Team conducts ongoing research to evaluate performance of reactor cooling system

Team conducts ongoing research to evaluate performance of reactor cooling system
Credit: Texas A&M University

On March 11, 2011, Japan was rocked by an earthquake and tsunami that caused the shutdown of the Fukushima Daiichi plant's active nuclear reactors, disabled all sources powering core cooling systems and caused three of the reactor cores to overheat. The resulting meltdowns caused the release of radioactive material into the surrounding area, a disaster that has spurred investigations and research into the performance of the safety systems installed in these reactors.

Despite the effects of the disaster, the Reactor Core Isolation Cooling (RCIC) system performed much better than expected within units two and three, operating in unit three up to eight times longer than intended in those conditions. Understanding the cause behind the RCIC system's performance and applying it to U.S. reactors is where Sandia National Laboratories and the Department of Nuclear Engineering's Dr. Karen Vierow come in.

"I'm looking at the system from a couple of viewpoints," Vierow said. "One being, how did it run for so long without power and two, can we take credit for the system in our U.S. reactors to operate for extended times without power? The two times the safety system was called upon, it operated far beyond what we currently take credit for."

The RCIC system in the Fukushima Daiichi unit two and three reactors use a steam-driven turbine to power a pump that returns water to the reactor core and cools it. The system needs power to regulate the turbine to cool the reactor but can run on battery power for four to eight hours during what are called "isolation conditions", conditions present during the Fukashima incident where the reactor was isolated from its primary power source. However, during the incident, two of the reactors continued to be cooled on the RCIC system for 20 hours and 70 hours, respectively, despite exceeding the four to eight hour window to battery power the system. Understanding why the system performed as well as it did can benefit the 25 boiling water reactors in the United States that also operate the RCIC system.

"We do not completely understand why the RCIC System operated for this long even though it is a good thing," Vierow said. "We'd like to know how it performed under these conditions and how we can assure that the same system in our national reactors would operate as well."

Vierow is collaborating with researchers at Sandia National Laboratories on this project, which was initially funded by the U.S. Nuclear Regulatory Commission until Vierow later received a grant from the U.S. Department of Energy (DOE). Vierow's particular research application to discovering the secret of the RCIC System's performance lies in studying the cooling of the system in relation to thermal mixing in the containment. Vierow began to look at the thermal mixing and the condensation of steam in the reactor's suppression chamber to see where the thermal energy is distributed and how it effects the RCIC System.

Vierow and her team are also gathering new scientific data on the reactor's turbomachinery and are convinced that steam and water enter the turbine during its operation, despite the fact that turbines are designed for gas-phase intake only.

"If we can understand the system better and how the turbine behaves when it ingests the steam and water two phase flow, we can use that information to predict how the system would operate in our U.S. BWRs," Vierow said. "This will help provide guidance to whether the RCIC System in our BWRs can be used for longer than the duration that we currently allow them to be used for."

Vierow and her team will use this data to develop detailed numerical models of the steam-water two-phase flow behavior in the turbine, which will give them the knowledge to suggest changes to the RCIC System design or other improvements to ensure that the system can be counted on for extended periods of time. The data Vierow has gathered on thermal mixing in this RCIC System could also be used in other reactor applications.

"It's a system designed for isolation events, but we saw that it has a large potential for a loss of power situation which we call station blackout," Vierow said. "The Fukushima reactors were under station blackout for several days and if this RCIC System is already in place for 25 of our reactors for isolation events [then] it could also have a very important role in station blackout events. It then gives this system a whole new role and needs to be evaluated for how long it can be used."


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Citation: Team conducts ongoing research to evaluate performance of reactor cooling system (2016, July 21) retrieved 21 August 2019 from https://phys.org/news/2016-07-team-ongoing-reactor-cooling.html
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Jul 21, 2016
Give it up, and spend the rest of the money finding a way to safely store the astounding amount of intensely-radioactive waste already generated.

Or spend it on alternative energy for which we do not need dangerous technologies.

Jul 21, 2016
Give it up, and spend the rest of the money finding a way to safely store the astounding amount of intensely-radioactive waste already generated.
"..wind industry may well have created more radioactive waste last year than our entire nuclear industry produced in spent fuel."
http://institutef...inerals/
http://e360.yale....ks/2614/

Jul 22, 2016
I have worked on reactors as a steamfitter since they first started being built. I have seen huge ice trays built overhead to dump on reactor in case of a problem Along with several other methods of cooling them
I am not a engineer and don't pretend to be. I have always wondered why instead of trying to cool the core, why they don't use the molten core itself to shut down reaction. I understand that there has to be a critical mass to go and stay critical. Why not build a large pyramid under the core with channels down the sides so if core melted thru the cement containment it would land on the tip of the pyramid and in it's molten state go separate ways down the sides. I know it's as hot as the sun and would quickly burn thru the pyramid but not before it started spreading out. At which point you attempt to start cooling it.

Jul 22, 2016
rderkis, it is called a "core spreader", and just because they have such faith in their monsters, they already have invented it.

But that is like inventing a horse roundup after the barn door was left open.

Jul 22, 2016
I am not a engineer and don't pretend to be.
this does not apply to gskam.

Jul 22, 2016
What do they do with the molten blobs of intensely-radioactive material? They cannot even view the stuff at Fukushima because the radiation kills everything, including the robots.

Meanwhile, the wind turbines at Altamont have produced power for decades without any waste at all, let alone that stuff we cannot even find ways to store. And they operate at peak, when we need it most.

Jul 22, 2016
it is called a "core spreader", and just because they have such faith in their monsters, they already have invented it.
But that is like inventing a horse roundup after the barn door was left open.


Invention, no just a idea. Just like a horse roundup is not a invention but perhaps it could be called a procedure..
And a horse roundup after the barn door has been left open, only makes sense to me.

Jul 22, 2016
It is an invention, and not just an idea. It is a physical device.

But you emplace the device before your reactor melts down, something they said was impossible.

Jul 22, 2016
..at Fukushima because the radiation kills everything..
no human being was killed by radiation at Fukushima Daiichi.
..the wind turbines at Altamont..
a bunch of ugly intermittent bird-choppers/landscape-destroyers with strong reliance on fossil fuels to prevent instabilities on the grid.

Jul 22, 2016
It is an invention, and not just an idea. It is a physical device..

A horse roundup is a invention?
Or was that just a poor analogy?

Jul 22, 2016
It is an invention, and not just an idea. It is a physical device.

But you emplace the device before your reactor melts down, something they said was impossible.
I googled "horse roundup" and could find no such device.
http://www.wildho...ups.com/

-Is this some kind of drone or helicopter or mechanical dog george?

Please provide a link describing such a device.

Is this one?
https://www.youtu...WvLpCdTg

Jul 22, 2016
Is this one george?
https://www.youtu...rMRTVnYE

-It is cool but probly wasnt invented for rounding up horses. But maybe you could use your talents to bullshit someone into buying one for that purpose.

Jul 23, 2016
Meanwhile, . . . .

http://www.theeco...ond.html

Jul 23, 2016
From above:
"And EDF is now facing a big, unexpected headache of its own: yesterday morning investigators from France's Financial Markets Authority (AMF) made a dawn swoop on EDF's offices, demanding a meeting with EDF's secretary general, Pierre Todorov, and the production of series of documents. A surprised witness told Le Monde that it was "a real search, even if it does not bear the name".

The documents concerned EDF's €55 billion 'major overhaul' of all its French nuclear power plants, and the €22 billion Hinkley C project: in both cases the key question being whether EDF wrongfully concealed information from shareholders who have lost 45% of their value in company in three years, while in late 2015 the company was excluded from the CAC 40 index flagship of the Paris Bourse."

Jul 23, 2016
"€22 billion Hinkley C project"

-------------------

For ONE powerplant with one reactor? Are they completely nuts?

How many wind turbines, PV generating stations, geothermal plants, zero-energy buildings could we build with that money? None of those produce intensely-radioactive waste we cannot even store yet, and their "fuel" is essentially free, and never runs out.

Jul 23, 2016
"€22 billion Hinkley C project"

-------------------

For ONE powerplant with one reactor? Are they completely nuts?

How many wind turbines, PV generating stations, geothermal plants, zero-energy buildings could we build with that money? None of those produce intensely-radioactive waste we cannot even store yet, and their "fuel" is essentially free, and never runs out.
And so what does this have to do with a horse rounder-upper?

Are you trying to change the subject??

"But there is something else about the speech of psychopaths that is equally puzzling: their frequent use of contradictory and logically inconsistent statements that usually escape detection."

"And so on. The point that the researchers noted was that psychopaths seem to have trouble monitoring their own speech."

"gib·ber·ish
ˈjib(ə)riSH/
noun
unintelligible or meaningless speech or writing; nonsense.
"he talks gibberish"
synonyms: nonsense, garbage, balderdash, blather, rubbish"

Jul 23, 2016
"EDF's 'final investment decision' on the Hinkley C nuclear power station next week will be pure theatre, writes David Toke. The truth is that no concrete is to be poured until 2019 at the earliest. Meanwhile post-Brexit UK is running out of money to pay for it, and EDF is under investigation by the Financial Markets Authority for concealing information on Hinkley from investors."

Is that what we want for our future? A 22 billion-Euro economic and technical disaster?

I predict it will not generate any power, but may bankrupt a nation.

Jul 23, 2016
Quite frankly, designing a nuclear reactor requiring actively powered cooling systems is an epic engineering fail. Only dim-witted, greedy corporate bureaucrats and their cronies in government would allow this to happen. We should drop them all into Fukushima and tell 'em to lick up all the radioactive waste.

Jul 24, 2016
Any nuclear reactor is now passe. We do not need such dangerous and nasty technology, we have alternatives now. Clean ones.

With PV and wind and geothermal and others, we do not need fuel, and do not produce nasty waste. The only reason we still have nukes is the economic and political power of the builders, who get LOTS and LOTS of money for their stuff, leaving us with waste nobody can even safely store.

Give it up before the entire Earth is contaminated with that folly.

Jul 24, 2016
With Chernobyl, Fukushima,and the dozens of "problems" the public is unaware of, plus the unsustainable cost of the physical plant, nuclear power should have been dead decades ago.

The reason we are still stuck with it is Big Money, and the politicians it owns. If you like it, go buy power from one, then keep the waste generated by that use. I do that with my solar cells, they can do it, too, . . right?

Jul 24, 2016
With PV and wind and geothermal and others, we do not need fuel,..
In fantasy world, fossil fuels are unnecessary to mine/manufacture and to compensate intermittency of eco-friendly bird-choppers/landscape-destroyers, but in the real world, renewables and fossil fuels are ever symbiotic and produce much more waste per unit of energy generated than carbon-free nuclear power.

Jul 24, 2016
Safety research is always a good idea when you have the data to do it.

Jul 24, 2016
We still do not know the true cost of nuclear power, just the minimum. We do not have any real way to store the intensely-radioactive and exothermic waste from this huge folly.

How much will it cost to guard,with deadly force, this stuff for about 200,000 years? Got any idea? And how are you going to store it? Found a proven way yet?

How many more Fukushimas and Chernobyls and the next ones will it take before we stop this madness?

Jul 24, 2016
So Gracie likes unsafety.

Noted.

Jul 24, 2016
We still do not know the true cost of nuclear power, just the minimum. We do not have any real way to store the intensely-radioactive and exothermic waste from this huge folly.

How much will it cost to guard,with deadly force, this stuff for about 200,000 years? Got any idea? And how are you going to store it? Found a proven way yet?

How many more Fukushimas and Chernobyls and the next ones will it take before we stop this madness?

Jul 24, 2016
200,000 years?
a pathological charlatan cheater engineer is unable to understand that "the more radioactive an isotope is, the faster it decays."
"The radioactive elements in the spent fuel have short half lives, and the radioactivity of the spent fuel is down to one percent of the original level in 300 years. The spent fuel casks can be safely stored"
http://www.world-...agement/
http://www.braine...-nuclear
bogus-environmentalists are unable to understand that their ecologically hypocritical means of energy production are causing much more impacts on the environment than carbon-free nuclear power.

Jul 25, 2016
intensely-radioactive and exothermic waste
"Modern reactor technology has advanced so that we can re-use waste stockpiles and old warheads to produce clean electricity for hundreds of years without mining more uranium."
"We have been misled by fearmongers."
"Nuclear power is not the bogey that anti-nuclear groups have led us to believe. It has the lowest death rate per kilowatt hour of any generating technology including wind and solar."
"New nuclear power plant designs can shut down safely using the laws of physics, without the need for back up generators or an operator present."
http://mothersfor...ne-brook

Jul 25, 2016
Sleazoids for rent.

See above.

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