Japan's Nukes Following Earthquake

[Superdave7]

Oh really? Wow yeah that's right, they were talking about moving them to the SAMPs (SAGs). Didn't think it would happen that fast. But honestly, that is where they belong. Just look at this event.... they are clearly deep into their SAMPs, if anything, and that is where this gassing would occur.

Justin

I would say very true on the "deep into the SAMPS" comment, however, our plant manager this morning said that that plant DOESN'T have SAMP/SAGs.....yikes!

On a side note, the seawater injection was stopped for awhile on one of the units, then restarted.  I heard a bit on the radio (trustworthy? who knows) that the OPERATORS let the pump run out of fuel.  I think they were using a diesel driven fire protection pump.  We have 2, with 2 different water sources, that have fuel tanks that would have to be refueled fairly frequently.

[Superdave7]

The EOP charts would have directed some thermal recombiner operation for a while and then would have directed sprays and such... all of which would have been unavailable with no power.  Let's not forget, the ability to even monitor for H2 would have been lost due to lack of power.  I agree though, at least having the charts would have put that in front of you early.  As far as not practicing the Severe Accident Guidelines much I truly believe that will be high on the list of training solutions.  With the devestation, I doubt the emergency response organization even got to the plant early enough - that leaves Operations on its own.  Operators are highly skilled, smart and capable but when you enter the SAG's you really need a lot of technical assistance to make informed decisions.  You also need a crap load of available support teams.

XF

Speaking of Hydrogen Recombiners, we *ahem*..... spared those in place.   DOH!!!

[JustinHEMI05]

I would say very true on the "deep into the SAMPS" comment, however, our plant manager this morning said that that plant DOESN'T have SAMP/SAGs.....yikes!

On a side note, the seawater injection was stopped for awhile on one of the units, then restarted.  I heard a bit on the radio (trustworthy? who knows) that the OPERATORS let the pump run out of fuel.  I think they were using a diesel driven fire protection pump.  We have 2, with 2 different water sources, that have fuel tanks that would have to be refueled fairly frequently.

I am going to save my comments about some of my thoughts about operator knowledge and ability throughout all of this, until all the fact are on the table.

I kind of had a feeling they didn't have procedures quite like ours, just based on the updates coming out.

[RRhoads]

I am going to save my comments about some of my thoughts about operator knowledge and ability throughout all of this, until all the fact are on the table.

I kind of had a feeling they didn't have procedures quite like ours, just based on the updates coming out.

Excellent idea...
All the arm-chair QB  is no substitute for whats really going on over there....
Information as to what steps have been taken are out there esp for those who are in the House tech realm.
speculation here only adds to the confusion to the folks looking on this site for some information.

[Xenon_Free]

So what is the status of the spent fuel pool cooling? Has anyone heard/read anything?

Justin

I have not read nor heard anything at all.  For my uninformed two cents, it seems reasonable to assume Unit 1 spent fuel pool intact, not sure about unit 3 - this is based soley on the video of the explosion and pictures after.   People need to understand that the fuel is stored in steel/borated plate racks, under 20+ feet of water in a steel lined pool surrounded by concrete.  And unless the plant recently had an outage the heat load in the pool is relatively low, this gives a lot of time to add water to the pool to keep everything in check.  Even the roofing materials in the pool should not have impacted the fuel too greatly by itself.  But as Justin pointed out - the earthquake changes everything.

XF

[Pman52]

http://www.nrc.gov/reading-rm/doc-collections/news/2011/11-047.pdf

This might be common knowledge by now, but Japan's government has formally asked the U.S. NRC for assistance with the troubled reactors.  We've already sent two BWR experts over to help with technical advice.  Hopefully they can get this situation under control quickly.

[caerbannog]

If these were PWRs, they couldve possibly been steaming away on natural circ all this time. 

[Xenon_Free]

If these were PWRs, they couldve possibly been steaming away on natural circ all this time. 

It has been a while since I worked at a PWR... IIRC you would use the S/G to dump heat from the primary system adding water to the steam generator via steam driven emergency feedwater pumps.  Cooling down the reactor would have required makeup - from safety injection tanks or something like it?  Anyway the Emergency feedwater pumps still need a suction source - I can not remember one that would be available in this case???

[OldHP]

Don't you just love the media take on this? 

Two headlines (different parts of the US) I've read today are equating the loss of life resulting from the 8.9 - 9.0 earthquake and resulting tsumami with the problems at the nuclear facilities.

One of the articles suggested that no lives would have been lost if it wern't for the nuclear problems - even as bodies carried out to sea with the receding surf were washing up on shore.

[Pman52]

It has been a while since I worked at a PWR... IIRC you would use the S/G to dump heat from the primary system adding water to the steam generator via steam driven emergency feedwater pumps.  Cooling down the reactor would have required makeup - from safety injection tanks or something like it?  Anyway the Emergency feedwater pumps still need a suction source - I can not remember one that would be available in this case???

Would it pull from the Condensate storage tank or RWST?  After you have dropped the temp on your primary system, you'll eventually lose the ability to produce steam in the S/Gs.  Then you would have to kick over to the RHR system.  But in this situation what would you do without power?  RHR/LPIS involves use of the EDGs.  How would you go about removing decay heat from the position of having lost your EDGs? You would have your cold leg accumulators on the event of a LOCA but what good would these do as far as long term effects of not having use of the RHR system?

[matthew.b]

I worked at a PWR, but I'm sure not going to claim a PWR would have fared better!

It has been a while since I worked at a PWR... IIRC you would use the S/G to dump heat from the primary system adding water to the steam generator via steam driven emergency feedwater pumps.

At the plant I worked at the AFW pump required DC power to operate, period.  The AFW feed valves were DC and could be positioned by hand.  The problem was the throttle valve.  It was hydraulic with direct control by the electronic governor.

The steam dumps could be problematic after 8 hours of no power.  The operator would have to be very careful with his number of manipulations not to waste his bottled air away without and EDG to pump up the air tanks.

Cooling down the reactor would have required makeup - from safety injection tanks or something like it?

Yeah, the problem is guaranteeing a void free primary that wouldn't impede natural circulation.  Beyond 8 hours is a problem here too.

Anyway the Emergency feedwater pumps still need a suction source - I can not remember one that would be available in this case???

Normally it is from the condensate storage tank with service water backup.  The fire main is a final backup if the plant is outfitted with the proper connections.  Having a working fire truck would be the last line of defense.

[Incline]

I just saw the news on CBS and Katie had an "expert" on explaining how the reactor worked. He did a good job on explaining everything, but he found it "troubling" that the diesel generators did not fire up. If he had done some legwork as an expert, he would have found out that the fuel oil tanks (yes, they were above ground) were swept out to sea with the tsunami. Gee...how far does your car run on no gas?

[matthew.b]

Would it pull from the Condensate storage tank or RWST?  

CST feeds the AFW into the steam generators.  RWST feeds the primary side pumps and there is no ability to interconnect.  RWST is contaminated and the secondary is supposed to be clean so they don't interconnect.

After you have dropped the temp on your primary system, you'll eventually lose the ability to produce steam in the S/Gs.  Then you would have to kick over to the RHR system.  But in this situation what would you do without power?  RHR/LPIS involves use of the EDGs.  How would you go about removing decay heat from the position of having lost your EDGs? You would have your cold leg accumulators on the event of a LOCA but what good would these do as far as long term effects of not having use of the RHR system?

In a station blackout you don't let the plant cool enough to stop the steam driven AFW.

[matthew.b]

I just saw the news on CBS and Katie had an "expert" on explaining how the reactor worked. He did a good job on explaining everything, but he found it "troubling" that the diesel generators did not fire up. If he had done some legwork as an expert, he would have found out that the fuel oil tanks (yes, they were above ground) were swept out to sea with the tsunami. Gee...how far does your car run on no gas?

We had 8 hours in the generator room.  I take it this plant didn't.  I wonder how common storage by the generator is?

[hamsamich]

Read in an article a DG was flown in but the plugs didn't work...


So when they got to the point they were going to put service/sea water in, what motive force was used for that?  most likely one?


anybody have any idea on this one?  I'm assuming they finally got some kind of power back to do this?

[PJMcG]

Whatever Glenn Beck said to bring a rational voice to the press, Shepard Smith just erased it in his breathless description of another explosion.

Apparently there was just an explosion at Fukushima Daiichi Unit 2.

[Pman52]

In a station blackout you don't let the plant cool enough to stop the steam driven AFW.

Gotcha...so in their case it would have all happened right away so you would maintain the plant so you could run your AFW pump.

I have no PWR experience but trying to learn something.  It's challenging to think about the situations of either plant type.  Thanks for sharing information.

[remer]

Word is that Unit 2 just suffered a hydrogen explosion. No real sources or info yet.

[ski2313]

If these were PWRs, they couldve possibly been steaming away on natural circ all this time.

That was my thought as well... (from my limited knowledge of the difference(s) between PWR and BWRs)..

[tr]

In a PWR you've also got the issue of making up to the primary for reactor coolant pump seal bleedoff.  While this is typically small during normal operation (say 6 gpm), over a long period of time it starts to become becomes significant (over 8500 gallons lost from the reactor coolant system per day).  

Depending on the seal design, the leakage could increase fairly dramatically once AC powered seal cooling is lost.  At 25 gpm, the leakage is up to 36,000 gallons per day.  

Total RCS volume is probably on the order of 50,000 gallons to 100,000 gallons depending on the specific PWR plant design involved.

[thenuttyneutron]

If these were PWRs, they couldve possibly been steaming away on natural circ all this time.  

The station blackout was not the issue.  The EDGs ran for an hour as they were supposed to do.  The Tsunami took out the EDGs.  Knowing now that it was a 30 ft tall wave, it would be hard for any nuke plant to survive.  If a wave like that had hit my plant, it would have taken out all of the EFW pumps.  I don't know how long the turbine driven pumps could run under water, but I bet it is not long.

You also have to consider the suction source.  If your CST is gone, your pumps will not matter anyway.  The pumps do have backup sources like fire water or Service Water but those would probably be gone too.  This was really a worst case situation.  

These plants were designed for a Tsunami hit.  This tsunami was just too big for them to handle.   Like any nuke plant currently in operation, if you break enough emergency systems, you will damage/melt the core.

In a PWR you've also got the issue of making up to the primary for reactor coolant pump seal bleedoff.  While this is typically small during normal operation (say 6 gpm), over a long period of time it starts to become becomes significant (over 8500 gallons lost from the reactor coolant system per day).  

Depending on the seal design, the leakage could increase fairly dramatically once AC powered seal cooling is lost.  At 25 gpm, the leakage is up to 36,000 gallons per day.  

Total RCS volume is probably on the order of 50,000 gallons to 100,000 gallons depending on the specific PWR plant design involved.

Seal Leakage drops significantly when the RCPs are stopped.  That would not be my concern.  I would however be nervous about the shrink of the RCS water after a long time.

[matthew.b]

In a PWR you've also got the issue of making up to the primary for reactor coolant pump seal bleedoff.  While this is typically small during normal operation (say 6 gpm), over a long period of time it starts to become becomes significant (over 8500 gallons lost from the reactor coolant system per day).  

IIRC, isn't it 6 GPM PER PUMP?

[PJMcG]

You also have to consider the suction source.  If your CST is gone, your pumps will not matter anyway.  The pumps do have backup sources like fire water or Service Water but those would probably be gone too.  This was really a worst case situation.  

These plants were designed for a Tsunami hit.   Like any nuke plant currently in operation, if you break enough emergency systems, you will damage/melt the core.

I knew the EDG were damaged by the tsunami; I had not heard about CST etc. being damaged.  Does anybody have any information on the damage to aux systems, tanks, etc.?  Maybe before and after aerial photos.  The post Unit 3 explosion is useful, does anybody have a before photo for comparison?

[thenuttyneutron]

IIRC, isn't it 6 GPM PER PUMP?

Not at my plant.  I am used to 1.2-1.3 total seal loss via seal return and seal leak off with the pump running. The total seal losses almost goes away when the pump is stopped.  The pump would leak off more the lower in pressure you go however.

I knew the EDG were damaged by the tsunami; I had not heard about CST etc. being damaged.  Does anybody have any information on the damage to aux systems, tanks, etc.?  Maybe before and after aerial photos.  The post Unit 3 explosion is useful, does anybody have a before photo for comparison?

I am just trying to illustrate that a wave of this size would leave my PWR in serious trouble.  I don't know all the stuff that they lost.

[Incline]

We were told fuel oil tanks swept out to sea and the basement of their turbine building was flooded with sea water, which is where the ac to dc switchgear is, along with the loss of off site power. The design basis was for a 7 meter tsunami wave and they had a 1000 year 10 meter wave. Seems everything with the plant was ok from the quake, it was the wave/quake and no power that put them in a bind.