Japan's Nukes Following Earthquake

[JustinHEMI05]

Why would you assume a unit with no AC power in station blackout would have condensate? I thought that procedure was your forte?

Because of news reports that they had power.

[Nuclear Renaissance]

primary containment flooding is not a samg, it's an eop in a bwr 4.

I am sitting here in a BWR/4 looking at the primary containment flooding chart, and it says SAMG at the bottom. Hmmm.....

[Fermi2]

yeah you're probably right on that with the samg. they were changing some of the flow charts when i left the bwr world.

they lost offsite power so condensate would not be available

i'll guarantee they are not flooding containment. i'll venture the sea water is from the fire suppresion system

[JustinHEMI05]

I am sitting here in a BWR/4 looking at the primary containment flooding chart, and it says SAMG at the bottom. Hmmm.....

Could you outline what had to go wrong for them to get there?

[Fermi2]

he can't because it's impossible without a huge arse breach in the reactor vessel.

[Nuclear Renaissance]

You get to primary containment flooding if you have no other reliable injection source to the vessel. Continued station blackout gets you most of the way there - an explosion in secondary containment does the rest.

Earthquake causes loss of grid

Loss of offsite power causes scram, Main Steam Isolation, and diesel generator start

Tsunami wave trips diesels an hour later – station blackout

Steam-driven systems are only means of injection – it is necessary to stay at pressure to maintain motive force

No AC means no containment cooling – HPCI should not be used due to its very high exhaust steam discharge into containment

Level is held low, in part to minimize injection (and resultant RCIC-exhaust containment heatup) and in part to stay on DC-powered level instruments

Containment venting becomes necessary to avoid overpressurizing containment – they probably were considering venting early with uncertainty of quake damage to containment

8 hr battery coping time is exceeded – RCIC becomes non-functional in auto

Local manual operation of RCIC becomes necessary (news reports said 4 operators were in the reactor building basement), meanwhile level continues to lower, challenging fuel

Hydrogen buildup in reactor building causes explosion, obliterating secondary containment and possibly damaging injection penetrations (most are AC-powered anyway). News reports said there were on Steam Condensing mode after the MSIV closure, which creates a direct vessel dome path to the RHR heat exchangers.

Enter containment flooding.

[Fermi2]

bs not credible

once they covered the core none of that was credible.

and they did cover the core.

the explosion emanated outside containment and it looks like the blowout panels did their job.

there is no mechanism for getting hydrogen inside the secondary containment and a internal drywell explosion is impossible.

[thenuttyneutron]

STRATFOR time

http://www.stratfor.com/analysis/20110312-red-alert-nuclear-meltdown-quake-damaged-japanese-plant?utm_source=redalert&utm_medium=email&utm_campaign=110312%284%29&utm_content=readmore&elq=d069624ee7394c6d95bed6aab634bf54


they have videos towards the bottom.

This is a very good example of a bad article.  Just the first few paragraphs are bullshit.  We need to do a better job teaching the public what a meltdown really is (decay heat).

What will this mean for the future of nuclear power?  Will the Nuclear Renaissance (not the forum name) be put off again for a few decades?

[Nuclear Renaissance]

blowout panels?!? did you see the video - something tore secondary containment apart with extreme prejudice. frankly i'm surprised primary containment survived that intact.

why would the Japan-NRC equivalent say that a partial melt was likely, if you think they have full core coverage? why are they saying right now that they are entering primary containment flooding, which we all know is a last resort?

[Fermi2]

yeah those are the bowout panels and metal wall surrounding the reactor building, not the structure itself.

no one said anyone was entering primary containment flooding, what they said was saea water was entering the containment, there is a difference.

they had an explosion in the turbine building

let me ask, exactly how many licenses, specifically sro licenses have you obtained?

[Nuclear Renaissance]

They had an explosion in secondary containment. This has been put out multiple times.

From mulitple sources: "Government officials painted a hopeful picture, saying crews had begun implementing a backup plan to flood the reactor containment structure with sea water, a plan that will take 2 days." Sounds exactly like containment flooding.

I have 1 BWR/4 SRO license, same as you. I have 4 years experience engineering BWR/6s as well.

[Fermi2]

they said the explosion happened outside the building. released by their government.

and you used your license for?

you're babbling

[mrmike83]

I thought that the standby liquid control was a last ditch effort in this situation. Why not blow the valves and inject sodium pentaborate?

[retired nuke]

I thought that the standby liquid control was a last ditch effort in this situation. Why not blow the valves and inject sodium pentaborate?

SLC is for reactivity. From what I've read, reactivity isn't the problem. Cooling is. Decay heat removal will not be affected by SLC injection as far as I know....

Just the opinion of an ex-cook, RP Tech..... (with multiple fishing licenses... )

[JustinHEMI05]

he can't because it's impossible without a huge arse breach in the reactor vessel.

Normally I agree but the quake changes everything.

@Nuclear Renaissance, thanks for that. Good stuff.

[Nuclear Renaissance]

See 1 (explosion in secondary containment) and 2 (primary containment flooding):

At 20:30 local time Japan Sat 3/12/11 Chief Cabinet Secretary Edano announced at the press conference as follows:

1. Hydrogen explosion occurred at 15:36 in between primary containment and reactor building of Fukushima Daiichi unit 1.  Walls of reactor building were blown out or damaged.
2. It was confirmed that unit 1 containment integrity was maintained. Explosion was not inside the primary containment as it is inert.
3. Radiation level at the Fukushima Daiichi site border once increased when containment vent was conducted and reached 1,015 micro Sv per hour around the time when explosion occurred; however, the radiation level turned to decrease after the explosion down to 860 at 15:40 and 70.5 micro Sv per hour at 18:58.
4. Government has agreed to TEPCO decision to fill the entire containment up with sea water.  The filling sea water will contain boron.  TEPCO started the work for filling up at 20:20.

[Nuclear Renaissance]

SLC is for reactivity. From what I've read, reactivity isn't the problem. Cooling is. Decay heat removal will not be affected by SLC injection as far as I know....

Just the opinion of an ex-cook, RP Tech..... (with multiple fishing licenses... )

All rods are in, but in a partially-melted core, re-criticality is not necessarily assured, so boron is prudent during flooding.

[JustinHEMI05]

All rods are in, but in a partially-melted core, re-criticality is not necessarily assured, so boron is prudent during flooding.

Good point.

[DHHII]

SLC is for reactivity. From what I've read, reactivity isn't the problem. Cooling is. Decay heat removal will not be affected by SLC injection as far as I know....

Just the opinion of an ex-cook, RP Tech..... (with multiple fishing licenses... )

Yes, but how many poetic licenses do you have?

[Missouri]

Fox news just reported that there there were 3 workers sent to the hospital with symptoms of radiation sickness. It's probably BS but I guess you never know.

[PJMcG]

Many thanks to those who started and contributed to this thread.  Accurate information is nearly impossible to find and the MSM has been horrible.  Thanks to this thread, I followed the TEPCO press link and most recently found this:

Press Release (Mar 12,2011)
Plant Status of Fukushima Daini Nuclear Power Station (as of 8pm March 12th)

http://www.tepco.co.jp/en/press/corp-com/release/11031230-e.html

Which states among other things that:
" - Offsite power is available "
  and
"- Injection of water into the reactor is done by Make-up Water Condensate
System."

This strikes me as great news!!  I'm surprised this board hasn't lit up!

Sadly, they also report the fatality of a crane operator.

[ski2313]

Somewhat off topic...

But what are the ramifications, if any, back here in the U.S. of the nuclear events of this weekend in Japan? Will there be a knee-jerk reaction from the (non-NRC) feds?

[Bigchris]

"Tokyo Electric earlier said it had lost control of pressure building up in three reactors at the Dai-Ichi power plant. Temperatures in the control room rose to higher than 100 Celsius (212 Fahrenheit), said Naoki Tsunoda, a company spokesman." http://www.bloomberg.com/news/2011-03-12/explosion-destroys-walls-of-japan-reactor-building-nhk-reports.html

212 Deg F in the control room?  That must have made it hard to work in there.

Side note- This is a great website. Many thanks to everyone who contributes.

[gaetano01]

they said the explosion happened outside the building. released by their government.

and you used your license for?

you're babbling

From the Japanese Government's mouth:

TOKYO, March 12 (Reuters) – Tokyo Electric Power Co plans to fill a leaking reactor at the Fukushima Daiichi power plant with sea water to cool it down and reduce pressure in the unit, Japan's top government spokesman said on Saturday.

"The nuclear reactor is surrounded by a steel reactor container, which is then surrounded by a concrete building," Chief Cabinet Secretary Yukio Edano said.

"The concrete building collapsed. We found out that the reactor container inside didn't explode."

Japan earlier in the day warned of a meltdown at the reactor at the plant, damaged when a massive earthquake and tsunami struck the northeast coast, but said the risk of radiation contamination was small.

"We've confirmed that the reactor container was not damaged. The explosion didn't occur inside the reactor container. As such there was no large amount of radiation leakage outside," he said.

"We've decided to fill the reactor container with sea water. Trade minister Kaieda has instructed us to do so. By doing this, we will use boric acid to prevent criticality."

Edano said it would take about five to 10 hours to fill the reactor core with sea water and around 10 days to complete the process.

Edano said due to the falling level of cooling water, hydrogen was generated and that leaked to the space between the building and the container and the explosion happened when the hydrogen mixed with oxygen there.

http://af.reuters.com/article/energyOilNews/idAFTKZ00680620110312

[PJMcG]

"... Temperatures in the control room rose to higher than 100 Celsius (212 Fahrenheit), said Naoki Tsunoda, a company spokesman."

Had to be lost in translation.  Much above 125 to 135 F becomes uninhabitable after a few minutes.

This may be that to which the spokesman was referrring:

"- At 5:22am, the temperature of the suppression chamber exceeded
  100 degrees. As the reactor pressure suppression function was lost,
  at 5:22am, it was determined that a specific incident stipulated in
  article 15, clause 1 has occurred."