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1 meadows-rovat (mind)  114 sor     (cikkei)
2 Re: uran (mind)  41 sor     (cikkei)
3 Re: uran, ma mar inkabb plutonium (mind)  62 sor     (cikkei)

+ - meadows-rovat (mind) VÁLASZ  Feladó: (cikkei)


The place to watch for global warming -- the sensitive point, the canary
in the
coal mine -- is the Arctic.  If the planet as a whole warms by one
degree, the
poles will warm by about three degrees.  Which is just what is happening.

Ice now cover 15 percent less of the Arctic Ocean than it did 20 years
ago.  In
the 1950s that ice averaged 10 feet thick; now it's less than six feet
At the current rate of melting, in 50 years the northern ocean could be ice-fre
all summer long.

That, says an article in Science of January 19, would be the end of
polar bears. 
In fact many creatures of the Arctic Ocean are already in trouble.

Until recently no one knew that there were many creatures of the Arctic
In the 1970s a Russian biologist named Melnikov discovered 200 species
of tiny
organisms, algae and zooplankton, hanging around ice floes in immense numbers,
forming slime jungles on the bottoms of bergs and plankton clouds in
every break
of open water.  Their carcasses fall to the bottom to nourish clams,
which are
eaten by walruses.  Arctic cod live on algae scraped off the ice.  The
cod are
eaten by seabirds, whales, and seals.  The king of the food chain, hunting
mainly seals, is the great white bear.

That was the system until the ice started to thin.  In 1997 and 1998 Melnikov
returned to the Beaufort Sea and found most of the plankton species,
many named
by him (and for him), were gone.  The ice was nearly gone.  Creatures dependent
on the plankton (like the cod), or on the ice for dens (seals) or for travel
(bears) were gone too.

Many had just moved north, following the ice, but that means moving
farther from
land, with widening stretches of open water between.  Creatures like the black
guillemot, a bird that depends on land for shelter and the ice floe for food,
can no longer bridge the gap.

The Arctic is changing faster than scientists can document.  Inuit hunters
report that ivory gulls are disappearing; no one knows why.  Mosquitoes are
moving north, attacking murres, which will not move from their nests, so they
are literally sucked and stung to death.  Caribou can no longer count on thick
ice to support their island-hopping in search of the lichens that
sustain them. 
One biologist who spots caribou from the air says, "You sometimes see a caribou
trail heading across [the ice], then a little wormhole at the end with a bunch
of antlers sticking out."

Hudson's Bay polar bears are thinner and are producing fewer cubs.  With
the ice
going out earlier, their seal-hunting season is shrinking.  Hungry bears retrea
to land and ransack garbage dumps.  The town of Churchill in Canada has more
jail cells for bears than for people.  The bears are also weakened by toxic
chemicals that drift north from industrial society and accumulate in the Arctic
food chain.

Every five years the world's climatologists assess current knowledge about
global warming.  Their latest report was just released.  It erases any doubt
about where this warming is coming from and warns that we ain't seen nothing
yet.  If we keep spewing out greenhouse gases according to pattern, we
will see
three to ten times more warming over the 21st century than we saw over
the 20th.

Some biologists are saying the polar bear is doomed.

A friend of mine, in response to this news, did the only appropriate
thing.  She
burst out weeping.  "What am I going to tell my three-year-old?" she
Any of us still in contact with our hearts and souls should be sobbing
with her,
especially when we consider that the same toxins that are in the bears
are in
the three-year-old.  And that the three-year-old over her lifetime may witness
collapsing ecosystems, north to south, until all creatures are threatened,
especially top predators like polar bears and people.

Is there any way to end this column other than in gloom?  Can I give my friend,
you, myself any honest hope that our world will not fall apart?  Does
our only
possible future consist of watching the disappearance of the polar bear, the
whale, the tiger, the elephant, the redwood tree, the coral reef, while fearing
for the three-year-old?

Heck, I don't know.  There's only one thing I do know.  If we believe
that it's
effectively over, that we are fatally flawed, that the most greedy and
short-sighted among us will always be permitted to rule, that we can never
constrain our consumption and destruction, that each of us is too small and
helpless to do anything, that we should just give up and enjoy our SUVs while
they last, well, then yes, it's over.  That's the one way of believing and
behaving that gives us a guaranteed outcome.

Personally I don't believe that stuff at all.  I don't see myself or the people
around me as fatally flawed.  Everyone I know wants polar bears and
three-year-olds in our world.  We are not helpless and there is nothing wrong
with us except the strange belief that we are helpless and there's something
wrong with us.  All we need to do, for the bear and ourselves, is to stop
letting that belief paralyze our minds, hearts, and souls.

(Donella Meadows is an adjunct professor at Dartmouth College and
director of
the Sustainability Institute in Hartland, Vermont.  See www.sustainer.org)
+ - Re: uran (mind) VÁLASZ  Feladó: (cikkei)

Kedves Fidusz!

Te is ajanlottal egy web-site-ot a fenti temaban. Miutan a tema 
erdekel mar meg is neztem. Az elejet. Engedj meg nehany 
idezetet az elso nehany bekezdesbol.

>Egy átlagos 800 megawatt teljesítményő reaktor 25 ezer tonna 
>fűtőanyagot használ fel évente
Csak 3 nagysagrend tevedes.

>lövedékekkel, vagy azok részeivel való érintkezésből
>származó besugárzás elérheti a 2 mSv-t óránként.
Ennek nem szamoltam utana, de saccra - fuggetlenul attol, hogy 
mit nevezunk erintkezesnek meg reszeinek - legalabb ugyanannyi.

>Ilyen sugárzásnak kitéve egy személy fél óra alatt eléri az egy 
>éves maximális sugárzási dózist.

Igy is lehet fogalmazni. De azt is lehet mondani, hogy a 
termeszetes hatter sugarzas Magyarorszagon 2.8 mSv/ev, vagyis 
fel ora, annyit jelent, mintha egy ev alatt 17 honapot elne valaki, 
vagy pl. 2000 m magasan lakna (ez pl. Peruban siksagnak szamit) 
vagy az egy ev 12 honapjabol 3-4-et Bp. helyettt Keralaban toltene.

Kerdesem: olvassam tovabb?

Felreertes ne legyen! Nehogy barki is azt higye, hogy nekem 
tetszik ez az urantartalmu lovedek. De ebbol a radioaktiv sugarzas 
a legkevesbe artalmas. (Az egeszsegre nem veszelyes 
lovedekekben egyebkent sem hiszek.) Veszelyes, mert lovedek. 
Veszelyes, mert mergezo nehezfem (mint az olom, az on, a nikkel 
vagy meg sokan masok). Radioaktivitasa elhanyagolhato. Meg 
akkor is, ha valaki megeszi. Hallottatok mar arrol, hogy a 
szegenyitett urant sugarvedelmi falkent is alkalmazzak? Pedig igy 
Tisztaban vagyok avval, hogy sugarfobiat csak pszichologus tud 
gyogyitani, muszaki ember nem, de imadok a pusztaba kiabalni.

Gács Iván
+ - Re: uran, ma mar inkabb plutonium (mind) VÁLASZ  Feladó: (cikkei)

Kedves Kobor Joska es maganlevelben iro'k!

Mindnyajan a plutoniumot emlegetitek. Lenyegeben a kerdesek 
hasonlok, itt most azert Kobor Joska kerdeset idezem, mert az 
volt nyilvanos.

>Ja, es mit szoltok a plutoniumhoz ? Erre szeretnek valami 
>epkezlab magyarazatot kapni a nuklearis technologia 
>szakembereitol ! Eddig naiv nemtudomkakent azt hittem, hogy
>a szegenyitett uranium az elsodleges urandusitas egyik 
>vegtermeke, de ezek szerint reprocesszalasi-tovabbdusitasi 
>folyamatbol szarmazo anyagbol is keszult lovedek ! Miert ? En 
>ugy tudtam, hogy a keletkezo kiegett futoelemeknek csak 
>kevesebb mint 10 szazalekat reprocesszaljak. Miert
>eppen e tiz szazalek tovabbfeldolgozasabol szarmazo anyagbol 
>kellett lovedeket csinalni ? Ezt is ki kellett probalni ? Vajon hogy 
>megy ez a gyakorlatban ? Ez buli talan az amugy eleg nagy 
>anyagi gondokkal kuzdo nuklearis energetikanak ? 

Felek, hogy sejtem a megoldast (bar nem tudom, hogy a 
plutonium jelenletet csak felteteleztek, vagy bizonyitottak). 
Valoszinuleg a 10% reprocesszalasi arany jo. A polgari celu 
atomeromuvek uzemanyaganal. A katonai felugyelet alatt uzemelo 
reaktoroknal ez kozel 100%, hiszen azok celja - egyebkent 
egeszen mas reaktortechnikai jellemzok mellett - a plutonium 
termeles. Plutonium a termeszetben nincs, tehat csak reaktorbol - 
kiegett uzemanyagbol - szarmazhat (ha van). Tehat katonai 
reaktorokban alacsony kiegetesi szint mellett (akkor "kedvezo" a 
plutonium izotoposszetetele az atombombahoz) alig fogy az uran. 
Kezenfekvo tehat az ujrafeldolgozasa (ami a plutonium kinyeres 
miatt ugyis szukseges) utani uran ujradusitas. Nyilvan ennek a 
dusitoi hulladeka, szegenyitett uranja is valahol gyulik. A 
lovedekeket a hadiipar kesziti. Gondoljatok, hogy a hadiipar "az 
amugy eleg nagy anyagi gondokkal kuzdo nuklearis 
energetikanak" akar segiteni? Lehet, hogy messzirol nezve a 
nuklearis hadiipar es a nuklearis energetika kozeli rokonoknak 
latszik (mint pl. a Siriusrol a Fold es a Mars), de innen az 
energetikabol vajmi keves kapcsolatot latok az energetika es Mars 
isten kozott.
Hive vagyok az atomeromuveknek, de a fegyvergyartasnak nem. 
Akar tartalmaz urant, akar nem. A valodi (primer) szegenyitett uran 
felhasznalasat elsosorban haditechnikai ertelemben vett 
hatekonysaga miatt nem latom jonak, nem pedig radioaktivitasa 
miatt. De ha igaz, hogy reaktort megjart, plutoniumot is (akarcsak 
nyomokban is) tartalmazo anyagot hasznaltak fel, azt meg sokkal 
nagyobb disznosagnak tartom. Ebben - azt hiszem - 
Amiben nem ertek egyet, az foleg az, hogy a nuklearis energetika 
anyagi gondokkal kuzd. Valodi anyagi gondokra gondolok. Allami 
beavatkozassal mindig lehet gondot krealni. Most pl. azert kellett 
levaltani a Paksi Atomeromu vezerigazgatojat, mert az atomeromu 
nyeresege 2000-ben a harmadara csokkent. A villamosenergia 
atveteli arat jogszabalyok hatarozzak meg. Ez az atomeromu 
eseten tavaly valahol 5.5 es 6 Ft/kWh kozott volt, a magyar 
rendszer atlagaban 8 es 10 kozott. Paks 14 milliard kWh 
vill.energiat termel evente. 10 filler/kWh arcsokkantes kozel 1.5 
milliard Ft/ev bevetel csokkenest eredmenyez. A nyereseg tavalyi 
csokkenese kb. 3 md Ft volt, durvan 20 f/kWh. Vagyis rendeleti 
uton lehet valsagot csinalni, de ez nem az atomeromu 
atomeromusegebol ered.
Gács Iván