Potential problems may be building up at Chinese nuclear plant... 8

[phamENG]

Half of their international sites are located in the US. I'd bet they're more afraid of the NRC putting a magnifying glass on their operations here than they are about Chinese regulators. So if they preemptively provide information to show that they're managing the situation responsibly...maybe they hope the blame will land elsewhere if anything goes wrong?

 

[phamENG]

electricpete - looks like you had the same idea

 

[electricpete]

Yeah, we're looking at it the same way.
Companies feel an obligation to be open with their regulator. If there's a grey area in some cases it may be better to share too much information than too little. You may end up having to answer some questions but at least you won't look like you're trying to hide something.

=====================================
(2B)+(2B)' ?

 

[dik]

thanks... didn't know that. Involvement in the US wasn't mentioned in any of the articles I saw...again, thanks. As far as sharing information, it's a balance between safety and fiduciary responsibility. I can see a few foreign 'noses out of shape'.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[bones206]

If their fuel is used and licensed in the US, it may be a regulatory requirement to disclose adverse events to the NRC, regardless of what country it happened in.

 

[davefitz]

Other websites indicated that the US gov't has cautioned some industries to restrict transfer of technology to China, and framatome is requesting the US to allow them enough slack so that they can address an unsafe situation.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[Alistair_Heaton]

Seems edf are saying shut it down and the Chinese are saying no.

 

[FacEngrPE]

EPR design has a primary coolant loop that if tight will confine the surface contamination to the inside of the primary coolant loop.
Surface contamination will complicate exposure control during future maintenance.

Some literature is available from EPRI on fuel cladding leaks, mitigation.

https://duckduckgo.com/?t=lm&q=EPRI+fuel+clading+leak&ia=web

https://www.google.com/search?q=EPRI+fuel+clading+leak&gws_rd=ssl

 

[MechinNC]

Some gaseous fission products are expected. And sometimes there is a cladding failure that causes a big increase in gaseous fission products. The plant I worked in (GE BWR) had this happen occasionally. We drew off the non-condensable gasses and analyzed them, that gave you an indication of cladding integrity. If activity in the off gas went high, it was like "crap, we got a leaker". What we did then was a matter of degree. If bad enough we would shut down the plant, open up the core, find the leaking fuel bundle and replace it. Expensive and 2-3weeks of shutdown.

It is really the same on a PWR. You have the same non-condensable gasses, you just draw them off from a different place. Primary loop (guess the pressurizer) on PWR, on BWR the condenser air ejector.

On our BWR, we would run our off gas through a chemical process to grab what we could chemically, then route the remaining (mostly noble gasses) through a farm of charcoal beds that would give enough residence time for those isotopes to decay off. What was vented out up the stack had very low activity. If high enough to approach reg limits, shut it down and fix it.

As long as we did not break those limits, it became a commercial decision, and I figure the Chinese plant is at the same decision threshold (although the limits might be quite different!!). Run a plant with a known leaker and it craps up other parts of the plant, complicating maintenance down the road. ("craps up" is an industry term for radioactive particles in fluid systems or deposited on hard surfaces) Filters get highly radioactive and must be handled differently, etc.

But the systems are designed for this (to a degree) and it does not put the plant safety or the public at risk (again, to a degree!!).

But we are talking about the Chinese here, and their risk tolerance is apparently different than the French!!!

 

[byrdj]

Hello MechinNC,
If I guessed correctly from your handle,
I worked at that Power Plant. (BNP ?)
(but not on the Rx side)

 

[Alistair_Heaton]

They are apparently screwed for power in the area so it goes offline it's into rolling blackouts of domestic to keep industry up

 

[MechinNC]

Byrd- Yep, I was s systems engr at Brunswick here in NC. Was not focused on the Rx, but with the mix of stuff I did, I rubbed elbows with the nukes and also had one project specific to off gas system and cladding leak. Did submarine plant overhauls prior.

 

[Pud]

Reactor shut down today.


Politicians like to panic, they need activity. It is their substitute for achievement.

 

[Alistair_Heaton]

As we have people that really know....

What happens now? 3-4 weeks cool down and let the short life isotopes do their thing. Open the kettle up and play hunt the buggered rod out of 60 000 or will they have a better idea where the problem ones are and it will be more targeted.

 

[MechinNC]

Cooldown is a matter of days, not weeks. Then you pull the RX head and sample the water over each fuel element. Since there is decay heat in each, there is flow above each. The samples pick up which element has the leaker. The exact details of this process was not my field, but the above is pretty close.

Each fuel element is an bundle of a bunch of rods. The rods are like 10mm in dia and an array of like 12x12, so 144 rods per bundle. This varies with reactor type, bigger/smaller/fewer/more. One rod leaks in a bundle, you don't go after the specific rod, you just replace the whole bundle.

If late in the fuel cycle (most cycles are like 20-24months of full power running), you might elect to do a refuel. Most refuels are like 1/3d of fuel elements replaced, and other shuffled to take advantage of different neutron flux in different areas of the core. The nukes (nuclear engrs) earned their keep figuring the shuffle details. Not my gig.

If early in the fuel cycle (which this one sounds like) you just replace the leaker, and maybe others that have the same lot number, etc, commercial decision there. Then you make a phone call to your fuel supplier warranty desk!!!

 

[Alistair_Heaton]

That's the sort of process description I like.

Thanks

 

[MacGyverS2000]

LPS given to Mech... clean, concise, etc.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[rb1957]

how do you spell "chernobyl" ?

And to Alistair, replying to "I seem to remember elevated xenon is a indicator of it having been in an iodine pit." ... yeah xenon is bad news if you don't expect it, anticipate it.


another day in paradise, or is paradise one day closer ?

 

[Alistair_Heaton]

It's a English word the local Ukrainian and Russian scripts it's completely different.Чернобыль


The locals round me don't call it that they refer to it as Pryp'yat. When talking about it. Which is the workers city next to it.

There is about 5% of the population registered as radiation victims.

 

[Alistair_Heaton]

Here is as good as any.


Ukraine has just issued the license for them to start work demolishing the upper structures of Chernobyl.

Neutron flux levels are still climbing steadily and they don't know why.