sure most folks on the inside are familiar with the fluidity of events there that they know what to expect and what they cannot expect.

    I must say, netudiant, you're asking some of the best questions yet. Thank you for your comments and questions. They are very timely and very relevant.