Tepco Presser: Fuel Rods in Reactor 1 melted down to bottom of containment

[flamingdem]

http://ex-skf.blogspot.com/2011/05/tepco-press-conference-ongoing.html

Wednesday, May 11, 2011
TEPCO Press Conference Ongoing, Matsumoto Says Fuel Rods in Reactor 1 Melted Down to the Bottom of RPV

Quick note. TEPCO's Matsumoto answering questions.

About the fuel rods inside the RPV of Reactor 1:

"The fuel rods probably do not retain the original shape any more. Our understanding is that they have melted down to the bottom of the RPV. We do not have the data yet to deny that the melted fuel has leaked into the Containment Vessel."

Access to the basement of the Reactor 1 reactor building:

"No information yet on the radiation level in the basement."

Matsumoto seems to think that there is some water remaining in the RPV and cooling the melted fuel at the bottom.

[phantom power]

1. "The fuel rods probably do not retain the original shape any more."

I nominate that one for QOTD.

:hide:

[flamingdem]

2. Yes indeed, good one nt

[FBaggins]

3. MOTO. n/t

[Fledermaus]

15. WHERE'S THE CORIUM NOW?!?!?!?!?

[Barrett808]

4. WSJ: Leak suggests severe damage - 11 million liters of water unaccounted for

... Reactor No. 1's pressure vessel, a cylindrical steel container that houses the nuclear fuel, is holding only half as much water as previously thought, raising questions about where the 11 million liters of water injected into the vessel has gone, Tepco said. It acknowledged the possibility of a hole at the bottom larger than has previously been considered.

Tepco also suspects water is leaking from the beaker-shaped containment vessel that holds the pressure vessel—most likely from a tube-shaped suppression chamber at its base. The pressure vessel can hold about 330,000 liters of water and the containment vessel some 7.5 million liters. ...

TEPCO: ‘We don’t know where the water has gone’ – 11 million liters of radioactive water unaccounted for

[flamingdem]

6. Ground water contamination is a massive issue now

How long until it impacts the rest of the area?

[flamingdem]

8. Tepco says nuclear fuel may have melted through and caused leak in #1 - "company is worried"

“Nuclear meltdown at Fukushima” — TEPCO worried fuel burned a hole through bottom of containment vessel
May 12th, 2011 at 10:10 AM



Nuclear meltdown at Fukushima plant, Telegraph, May 12, 2011:

One of the reactors at the crippled Fukushima Daiichi power plant did suffer a nuclear meltdown, Japanese officials admitted for the first time today, describing a pool of molten fuel at the bottom of the reactor’s containment vessel.

<..> Now the company is worried that the molten pool of radioactive fuel may have burned a hole through the bottom of the containment vessel, causing water to leak.

“We will have to revise our plans,” said Junichi Matsumoto, a spokesman for Tepco. “We cannot deny the possibility that a hole in the pressure vessel caused water to leak”.

Tepco has not clarified what other barriers there are to stop radioactive fuel leaking if the steel containment vessel has been breached. Greenpeace said the situation could escalate rapidly if “the lava melts through the vessel”.

[AtheistCrusader]

10. I like how in the headlines, both articles you quoted conflate 'containment' with 'RPV'.

The reactor pressure vessel, and the containment are separate entities.

Not trying to dismiss, but seriously, one is orders of magnitude worse than the other.

[flamingdem]

11. you are correct nt

[AtheistCrusader]

13. Here's hoping the containment can resist the corium.

Possible for the water to be escaping the containment in ways that do not require a gaping hole in the bottom of the containment from corium burning through, so hope remains.

But this means any sort of cleanup/decommission like TMI is off the table.

[kristopher]

17. It is established that containment has been breached.

They have pumped in more water than both the reactor vessel and the containment area can hold. They don't know where the leak is in either the reactor vessel or the containment structure.

[AtheistCrusader]

18. Yeah, I just said that, thanks.

Has nothing to do with whether the corium has breached the containment.

[kristopher]

25. I was restating clearly what was known. And I think it might relate to the corium also

If you add in the fact that reactor vessel is still holding a lot of water it indicates the breach to be somewhere other than the bottom, doesn't it?

When the rods melted it got above 2700C in there so what does that do to the structure of the entire steel vessel?

Finally, they have located another outflow of highly radioactive water from conduit tubes outside #3 into the ocean. They have no idea of the origin of the water.

[AtheistCrusader]

27. Not necessarily.

The breach could be at the bottom, but not very large. TEPCO has not made it clear how much water they are continuing to pump into the core, they may be adding water at a rate that has reached equilibrium with the hole in the bottom of the RPV, if there is one. The RPV could be leaking at a burn through at the bottom, service ports, a fracture, etc.

There are other possibilities as well, such as, the water provided neutron moderation in this reactor, and the core control rod system may no longer be inserted. Might explain the re-criticality claims (unsubstantiated at this point) Unfortunate and huge flaw in the LWR design, I would argue, no gravity failsafe for the control rods, as in the BWR designs.

It would be very beneficial if we knew exactly what was happening inside the core on this reactor. 2 was in arguably worse shape, as well.

Sorry about snapping at you, I misinterpreted your intent above.

[Poll_Blind]

5. This could present extreme difficulties in cooling the fuel. If it has pooled together then....

...it is likely to have far less surface area than it did when it was contained in all the rods. The less surface area, the more difficult it is to cool the fuel. Not to mention the increased likelihood of running, continuous criticalities and extremely dangerous releases of neutron radiation.

Aside from being deadly, neutron radiation on this scale has a high probability of turning non-radioactive material radioactive, depending on the material itself.

So it really is the gift that keeps on giving!

PB

[flamingdem]

9. And let's not forget that the Spent Fuel Pool @ no. 4 is listing

and they're worried it will fall over... then watch them just give up on the place since it will be impossible to work there. And those of us on the West Coast of the USA will get a nice nuclear suntan this summer.

[meow mix]

12. sitting there waiting for the next earthquake..

np theyll be able to "shore it up" just fine :eyes:

[AtheistCrusader]

20. Changing the geometry of the fuel actually changes the criticality potential of the fuel.

So, even though the surface area problem is bad, as you mentioned, the criticality issue isn't so bad at these enrichment levels.

Still a goddamn cluster... but.

[Kablooie]

7. Wikipedia has no mention of Japan or Fukushima in the Nuclear Meltdown article. Odd.

[uppityperson]

14. Thank you and others who post in this forum.

I am glad to come find news and not have to wade through the back and forth snarking in GD. I appreciate having this forum to look at. I don't post often here but I read it regularly. Thanks.

[defendandprotect]

16. The other shoe dropping -- ? Fuel Rods MELTED DOWN ... !!!

[NNadir]

19. Wow. I bet that everyone in Japan died from radiation poisoning.

How is it then, that there's anyone around to make stuff up for the benefit of scientifically illiterate anti-nukes?

[jpak]

21. What a stupid post - oh yeah, Japan has dumped nukes (35 now shut) for renewables

The NEI nuclear fantasy world has evaporated - it's over.

Scientifically illiterate anti-nukes win

yup

:rofl:

[ReturnoftheDjedi]

23. this guy pisses in his pants a little each time a nuke plant shuts down forvever.

[AtheistCrusader]

28. Actually, most of us 'piss our pants' when more carbon-based fuels come online to pick up the slack.

Which is what is happening in Japan right now.

[ReturnoftheDjedi]

22. how far up your ass is the hand of the nuclear industry?

[Name removed]

24. Deleted message

Message removed by moderator. Click here to review the message board rules.

[Fledermaus]

26. ??????????