Independent review challenges safety of new nuclear plant design

[kristopher]

AP1000 Containment Leakage Report Fairewinds Associates - Gundersen, Hausler, 4-21-2010.pdf
Body

* There have been more than 80-identified problems with containment systems over the last 45 years.
* Several containment liners have developed through-wall rust holes.
* The AP1000 design is unique, with only one containment barrier.
* The AP1000 design is more susceptible to rust than existing designs.
* The AP1000 Chimney effect will cause any radiation leakage to be released directly into the environment.
* The AP1000 has the likelihood of releasing higher levels of radiation after an accident than existing reactor designs.

http://fairewinds.com/AP1000-Containment-Leakage-Report-Fairewinds-Associates-Inc

Or as the NYT put it:

As Southern Company and its partners, armed with federal loan guarantees of $8.3 billion, move toward construction of two new reactors at a site near Augusta, Ga., opponents are taking aim at the design details.

The reactor, the Westinghouse AP 1000, is also planned for several other locations, but has not yet been fully approved by the Nuclear Regulatory Commission. It is intended to be far safer than existing plants, ensuring that there will be no fuel melting in an accident by relying for its cooling on forces like gravity and natural heat flow instead of pumps, pipes and valves. That concept gives the AP 1000 its name, for Advanced Passive. (The 1,000 refers to the power rating in megawatts, although the actual power output is a less picturesque 1,154.)

A critical feature of the design is an unusual containment structure. One part is a free-standing steel dome, 130 feet high, surrounded by a concrete shield building and topped with a tank of emergency water.
The commission has raised concerns about whether a shield building would be strong enough to survive an earthquake. Westinghouse submitted a detailed report last month and plans another in May to demonstrate that the building is adequate.

But on Wednesday, Arnie Gundersen, a nuclear engineer commissioned by several anti-nuclear groups, released a report suggesting a different hazard.

In existing plants, he pointed out, the containment consists of a steel liner and a concrete dome, but sometimes the steel liner has rusted through.

In the new Westinghouse design, the liner and the concrete are now separated, to allow air to flow between them, so the temperature inside the steel structure will be kept down by natural forces. But if the steel rusts through, “there is no backup containment behind it,’’ Mr. Gundersen said.

In the new design, he said, metal baffles bolted to the steel direct the air flow, and those baffles are a spot where moisture from the atmosphere could collect. At coastal plants, salty water could collect, and inland, it would be evaporating water from the cooling towers. Inspection, he said, would be difficult....
http://green.blogs.nytimes.com/2010/04/21/critics-challenge-safety-of-new-nuclear-reactor-design/?src=busln

It helps to be aware of what happened at Davis Besse:

The reactor core at the Davis-Besse nuclear plant sits within a metal pot designed to withstand pressures up to 2,500 pounds per square inch. The pot -- called the reactor vessel -- has carbon steel walls nearly six inches thick to provide the necessary strength. Because the water cooling the reactor contains boric acid that is highly corrosive to carbon steel, the entire inner surface of the reactor vessel is covered with 3/16-inch thick stainless steel.

But water routinely leaked onto the reactor vessel's outer surface. Because the outer surface lacked a protective stainless steel coating, boric acid ate its way through the carbon steel wall until it reached the backside of the inner liner. High pressure inside the reactor vessel pushed the stainless steel outward into the cavity formed by the boric acid. The stainless steel bent but did not break. Cooling water remained inside the reactor vessel not because of thick carbon steel but due to a thin layer of stainless steel. The plant's owner ignored numerous warning signs spanning many years to create the reactor with a hole in its head.

Workers repairing one of five cracked control rod drive mechanism (CRDM) nozzles at Davis-Besse discovered extensive damage to the reactor vessel head. The reactor vessel head is the dome-shaped upper portion of the carbon steel vessel housing the reactor core. It can be removed when the plant is shut down to allow spent nuclear fuel to be replaced with fresh fuel. The CRDM nozzles connect motors mounted on a platform above the reactor vessel head to control rods within the reactor vessel. Operators withdraw control rods from the reactor core to startup the plant and insert them to shut down the reactor.

The workers found a large hole in the reactor vessel head next to CRDM nozzle #3. The hole was about six inches deep, five inches long, and seven inches wide. The hole extended to within 1-1/2 inches of the adjacent CRDM nozzle #11. The stainless steel liner welded to the inner surface of the reactor vessel head for protection against boric acid was at the bottom of the hole. This liner was approximately 3/16-inch thick and had bulged outward about 1/8-inch due to the high pressure (over one ton per square inch) inside the reactor vessel.

What could have happened?

A loss-of-coolant accident (LOCA) occurs if the stainless steel liner fails or CRDM nozzle #3 is ejected. The water cooling the reactor core quickly empties through the hole into the containment building. The containment building is made of reinforced concrete designed to withstand the pressure surge from the flow through the break.

To compensate for the reactor water exiting through the hole, water inside the pressurizer (PZR) and the cold leg accumulators flows into the reactor vessel. This initial makeup is supplemented by water from the Refueling Water Storage Tank (RWST) delivered to the reactor vessel by the high, intermediate, and low pressure injection pumps. The makeup water re-fills the reactor vessel and overflows out the hole in the reactor vessel head. Approximately 30 to 45 minutes later, the RWST empties. Operators close valves between the pumps and the RWST and open valves between the low pressure injection (RHR) pumps and the containment sump. Water pouring from the broken reactor vessel head drains to the containment sump where the RHR pumps recycle it to the reactor vessel. A cooling water system supplies water to the RHR heat exchanger shown to the left of the RHR pump to remove heat generated by the reactor core.
On paper, that's how the safety systems would have functioned to protect the public. But the following examples suggest that things might not have gone by the book:

-The Three Mile Island nuclear plant experienced a loss of coolant accident in March 1979. Emergency
pumps automatically started to replace the water flowing out the leak. Operators turned off the pumps
because instruments falsely indicated too much water in the reactor vessel. Within two hours, the reactor
core overheated and melted, triggering the evacuation of nearly 150,000 people.

-At the Callaway nuclear plant in 2001, workers encountered problems while testing one of the emergency
pumps. Investigation revealed that a foam-like bladder inside the RWST was flaking apart. Water carried
chunks of debris to the pump where it blocked flow. The debris would have disabled all the emergency
pumps during an accident.

-At the Haddam Neck nuclear plant in 1996, the NRC discovered the piping carrying water from the RWST
to the reactor vessel was too small. It was long enough but it was not wide enough to carry enough water
during an accident to re-fill the reactor vessel in time to prevent meltdown. The plant operated for nearly 30
years with this undetected vulnerability.

-At several US and foreign nuclear power plants, including the Limerick nuclear plant 8 years ago, the force
of water/steam entering the containment building during a loss of coolant accident has blown insulation off
piping and equipment. The water carried that insulation and other debris into the containment sump. The
debris clogged the piping going to the emergency pumps much like hair clogs a bathtub drain. According to
a recent government report, 46 percent of US nuclear plants are very likely to experience blockage in the
containment sumps in event of a hole the size found at Davis-Besse opens up. For slightly larger holes, the
chances of failure increase to 82 percent.<1>

Thus, events at Davis-Besse may have gone by the book had the stainless steel failed it would have become the subject of many books on the worst loss of coolant accident in US history...
UCS -- Aging Nuclear Plants -- Davis-Besse: The Reactor with a Hole in its Head

http://www.ucsusa.org/assets/documents/nuclear_power/acfnx8tzc.pdf







Scapegoating of Davis Besse by NRC
http://www.ucsusa.org/news/press_release/federal-agency-scapegoating-0141.html

Retrospective
http://www.ucsusa.org/nuclear_power/nuclear_power_risk/safety/davis-besse-retrospective.html

[provis99]

1. ahh, so what if a nuclear power plant melts down every now and then.

We'll learn to live with nuclear radiation in order to protect the environment.:crazy:

[Dogmudgeon]

2. We've had to do so since we learned to burn coal

http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html">Coal combustion releases a great deal of uranium and thorium in particulate form, dwarfing Chernobyl's release in volume and half-life.

However, as bad as that seems, it's the mercury that's the worst of the lot. The cadmium and arsenic aren't so pleasant, either.

Unfortunately, nobody likes to make hip, witty bon mots about anything other than radionuclides.

--d!

[kristopher]

3. So your point is that nuclear catastrophe is ok because coal sucks?

There is no arguing the toxicity of coal ash nor the lethality of the cumulative emissions from coal; but the comparison of the diffuse radioactive component of coal emissions is nothing more than a red herring to detract from the concentrated radioactive waste of nuclear power.

Chernobyl has killed hundreds of thousands of people to date and will continue to wreak havoc for decades to come.

Annals of the New York Academy of Sciences
Volume 1181 Issue Chernobyl
Consequences of the Catastrophe for People and the Environment, Pages 31 - 220

Chapter II. Consequences of the Chernobyl Catastrophe for Public Health

Alexey B. Nesterenko a , Vassily B. Nesterenko a ,† and Alexey V. Yablokov b
a
Institute of Radiation Safety (BELRAD), Minsk, Belarus b Russian Academy of Sciences, Moscow, Russia
Address for correspondence: Alexey V. Yablokov, Russian Academy of Sciences, Leninsky Prospect 33, Office 319, 119071 Moscow,
Russia. Voice: [phone]; fax: [phone]. [e-mail]
†Deceased


ABSTRACT

Problems complicating a full assessment of the effects from Chernobyl included official secrecy and falsification of medical records by the USSR for the first 3.5 years after the catastrophe and the lack of reliable medical statistics in Ukraine, Belarus, and Russia. Official data concerning the thousands of cleanup workers (Chernobyl liquidators) who worked to control the emissions are especially difficult to reconstruct. Using criteria demanded by the International Atomic Energy Agency (IAEA), the World Health Organization (WHO), and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) resulted in marked underestimates of the number of fatalities and the extent and degree of sickness among those exposed to radioactive fallout from Chernobyl. Data on exposures were absent or grossly inadequate, while mounting indications of adverse effects became more and more apparent. Using objective information collected by scientists in the affected areas—comparisons of morbidity and mortality in territories characterized by identical physiography, demography, and economy, which differed only in the levels and spectra of radioactive contamination—revealed significant abnormalities associated with irradiation, unrelated to age or sex (e.g., stable chromosomal aberrations), as well as other genetic and nongenetic pathologies.

In all cases when comparing the territories heavily contaminated by Chernobyl's radionuclides with less contaminated areas that are characterized by a similar economy, demography, and environment, there is a marked increase in general morbidity in the former.

Increased numbers of sick and weak newborns were found in the heavily contaminated territories in Belarus, Ukraine, and European Russia.

Accelerated aging is one of the well-known consequences of exposure to ionizing radiation. This phenomenon is apparent to a greater or lesser degree in all of the populations contaminated by the Chernobyl radionuclides.

This section describes the spectrum and the scale of the nonmalignant diseases that have been found among exposed populations.

Adverse effects as a result of Chernobyl irradiation have been found in every group that has been studied. Brain damage has been found in individuals directly exposed—liquidators and those living in the contaminated territories, as well as in their offspring. Premature cataracts; tooth and mouth abnormalities; and blood, lymphatic, heart, lung, gastrointestinal, urologic, bone, and skin diseases afflict and impair people, young and old alike. Endocrine dysfunction, particularly thyroid disease, is far more common than might be expected, with some 1,000 cases of thyroid dysfunction for every case of thyroid cancer, a marked increase after the catastrophe. There are genetic damage and birth defects especially in children of liquidators and in children born in areas with high levels of radioisotope contamination.

Immunological abnormalities and increases in viral, bacterial, and parasitic diseases are rife among individuals in the heavily contaminated areas. For more than 20 years, overall morbidity has remained high in those exposed to the irradiation released by Chernobyl. One cannot give credence to the explanation that these numbers are due solely to socioeconomic factors. The negative health consequences of the catastrophe are amply documented in this chapter and concern millions of people.

The most recent forecast by international agencies predicted there would be between 9,000 and 28,000 fatal cancers between 1986 and 2056, obviously underestimating the risk factors and the collective doses. On the basis of I-131 and Cs-137 radioisotope doses to which populations were exposed and a comparison of cancer mortality in the heavily and the less contaminated territories and pre- and post-Chernobyl cancer levels, a more realistic figure is 212,000 to 245,000 deaths in Europe and 19,000 in the rest of the world. High levels of Te-132, Ru-103, Ru-106, and Cs-134 persisted months after the Chernobyl catastrophe and the continuing radiation from Cs-137, Sr-90, Pu, and Am will generate new neoplasms for hundreds of years.

A detailed study reveals that 3.8–4.0% of all deaths in the contaminated territories of Ukraine and Russia from 1990 to 2004 were caused by the Chernobyl catastrophe. The lack of evidence of increased mortality in other affected countries is not proof of the absence of effects from the radioactive fallout. Since 1990, mortality among liquidators has exceeded the mortality rate in corresponding population groups.

From 112,000 to 125,000 liquidators died before 2005—that is, some 15% of the 830,000 members of the Chernobyl cleanup teams. The calculations suggest that the Chernobyl catastrophe has already killed several hundred thousand human beings in a population of several hundred million that was unfortunate enough to live in territories affected by the fallout. The number of Chernobyl victims will continue to grow over many future generations.

The good news is that we don't need to jump from the coal frying pan into the nuclear fire since we can solve our energy security, climate change and air pollution mortality problems with renewables.

Abstract here: http://www.rsc.org/publishing/journals/EE/article.asp?doi=b809990c

Full article for download here: http://www.stanford.edu/group/efmh/jacobson/revsolglobwarmairpol.htm


Energy Environ. Sci., 2009, 2, 148 - 173, DOI: 10.1039/b809990c

Review of solutions to global warming, air pollution, and energy security

Mark Z. Jacobson

Abstract
This paper reviews and ranks major proposed energy-related solutions to global warming, air pollution mortality, and energy security while considering other impacts of the proposed solutions, such as on water supply, land use, wildlife, resource availability, thermal pollution, water chemical pollution, nuclear proliferation, and undernutrition.

Nine electric power sources and two liquid fuel options are considered. The electricity sources include solar-photovoltaics (PV), concentrated solar power (CSP), wind, geothermal, hydroelectric, wave, tidal, nuclear, and coal with carbon capture and storage (CCS) technology. The liquid fuel options include corn-ethanol (E85) and cellulosic-E85. To place the electric and liquid fuel sources on an equal footing, we examine their comparative abilities to address the problems mentioned by powering new-technology vehicles, including battery-electric vehicles (BEVs), hydrogen fuel cell vehicles (HFCVs), and flex-fuel vehicles run on E85.

Twelve combinations of energy source-vehicle type are considered. Upon ranking and weighting each combination with respect to each of 11 impact categories, four clear divisions of ranking, or tiers, emerge.

Tier 1 (highest-ranked) includes wind-BEVs and wind-HFCVs.
Tier 2 includes CSP-BEVs, geothermal-BEVs, PV-BEVs, tidal-BEVs, and wave-BEVs.
Tier 3 includes hydro-BEVs, nuclear-BEVs, and CCS-BEVs.
Tier 4 includes corn- and cellulosic-E85.

Wind-BEVs ranked first in seven out of 11 categories, including the two most important, mortality and climate damage reduction. Although HFCVs are much less efficient than BEVs, wind-HFCVs are still very clean and were ranked second among all combinations.

Tier 2 options provide significant benefits and are recommended.

Tier 3 options are less desirable. However, hydroelectricity, which was ranked ahead of coal-CCS and nuclear with respect to climate and health, is an excellent load balancer, thus recommended.

The Tier 4 combinations (cellulosic- and corn-E85) were ranked lowest overall and with respect to climate, air pollution, land use, wildlife damage, and chemical waste. Cellulosic-E85 ranked lower than corn-E85 overall, primarily due to its potentially larger land footprint based on new data and its higher upstream air pollution emissions than corn-E85.

Whereas cellulosic-E85 may cause the greatest average human mortality, nuclear-BEVs cause the greatest upper-limit mortality risk due to the expansion of plutonium separation and uranium enrichment in nuclear energy facilities worldwide. Wind-BEVs and CSP-BEVs cause the least mortality.

The footprint area of wind-BEVs is 2–6 orders of magnitude less than that of any other option. Because of their low footprint and pollution, wind-BEVs cause the least wildlife loss.

The largest consumer of water is corn-E85. The smallest are wind-, tidal-, and wave-BEVs.

The US could theoretically replace all 2007 onroad vehicles with BEVs powered by 73000–144000 5 MW wind turbines, less than the 300000 airplanes the US produced during World War II, reducing US CO2 by 32.5–32.7% and nearly eliminating 15000/yr vehicle-related air pollution deaths in 2020.

In sum, use of wind, CSP, geothermal, tidal, PV, wave, and hydro to provide electricity for BEVs and HFCVs and, by extension, electricity for the residential, industrial, and commercial sectors, will result in the most benefit among the options considered. The combination of these technologies should be advanced as a solution to global warming, air pollution, and energy security. Coal-CCS and nuclear offer less benefit thus represent an opportunity cost loss, and the biofuel options provide no certain benefit and the greatest negative impacts.

[Statistical]

4. "The AP1000 design is unique, with only one containment barrier." A complete lie.

The AP1000 doesn't have a single containment.

Like all reactors it has a sealed fuel assembly (containment #1), reactor pressure vessel (containment #2) and a steel containment structure (containment #3).

NRC regulations require that all reactors built in the US (past and future) have 3 levels of containment.




Traditional (GenII) PWR:
fuelassembly(#1)-reactor(#2)-SteelContainment(#3)-Concrete

AP1000
fuelassembly(#1)-reactor(#2)-SteelContainment(#3)-Space-Concrete

The only difference between the AP100 and a Gen II PWR is that there is a space between the concrete missile shield and the steel containment structure to facilitate passive cooling. This feature along with others makes the reactor safer because it is able to cool without any electrical power.

As usual the anti-nukkers need to rely on lies to continue their luddite agenda.

[kristopher]

5. You figure out how to better explain that in a bullet point summary

There is detailed information available for clarity.
http://fairewinds.com/AP1000-Containment-Leakage-Report-Fairewinds-Associates-Inc



You must not understand how much like chickenshit your nitpicking objections" and your "you lie" mentality appears.

[Statistical]

6. Nitpicking really?

AP1000 reactor has 3 containment layers.
All western reactors have 3 containment layers.
To indicate otherwise is dishonest. Period.

The "bullet point" states reactor has a single containment layer and then provides details on corrosion risk. That is completely false. Do you think that was accidental? Really? That it wasn't intentional to make a casual observer go "single containment layer and if is corrodes it will breach and dump radiation into atmosphere" OH NOES OH NOES.

Of course the reality is that COULD HAPPEN except it would require all 3 containment layers to fail AT THE SAME TIME and not be detected in time.

If containment structure corrodes through but reactor containment is solid then there is no radiation release.
If containment structure is solid and reactor breaches then there is no containment release.
IF containment structure and reactor corrode at the same time (and nobody detects either one) and the fuel assembly holds then there is no radiation release.

It is only when all three components fail AT THE SAME TIME (and none are detected) that a radiation release will occur. This is the same on AP1000 as it is on any other reactor ever built in the United States. A fact "accidentally" left off of a page long article. Wonder why that was?

Up = Down
War = Peace
1 = 3
All anti-nukers have is lies and more lies.


Obama supports nuclear power.
American supports nuclear power.
The Climate Change bill is going to include even more support for nuclear power.
55 reactors under construction right now (55.4 GW)
98 reactors in planning.

[kristopher]

9. That is nitpicking chickenshit.

You are miffed that reactor vessel isn't labeled containment even though it isn't the common method of nomenclature to refer to it in that manner.
Here is your graphic without your adornments:


Reactor vessel and containment - not the same; although one would not be able to discern that with your initial false labeling of the drawing. It is also clearly different than any other design in that the concrete is not performing the function of containing gasses that corrosion of the metal containment layer might release; instead it is, by design, working as a chimney to release the gas.

I'm sorry but your "criticism" amounts to picking on the definition of a word (and you have no basis for even that) while totally ignoring the substance of the problem being highlighted in the design. Your dismissal of potential corrosion problems with the containment design with an unjustified attack on the verbiage in the report is more of the same type nitpicking chickenshit that characterizes all of your recent defenses of the Republican's nuclear energy policy.

"It is only when all three components fail AT THE SAME TIME (and none are detected) that a radiation release will occur" you wrote. Well, D'uh!

The fact is the reactor appears to have a significant flaw that needs to be addressed before it is brought online. The point of containment is that it is designed to contain a failure. What you apparently endorse is that we should ignore the potential for corrosion and weakening of the single layer of "containment" and trust that the reactor vessel will never need it.

And if it is an example of dishonesty in the debate that you want then you need look no further than your continued use of that deceptive graph about public attitudes regarding nuclear power. That presentation of data is not the sentiment that the underlying poll reveals. First, here is a clear image of public support for nuclear:

Associated Press/Stanford University Poll conducted by GfK Roper Public Affairs & Media. Nov. 17-29, 2009. N=1,005 adults nationwide. MoE ± 3.1.

"In general, would you favor or oppose building more nuclear power plants at this time?"
Favor 49 Oppose 48 Unsure 3

***********************************************************************

CNN/Opinion Research Corporation Poll. Oct. 16-18, 2009. N=1,038 adults nationwide. MoE ± 3.

“To address the country’s energy needs, would you support or oppose action by the federal government to ?” (Half Sample)

"Increase coal mining"
Support 52, Oppose 45, Unsure 3

"Build more nuclear power plants"
Support 52, Oppose 46, Unsure 2

"Develop more solar and wind power"
Support 91, Oppose 8, Unsure 1

"Increase oil and gas drilling"
Support 64, Oppose 33, Unsure 3

"Develop electric car technology"
Support 82, Oppose 17, Unsure 2

"Require more energy conservation by businesses and industries"
Support 78, Oppose 20, Unsure 2

"Require more energy conservation by consumers like yourself"
Support 73, Oppose 25, Unsure 3

"Require car manufacturers to improve the fuel-efficiency of vehicles sold in this country"
Support 85, Oppose 14, Unsure 1

Asked of those who support building more nuclear power plants:
"Would you favor or oppose building a nuclear power plant within 50 miles of your home?"
Favor 66, Oppose 33

What the graphs stats used charts is actually how worried people are about energy and climate. The underlying poll asks if nuclear should be "one of the ways" to provide electricity for the US.

Influences on that graph:
1) Nuclear already IS one of the ways, so the reader must be in favor of decommissioning nuclear power in a time of uncertainty regarding energy security and climate change to be "opposed".

2) The answers are divided into 4 categories; and what isn't shown is that the shift to "strongly support" has only changed a couple of percentage points.

3) When you compare the Gallup poll with the two posted above (those are typical of polling on the issue) you can see the way energy security is a higher priority than environmental issues for those who state direct support for nuclear power as it is identical to the results for building more coal plants, and tracks the approval of drilling for petroleum closely.

The use of that graph is a standard attempt to create foster "the bandwagon effect"


I wonder what the results of polling would be if respondents were shown this graph first:


Full cost report by Cooper here:
http://www.olino.org/us/articles/2009/11/26/the-economics-of-nuclear-reactors-renaissance-or-relapse
http://www.olino.org/us/articles/2009/11/26/the-economics-of-nuclear-reactors-renaissance-or-relapse

[Statistical]

10. Concrete doesn't contain gases at high pressure (well at least not in the real world).

"It is also clearly different than any other design in that the concrete is not performing the function of containing gasses"

Once again you are wrong. It is clearly different because it can be passively cooled (with no human operators and no electrical power) however concrete missile shield has never had the job of containing gases that is the job of the steel liner.

Concrete doesn't contain gases, certainly not gases at high pressure, it is porous.

NRC regs requires a containment building handle a variety of stresses:
1) contain overpressure for steam explosion
2) handle accidental or intentional impacts from outside (missiles, aircraft, natural disasters)
3) prevent accidental release of nuclear material in event of a failure inside containment.

As such the containment building consists of multiple layers. Now in the past the design simply put the steel layer and concrete layer together. However nothing in the regs requires that. If concrete could prevent release of gases there would be no need for expensive steel liner to begin with. Just build the whole containment out of concrete.

You make the false assumption that concrete layer is used to prevent escape of gases and that leads you to false conclusion. The concrete layer is designed to handle high speed impacts (missile shield). The steel layer is designed to prevent release of radioactive material. Combined they are provide enough strength to withstand a worst case overpressure (about 10 atmospheres of pressure).

Now the AP100 design has some disadvantages in terms of cost. By putting steel layer and concrete layer together you get improved strength with less material (which is why all previous reactors do). Since AP1000 seperates the layers both now need to be thicker, heavier, higher strength to meet the NUREG-1150 requirements. The thicker concrete missile shield isn't that big of a deal but the AP1000 requires roughly the steel containment to be about 3x as thick. Steel is expensive especially high tensile strength corrosion resistant steel. So why do that? Why spend MORE money on steel when trying to lower cost of nuclear power?

Because existing reactors have one (although highly improbably flaw). In loss of all electrical power fission can still be stopped but decay heat will eventually melt the reactor. By having the steel layer exposed to air it acts as a giant heat sink, this is added by cooling the steal with water (via gravity) and air via natural draft. In an overpressure event water from emergency cooling tank cools outside of steel layer and heat is transferred out of the reactor PASSIVELY. The water tank and passive design can cool decay heat without any human response or even any electricity on site (to run pumps).

You love to bash how new reactors are more expensive. This is an example of why. The newer design is more expensive and It is unlikely this passive cooling will ever be needed however it provides a final line of defense beyond what existing reactors have.

So:
AP1000 w/ hole in steel liner and radioactive material loose in containment = leaks
Gen II PWR w/ hole in steel liner and radioactive material loose in containment = leaks

Of course both those scenarios ignore the fact that containment is not radioactive under normal operations (and not even radioactive under most emergency situations).

So
1) an accident would need to occur
2) fuel assembly would need to breech (likely from overheat)
3) the reactor would need to breech or be intentionally depressurized
4) the containment would need to have an undetected hole in steel liner

If even one of those things is not true then by virtue of defense in depth radiation would note be released from structure.


Funny thing is NRC tests the steel liners of containment structure by over-pressurizing containment building. If there is a hole pressure will drop and the rate of pressure drop helps to estimate the size of the hole. If concrete contained gasses at high pressures well then that test would be kinda useless huh?

[kristopher]

11. More bullshit sophistry.

Your #3: 3) prevent accidental release of nuclear material in event of a failure inside containment.

[Statistical]

12. Yeah that is the function of the steel liner because .........

CONCRETE CAN'T CONTAIN GASES AT HIGH PRESSURE! :rofl:

Trying to use concrete to stop release of radioactive gases is kinda like having a screen door on a submarine.

Luckily nuclear engineers are smarter than that and use AIR-TIGHT material - steel to produce an air-tight barrier to prevent release of radioactive material.

[kristopher]

13. Yet more bullshit sophistry.

The concrete mated to the steel is a two wall barrier to the gasses.

[Statistical]

14. And what happens if there is a hole in the steel?

The concrete magically stops gasses by itself or the containment leaks because the steel is what is airtight?

So a hole in conventional containment will leak pressurized air and a hole in a AP1000 containment will leak pressurized air.
Of course a leak only matters if containment is flooded with radioactive material otherwise it is simply air non-radioactive air leaking.

Please let us know how many times in last 50 years in the United States that containment has been flooded with nuclear material at a commercial power reactor?
To those playing at home he already knows the answer. Grand total is 0.

Of course a hole in containment can be detected. Reactors are constantly hot, the air inside containment is hot.

combined gas law tells us that since temperature is higher and volume is fixed (air tight) pressure will be higher in containment than outside.



If a leak were to develop pressure would drop as pressure between inside and outside of containment equalized. Air pressure inside containment is constantly monitored. A pressure drop is a trip event (emergency reactor shutdown) because it means that containment is no longer airtight.

To supplement that the NRC checks containment strength during refueling outages by over-pressurizing the containment building.
Any hole in steel liner (or in this case steel structure) will cause a pressure drop and the reactor won't be cleared to go critical again until it is found and patched.


So:
If containment was flooded with radiation (which has never happened not even once in the United States) and a hole was undetected in containment wall (which would have to violate the combined gas laws) then yes radiation would be released from containment.

Of course the same thing would happen in an existing GenII PWR.

[kristopher]

15. Well with that logic let's just get rid of all safety systems.

You are, literally, unbelievable.

[Statistical]

16. We aren't getting rid of safety systems we are adding a whole new layer of redundant systems.

We are adding a whole new level of safety systems. Passive safety. A reactor that can cool itself even in the most dangerous type of accident, Loss of Coolant Accident.

So we have:
* normal cooling (routine operation 4 pumps running at 50% power to cool reactor and transfer heat for steam)
* redundant cooling (2 of 4 pumps running at full power can cool reactor in loss of 1 or 2 pumps)
* redundant electrical power (onsite, offsite, and 2 backup generators)
* redundant flywheel power (pumps are connected to flywheels which can keep them spinning even in loss of all power)
* quadruple redundant decay heat cooling (4 pumps only one is needed to cool reactor after a trip - fission stops decay heat remains)
* forced emergency cooling (in case of routine cooling system failure)
* depressurized cooling (depressurize the reactor and cool the steam via emergency water tank)
.....
now we add passive cooling. If every human operator was dead and all 4 sources of power gone, pumps destroyed, emergency cooling failed, and depressurized cooling has failed the containment itself can acts as a heat sink and transfer heat away from the damaged reactor.

Likely never in my lifetime, my kids lifetime, and their kids lifetime will we ever see an event where all that is needed but it is there just in case.

[kristopher]

18. And in the process creating a potential for failure.

They are CHANGING WHAT HAS WORKED TO TRY A NEW DESIGN.

That design has an identifiable flaw.

You would rather ignore it because it might make harm the chances for "The Nuclear Revival".

That says it all.

[Statistical]

19. No the added safety is far worth the change and this non-existent risk.

IN ANY REACTOR IF THE STEEL LINER HAS A HOLE IT WILL LEAK RADIATION.

Concrete can't stop radioactive gases. If it could we would save a couple hundred million bucks and just build containment out of concrete.

The AP1000 containment structure is MORE expensive than a traditional PWR. This doesn't make the reactor more economical or last longer. It simply makes the reactor even safer in the virtually impossibility that all existing safety systems fail at the same time.

[FBaggins]

20. Welcome to the nuclear club!

What size t-shirt do you want?

Thanks for admitting that what currently exists has worked just fine.

But you eventually need to come around to the fact that there is no single "current design". There's absolutely no reason not to improve safety levels on areas where plants HAVE failed (human error) in the past... and to unite plant design for significant cost efficiencies.

That design has an identifiable flaw.

Bull. It has an invented flaw. Just 'cause you're selling doesn't mean that anyone else has to buy it.

You would rather ignore it because it might make harm the chances for "The Nuclear Revival". That says it all.

Lol! Exactly the opposite is true. They would rather lie than accept the truth because the truth harms their chances of scaring people in to doing what they want.

[FBaggins]

7. Bullets? No problem.

Bullet #1 - They lied

Bullet #2 - You bought it

Bullet #3 - You're trying to sell it

[joshcryer]

8. Thanks for the informative post.

[NNadir]

17. My INDEPENDENT opinion is that anti-nukes citing each other and declaring themselves INDEPENDENT

evokes the spelling of this word: L-I-A-R-S.

Most anti-nukes are independently owned agents - often highly paid "independently owned" - in the Greenwashing industry.

The number of anti-nukes who understand nuclear technology is exactly what's it's always been: Zero.