Car generator to power house

[clare]

It reads the TRACTION battery voltage for the restart. The 12 volt battery is NOT the traction battery.

[dpb]

I know the accident precursors and sequences of events pretty well. Well enough to know both the minimal similarities and, more importantly, the differences.

The point is the designs and root causes are so different as to make the incidents of only marginal use to compare. Chernobyl is fundamentally so far removed from the other two as to be completely useless for any comparison whatsoever as to any LWR accident as, again, the causative reason for the dispersion of fission products was the graphite fire plume and no containment.

That the other two were LOCAs in a sense is true but of little consequence other than to demonstrate that the safety systems did, in fact, despite operator intervention and error, succeed in mitigating the consequences to no more than equipment damage with no offsite consequences of significance.

--

[trader4]

Help me out here. How exactly then does the 12V battery get recharged? One would think it would be tied into and be recharged via the main battery. It would seem pretty stupid to have a design where the 12 volt battery could be exhausted and not recharged from the main battery. Also, if this 12V battery is used to start the car, then not recharging it via the main battery could leave you stranded with a car that won't start, but has a fully charged huge main battery battery. That doesn't seem right.

[hallerb]

well despite your protests TMI came very close to breaching the containment, which would of created a chernobyl.

containment was key, but isnt 100% in a true melt down.

curious if a reactor around new york somehow failed creating a chernobyl like situation, what effect would that have to our economy?

how about more cancers?

is it worth the risk?

[ransley]

e:

It does auto restart when key is set to on, and everything is recharged when low but the traction battery triggers the motor, then it shuts off by itself. I bet the motor starter battery is never let to go below 12.8 when running and charges to about 13.3, just as your car does it. The 12v lead acid only starts the little 4 cil motor. Its my logical guess and I bet its right.

[ransley]

te:

If you put a load on the 12v lead battery with car off the traction battery keeps it charged till the traction battery needs charging.

[dpb]

Despite _your_ protestations, TMI didn't "come very close" to breaching containment. There has been a lot written by folks of "what if" and rash conjectures, but facts of the actual scenario aren't so. Once the relieving shift arrived and restarted the RCPs the plant was on the way to situation recovery.

And, for the last time, the differences in design between Chernobyl (and the lack of _any_ containment) mean that there is not a physical process that could cause a "chernobyl-like" situation from a LWR. Finis. Over. Done. Can't happen w/o the requisite ingredients. Requisite ingredients don't exist elsewhere. Believe it. It's so.

--

[dpb]

On Dec 30, 8:46 am, dpb wrote: ...

To clarify, there was a significant concern _during_ the accident with many postulated problems and scenarios. The "H bubble" is just one example, but analysis showed that there was insufficient free oxygen inside the reactor vessel for ignition so the fear of rupture owing to an H explosion was misplaced.

Similarly, evaluation showed that while there was significant fuel melt, there was from the "Report to the President" -- "e. There is no indication that any core material made contact with the steel pressure vessel at a temperature above the melting point of steel (2,800=B0F)."

Subsequent analysis and evaluation showed similar conclusions of actual conditions as compared to the rampant speculation and fears raised during the accident itself.

In fact, as noted previously, the most interesting conclusion from the report is really also the most important. That is --

"2. Equipment failures initiated the events of March 28 and contributed to the failure of operating personnel (operators, engineers, and supervisors) to recognize the actual conditions of the plant. ... These operating personnel made some improper decisions, took some improper actions, and failed to take some correct actions, causing what should have been a minor incident to develop into the TMI-2 accident."

In a nutshell, if the operators had done nothing but let the automated safety systems function (which they did until operator intervention throttled back/shutdown HPI pumps), there would have been nothing but a relatively short outage to repair the PORV and the plant would have been back in operation.

In hindsight, that the accident did occur did provide several benefits as well as the discomfort of the utility and the general effect on public perception (which was going south anyway, but TMI certainly made a major contribution).

These benefits include

1. Improvement in procedures and training as well as design and modifications to better respond
2. An full-scale experimental verification of the effectiveness of safety systems to mitigate catastrophic failure in spite of serious operator error, and
3. The test data that would otherwise never have been available for verification and improvement of reactor safety design models to an extent otherwise only possible via theoretical work.

Overall, these will contribute significantly (and already have via the aforementioned modifications and procedure and training upgrades) to the enhanced operational safety and reliability of commercial nuclear power throughout the world, not just the US.

--

[dpb]

...

I had presumed you were previously talking about Fermi I, but with your insistence on repeating cooling _water_, I gather you must have intended Toledo instead of Detroit and been talking about Davis- Besse. I had noted the substantial differences owing to the fact that Fermi I was a LMFBR, not a LWR so the situation is much different.

If, instead, you did mean Davis-Besse, yes, that (as well as an incident at Rancho Seco) was a case that was, indeed, similar precursor to TMI-II where the PORV lifted and didn't reseat. What both of those instances showed, again, however, was that the safety systems operated as designed and intended.

There were subsequently modifications made to the PORV on all similar plants to a) mitigate the tendency of the PORVs to not reseat, and b) provide firm indication to operators of position

--

[hallerb]

wasnt bessie reactor permanetly damaged and shut down, when nearly brand new?

has there ever been a decominshing and clean up of a commercial reatcor in the US? other than the first US plant in shippingport pa?

other plants have been closed but none have been deconstructed, too hazardous costs too much........

heres a good question?:)

the cost per killowatt hour of nuke generated power never includes the real cost of long term core disposal costs..... why is that?

have you seen the national geographic show aftermath population zero?

very interesting about the used core storage pools, and what happens to these non hardened buildings if cooling water fails

[dpb]

On Dec 30, 2:44 pm, " [e-mail]" wrote: ...

No. It's still operating (a quick check showed it's at 98% capacity at the moment)

We went thru this a month ago as well--I'm not rehashing split milk.

Mostly for the reasons previously outlined -- we have a currently mandated waste policy that operating utilities and other vendors/ suppliers must abide by. There's no alternative currently legally allowed.

a) Never heard of it.

b) Again, no credible massive scenario and if concerned then looking to get Yucca Mountain operational and the pool contents shipped thereto asap should be your primary goal.

--

[dpb]

On Dec 30, 2:57 pm, dpb wrote: ...

Re: Davis-Besse

...

BTW, NRC collects plant operational data every morning between 4 and

8AM EST from all 102 operating reactors.

For these unreliable plants you're so negative about, the data this morning show:

NRC # Reactors Average Reported Power Region in Region Status 12/30/08

1 26 99.8 2 33 100 3 23 96.0(1) 24 92.2 4 20 99.9(1) 21 95.1 Totals 102 99.0(1) 104 97.1

(1) Excluding plants in outage

Not too shabby...

--

[makolber]

Well that is kind of the point....., You can't really anticipate all the unexpected things that can happen....

Mark

[clare]

So the 12 volt battery is charged by a dc-dc converter? That WOULD make a difference.

[clare]

The 12 volt battery does not start the engine. If they are using a dc-dc converter they hardly need a 12 volt battery. Sure don't need a large one.

The iDc converter portion of the inverter drive pack is apparently good for a maximum of 100 amps so the battery "protects" the converter if a short power surge of over 100 amps is required

[clare]

I did more sesearch.

There is NO 12 volt alternator charging system. There is a DC converter that runs off the traction battery to supply the 12 volt loads (and charge the somewhat redundant 12 volt battery). The engine starts of the high voltage traction pack, ( there is NO starter motor) and it is only allowed to drop either 40% or to 40% charge (information is contradictory) so the vehicle always has enough powe to restart. The 12 volt conveerter does not run unless the "ignition" is turned on - so the 12 volt battery is required to operate interior lights etc when the "key" is turned off.

It would be impossible to run a larger inverter off the 12 volt battery than the 1000 VA unit he apparently was using.

[dpb]

Well, not really. Certainly another way to consider is that LOCAs _were_ anticipated and included in the design criteria for safety systems--all that was needed really was to let the system do its job. It was the intervention that caused the size of the problem.

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[dpb]

That was Fermi I. It wasn't a _water_ deflector, Fermi I was an LMFBR (as I said earlier). The coolant was liquid sodium.

--

[dpb]

...

It would be somewhat futile to collect operating data on non-operating reactors wouldn't it, particularly when the list is titled "Operational Data"?

But, even if it were, the overall system availability this morning would still have been >96%.

How would that compare for the total installed solar or wind capacity today you suppose? :)

--

[hallerb]

so how many plants worldwide have failed and been shut down permanetly?