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and opens up floor for questions (my computer froze and i couldn't get everything)
this is a press conference for the foreign press, btw
Q: about the explosions & radiation exposure in the area, this seems serious but on tv we have commentators close to the gov't who dismiss it. i'm only an amateur but it seems to me that when you get an xray it's only a one-time exposure and you don't need to be decontaminated, don't we need a more serious approach.
A: i'm not an expert in radiation exposure either but as you point out, there's a difference between being exposed for an instant & having this material cling to your clothes. it's the length of time you;re exposed that matters, so i believe any comment comparing these exposures to xrays should be used with caution. for example, if youre exposed to xrays 3 time, everyone knows that you are raising risk every time you get an xray. any exposure has an incremental effect. we need to explain what kind of exposure over what time.
Q: i'm from Intelligence Weekly. i want to make sure i understand. you say tsunami fouled up cooling so they dipped into the suppression pool...didn;'t catch, so if hydrogen is a problem why don't you have a hydrogen recombiner?
A: first, tsunami hit plant, cooling system damaged, power disrupted. exact situation for every plant/reactor a little different. your second question about hydrogen recombiner applies to pressurized reactors, with boiling water reactors we use nitrogen.
to add -- at 6:20 today, the 14th, it is suspected the fuel rods are completely outside of the water, they are trying to introduce more water they are running out of fuel to run the pumps.
German, i think the situation is serious, we should hurry & ask our questions and write our stories
Q: Indian reporter: Have you designed any of the vessels which are now exploding and what is the standard of the outside pressure the reactor housing (?) is supposed to stand up to?
A: i was on the design team for these vessels, my specialty was tolerance of these vessels, as you suggested, these vessels are susceptible to relatively low pressure from outside. when situation like this occurs we should be -- there's a valve in these vessels that prevents this kind of situation, where there is less pressure inside than outside.
Q: German: we heard the rods are/may be fully exposed, what does it mean.
A: depends on the time factor. if the situation continues for some time, it will be serious. according to the announcement by tepco, they cannot deny the possibility that the core has melted, however we are doing our best to counteract.
Q: you said that when you saw the explosion today you said it was different than the first & we the amateurs also thought so. can you tell us why. second, in regard to #3, because it uses a different kind of fuel, what exactly are we faciing?
A: i don't know the precise reason but one thing we can say about the explosions is the #3 explosion release a much larger amount of hydrogen; also how much time has elapsed before it ignites also affects. i'm just saying as a general thing. when we look at what happened with 3.
as you pointed out, 3 uses mox fuel and there's possibility of plutonium release with that. the melting point for mox is lower, so more of a risk of something bad happening.
Q: I understand that after power is off, the fuel rods lose heat. how many days will that be? also, number 1 reactor, there's been no news so i assume things are going well. also.. (couldn't hear, fuzzy)
A: second question first: the fact that fuel rods in one are submerged is very positive. however, the makeshift circulation system in place takes longer to cool the fuel.
first question: there's so many factors that affect the length of time so i can;'t answer.
Q: many of the foreign press have been using the word meltdown & you used the word too, can i ask you for precise definition, when i hear it i think of complete destruction of core & radiation release with, eg. some kind of smoke. is this what you mean?
A: when we talk about complete meltdown we talk about complete melt of fuel rods with melted debris in bottom of reactor vessel, situation at three mile island where this debris remained for some time and as a result much of the steel vessel melted away and it got to a dangerous point which they were able to stop before it melted the vessel compeltely.
in order to counteract this, engineers try to put water into the vessel, however there is always the possibility debris could react with water & produce hydrogen explosion.
so the latest announcement is that some meltdown of rods has occurred and so there is some melted debris.
Q: in regard to currnet situation, how much time do we have for this cooling process to succeed before we have terrible situaiton. and what is worse case scenatio.
A: in worse case scenario it would take some time. i can;t be precise because there are so many factors. we can't see exactly what is happening inside the reactors. at three mile island it was not clear what had happened inside reactors until 10 years later.
if a terrible situation happened at one reactor, ramificationn would be that people working to control situation in other units would not be able to continue.
Q: (another official,not sure who he is) as doctor goto explained, there were explosions in 1 & 3. for the first, containment building walls & roof were destroyed. in regard to the second explosion probably the actual girders were destroyed. it was more violent. its been reported that the pump car providing water was also blown away (i think he means the fire pumper truck). so its surmised that the explosion hindered the work being done on nunber two of inserting sea water.
also, re mox fuel. as dr. goto mentioned, one of the causes of using it is lower melting point. which means higher risk for melting of the core. also its a type of plutonium so toxicity is higher.
it is possible hypothetivcally that radiation can be doubled with mox.
German: i'll take two questions & close the session. dr. goto will come again tomorrow.
Q: Financial Times reporter: mr goto you have worked in the industry many years, you're now very critical of your employer of many years, is there an incident which has provoked this?
A: i'm basically a structural engineer, my fundamental background was in shipbuilding then i moved into container design. when i started working in this field i undertood that this was the last bastion to defend people from accidents. but as i pursued my research i realized it was not an adequate line of defense -- for example, in severe events like earthquakes. these vessels have the possibility of cracking or being destroyed, though the likelihood is low. but as we see, quake can cause damage to multiple systems, and i realized these containments weren't invincible. it took for me the kanizaki-kanagazawa nuke accident to realize this.
Q: what advice what might you give to mr kan and other japanese officials who are supposed to have some expertise in the nuclear field, what kind of questions should the government officials be asking the nuclear people?
A: i ask myself this...therefore only way i can help is to tell what i know as a person with some kind of expertise. one thing i know is people in charge aren;'t necessarily the people with the most tech knowledge, or if they do, sometimes in the process of giving info to the public, it might be changed. i udnerstand it's irresponsible to incite panic but when we are dealing with human life everything should be done to ensure safety so what concerns me is whether policies being taken ensure safety.
first we need to make sure people in charge have correct and accurate information and that the information be public. i believe there;'s a lot of info being collected, monitoring posts measuring radiation levels, this should be made public, i believe this kind of data being presented on a regular basis is the basis for whatever actions (e.g. evacuation) should be taken.
this kind of situation is constantly evolving. i beleive the govt and nuke safety commission should take a proactive approach and produce policies that will create the least damage. i dont mean to criticise the people involved who are doing their frantic best to correct the situation so critizing is not the best way to help the situation but accurate info on timely basis and proactive measure and not waiting until situation gets bad and then reacting is best approach.
so i have great sceptism and wonder if people at the top levels have enough info to make a good judgement ( i think he;s talking about the politicians). and whether that infomration is being reflected in the policies taken i have some skepticism.
thanks.
Q: you mentioned earlier that containment vessels were not invincible. did your colleagues and employers think and why did they not reflect this in corporate actions?
A: i think this depends on each designers fundamental beliefs. but my reserch was very specific. i was researching the actual tolerance of the vessels. some engineers aren't thinking about this point. it wasn;'t until about 1994 that the authorities recognized the problem of vessels being subjected to more pressure than it was designed to stand; they judged that this was so rare and didn't make it obligatory to raise the standards. it was made "voluntary" for each company. the people were able to choose to do it or not.
German: last question please
Q: question about different kinds of accidents --
A: in this kind of situation you might have other kinds of explosions - hydrogen, steam -- or corrosion -- there are many things that might happen. to ensure these don't happen -- many decades of research. but things have a way of creeping into these failsafe mechanisms.
German: i would like to close this session & the plan to have you back tomorrow from 7 to 8 and give us update mr. goto.
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