Best New Reactor Design

[Broadzilla]

Mitsubishi new design is noteworthy. Comanche Peak is buying? 2 of them.

Maybe, the NRC hasn't certified the design yet and say it won't be for quite some time.

Mike

[deaztrailnutz]

Allis And Chambers used a dedicated steam drum. All the first generation BWRs used Smaller versions of PWR Containments. When GE started to build them bigger they had to go to the Pressure Suppression type containment otherwise the containment would have had to be 8 times larger than a similar PWR Containment. Given a PWR containment is about 2.5 to 3.0 Million Cubic feet...

The PWR world went with the large freestanding containments AND the infamous Ice Condenser. I'm STILL shaking my head on how they came up with that solution. I work at an Ice Condenser Plant.

Mike

How does an ice condenser work?  I hear alot of bruh-ha-ha over them

[Marlin]

Containments have to contain a projected pressure surge from steam release in an accident this can be done through the volume of the containment. The volume can be reduced by operating in a subatmospheric pressure or by using a heat sink to condense the steam. The ice condensor is essentially a compartment isolated from the rest of the volume of the containment that is inside the pressure vessel with blowout panels to allow stem to enter the chamber full of crushed ice during an accident.

[Broadzilla]

If y'all want a slightly more detailed version I'd be happy to provide it without a huge amount of Technospeak. The one thing Marlin said, about it being crushed ice is true and makes sense but when I first saw it I was amazed. I initially thought Ice Condensers were huge blocks of ice.

Mike

[deaztrailnutz]

How much ice is required for plants like McGuire or Cook?  How is the ice maintained & stored?

[Limited Quanity]

If y'all want a slightly more detailed version I'd be happy to provide it without a huge amount of Technospeak. The one thing Marlin said, about it being crushed ice is true and makes sense but when I first saw it I was amazed. I initially thought Ice Condensers were huge blocks of ice.

Mike

Hey ain't nothing like walking into a 15 deg F freezer, spending 15 min. (shiver)  walking on top of >2.4 million lbs of ice for a survey, checking doors, or AHU's, and then walking back into the real world at 90+ deg.  Takes a few minutes for your safety glasses to unfog, huh!  Gotta be careful!

[Roll Tide]

How does an ice condenser work?  I hear alot of bruh-ha-ha over them

Wouldn't this be "off-topic" for "Best New Reactor Designs"? Not to be a stickler here, but ice condensers have less future than Edsels...

[Broadzilla]

Wouldn't this be "off-topic" for "Best New Reactor Designs"? Not to be a stickler here, but ice condensers have less future than Edsels...

TECHNICALLY Ice Condensers have a brighter future at least near term than any new type of containment. I dare say the next nuke licensed in this country will be an Ice Condenser Plant. Just a hunch though.

Mike

[RDTroja]

The PWR world went with the large freestanding containments AND the infamous Ice Condenser. I'm STILL shaking my head on how they came up with that solution.

According to the tales of yore (many moons ago...) the ice condenser plant was developed to reduce containment volume to enable the construction of Atlantic 1 & 2 which were designed to float... yes, I said float. They were envisioned to be able to respond to power shoratges up and down the Atlantic coast and 'plug in' to any city that needed the power. Gotta love the ideas that people came up with.

[Roll Tide]

yes, I said float. They were envisioned to be able to respond to power shoratges up and down the Atlantic coast and 'plug in' to any city that needed the power. Gotta love the ideas that people came up with.

Guess that explains the current emphasis on "fitness for duty". Definitely a smokey haze in that room... 

[Limited Quanity]

TECHNICALLY Ice Condensers have a brighter future at least near term than any new type of containment. I dare say the next nuke licensed in this country will be an Ice Condenser Plant. Just a hunch though.

Mike

I say we're just waiting on the new checkbook to come in starting this next fiscal year.  Just told the $20 mil. is just about gone.  Most walkdown personnel and support groups will be gone at the end of the month.  Then we sit and wait....

[Nuclear NASCAR]

TECHNICALLY Ice Condensers have a brighter future at least near term than any new type of containment. I dare say the next nuke licensed in this country will be an Ice Condenser Plant. Just a hunch though.

Mike

So Watts Bar is an ice condenser plant, huh?

[Broadzilla]

So are Sequoyah, McGuire and Catawba.

Mike

[Limited Quanity]

So are Sequoyah, McGuire and Catawba.

Mike

So is DC Cook.

[Broadzilla]

Yeah DC Cook was almost the death of Ice Plants everywhere!

Mike

[Roll Tide]

So Watts Bar is an ice condenser plant, huh?

My bet is that WBN2 is the last of the breed. Talk about penny-wise and pound foolish. Tons of money for ice for the life of the plant versus constructing a larger containment initially.

[OldHP]

The ICC was conceived of for Atlantic 1 & 2 which were floaters - but not mobile, i.e., plug into any city (that was another concept - similar to MH1A, but using the ICC).  Atlantic 1 & 2 were to be off-shore, adjacient to and accessed through the Salem Hope Creek complex, because there simply wasn't enough space to build another two units at the site. Those units went away along with Hope Creek 2.
The sales pitch concept was that after 10 yrs of operation you added water to replace the ice weight lost through sublimation.  At 20 years you refilled!
Concept Circle-Bar - Proven Wrong - as anyone familiar with the IC plants knows!  But Circle-Bar had enough marketing skill to convince land based Utilities that they would work for low profile containments that would be acceptable to the public.
If TVA decides to go forward with WB-2, then Mike is right an ICC will be the next plant to come on line.  But, as for the next generation of plants, the AP-1000 would be a safe bet since it is the only one approved right now.

[RDTroja]

As I heard the story 100 years ago, Atlantic 1 & 2 found a home at Salem after someone ran out of good drugs long enough to figure out that the concept of moving them was absurd. Then they became 'fixed'. Artificial Island was originally designed for 12 nuclear plants and when I was first there they were still talking like they were all going to be built.

[OldHP]

Correct - Except that 1 & 2 actually went the route of CPs. 3 -12 never got past the drawing board, along with Atlantic 13 - 24 and STP 3 - 8.

[Smooth Operator]

In reference to ice condensers...

So how do you keep these large chunks of ice from melting? I am imagining some pretty robust refrigeration machines. Also, when is the ice changed out? Is this a refueling outage project or is there some sort of engineered system to allow change at power or reduced power?

[Broadzilla]

The reactor and SG and Pzr are either inside a wall called the Polar Crane wall or are inside enclosures.

The Ice Condenser is insulated from the heat sources. It has Doors that open into the Lower Containment where the RCS and Piping is. The ice itself is in 1944 12 foot tall baskets. The baskets are lattice in construction. These baskets are stacked 4 high in a 300 degree arc inside containment. The ice itself is like a snow cone. The ice is made by Ice machines outside containment. Essentially borated water is sprayed onto a barrel and the ice is knocked off the barrel and blown via elephant trunk into the baskets. There's well over 2.5 million pounds of ice in the ice condenser. The Ice Basket area is called Lower Ice
Above the Ice Baskets are the Intermediate Doors, then a plenum then the upper doors. This area is called Upper Ice. In this area are a lot of Airhandling Units. These units have ductwork going to the bottom of lower ice. There is a Glycol System outside containment consisting of Pumps and chillers. These lower glycol temperature to about 5F, then pump the glycol to the Air handlers to keep the Ice Condenser below 27F. The optimum level is 18-20F to minimize sublimation. The Air Handlers and Chillers and pumps are Non Safety Related. Post accident the pipes penetrating containment isolate. We also keep the ice borated to 2500-2700 PPM and at a PH of about 9 to 9.5. The  borated ice is to ensure Ice melt cannot dilute water coming in via the ECCS. The PH is to scrub Iodine. Ice Plants have an Upper and Lower containment that are sealed from each other.

Below the stacks of ice baskets are flow distributors that turn the steam from a LOCA up into the Ice Condenser.
1: Loca Happens
2: Lower Ice Doors Open
3: Steam is turned upwards into the ice baskets.
4: Steam flows through Ice Baskets, blows open the Intermediate Doors (Which are directly above the baskets)
5: Upper Doors blow open whatever is left blows into upper containment. Condensed water is directed back to lower containment via pipes.
6: Ice is designed to last about 60 minutes.
7: 10 Minutes after the accident starts Containment Air Return Fans start to blow any air and non condensables back into lower containment.

In answer to your other questions:

1: No if possible we never let the Ice Condenser above 27F even in outages. (about 29 is the max I've seen during an outage)
2: During outages they weigh a sample of Ice Baskets to ensure they are within Tech Spec Values, we also take core samples and boron samples.
3: The only work online inside containment is on the Air Handling Units and inspections to ensure the doors are not iced shut.

There is also a glycol system to cool the floor of the ice condenser down so the floor doesn't buckle. DC Cooks floor buckled because they didn't pay good attention to this system.

During outages, at least at SQN the Ice Condenser is a clean area in spots. Also it's weird seeing guys going into containment in coats for Ice Condenser entries.

[Smooth Operator]

Thanks for that knowledge.

Follow up: Is all the Ice Machine system considered Tech-Spec like an ECCS train/component? You mentioned tech spec related samples, but I was wondering if everything associated with the Ice Condenser is tech spec?

If it is, I am wondering why was the Ice Condenser design chosen over just building a bigger/thicker containment?


Edit: I re-read BZ post and see the chillers, glycol pumps and air handlers are not safety related. Does that mean they are not tech spec. If they are not safety-related, then what operation limits exist if you lose your snow cone machine?

[Broadzilla]

The Doors, Ice, Ice Baskets, and Ice Temperature Measuring system are TS. The Glycol, AHU, Chillers, and Pumps are not.
The containment isolation valves for the glycol piping are TS.
The hatches between upper and lower containment are TS.
Containment Air Return Fans are TS
The drain between Upper Containment and lower is TS .
Upper and lower containment have different Max Temperatures and oddly a lower temperature limit too.


Simple: An effort to build a smaller containment vessel that can withstand a lower pressure. Ice Containment Design limit is 12 # ie save money

[Smooth Operator]

I am wondering if over a 30 year license, the cost to maintain the ice condenser will be greater than the build cost of a bigger containment and its maintenence?

[Broadzilla]

No idea! I guess someone figured it is though in truth Ice Condensers are a Pain in the butt!

[RDTroja]

No idea! I guess someone figured it is though in truth Ice Condensers are a Pain in the butt!

I found the pain in my head, which I kept hitting on too-low hanging objects, and my back which I hurt trying st squeeze around in all the too-cramped spaces.

The whole thing was a pain in the ice.

[Broadzilla]

I found the pain in my head, which I kept hitting on too-low hanging objects, and my back which I hurt trying st squeeze around in all the too-cramped spaces.

The whole thing was a pain in the ice.

LOL.

When you're the guy who has to evaluate the Condition reports for "We dropped this into lower ice and can't find it" or this ice basket is stuck so we're justifying weighing another, OR his ice basket is too light but the average weight of the others is higher than needed plus we believe it won't create an unanalyzed flow channel due to early melt.... well you'll know why I hate the dang thing.

Plus lets face it, usually the chillers and pumps aren't in the greatest shape and are most likely to fail in the hottest week of summer.

Cool concept though.

[OldHP]

When you're the guy who has to evaluate the Condition reports for "We dropped this into lower ice and can't find it" or this ice basket is stuck so we're justifying weighing another, OR his ice basket is too light but the average weight of the others is higher than needed plus we believe it won't create an unanalyzed flow channel due to early melt.... well you'll know why I hate the dang thing.
Plus lets face it, usually the chillers and pumps aren't in the greatest shape and are most likely to fail in the hottest week of summer.
Cool concept though.

BTDT

The sales pitch sales pitch concept was that after 10 yrs of operation you added water to replace the ice weight lost through sublimation.  At 20 years you refilled!
Concept Circle-Bar - Proven Wrong - as anyone familiar with the IC plants knows!  But Circle-Bar had enough marketing skill to convince land based Utilities that they would work for low profile containments that would be acceptable to the public.

Every outage means IC work.

I found the pain in my head, which I kept hitting on too-low hanging objects, and my back which I hurt trying st squeeze around in all the too-cramped spaces.

The whole thing was a pain in the ice.

Pre TMI mods you could walk  like a normal person , unfortunately the folks they hired (at least for MNS & CNS had no concept of accessability.  Just over support!

[GLW]

The Pebble Bed reactor made a big splash for a while and South Africa at one time intended to build one. Lately there has not been much noise about it, has it gone by the wayside?

Scheduled for 2013,....

New date: 2015,.....

http://nextbigfuture.com/2011/03/china-210-mwe-pebble-bed-reactor-starts.html

[alasfreedom]

Hello All!

My first time posting.  Need help from some experts - Working on a class presentation for a Rad Protection class.  I have had the (dis)pleasure of working as an Ice Tech. @ CNS.  Want to use it as a topic for my presentation...but, don't know a lot about the technical working.  Who wants to volunteer to be a subject matter expert or point me in the direction of one said person?

Much appreciation.