How Can Nuclear Plants Improve Emergency Core Cooling Systems?

In summary: One might wish to review the requirements for the HPSI/LPSI systems."Yes, there are requirements for the pumps (particularly for the capacity and seismic qualification).
  • #36
nikkkom said:
Granted, *I* did not know this before Fukushima, but I don't live in Japan.

Well you made me think with that one.
I didn't know it either.
And i never considered that somebody living there might be better aware of local natural history than i.

[PLAIN said:
http://carnegieendowment.org/files/fukushima.pdf][/PLAIN]
First, there appears to have been insufficient attention given by TEPCO and
NISA to historical evidence of large earthquakes and tsunamis. Best practice, as
promulgated by the IAEA, requires the collection of data on prehistorical and
historical earthquakes and tsunamis in the region of a nuclear power plant in
order to protect the plant against rare extreme seismic events that may occur
only once every ten thousand years.
36
Historical data was used in assessing plant
safety. The original design-basis tsunami for Fukushima Daiichi of 3.1 meters
was chosen because a 1960 earthquake off the coast of Chile created a tsunami
of that height on the Fukushima coast.
37
However, greater attention should have
been paid to evidence from further back in history. Over the last decade or so,

12
|
Why Fukushima Was Preventable

Historical data was used in assessing plant
safety. The original design-basis tsunami for Fukushima Daiichi of 3.1 meters
was chosen because a 1960 earthquake off the coast of Chile created a tsunami
of that height on the Fukushima coast. 37 However, greater attention should have
been paid to evidence from further back in history. Over the last decade or so,
evidence of much larger tsunamis in and around Miyagi has emerged. Japanese
researchers have discovered layers of sediment that appear to have been depos-
ited by tsunamis and have concluded that the region had been inundated by
massive tsunamis about once every one thousand years. 38
They have attributed
the most recent of these events—in 869 AD—to a magnitude 8.3 earthquake.
More generally, given the historical record of tsunamis in Japan, TEPCO and
NISA should have been much more conservative in defining the design-basis
tsunami. For instance, one compilation of historical tsunamis in and around
Japan lists twelve events since 1498 having a maximum amplitude of more than
10 meters, six of which had a maximum amplitude of over 20 meters. 39

Of course, such “red flags” are much easier to spot with the benefit of hind-
sight than they are ahead of a disaster. The challenge of sifting through and
evaluating the stream of potentially relevant geophysical studies to extract
data important to nuclear power plant safety should not be underestimated.
Perhaps not surprisingly, there has been a fairly bitter debate within Japan
about whether academia did not provide suitable warnings or whether it did
and industry and regulators ignored them.
Nonetheless, Japan has a historical
legacy of severe tsunamis; it does appear that heeding this record, especially
as it relates to the area around the plant, would have led to an upward revision
of the design basis
for Fukushima Daiichi Nuclear Power Station and perhaps
consequently to infrastructural improvements to better defend the installation.

As i said, such things are debated within the bureaucracy by endless memos ( See Parkinson's "Law of Delay", chapter "The Paper Blob").
You blame the executives, i blame the bureaucrats.

I say "to-may-to", you say "to-mah-to" ? :)

old jim
 
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  • #38
gmax137 said:
Where did you get that idea? I don't know what the long-term contract cost of a MW-hr is but I would guess that $30 is about right. At 9 million MW-hr per year, and say $30 per MW-hr the revenue is one-quarter of that.

So the four-unit station makes about one billion $.

Regarding revenue-versus-profit:

IIRC for nuclear stations, fuel and maintenance are relatively small fraction (10-20%) of their revenue - the biggest expenses are in initial planning and construction stages. Please correct me if I'm wrong.
 
  • #39
Interest is a lot of that cost.

Way back when, my old plant that cost only $120 million to build could produce power for two-ish cents a KWH , half what a billion dollar plant of similar capacity could do just a few years later .
Back then a kwh was only a nickel retail .
By contrast - my Father-in-law's refractory plant in Niagara Falls was buying that wonderful hydro power for 1/10 cent per kwh, around half our nuclear fuel cost at the time.
Nothing beats hydro. Its advantage over wind is it's concentrated.
US side of Niagara Falls is about 2.4 gigawatts . see http://www.nypa.gov/facilities/niagara.htm
That's equivalent to thousands of windmills and it's way more reliable. Cost per kw to build wind is , well, beyond reason IMHO. The industry exists because of tax credits.
But , every KWH that's made by a windmill is one pound of coal that doesn't have to be dug out of the ground. (For a realistic peek into a coal mine see movie "October Sky" * .In mid 70's when the low grade fuel oil that our fossil plants burned went from $4 to $12 a barrel the fuel cost differential suddenly became substantial. .
Energy companies then got into the uranium business. We had some Exxon fuel assemblies.
[PLAIN said:
http://www.nytimes.com/1986/12/24/business/company-news-exxon-plans-sale-of-nuclear-unit.html]Exxon[/PLAIN] Nuclear, founded by the world's largest oil company in 1969, designs, manufactures and markets pressurized and boiling-water reactor fuels and provides related services for electric utilities.
At today's oil prices we can thank the Lord for natural gas. It burns a lot cleaner, too. Much as i dislike coal fuel I'd hate to see it go away - we just don't have a viable replacement for it. Just the electricity to heat a hundred million twenty gallon hot showers in the morning amounts to miles of coal cars... i once calculated how many but have since forgot. Try it - 100 tons of coal in a car, 10,000 BTU's per pound of coal, 40% efficient power plant, shower water gets40 degree rise ...Nuke fuel will continue be priced just enough below fossil to keep both viable.
http://www.world-nuclear-news.org/ee-double_nuclear_by_2040_says_exxon-1309138.html
Exxon Mobil's figures spurred a lively and wide-ranging debate amongst Khemakhem's fellow speakers in a panel discussion on energy and nuclear power. Ron Cameron, head of nuclear development at the OECD Nuclear Energy Agency (NEA), led a call for greater transparency over prices across the energy sector. Growth in renewables of the scale seen in recent years had been made possible through subsidies, but the way subsidies had been handled in some countries had been an "economic disaster", he said. Consumers were effectively being asked to pay for the transition into renewables, he said, pleading for the hidden costs of renewables to be made clear, with no disconnect between wholesale cost of electricity and the price. "Affordability is an issue," he remarked.

Nuclear should be seen as complementary to rather than in competition with renewables, the panellists felt. Nuclear could play a vital role in providing affordable baseload power to support the intermittent nature of many renewables,

Sorry - i got off topic.

old jim

* re October Sky - The movie is interesting, suitable for kids., Chris Cooper and Laura Dern deliver their usual great performances, and best of all it shows up in Walmart's $5 pile.

Coal railcar metrics here http://www.bnsf.com/customers/equipment/coal-cars/
 
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  • #40
jim hardy said:
Interest is a lot of that cost.

Way back when, my old plant that cost only $120 million to build could produce power for two-ish cents a KWH , half what a billion dollar plant of similar capacity could do just a few years later .
Well the topic moved to another dimension but I too have my point of view about this. Soon after F-D accident we heard term like "stress test" and most plants spared a group of their manpower for strengthening some post Fukushima weaknesses in their plants. I found most of their recommendations something like "last deperate efforts after some unforeseen accident" (maybe these peoples have refined now...). Do some other person too feel like this? or these things are helpful?
 
  • #41
Muti said:
Well the topic moved to another dimension but I too have my point of view about this. Soon after F-D accident we heard term like "stress test" and most plants spared a group of their manpower for strengthening some post Fukushima weaknesses in their plants. I found most of their recommendations something like "last deperate efforts after some unforeseen accident" (maybe these peoples have refined now...). Do some other person too feel like this? or these things are helpful?
NPPs have routine testing procedures. Following an event like the failure at FD, testing may be revised, and "stress tests" may be devised to discover deficiencies in the design or operation. Severe accident mitigation guidelines may be found to be satisfactory, or maybe found to be deficient. Ostensibly, deficiencies are corrected through new infrastructure and/or operating procedures.

Clearly, FD was not prepared for the magnitude of the tsunami that took out the emergency equipment (DGs and buses). In fact, much of the coastline was not prepared based on the videos of whole villages and towns being overwhelmed. Very little of the coastline was protected, but clearly some places were. It's certainly tragic the FD was not better protected.
 
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