This is the 3rd and last part of the press conference video available at tye link given by turi a few messages above. I said I will make it shorter but in the end I decided to keep the same format, this time, till the end. In the future I'll try to watch and summarize.
<<<Let me insert a short "disclaimer" here, this is just a quick on-the-spot translation which I by no means claim to be perfect - I have been known to make plenty of mistakes even on written documents, so... if you see something weird it may well be a mistake; if you feel it is important let me know and I will double check that particular place for you.>>>
(1:28:50) Q: Is the sediment getting more frequent, is the amount increasing towards the center of the pedestal? A: No at this time we cannot say anything like that. Q: Above the pedestal, there is a similar size cilindric equipment isn't it. The RPV? A: The pedestal is slightly smaller, at 5m diameter. The RPV is 5.5m in diameter.
(1:30:30) Q: Are these video images the result of some enhancing processing, to remove fog, to improve contrast etc. - or are they raw footage. A: Previous images have been enhanced, I think there is a possibility that some enhancing/processing has been done on these two. Q: In that case some of fog, as well as some of the artifact due to radiation might have been removed. A: There can be that too, to some degree... I couldn't say. Q: Those few water droplets that wee see in those images, they couldn't possibly account for 4.5 tons per hour, what do you think? A: Well... the whole pedestal area is pretty large, it's possible that in places we couldn't see this time there is more flow... again, this too is hard to call right now. Q: I couldn't help thinking, wasn't it possible to extend that pipe a little longer, to see farther? A: This was just a preliminary step in view of the inspection using the scorpion robot. The point was just to see whether we have access enough to place that robot there at the entrance into the pedestal area. If later on such a procedure could be useful for some purpose, and could be improved - we will analyze that posibility too.
(1:38) Q: I'm seeing a bit of contradiction between the possibility that the grating might have been melted by the hot fuel and the fact that much of the equipment in the pedestal seems intact... What did the simulations say, that the RPV was pierced right in the center or is it possible that it failed somewhere on a side... A: The simulations did not follow such an angle... The RPV has a drainage pipe right in the center so perhaps it is easy to consider that that's the weakest spot, but we simply don't know yet.
(1:39:51) Q: Can you tell us something about the team, the number of workers who carried out these operations, the exposures. Also what is the atmosferic radiation level in the area where these people worked. A: There were 4 teams each made of 4 men. The teams would take turns one after another, and there were about 3 full turns. Additionally there were 2 people doing decontamination. The planned maximum exposure was 3 mSv; thanks to shielding and working in shifts, the average value was 0.37 mSv per person. However the highest exposure was 1.23 mSv. The atmospheric radiation was similar to last time, about 3~6 mSv/h in front of shielding. Q: About that maximum exposure value... I'm thinking if that was a person who also worked last Thurdsay in the other preliminary inspection..? Or should we understand the people of today didn't work last Thursday. A: People who reached a certain level of exposure will help in other ways, preparations etc - but not work in the first line. Q: So some of them did work on Thursday and again this time? A: Yes some of them do, these are teams that have had a lot of training on mockup, they are trained to work efficiently in teams and in the shortest time possible. Q: The next inspection with the scorpion robot - will there be new people working on that, or the same teams that worked this time. A: The 4 teams of 4 that worked this time will perform the basic initial operations, pipe insertion etc. Q: The exposure in this case, as a total, are there some limits that are established? A: Certainly, the management of exposure is a priority theme and a lot of consideration is given during planning to such aspects. We have a plan that calls for limiting exposure to a maximum of 3 mSv per day, but have been able to limit actual exposure values to a 10th of this value. Q: So you don;t have an overall, long-term exporure limit (say 20 mSv over a certain period), instead you're watching for a 3 mSv/day limit.
(1:44) About the sediments that we saw, will the scorpion robot be able to drive over it, avoid it, in general do a good job in spite of that sediment? A: We will do a lot of work at Toshiba (mockup) to check for those things. The data we got this time wil be very useful in that sense.
Q: ABout the watter that seems to be falling down in the PCV. What can you do to find out the leaking place and what is the significance of such a discovery for the future operations aimed at removing the debris. A: We know from the muon measurements that a lot of the fuel is probably still in the RPV. Who knows, maybe the conclusion will be that it is easiest to approach the debris from the top of the RPV. But we have much more to find until then. Q: If you are to use the flooded approach you must be able to make the RPV watertight... A: That is one possibility, flooding the whole PCV is another one, we still have much to learn before we decide that. Q: The previous finding given by the muon measurement indicated that a significant part of the fuel is still in the RPV, however we see all this debris on the platform and in the pedestal area, if that turns out to be nuclear fuel, is it an unexpected result that contradicts the muon finding? A: I wouldn't say so, the muon measurement is not a very precise one, it just says that a lot or the majority of the fuel is still in the RPV, it doesn't say no fuel leaked out... Since water is now leaking it is quite likely that the melted 2000-3000 degrees hot fuel flowed here and there over the grating, and might have melted the grating here and there, depending on the place. Q: The scorpion robot will give you information about the extent, the spreading of this sediment, but will it be able to measure some of its properties too? such as the hardness, the "feel"... A: Well maybe we'll be able to get a feel of it, a limited feel, from how the tracks of the robot will go over it. But there is no arm on this robot to extend to and grasps the debris. The camera will get really close to it too, and that might help in that sense a little. If the robot track sinks into that stuff it will mean it is soft; if it climbs over it that will suggest a harder, metal-like composition... this will give us a hint. Q: COuld you tell us again what are the objectives of the next, scorpion robot inspection. And what are you going to be analyzing in the following days. A: The scorpion has two cameras, with high resistance to radiation. Also, the fact that we have two cameras, one in the front, one in the back near the light source, will allow us to get a sense of depth and will help avoid some light artifacts/problems. We're hoping to get some very good imagery. We'll have a thermometer on it too, and a (integrative) radiation meter. We'll get an idea of the radiation level in the pedestal. We will use all that information in the analysis aimed at finding the best solutions for removing the nuclear fuel debris.
