Nuclear power safety (was - argument in the Woke thread)

[billvon 2,990]

(Warning - long)

Winsor recently refloated the always popular nuclear-is-expensive-because-of-those-goddamn-hippies argument.  Since he's not reading my posts any more, and since that's not relevant to the woke-bashing that's going on in that thread, I thought I'd break it out into a separate thread.

First off, of course there is an element of cost associated with protests.  When people don't like nuclear power (or aviation, or skydiving, or drag queens, or whatever) they protest, and those protests invariably make it more difficult/expensive to do whatever those people wanted to do initially - through demanding more regulation, or lobbying to deny permits, or promoting the bad over the good.  In the case of nuclear power, however, that has very little to do with the rising costs.

As a pilot and a skydiver, one thing I learned early on is that most aviation regulations were written in blood.  The FAR that requires pilots to check the weather before they take off if they are flying to a different airport?  That's not there because "bushy tailed Liberal Arts types in Boston/Cambridge" hated airplanes and wanted to screw up aviation.  They are there because of the deaths of pilots who were surprised by weather after they took off.

There are similar reasons for many of the regulations involved with nuclear power.  The limits for worker exposure?  That's not there because scaredycat liberals want to shut down nuclear power.  That's because early on several people were injured and killed by radiation from poorly designed experiments and reactors.  The Demon Core, for example, killed two people working with it.  At that point, the risks of gamma radiation were known, but no one had been exposed to a fatal dose of neutron radiation before - something you can only get from a nuclear chain reaction, or via a very complex sort of particle accelerator.  After those two deaths, more work was done on neutron radiation risks, and new limits were put in place.  More regulations!

Side note here - the reason most nuclear reactors are possible at all is due to a quirk of physics called "neutron cross section."  It's basically the probability of a neutron hitting the nucleus of a fissile atom.  Einstein's work made it clear that the slower the neutron, the more likely it was to hit that nucleus.  This is important because "prompt criticality" - the sort of chain reaction we all learned about in school, and how nuclear bombs detonate - is VERY hard to regulate, since the reaction waxes and wanes over the course of hundreds of microseconds, too fast for humans to reliably control (as the physicists working with the Demon Core learned to their dismay.)  However, it is possible to design nuclear reactors that cannot go prompt-critical, and can only reach criticality with delayed, or thermal, neutrons.  These are neutrons that pass through a moderator (like water) and are slowed, as well as neutrons that are natually emitted from fission, just more slowly.  This allows design of reactors with power time constants of seconds or tens of seconds, which makes regulation via control rods possible.  Even better, if they lose their moderator (i.e. they lose coolant) the reaction slows automatically.  In fact, if the reactor even just gets too hot and boils the water, the voids in the water moderator automatically reduce power generation (i.e. it has a "negative void coefficient.")

This gave early reactor designers perhaps a bit too much confidence in the inherent safety of nuclear power.

As people started working on reactors for power in peacetime, we saw some of those irrational emotion driven types Winsor was referring to in his post - but initally they were on the side of nuclear power.  Nuclear power was so safe, easy and efficient, according to Atomic Energy Commission Chairman Lewis Strauss, that "it is not too much to expect that our children will enjoy in their homes electrical energy too cheap to meter."  He saw so much of the promise of nuclear energy (both fission and fusion) and so little of the drawbacks that the future looked rosy indeed.

Turns out, though, nuclear power is hard to do well.  For example, if there is a LOCA (loss of coolant accident) in water-moderated reactor, the chain reaction does indeed stop.  But the fuel is now full of short lived isotopes due to the neutron bombardment during operation, and those isotopes also decay and release neutrons.  Not enough to sustain a chain reaction, but enough to cause additional fission and a LOT of heat.  So although the reactor has technically shut down, it will still happily melt into a puddle of spent nuclear fuel, nuclear waste, moderator and steel.  And it's hard to keep a reactor full of that stuff safe.

And reactor designers started discovering this almost immediately.  In most parts of the world, those designers have been very lucky that their mishaps have, for the most part, not resulted in large public health threats or loss of life.

The first meltdown occurred at reactor EBR-1 in Idaho in 1955.  This was a breeder reactor, so different design and different coolant, but same basic idea.  A power excursion caused a partial meltdown, but cooling was restored and the core solidified before anything worse happened.

The next occurred at the same facility, but in a different reactor - this time an experimental boiling water reactor.  It was designed to not go prompt-critical for all the reasons listed above.  However, when a technician removed a single control rod from the reactor, it did indeed go prompt-critical.  Fortunately the core disassembled itself before nuclear weapon yields were reached, but the power excursion (20 gigawatts in a reactor designed to handle 3 megawatts) caused an explosion that killed three men in a fairly gruesome fashion.

How could this have happened?  This reactor was designed to be SAFE!  It could not go prompt critical!  Turns out two factors allowed this.  One, some of the neutron poisons inside the reactor (that reduce reactivity) had corroded and flaked off.  Two, it turns out that it takes water some milliseconds to boil, and this event happened in microseconds, so the voids could not form fast enough to shut down the reaction.

Lesson learned.  More regulation of nuclear power plant operation.

In 1977, the nuclear reactor at the Millstone Nuclear Power Plant had its coolant level drop while the reactor was powered down, exposing the fuel elements to air (actually steam.)  A hydrogen explosion occurred, which damaged the reactor and seriously injured one worker.

How could this have happened?  There's no hydrogen in a reactor!  Where did it come from?  The hot fuel elements, clad in zirconium, reacted with the steam to generate the hydrogen.

Lesson learned.  More regulation of nuclear power plant operation.

Then Chernobyl happened.  Fortunately for us the RBMK reactor is so different from US designs that a similar accident almost certainly can't happen here.  But again the accident was due to something that no one had considered - that there is an operating regime for a reactor where poisons build up so quickly that it shuts down the reactor, and when they burn off (as they do eventually) then the reactor can restart so violently that it, again, goes prompt critical.

So probably no effect on US reactors; ours can't go prompt critical.  Although we initially thought the same thing about the SL-1 reactor in Idaho.

Lesson learned.  This time, no new regulations for the US.

There are about a dozen of these.  Three Mile Island, the most visible US incident, was the result of two mechanical failures and three coincident operator errors.  And despite all the reassurances from the utility, the incident came very close to a containment breach - most of the core did in fact melt down, and a lot of it ended up on the bottom of the vessel.  During the investigation, it was discovered that valves to the emergency feedwater supply were closed and never opened, there was no clear indication on the reactor status panel that the PORV was stuck open, and an operator actually shut off the emergency high pressure injection system.

So failures of training, equipment and instrumentation.  Lesson learned.  More regulation of nuclear power plant operation.

Then outside the US came Fukushima.  A textbook case of how to shut down a nuclear reactor in an emergency, and everything looked good.  But then a tidal wave damaged - not the reactor, not the control room, but the power lines and the generators that provided cooling water for the reactors when shut down.  And THEY melted down.

So failure to take into account protection of the entire plant - not just the reactor.  Lesson learned.  More regulation of nuclear power.

These new lessons are why it's so hard to build new nuclear power plants.  Recently the first nuclear reactor in decades opened at the Vogtle facility in Georgia.  This was a simplified Gen IV design that's referred to as "walk-away safe" - no power needed to cool the reactor after an emergency shutdown.  It was so simple that an early ad from GE for the reactor's original design touted "first concrete to fuel load in 36 months."  From the beginning of the planning to the first operation took 20 years and came in $20 billion over budget.  No protesters, just contractors screwing up, companies folding, and the usual very high level of quality required at a facility designed to safely contain a nuclear chain reaction.

I keep hoping that, someday, we will get a Gen IV reactor design (or, heck, even a fusion reactor) that does indeed meet the promise made by Strauss all those years ago.  What keeps us from getting there is not those goddamn hippies, and it's not evil liberals in suits toting briefcases.  It's the fact that nuclear power is hard to do well, and we as a society have (wisely) demanded that it's done right.

 

[BIGUN 1,306]

1 hour ago, billvon said:

Warning - long

It may be long, Bill. but it's a very informative read. Thank you. 

[billeisele 130]

14 hours ago, billvon said:

(Warning - long)

Winsor recently refloated the always popular nuclear-is-expensive-because-of-those-goddamn-hippies argument.  Since he's not reading my posts any more, and since that's not relevant to the woke-bashing that's going on in that thread, I thought I'd break it out into a separate thread.

First off, of course there is an element of cost associated with protests.  When people don't like nuclear power (or aviation, or skydiving, or drag queens, or whatever) they protest, and those protests invariably make it more difficult/expensive to do whatever those people wanted to do initially - through demanding more regulation, or lobbying to deny permits, or promoting the bad over the good.  In the case of nuclear power, however, that has very little to do with the rising costs.

As a pilot and a skydiver, one thing I learned early on is that most aviation regulations were written in blood.  The FAR that requires pilots to check the weather before they take off if they are flying to a different airport?  That's not there because "bushy tailed Liberal Arts types in Boston/Cambridge" hated airplanes and wanted to screw up aviation.  They are there because of the deaths of pilots who were surprised by weather after they took off.

There are similar reasons for many of the regulations involved with nuclear power.  The limits for worker exposure?  That's not there because scaredycat liberals want to shut down nuclear power.  That's because early on several people were injured and killed by radiation from poorly designed experiments and reactors.  The Demon Core, for example, killed two people working with it.  At that point, the risks of gamma radiation were known, but no one had been exposed to a fatal dose of neutron radiation before - something you can only get from a nuclear chain reaction, or via a very complex sort of particle accelerator.  After those two deaths, more work was done on neutron radiation risks, and new limits were put in place.  More regulations!

Side note here - the reason most nuclear reactors are possible at all is due to a quirk of physics called "neutron cross section."  It's basically the probability of a neutron hitting the nucleus of a fissile atom.  Einstein's work made it clear that the slower the neutron, the more likely it was to hit that nucleus.  This is important because "prompt criticality" - the sort of chain reaction we all learned about in school, and how nuclear bombs detonate - is VERY hard to regulate, since the reaction waxes and wanes over the course of hundreds of microseconds, too fast for humans to reliably control (as the physicists working with the Demon Core learned to their dismay.)  However, it is possible to design nuclear reactors that cannot go prompt-critical, and can only reach criticality with delayed, or thermal, neutrons.  These are neutrons that pass through a moderator (like water) and are slowed, as well as neutrons that are natually emitted from fission, just more slowly.  This allows design of reactors with power time constants of seconds or tens of seconds, which makes regulation via control rods possible.  Even better, if they lose their moderator (i.e. they lose coolant) the reaction slows automatically.  In fact, if the reactor even just gets too hot and boils the water, the voids in the water moderator automatically reduce power generation (i.e. it has a "negative void coefficient.")

This gave early reactor designers perhaps a bit too much confidence in the inherent safety of nuclear power.

As people started working on reactors for power in peacetime, we saw some of those irrational emotion driven types Winsor was referring to in his post - but initally they were on the side of nuclear power.  Nuclear power was so safe, easy and efficient, according to Atomic Energy Commission Chairman Lewis Strauss, that "it is not too much to expect that our children will enjoy in their homes electrical energy too cheap to meter."  He saw so much of the promise of nuclear energy (both fission and fusion) and so little of the drawbacks that the future looked rosy indeed.

Turns out, though, nuclear power is hard to do well.  For example, if there is a LOCA (loss of coolant accident) in water-moderated reactor, the chain reaction does indeed stop.  But the fuel is now full of short lived isotopes due to the neutron bombardment during operation, and those isotopes also decay and release neutrons.  Not enough to sustain a chain reaction, but enough to cause additional fission and a LOT of heat.  So although the reactor has technically shut down, it will still happily melt into a puddle of spent nuclear fuel, nuclear waste, moderator and steel.  And it's hard to keep a reactor full of that stuff safe.

And reactor designers started discovering this almost immediately.  In most parts of the world, those designers have been very lucky that their mishaps have, for the most part, not resulted in large public health threats or loss of life.

The first meltdown occurred at reactor EBR-1 in Idaho in 1955.  This was a breeder reactor, so different design and different coolant, but same basic idea.  A power excursion caused a partial meltdown, but cooling was restored and the core solidified before anything worse happened.

The next occurred at the same facility, but in a different reactor - this time an experimental boiling water reactor.  It was designed to not go prompt-critical for all the reasons listed above.  However, when a technician removed a single control rod from the reactor, it did indeed go prompt-critical.  Fortunately the core disassembled itself before nuclear weapon yields were reached, but the power excursion (20 gigawatts in a reactor designed to handle 3 megawatts) caused an explosion that killed three men in a fairly gruesome fashion.

How could this have happened?  This reactor was designed to be SAFE!  It could not go prompt critical!  Turns out two factors allowed this.  One, some of the neutron poisons inside the reactor (that reduce reactivity) had corroded and flaked off.  Two, it turns out that it takes water some milliseconds to boil, and this event happened in microseconds, so the voids could not form fast enough to shut down the reaction.

Lesson learned.  More regulation of nuclear power plant operation.

In 1977, the nuclear reactor at the Millstone Nuclear Power Plant had its coolant level drop while the reactor was powered down, exposing the fuel elements to air (actually steam.)  A hydrogen explosion occurred, which damaged the reactor and seriously injured one worker.

How could this have happened?  There's no hydrogen in a reactor!  Where did it come from?  The hot fuel elements, clad in zirconium, reacted with the steam to generate the hydrogen.

Lesson learned.  More regulation of nuclear power plant operation.

Then Chernobyl happened.  Fortunately for us the RBMK reactor is so different from US designs that a similar accident almost certainly can't happen here.  But again the accident was due to something that no one had considered - that there is an operating regime for a reactor where poisons build up so quickly that it shuts down the reactor, and when they burn off (as they do eventually) then the reactor can restart so violently that it, again, goes prompt critical.

So probably no effect on US reactors; ours can't go prompt critical.  Although we initially thought the same thing about the SL-1 reactor in Idaho.

Lesson learned.  This time, no new regulations for the US.

There are about a dozen of these.  Three Mile Island, the most visible US incident, was the result of two mechanical failures and three coincident operator errors.  And despite all the reassurances from the utility, the incident came very close to a containment breach - most of the core did in fact melt down, and a lot of it ended up on the bottom of the vessel.  During the investigation, it was discovered that valves to the emergency feedwater supply were closed and never opened, there was no clear indication on the reactor status panel that the PORV was stuck open, and an operator actually shut off the emergency high pressure injection system.

So failures of training, equipment and instrumentation.  Lesson learned.  More regulation of nuclear power plant operation.

Then outside the US came Fukushima.  A textbook case of how to shut down a nuclear reactor in an emergency, and everything looked good.  But then a tidal wave damaged - not the reactor, not the control room, but the power lines and the generators that provided cooling water for the reactors when shut down.  And THEY melted down.

So failure to take into account protection of the entire plant - not just the reactor.  Lesson learned.  More regulation of nuclear power.

These new lessons are why it's so hard to build new nuclear power plants.  Recently the first nuclear reactor in decades opened at the Vogtle facility in Georgia.  This was a simplified Gen IV design that's referred to as "walk-away safe" - no power needed to cool the reactor after an emergency shutdown.  It was so simple that an early ad from GE for the reactor's original design touted "first concrete to fuel load in 36 months."  From the beginning of the planning to the first operation took 20 years and came in $20 billion over budget.  No protesters, just contractors screwing up, companies folding, and the usual very high level of quality required at a facility designed to safely contain a nuclear chain reaction.

I keep hoping that, someday, we will get a Gen IV reactor design (or, heck, even a fusion reactor) that does indeed meet the promise made by Strauss all those years ago.  What keeps us from getting there is not those goddamn hippies, and it's not evil liberals in suits toting briefcases.  It's the fact that nuclear power is hard to do well, and we as a society have (wisely) demanded that it's done right.

 

Good stuff. My education requirement for the day is met. Now I can do stupid stuff. 

Because of our failure with VC Summer 3 I've closely followed the GA Power project. Those 2 utilities had different philosophies on PR. SCE&G was a keep quiet and just work, company. GA Power proactively was in the news.

The VC unit was years ahead of the GA unit and the budget was lower. Lower only because of a more favorable site condition. VC's failure was a plus for GA Power. Many of the tradesmen went to GA Power providing them additional workers with specific knowledge. They had already performed the required tasks at VC and applied that knowledge to accelerate the work without making the mistakes that occurred at VC.  Jump forward a few years and they have 2 operational units. 

Now that we know the actual cost, where in the US will the next AP1000 be built? Interesting that the 4 operational units and 6 under construction in China aren't talked about. In China there's much less oversight from things like an OSHA or NRC.

With the implosion of Westinghouse and Toshiba, I'm wondering who owns the blueprints/control documents for the plant. Westinghouse never finished them, they were creating them as the plant was under construction. That, and NRC review, was a major slowdown with VC construction. Maybe it's the Canadian investment group that bought the organization.

I've lost track of these type details but am glad to see the GA Power units finished and operating.

[wmw999 2,444]

1 hour ago, billeisele said:

Good stuff. My education requirement for the day is met. Now I can do stupid stuff. 

Yeah, that’s where I am… 

Wendy P. 

[olofscience 480]

17 hours ago, billvon said:

It's the fact that nuclear power is hard to do well

Then there's also the security and politics (nonproliferation) aspect - if thieves steal a wind turbine, they have a bunch of carbon fibre and gears. If they steal solar panels, they have some glass, silicon and aluminium. But if someone steals a nuclear fuel shipment? That already makes a big difference in costs if you need a small army to escort one shipment, and to secure the actual power plant site. Then the paperwork to make sure no nuclear material goes missing...

And we know Iran (and many other not-so-friendly entities) would love to get their hands on that stuff.

But, I guess this is all too complicated for them, much easier to just blame the liberals and those hippie environmentalists, right?

[Phil1111 1,149]

Meanwhile Germany is attempting to jump past nuclear to a renewable future. Its expensive and coal use has temporarily increased. They just shut down seven coal fired plants. The current government wants to end coal use in six years and has legislation requiring it in 14 years.

[SkyDekker 1,465]

4 hours ago, billeisele said:

Now I can do stupid stuff. 

Like quote the entire long post? 

 

Great read Bill!

[olofscience 480]

3 hours ago, Phil1111 said:

Its expensive and coal use has temporarily increased.

Not really...

 

Source: Why Germany ditched nuclear before coal—and why it won’t go back

[Phil1111 1,149]

18 minutes ago, olofscience said:

Not really...

 

Source: Why Germany ditched nuclear before coal—and why it won’t go back

I meant shutting down the nuclear power plants is expensive and the overall transition to clean energy has been expensive to German consumers. The wholesale price of electricity in Germany is almost twice that of the US

Initial coal use expanded as your charts show and now "Berlin has agreed to spend €16 billion to build four major natural gas plants to meet electricity demand in a major overhaul of the country's energy grid.... and ...Chancellor Olaf Scholz of the Social Democratic Party and the economy minister, Green Party politician Robert Habeck have stated that "Nuclear energy is over."

These new gas plants are solely intended to bridge over to a completely renewable grid bo 2038.

Edited May 6, 2024 by Phil1111

[JerryBaumchen 1,362]

22 hours ago, BIGUN said:

 

OK, this site is doing some strange stuff.  Once again I am unable to Reply to your post, Bill.  => So here I am trying my best using Keith's post.

As for nuclear accidents:  I want us to do the best we can to prevent them.  However, I accept them as a cost of doing business.  To me, it is like aviation; we no longer have fatalities on commercial airliners every year.  When, we do; I accept that as a cost of doing business.  And, back when I was a working stiff, I flew just about every week on a commercial airliner.

My one & only concern is the waste.  I for one, do not want to have my grandchildren [ and their heirs ad infinitum ] dealing with it.

The waste is deadly and is, for most discussions, forever.

Jerry Baumchen

PS)  Again, we need to reduce the number of us humans on this Earth of ours.

PPS)  Some info:  Nuclear waste at center of testy Nevada Senate race (thehill.com)

 

 

Edited May 6, 2024 by JerryBaumchen

[JoeWeber 2,720]

52 minutes ago, JerryBaumchen said:

PS)  Again, we need to reduce the number of us humans on this Earth of ours.

Then you have to be in favor of nuclear waste. 

[Phil1111 1,149]

1 hour ago, JerryBaumchen said:

OK, this site is doing some strange stuff.  ....

Its a republican conspiracy.

1 hour ago, JerryBaumchen said:

....PS)  Again, we need to reduce the number of us humans on this Earth of ours....

Conspiracy theories that are anti-science is helping. Putin is doing his best as are the proxies of Iranian mullahs.

[ryoder 1,590]

2 hours ago, JerryBaumchen said:

PS)  Again, we need to reduce the number of us humans on this Earth of ours.

Just watch the trailer:

https://www.imdb.com/title/tt16280912/

[JerryBaumchen 1,362]

1 hour ago, ryoder said:

Just watch the trailer:

https://www.imdb.com/title/tt16280912/

Hi Robert,

My hope is that it might not come to that.

However, that might be better than a Darwinian method.

Jerry Baumchen

Edited May 7, 2024 by JerryBaumchen

[BIGUN 1,306]

1 hour ago, ryoder said:

Just watch the trailer:

Apologies, I took the thread off-track. 

Edited May 7, 2024 by BIGUN