Can grinding and mixing nuclear waste solve the problem?

[Atomos]

This may seem extremely stupid, but what if we did the following:

1. Grinded up nuclear waste.

2. Mixed it with tonnes and tonnes of radio-inactive earth.

3. Put it back where we mined the uranium in the first place.

I understand that most of nuclear waste is just uranium, the remainder is more active radioactive isotopes like cesium and iodine.

So how would the area be any more radioactive than before the uranium ore was mined, especially after the more active elements had decayed to reasonable levels?

A problem I see is the chemical toxicity/affects, not related to radiation, of some of the compounds/elements within the spent fuel.

 

[Astronuc]

Spent fuel is more than just uranium and isotopes of Cs and I.

There is a spectrum of radionuclides, many of which are short-lived, which decay in hours, days, weeks, months, years. Every 10 half-lives, the specific activity decreases by 3 orders of magnitude (~1000, or actually a factor of 2¹⁰=1024). So in 30 half-lives, the activity has decreased by a factor of 1 billion, which great for most isotopes.

However, there are a few isotops that have half-lives of 100's or 1000's of years. Those must be kept immobile for millenia or 10's of millenia, and hence the challenge.

Then consider the matter of groundwater penetration, dissolution and consequent transport.

If one were to grind the waste - then one would likely have to calcine and vitrify it, i.e. convert it to a relatively impermeable state, and then surround it with something entirely inert.

The French do this with the waste from the reprocessing plant, i.e. after they remove the uranium, plutonium and most of the transuranics beyond Pu, in order to reuse/recycle the U, Pu and TU.

 

[Morbius]

T
I understand that most of nuclear waste is just uranium, the remainder is more active radioactive isotopes like cesium and iodine.

Atomos,

Yes - the largest percentage component of nuclear waste is the U-238 that was also the
largest component of the fresh fuel.

As Astronuc points out; there's more than just Cesium and Iodine in the nuclear waste;
there's a whole spectrum of nuclides.

However, they do fall into two classes; fission products and transuranics [actinides].

The transuranics [actinide] are those that are heavier than Uranium. Some also have long
half-lives; like Pu-239 with a half-life of 24,000 years. However, these materials can
also be used as fuel. They should be recycled back to the reactors as fuel. The USA
is also considering building "actinide burner" reactors, fast reactors that are particularly
adept at transmuting actinides to shorter lived nuclides.

The other class are fission products. They have short half-lives, so they are very
radioactive at first. However, that radioactivity dies down more quickly than the
actinides. In a relatively short time, these nuclides decay to activities that are
less than the original uranium that was dug up. You don't need to dilute them;
just wait long enough.

Nuclear waste disposal isn't so much a technical problem as it is a political problem in
the USA. There have been plans for nuclear waste disposal for as long as the USA has
had nuclear reactors.

It's just portrayed in the popular press as this overarching technical problem that nobody
knows how to solve. The problem is basically a political one - not a technical one.

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

Nuclear waste disposal isn't so much a technical problem as it is a political problem in the USA. There have been plans for nuclear waste disposal for as long as the USA has had nuclear reactors.

It's just portrayed in the popular press as this overarching technical problem that nobody knows how to solve. The problem is basically a political one - not a technical one.

While there is no doubt a large political problem, there are technical problems as well. For example, the metal containers for the radioactive material break down over time due to the presence of corrosive elements in the waste.

My own view is that it is a terrible waste to dispose of material that is in limited supply and which contains a huge amount of potentially useable energy (when the nuclear technology is developed to use it safely and securely). Just store it for another 60 years. Then we will be mining the waste instead of opening new low-grade uranium mines and dumping thousands of tonnes of chemically processed tailings in huge tailings pits.

AM

 

[Morbius]

While there is no doubt a large political problem, there are technical problems as well. For example, the metal containers for the radioactive material break down over time due to the presence of corrosive elements in the waste.

Andrew,

I'm afraid that's INCORRECT! This issue has been studied extensively and modeled
via computers and extensive accelerated laboratory testing:

http://www.llnl.gov/str/Glassley.html

http://www-cmls.llnl.gov/?url=science_and_technology-materials-yucca_mountain


The tests also have shown that the canister metals have extremely high resistance to all forms
of localized corrosion and stress corrosion cracking in environments relevant to the repository.
Also, no appreciable differences have been noted in corrosion rates obtained from the various
water compositions and temperatures. The testing results support Livermore’s models for
long-term prediction of the waste packages’ performance and strongly confirm the selection of
Alloy 22 for the outer canister.


Scientists at LLNL and other national labs involved in the Yucca Mountain Project
reported to then Secretary of Energy Bill Richardson that the development of the
Yucca Mountain project should proceed.

Corrosion of the metal containers is not expected untll LONG after the radioactivity
of the waste has decayed below levels at which the uranium ore was originally dug
from the ground, if the USA were to reprocess / recycle nuclear waste. The waste
containers now are being developed with lifetimes of over 10,000 years. If the USA
were to recylce / reprocess nuclear waste; such that only the fission products needed
to be buried; those decay to radioactivity levels lower than the original uranium in only
a few hundered years - NOT the 10,000. So the current 10,000 year metal containers
provide a very significant safety margin.

Additionally, the waste is locked in a matrix of borosilicate glass; the metal container is
just an additional layer of defense against migration of the waste; not the only defense.

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

Corrosion of the metal containers is not expected untll LONG after the radioactivity of the waste has decayed below levels at which the uranium ore was originally dug from the ground, if the USA were to reprocess / recycle nuclear waste. The waste containers now are being developed with lifetimes of over 10,000 years. If the USA were to recylce / reprocess nuclear waste; such that only the fission products needed to be buried; those decay to radioactivity levels lower than the original uranium in only a few hundered years - NOT the 10,000. So the current 10,000 year metal containers provide a very significant safety margin.

I agree that if the waste is first reprocessed to remove fission products and plutonium, there would be no problem at all. But that is not currently the plan. Unless the plutonium and higher actinides are removed, I think that the waste has to be stored for much longer than 10,000 years (Pu having a half life of 24000 years).

AM

 

[Morbius]

I agree that if the waste is first reprocessed to remove fission products and plutonium, there would be no problem at all. But that is not currently the plan. Unless the plutonium and higher actinides are removed, I think that the waste has to be stored for much longer than 10,000 years (Pu having a half life of 24000 years).

Andrew,

Even if the USA doesn't change its plans on reprocessing; the latest results on
accelerated corrosion tests show that these alloys will be fine for storage of even
long-lived actinides like Pu-239:

http://www.ocrwm.doe.gov/science/pdf/45088.pdf


"Based upon measurements of corrosion rates of passive metals, the waste
packages remain intact with no penetrations due to corrosion for durations of
10,000's and even 100,000's of years."


Dr. Gregory Greenman
Physicist

 

[Art]

I agree that if the waste is first reprocessed to remove fission products and plutonium, there would be no problem at all. But that is not currently the plan. Unless the plutonium and higher actinides are removed, I think that the waste has to be stored for much longer than 10,000 years (Pu having a half life of 24000 years).

AM

Reprocessing creates it's own problems in the shape of huge amounts of low level radioactive waste. France and Britain who took on reprocessing to get plutonium to build bombs dump most of the LLW their process generates into the sea.

Personally before any more reprocessing plants are built I'd like to see responsible proposals for how LLW is going to be managed and using the sea as a giant dustbin doesn't come under the heading of responsible.

 

[theCandyman]

Well, if the U.S. is looking into Yucca Mountain for spent fuel, I can't see why we'd need to find another place for low level waste.

I heard from one of my professors that at current rates, Yucca Mountain would last 30 years before being filled up. If we reprocess the waste, it would last 300 years.

 

[Art]

Well, if the U.S. is looking into Yucca Mountain for spent fuel, I can't see why we'd need to find another place for low level waste.

I heard from one of my professors that at current rates, Yucca Mountain would last 30 years before being filled up. If we reprocess the waste, it would last 300 years.

Reprocessing generates far more radioactive waste than it eliminates.

The actual figures for LLW produced through reprocessing and the LLW produced through the once through cycle are ~8,000 m3/GWe-yr (cubic meters per Gigawatt electricity-year) of low level waste for reprocessing compared with ~500 m3/GWe-yr LLW produced through the once through cycle.

It is a complete fallacy that reprocessing eliminates waste. The reality is it does the complete opposite!
http://www.ieer.org/sdafiles/vol_8/8-3/waste2.html

On a related topic people seem to get hung up on materials such as plutonium which have very long half-lives but the real danger to people comes from radioactive material with half lives comparable to human lifespans. The reason plutonium has such a long half-life is because it isn't very radioactive and so not very deadly. Picking up a block of plutonium will do you no harm at all whereas materials such as C-60 have much shorter half-lives (a little over 5 years) but are correspondingly far more deadly. Close exposure to 1 gram of C-60 for a few minutes is enough to kill you.

However if it is the long half life elements that concern you then you only need to look at some of the waste these plants are pumping into the ocean such as I-129 with a half life of 16 milllion years! And instead of the discharge of this element decreasing over time with better technology and filtraton systems in the case of Sellafield it has actually increased 10 fold since 1970.

The deposition of plutonium within 20 km of Sellafield attributable to aerial emissions has been estimated at 160-280 GBq (billion becquerels), that is two or three times plutonium fallout from all atmospheric nuclear weapons testing. In addition, significant quantities of radionuclides can become airborne in sea spray and be transported inland by the wind. The average activity due to actinides from the sea may occasionally exceed the international limit of 1 mBq/m 3 .

It has been estimated that over 40,000 TBq (trillion becquerels) of caesium-137, 113,000 TBq of beta emitters and 1,600 TBq of alpha emitters have been discharged into the Irish Sea since the inception of reprocessing at Sellafield. This means that between 250 and 500 kilograms of plutonium from Sellafield is now adsorbed on sediments on the bed of the Irish Sea. The migration of undersea deposits of actinides to coastal environments represents a long-term hazard of largely unknown proportions.

Technetium-99 (half-life 214,000 years) discharges have led to particular concern. In 1997, technetium concentrations in crustacean - particularly in lobster - reached 13 times the European Council Food Intervention Level (CFIL) in the vicinity of Sellafield. Some technetium concentrations above CFIL limits have also been found in molluscs (winkles, mussels, limpets and whelks). Recent environmental surveys along the Norwegian coast indicate a six-fold increase in technetium concentrations in seaweed since 1996. Concentration factors are greater than 1,000 for some biota such as macrophytic brown algae, worms and lobsters and are particularly high for some seaweeds (around 100,000). In 1999, a number of high concentrations of various radionuclides were also recorded in fish, shellfish, sediments and aquatic plants, some exceeding CFILs several times. Large uncertainties remain in the field of transfer of technetium in the biosphere.

http://www.n-base.org.uk/public/report_links/toxic_effects.html

America made a very sensible decision when it decided not to go down the reprocessing route.

 

[Morbius]

Reprocessing generates far more radioactive waste than it eliminates...
It is a complete fallacy that reprocessing eliminates waste. The reality is it does the complete opposite!

Art,

I'm afraid this is 100% WRONG!

Reprocessing is a chemical separation; so it CAN'T create any additional
radioactivity.

About 94% of the nuclear waste is U-238 that has not undergone any type of neutron
capture and transmutation.

This U-238 is no more radioactive than the day it was dug out of the ground.

Reprocessing nuclear waste REDUCES the amount of material to be disposed of.
It takes material out of the waste stream that DOES NOT need to be treated as
high level waste.

The anti-nuclear crowd has been propagating the MYTH that reprocessing increases
the amount of waste for a long time. Unfortunately, you fell for it.

Dr. Gregory Greenman
Physicist

 

[theCandyman]

That site seems like anti-nuclear propoganda effort. Also, I tend not to trust sources that cite economic benefits/problems as the first case against reprocessing. How can they call themselves enviromentalists if they're worried about the economy? One or the other in my opnion.

I wonder what makes up that 7956 cubic meters of "liquid discharges" that they say in included in the figure. Maybe something like water?

 

[Morbius]

That site seems like anti-nuclear propoganda effort.

Candyman,

EXACTLY!

In any case, it CAN'T BE MORE - haven't the IDIOT anti-nukes ever heard of the
conservation of mass?

As I stated in my response to Art; a chemical process like reprocessing can't make
ANY additional radioactivity; ONLY the reactor can do that.

The IDIOT anti-nukes are evidently counting the U-238 as LLW [ low level waste ]. The
U-238 IS mildly radioactive due to its half-life of 4.5 Billion years. However, the
radioactivity of the U-238 has NOTHING to do with the operation of the reactor.

The untransmuted U-238 was slightly radioactive when it was dug out of the ground, and
slightly radioactive when it went into the reactor, and slightly radioactive when it came out
of the reactor.

However, the untransmuted U-238 is no more radioactive than when it was dug out of the
ground - so nobody should be upset if you just PUT IT BACK the way you FOUND IT!

It's just another example of the lack of scruples of the anti-nukes; specious arguments
like this abound from them. However, a well-informed public that is well-versed in the
sciences, a service that this forum provides; will not be gullible enough to fall for it.

Dr. Gregory Greenman
Physicist

 

[Art]

Art,

I'm afraid this is 100% WRONG!

Reprocessing is a chemical separation; so it CAN'T create any additional
radioactivity.

About 94% of the nuclear waste is U-238 that has not undergone any type of neutron
capture and transmutation.

This U-238 is no more radioactive than the day it was dug out of the ground.

Reprocessing nuclear waste REDUCES the amount of material to be disposed of.
It takes material out of the waste stream that DOES NOT need to be treated as
high level waste.

The anti-nuclear crowd has been propagating the MYTH that reprocessing increases
the amount of waste for a long time. Unfortunately, you fell for it.

Dr. Gregory Greenman
Physicist

Morbius it is you who are WRONG!

The post I responded to was in relation to the VOLUME of radioactive material and as my post clearly shows the data I provided was in relation to the VOLUME of radioactive waste!

 

[Art]

Candyman,

EXACTLY!

In any case, it CAN'T BE MORE - haven't the IDIOT anti-nukes ever heard of the
conservation of mass?

As I stated in my response to Art; a chemical process like reprocessing can't make
ANY additional radioactivity; ONLY the reactor can do that.

The IDIOT anti-nukes are evidently counting the U-238 as LLW [ low level waste ]. The
U-238 IS mildly radioactive due to its half-life of 4.5 Billion years. However, the
radioactivity of the U-238 has NOTHING to do with the operation of the reactor.

The untransmuted U-238 was slightly radioactive when it was dug out of the ground, and
slightly radioactive when it went into the reactor, and slightly radioactive when it came out
of the reactor.

However, the untransmuted U-238 is no more radioactive than when it was dug out of the
ground - so nobody should be upset if you just PUT IT BACK the way you FOUND IT!

It's just another example of the lack of scruples of the anti-nukes; specious arguments
like this abound from them. However, a well-informed public that is well-versed in the
sciences, a service that this forum provides; will not be gullible enough to fall for it.

Dr. Gregory Greenman
Physicist

Are you being serious re the part I bolded?? Are you seriously suggesting U-238 ore is not dangerous to health. As someone who works in the industry you have to be aware that a study in 1980 showed that 50%! Yes, that's right! 1 in every 2 miners who had dug out uranium ore for America's nuclear program in the 50s and 60s died of lung cancer.

 

[Art]

That site seems like anti-nuclear propoganda effort. Also, I tend not to trust sources that cite economic benefits/problems as the first case against reprocessing. How can they call themselves enviromentalists if they're worried about the economy? One or the other in my opnion.

I wonder what makes up that 7956 cubic meters of "liquid discharges" that they say in included in the figure. Maybe something like water?

Did you look at the title of the second source I provided? It's a report commissioned by the European Parliament!

Here's a further extract from the same report showing the practical implications of Sellafields dumping policy;

Conclusions on Radionuclide Concentrations in the Sellafield Environment

Marine discharges at Sellafield have led to significant concentrations of radionuclides in foodstuffs, sediments and biota. Discharges lead to current concentrations in some foodstuffs, which exceed European Community Food Intervention Levels (CFILs). The transfer of technetium to the biosphere is of particular concern, because of its long half-life (214,000 years), its mobility in seawater and the high concentration factors in plants. Large uncertainties remain as to the transfer mechanisms and environmental fates of many radionuclides.

During the 1970s and 1980s, peak doses to critical groups in the Sellafield region possibly reached 2.5 to 3.0 mSv per year (as compared to a dose constraint of 0.3 mSv in the UK and 1 mSv in the EU). Latterly, doses to marine-related critical groups have declined to about 0.2 mSv per year.

A recent study commissioned by the German Federal Office for Radiation Protection, using German statutory dose assessment assumptions, calculated that annual doses from consumption of contaminated foodstuffs were more than 5 times the annual limit imposed by the European legislation and about 20 times the annual dose constraint used in the UK and Germany.

Most of the dose was received via the technetium contaminated seaweed fertiliser/animal feed/meat consumption pathway. The conclusion of the German study was that the Sellafield reprocessing facilities would not be "licensable" in Germany. European legislation does not prescribe specific assumptions in dose assessment models. The European Commission has responded that "the guidance currently being produced on realistic dose assessments will comment on this issue."

And as regards risk to humans

Conclusions on Doses Induced by Sellafield Discharges

Discharges to the Sellafield marine environment have led in the past to doses to critical groups exceeding 10 times current UK and 3 times EU limits. The doses calculated by the UK administration from current environmental radionuclide concentrations reach respectively 2/3 and 1/5 of the UK and EU limits. These doses remain problematic, considering that doses from past discharges and from direct radiation are not included. Doses calculated under German statutory dose assessment assumptions exceed UK and EU dose constraints. In addition, German dose limits for organs (also used in the US but not in the rest of the EU) would also be exceeded by the ingestion of relatively small quantities of seafood from Sellafield. The Sellafield reprocessing plants would not be licensable in Germany. Also very large uncertainties in dose estimates remain, with differences between 5th and 95th percentiles often exceeding several orders of magnitude. This raises the question of whether "realistic" assessments should be used rather than "conservative" dose assessments.

The risk potential of certain hazards at Sellafield is very large. Liquid high level wastes currently stored at Sellafield contains about 7 million TBq (2,100 kg) of caesium-137, which is about 80 times the amount released through the 1986 Chernobyl accident. Assuming a 50 percent release of caesium-137 in an accident at Sellafield, population dose commitment would range up to tens of millions of person-Sv resulting in over a million fatal cancer cases.

Is this an acceptable risk to you?

And if I apear to be a little ticked off over Sellafield it's because I live in Ireland and the British were kind enough to build their reprocessing plant on their east coast so that in the event of an accident the prevailing winds would blow the contamination over to us as happened in 1957. Plus of course we can't / won't eat sea food from the irish Sea as it is so heavily polluted with radiation.

 

[Morbius]

Morbius it is you who are WRONG!

The post I responded to was in relation to the VOLUME of radioactive material and as my post clearly shows the data I provided was in relation to the VOLUME of radioactive waste!

Art,

WRONG! WRONG! WRONG!

You are taking stuff OUT of the waste stream that doesn't need to be there.
It doesn't matter whether you are measuring by mass or measuring by volume;
if you are REMOVING material from the waste stream - you are REDUCING
the amount of waste.

If you take 95% of the MASS of the waste away, because it really isn't any more
radioactive than when you put it into the reactor; you also reduce the VOLUME
significantly too.

Here's a statistic for you. If you use nuclear power to generate all the electricity that
a family of 4 uses in 20 years with a once-through fuel-cycle - then the volume of waste
that must be disposed of [ prorated for this family ]; fits in a shoe-box.

if you reprocess; then the same electricity can be generated yielding a volume of waste
that fits in a "shot-glass" or "pill-bottle".

The plain facts are that 95% of the mass / volume of nuclear waste is stuff that is NOT
really radioactive waste. If you remove it; you reduce BOTH mass and volume.

I've argued this with many anti-nukes before. It all comes about because of a
misunderstanding of the science on their part. The anti-nukes think that if you
expose the reagents, the chemicals one uses to scavenge the uranium from the
waste, that the exposure of these reagents to the gamma and beta radiation from
the nuclear waste, that the reagents then become radioactive themselves and
contribute to the volume or mass of the waste.

That is just plain UNTRUE! Just because a material is exposed to gamma or
beta radiation, doesn't make it radioactive. That's why I stated that reprocessing
is a chemical process, not a nuclear process. Chemistry doesn't
alter the nucleus of the atom, which is what one needs to do to make it radioactive.
More stupidity and ignorance on the part of the anti-nukes.

That 50% of uranium miners died statistic is BOGUS too! Yes uranium miners in
the '50s and '60s did experience higher radiation exposure; but that 50% died as a
result has been debunked. Quit reading junk from the anti-nukes, and read what
good scientists like from Lawrence Berkeley Lab have to say:

http://www.lbl.gov/abc/wallchart/chapters/appendix/appendixf.html

Uranium miners of the '50s and '60s also turned out to be heavy smokers,
as compared to the general population.

Besides mining practices in the '50s and '60s pale compared to what is being
done NOW - and THAT'S what matters for the future.

Don't let the IDIOT anti-nukes make a fool of you,. THINK about it.

Dr. Gregory Greenman
Physicist

 

[Morbius]

Are you being serious re the part I bolded?? Are you seriously suggesting U-238 ore is not dangerous to health. As someone who works in the industry you have to be aware that a study in 1980 showed that 50%! Yes, that's right! 1 in every 2 miners who had dug out uranium ore for America's nuclear program in the 50s and 60s died of lung cancer.

Art,

For Heaven's sake, put your THINKING CAP ON!

U-238 is an alpha radiation emitter. Alpha particles outside the body can't
even penetrate the dead layer of skin. So as long as you don't breathe or
injest U-238; it can't hurt you.

When uranium is mined, the miners are grinding the rock face of the tunnel
exposing new surfaces. That creates air-borne dust. Even if you put water
sprays on to keep down the dust, the newly formed surfaces also release
radioactive gases that are daughter products of uranium.

However, when we go to put the U-238 back into an existing tunnel; we
don't need to grind new tunnel. The U-238 can be in any form we want;
metal, ceramic oxide... The point is - it WON'T be air-borne.

Encase the U-238 in a sealed metal box if you like. Drop it off in the tunnel,
and when you are through; backfill it. Who cares if the metal box survives.
If it breaks down after 1000 years; that will just mean that for 1000 years,
it had a steel isolation box that it wouldn't have had if it had never been
mined in the first place.

Dr. Gregory Greenman
Physicist

 

[Morbius]

America made a very sensible decision when it decided not to go down the reprocessing route.

Art,

NO - that decision has been decried by the National Academy of Science and
Engineering as a BIG MISTAKE!

The USA's BEST scientists disagree with it.

The founder of Greenpeace, Dr. Patrick Moore; endorses nuclear power:

http://www.greenspirit.com/logbook.cfm?msid=70

Dr. Gregory Greenman
Physicist

 

[Morbius]

Did you look at the title of the second source I provided? It's a report commissioned by the European Parliament!

Art,

Who cares who commissioned it! Who DID the study? WISE-Paris,
an anti-nuclear group. Hardly what I would call authoritative.

And as regards risk to humans Is this an acceptable risk to you?

How can one make a judgment; they didn't quantify the risk.

They hypothesize an accident. What is the risk - the PROBABILITY
of the hypothesized accident? Is the risk a million to one, a billion to one...?

Suppose we have 500 people in a 747 airliner. If all the engines quit, then
the plane will crash and all 500 people will be killed. Is that an acceptable
risk for you?

Don't you see how scientifically SHODDY such a statement is? People fly in
747 airliners all the time, because the probablility of that event happening is
next to nil.

So is the hypothesized release from Sellafield.

You just got "snookered" by anti-nuclear propaganda.

Keep believing in this tripe, and you will have your anti-nuclear merit badge in no time.

Dr. Gregory Greenman
Physicist

 

[Morbius]

I heard from one of my professors that at current rates, Yucca Mountain would last 30 years before being filled up. If we reprocess the waste, it would last 300 years.

Candyman,

Your professor is correct!

The anti-nuclear groups have been peddling this tripe for decades.

Occassionally they find someone who is gullible enough to believe it.

Dr. Gregory Greenman
Physicist

 

[russ_watters]

I agree that if the waste is first reprocessed to remove fission products and plutonium, there would be no problem at all. But that is not currently the plan. Unless the plutonium and higher actinides are removed, I think that the waste has to be stored for much longer than 10,000 years (Pu having a half life of 24000 years).

AM

Morbius, what is your opinion of the reasonable-ness of the 10,000 year criteria? Perhaps this is as much a political question, but my opinion is that it is a bet (or perhaps just a precaution) against technology and the death of civilization itself.

I don't see why we couldn't use a 100 or 200 year criteria with the understanding that we'd have to revisit the issue in the future. Odds are that's what we'll do anyway and in the meantime, we're just wasting money.

I've heard the 'what if we're not here in 200 years to revisit the issue/protect the site' argument, but my counter to that is - if we're not here (meaning civilization itself is gone), why do we care?

 

[russ_watters]

Well, if the U.S. is looking into Yucca Mountain for spent fuel, I can't see why we'd need to find another place for low level waste.

I heard from one of my professors that at current rates, Yucca Mountain would last 30 years before being filled up. If we reprocess the waste, it would last 300 years.

Minor clarification, major implication: Low level waste is so innocuous that it doesn't get treated all that much different than regular trash. We currently send it to special landfills (better isolated from the environment than typical landfills). Implication: this whole line of discussion is nothing more than an anti-nuclear power smokescreen.

 

[russ_watters]

Art, I'm going to have to stop this line of discussion. You are presenting wrong information as fact and we have higher standards of academic integrity in the engineering section than in the politics section (partially because so much of politics is pure opinion anyway). We don't allow the wanton spreading of misinformation that may confuse people who come here to learn.

 

[Morbius]

Morbius, what is your opinion of the reasonable-ness of the 10,000 year criteria? Perhaps this is as much a political question, but my opinion is that it is a bet (or perhaps just a precaution) against technology and the death of civilization itself.

I don't see why we couldn't use a 100 or 200 year criteria with the understanding that we'd have to revisit the issue in the future. Odds are, that's what we'll do anyway and in the meantime, we're just wasting money.

I've heard the 'what if we're not here in 200 years to revisit the issue/protect the site' argument, but my counter to that is - if we're not here (meaning civilization itself is gone), why do we care?

russ,

You are EXACTLY CORRECT!

The whole reason for making a repository that will last 10,000+ years; is
as a hedge that mankind will fall into another "dark ages" and we won't
know what nuclear waste is or how to handle it.

A geologic repository can be built so that it can be monitored. If something
starts to go wrong; the situation can be remedied.

The active assumption is that we will have lost our technology; entered
another "dark ages" due to some global cataclysm.

You are correct; if that happens; nuclear waste will be the least of our
problems.

Dr. Gregory Greenman
Physicist

 

[Morbius]

Implication: this whole line of discussion is nothing more than an anti-nuclear power smokescreen.

russ,

AMEN!

Dr. Gregory Greenman
Physicist

 

[Morbius]

However if it is the long half life elements that concern you then you only need to look at some of the waste these plants are pumping into the ocean such as I-129 with a half life of 16 milllion years!

Art,

What you are apparently ignorant of is that the activity or intensity of the radiation is
INVERSELY proportional to the half-life!

The whole reason that I-129 takes 16 million years for half of it to decay is because
its decay is so sporadic. Let's do the calculation for 1 gram of I-129.

Since the atomic weight of I-129 is 129; then the number of moles of I-129 in 1 gram is
1 gm / (129 gm/moles) = 0.007752 moles.

The number of atoms is Avogadro's Number times the number of moles =
(6.023e+23)(0.007752) = 4.669e+21 atoms.

Lets convert the I-129 half-life of 16 million years into seconds:
16 million years = 16 million years * 365.25 days/year * 24 hours/day * 3600 second/hour
= 5.049e+14 second.

Now the radioactive decay constant is the natural log of 2 divided by the half-life:
\lambda = ln 2 / half-life = ln 2 / 5.049e+14 sec = 1.37278e-15 inverse seconds.

Therefore, the radioactivity rate is the product of the number of atoms and the
radioactive decay constant = (5.669e+21)(1.37278e-15) = 6.4095e+6 decays/second.

If we convert this rate into Curies, the unit of radioactivity; 1 Curie = 3.7e+10 decays/sec;
then we have 6.4095e+06 / 3.7e+10 = 0.00017 Curies!

TRIVIAL!

If big numbers impress you; like that 16 million year half-life of I-129; then consider
the Potassium-40 [ K-40 ] that is found NATURALLY in your bones.

Potassium-40 has a half-life of 1.277 BILLION years.

That beats your I-129 half-life by a factor of 81.3!

Additionally, the radioactivity released by I-129 is a 194 keV beta [ an electron ].

The stupid anti-nukes have you all worked up over a moderate energy electron!

Believe me - there's natural cosmic radiation raining down on you right now that is
of MUCH greater concern.

Dr. Gregory Greenman
Physicist

 

[theCandyman]

What is ironic is that in the paragraph above mentioning I-129, Art basically said that Pu wouldn't harm you due to it's long halflife.

Art, are you just picking up facts from sources that support the opnion you've already generated? It would be best to do that math yourself, or even just use common sense to try to find out how you get more waste than what is input. If that was really the case, it wouldn't be much help, since the objective to is reduce waste in the first place.

Oh yes, if you eat a banana, you're eating 10 Bq (one decay a second) of K-40 that Morbius mentioned.

 

[Morbius]

Plus of course we can't / won't eat sea food from the irish Sea as it is so heavily polluted with radiation.

Art,

Much of that is IRELAND'S fault:

http://en.wikipedia.org/wiki/Sellafield

Technetium-99 is a radioactive element which is produced by nuclear fuel reprocessing, and
also as a byproduct of medical facilities (for example Ireland discharges approximately
6.78GBq of Technetium-99 each year despite not having a nuclear industry...

However, to put this in perspective:

In itself, the technetium discharges do not represent a significant radiological hazard, and
recent studies have noted "...that in the most recently reported dose estimates for the
most exposed Sellafield group of seafood consumers (FSA/SEPA 2000), the contributions
from 99Tc and actinide nuclides from Sellafield (<100 µSv) was less than that from 210Po
attributable to discharges from the Whitehaven phosphate processing plant and probably
less than the dose from naturally occurring background levels of 210Po." Because of the
need to comply with OSPAR, British Nuclear Group (the licencing company for Sellafield)
have recently commissioned a new process in which Technetium-99 is removed from the
waste stream and vitrified in glass blocks."


So the Tc discharge wasn't significant, it was BELOW the naturally occurring background
levels of 210Po. In any case, Sellafield is now going to remove the Tc from the waste
instead of discharging it into the sea.

Dr. Gregory Greenman
Physicist

 

[Morbius]

Art, are you just picking up facts from sources that support the opnion you've already generated? It would be best to do that math yourself, or even just use common sense to try to find out how you get more waste than what is input. If that was really the case, it wouldn't be much help, since the objective to is reduce waste in the first place.

Candyman,

I've seen this before so many times. Someone reads the propaganda from some
anti-nuclear website and they get all spun-up.

The problem, as you point out above; is the lack of "critical thinking".

If one reads that more radioactive waste is created than one had at the beginning,
then an inquiring scientific mind would ask "How did that happen?" Then one would
do more research to find out how the authors of the anti-nuclear article came to that
conclusion.

What one finds when one inquires, is that they assume that exposure to ANY form of
radioactivity makes non-radioactive material radioactive. That is just plain flat out
WRONG!.

It sounds plausible to many people; so they fall for it "hook, line, and sinker" which is
what the anti-nuclear crowd is hoping for. That's why "Physics Forums" does such a
great service. It can serve to debunk this crap; and immunize people from this sort of
"fear-mongering" by the IDIOT anti-nukes.

Dr. Gregory Greenman
Physicist

 

[russ_watters]

Ok, I think we've driven this into the ground. I wish I didn't have to lock it, but I think I do.