Oct 5,
So I am updating my theory about what caused this. It is not a steam explosion. I small hole developed in the top of the pin. Water got in, basically water got in to corroded the pin and some pellets. It is much like what Dominion and NRC said.
I still think this is much more serious that what has been admitted by them both…
Oct 4
10/5 No idiot, the fuel sits on the lower support. How thick our the baffles?
The baffles carries the weight of 15 million fuel pellets, the core support and the rest?
The core baffle of a PWR is loaded by the pressure difference between bypass and core and by temperature profiles developing from gamma and neutron heating and heat transfer into the coolant. Strain, deformation and gaps between the sheets resulting from this load are determined considering the effect of neutron irradiation induced creep of the core baffle bolts. The finite element code ANSYS® is applied for the thermal and mechanical analyses. The FE-model comprises a complete 45° sector of the core baffle structure including the core barrel, the formers, the core baffle sheets and about 230 bolt connections with non-linear contact between the single components and the effect of friction. The complete analysis requires three major steps:
Why the cancer?
Page 3-1 or 31?
Corner injection point...there has got to be a design reason for this gap. Bet it has something to do with core reflooding.
The cause of such extensive fuel cladding failure is secondary degradation by zirconium hydride.
Now I know what the core barrel is
10/5 The core barrel slides down inside of the reactor vessel and houses the fuel.
What the hell is the "former". Do you even need it?
No, I got to be missing something. The former is attached to the core barrel through a string of bolts and holes. There are holes through the vessel? Just tear along the dotted line?
Thanks to my EDF Friends below. These are the state operators of the France's nuclear system. How pathetic, they look more democratic and transparent than the USA? This would be my case for a national (USA) based nuclear plant operator. The expectation is, it is a government agency, thus more transparency than we have today.
Light Water Reactor Fuel Performance
Review of Degradation Phenomena affecting Fuel Rod Cladding
So North Anna had a cancerous wasting disease on their fuel rods for years? I am sure they picked it up in primary system coolant chemistry testing? Dissolving thrice
Note: I am hazy the role of zirconium hydriding is in A PWR and North. I think the North Anna 10 inch split is really more half the pin material missing. More looking like a half a circle for most of the 10 inches.This would imply zirc hybriding.
Real pictures of fuel road damage?
Hmm, "and other emergent issues. Going to have to make time for this". But it is not a teleconference.
Ok, do you have bolting or attachment problems with the baffle or the core support structure leading to the jet of water between the plates destroying the two fuel pins? Causing the baffle to vibrate?October 01, 2014
Title: Notice of Forthcoming Public Conference Call To Discuss North Anna Combined License
Application Requests For Additional Information And Other Emergent Topics
Date(s) and Time(s): October 16, 2014, 02:00 PM to 03:30 PM
Location: NRC Two White Flint North
11545 Rockville Pike
Rockville, MD
Category: This is a Category 1 meeting. The public is invited to observe this meeting and will have one or more opportunities to communicate with the NRC after the business portion of the meeting but before the meeting is adjourned.Purpose: To discuss the resoluation of North Anna COLA Requests for Additional Information.
Information Notice No. 98-11: Cracking of Reactor Vessel Internal Baffle Former Bolts in Foreign Plants
ENCLOSURE 2 TO AEP-NRC-2014-59 I&MCAP Document AR 2010-1804-10, Root Cause Evaluation Attachment, "Rx VesselCore Support Lug Bolting Anomalies"
How come they didn't report this in the newspaper?
"Due to the fact that the failure exceeded expected conditions, this event is being reported per 10 CFR 50.72(b)(3)(ii)(A), as any event or condition that results in the condition of the nuclear plant, including its principle safety barriers, being seriously degraded."
I'll be heavily updating this in the next few days!
I bet you the North Anna fuel pins looked like the top picture below. The gash I’d seen would be longer (about 10 inches), but the gash lips would be more protruding away from the pipe. A somewhat narrower crack, but the crack edges were peels back away from the pipe more. It was a lot more energetic pipe burst and different material than these copper pipes. The pins are about .5 inch to an inch wide. It wasn't a discreet weakness or force in the copper that began the pipe burst...it was more a 9 inch rod inside the pipe giving off a lot of power and energy violently turning the water into steam that created the crack.
Ok, this is what they are are saying. Again this is a example where this problem had showed up in the industry in the 1980s and 1990s. They just never spent enough money to eradicate the problem. They keep putting off permanently fixes the problem from one cycle to another, they spend enormous monies on fixing the same problem over and over again.
They probably need to totally off load the core, then go in and replace the core baffles. This is why Dominion is trying to put off globally fixing the problem, only fix the immediate symptoms of the damage pins, deal with the baffles in 18 months to 36 months.
It is a huge job and extremely timely. There seems to a hole in the baffle caused by some kind if process; either corrosion or some kind of poor maintenance where the flow vibrations caused the baffle plates to separate. The symptom in which they are fixing is the fuel damage and the pellets disintegrating in the coolant and plating out throughout plant...the root of the problem is the poorly designed and maintained baffle plate.
They probably need to totally off load the core, then go in and replace the core baffles. This is why Dominion is trying to put off globally fixing the problem, only fix the immediate symptoms of the damage pins, deal with the baffles in 18 months to 36 months.
It is a huge job and extremely timely. There seems to a hole in the baffle caused by some kind if process; either corrosion or some kind of poor maintenance where the flow vibrations caused the baffle plates to separate. The symptom in which they are fixing is the fuel damage and the pellets disintegrating in the coolant and plating out throughout plant...the root of the problem is the poorly designed and maintained baffle plate.
- If a gap between intersecting baffle plates becomes enlarged,the differential pressure across the baffle plate creates a water jet that impinges on adjacent fuel rods.
- be attributed to the water-jetting-induced motion of fuel rods in fuel assemblies that are adjacent to baffle plate joint locations with enlarged gaps.
The below is from the newspapers. It is totally inaccurate and a blatant lie to the public. Notice the benign stance of the newpapers without any pushback.
- In the last 18 months, a jet of water through a millimeter-size hole in the fuel rods’ support structure was squirting
- over the rods. That flow started them spinning and vibrating, Heacock said, a problem called “baffle jetting,” which has occurred at other nuclear reactors. The rods rubbed against
- the support structure, cutting grooves in them and eventually causing their tops to crack off.
I alway said, risk perspective is solely about damage and destruction of peoples health in the outcome of a severe accident. Why don't we put a dollar value on the possible loss of faith government and the nuclear industry...the ability to trust our institutions in a national crisis? The NRC allows these utilities to outright lie to us. Trust in our institutions is unbelievably precious and a lost of trust in a institution is very costly. Through risk perspective, we should put strict incentives where the NRC and the utilities the whole truth. I might make a case trust in institutions and government is at a historic lows. Most of the damage to the nuclear industry in TMI came out of the benzene communication of the event. The perception of mistrust in their political implications is enormously expensive. Why isn't this a consideration in risk perspectives? Why does our government allow the nuclear industry to communicate to us so dishonestly...why do you allow the licencees to practice the art of dishonesty so extensively?
Right, the solution to the seismic and plant safety issues in Fukushima tragedy has mostly come into the public realm through engineers about engineering solution. How come out nation hasn't had a great debate about licensee and NRC full disclosures and honestly? The foundation and infrastructure that built the nuclear disaster in Japan is basically about the nuclear village and trustworthiness of the institutions running and overseeing the plants.The public mistrust of these institutions are the greatest impediment to restarting the Japanese nuclear fleet. Really, how expensive is the lost of trust in the our institutions, in a federal agency and the nuclear industry.
- Event report (9/15): Initial inspection of the fuel assembly identified two (2) visibly split fuel pins of eight (8) to ten (10) inches long with visible damage to the top of the pins.
For clarity, Dominion owns two plant facilities of
Millstone, Surry, and North Anna. That is six plants. They recently shut down
Kewaunee. I consider corporate wide management
safety culture is seriously degraded…with 33% of their fleet showing serious
signs safety of culture deterioration.
It is not the whole story, the pellets are extremely radioactive. Lots of this stuff plates off in the core and throughout the primary system. It increases piping and component radiation levels, the compensation for that are extremely costly and time consuming.Two nuclear fuel rods found damaged during North Anna power plant refuelingBY PETER BACQUÉ Richmond Times-DispatchRICHMOND — Dominion Virginia Power has found two damaged nuclear fuel rods in its North Anna 2 power plant during the Louisa County reactor’s scheduled refueling in earlier this month.The Richmond-based utility said it believes that about 15 uranium fuel pellets came out of two rods and entered the reactor cooling system.However, because the radioactive uranium is contained in the reactor system, the damage has “no radiological consequence to it,” said David A. Heacock, president and chief nuclear officer of Dominion Nuclear, a subsidiary of Dominion Resources Inc., the parent company of Dominion Virginia Power.
Ok, if the tops slowly cracked open, how did the pellets come out"? The way this goes is it had been a known leaking over many cycles...they have radiochemistry about this. It is in their documents. Up on a start up water seeps into the cracks. The uranium in the pin becomes super moderated, as a rod passes near by upon startup, high local power cause a very fast heat up of the water in the pin. Lots of slow power making neutrons are made. The pin has a steam explosion, either the pin itself cracks open and you know it is explosion related, or the top is blown off. That is the mechanism that expels pellets out in the coolant.“It’s a fairly low safety significance issue,” said Roger Hannah, a spokesman for the Nuclear Regulatory Commission in Atlanta. “Even though the fuel is damaged, it’s in a closed system, so you don’t have the concern for an environmental release” of radioactivity.Cooling water flows though the reactor’s internal cooling baffles at the rate of 300,000 gallons a minute.In the last 18 months, a jet of water through a millimeter-size hole in the fuel rods’ support structure was squirting over the rods. That flow started them spinning and vibrating, Heacock said, a problem called “baffle jetting,” which has occurred at other nuclear reactors. The rods rubbed against the support structure, cutting grooves in them and eventually causing their tops to crack off.
What has changed to cause this? These plants has been operating since 1980, so why hasn't this showed up in the past. Why has changed causing this.
Remember, when the first pin pops it creates an unmistakable and immediate large signature in the radiochemistry. They immediately know what happens...and they are monitoring the other pin pops, monitoring the conditions of the degradation pins.
It would be troubling if the pins were in the vicinity of each other. I would wonder if the large neutron population created a over power condition in the surrounding area causing a cascade of overpower pin causing the other pim pop.
By the way, these guys won't be able to use a regular storage cask...
Why didn't all the pellets come out,
because there are welded caps creating individual cells of seven or eight
pellets. After each eight fuel pellets, they put in a welded plug just so some day they don't "expel" all the 270 pellets.
I was the first one to report publicly about these problems in 1991 at Vermont Yankee in 1991?Having this occur at a plant is unbelievably unprofessional.
Ask them what the radiation level is at the surface of the pellet. I bet we are talking 100,000 rem to millions of rems. Five rems I believe is the yearly limit for employees.Seven or eight fuel pellets came out of each of the two zirconium-alloy fuel rods, Heacock said. “We have accounted for about eight of the pellets,” he said. “We believe the rest have been pulverized in the normal filtration mechanism,” which will recover the nuclear material.
It actually looks like they lost control of power making density in the core.
It actually sounds like five other pins where damaged. I like to see pin sipping record of this plant.“We’ve cleaned the entire reactor vessel,” Heacock said. “Now we’re inspecting the entire reactor refueling cavity.”In the critical area of the replaced assembly, Dominion Virginia Power has installed seven stainless steel rods so coolant flow cannot damage uranium-filled rods, Heacock said.
This is the moniker of the nuclear industry, "why fix the problem immediately, when you can put it off fixing problem for 18 months or 36 months.“The long-term fix is to modify the way the water flows in the baffle so there’s no possibility of baffle jetting,” he said. That modification will be done either in 18 months at the unit’s next refueling or during the refueling after that.
J. Wellington Wimpy (Popeye the Sailor Man): "I'll gladly pay you Tuesday for a hamburge today."
“I will gladly pay you in 18 month or 36 month for less short term safety of tomorrow.”
Considering the unprecedented three special inspection at Millstone over unfixable maintenance and operation problems with a critical turbine driving safety pump and not the
I'll bet you the pins were knowingly leaking...pin hole leaks...the cycles before the popped tops? It is dangerous to restart a plant with a knowingly pin holes leak. Why did sipping miss this?Made from uranium dioxide, the ceramic pellets are about half an inch long and three-eighths of an inch in diameter. A 12-foot-long fuel rod —called a “pin” — at North Anna 2 contains either 360 or 372 pellets, depending upon the vendor. The reactor has 157 fuel assemblies, each of which holds 264 rods.The damaged fuel assembly has been placed into the plant’s spent fuel pool. “No abnormal increase was noted on any radiation monitor either after or during fuel assembly movement,” the company told the Nuclear Regulatory Commission.The failed fuel assembly had been used during three 18-month operating cycles at North Anna and was not scheduled for reuse.
Basically what you are seeing here is a policy of the NRC, where the NRC expects and approves of a utility giving the happy spin of a event at these plants.Radiation dose rates around the reactor are 4 percent lower than they were 18 months ago, the company said, because of efforts to reduce the rates.Refueling outages for Dominion Virginia Power’s nuclear power plants usually take about a month. The latest refueling began Sept. 7.
“At this point,” said the Nuclear Regulatory Commission’s Hannah,“we see no reason why, with new fuel in there, they couldn’t restart the reactor.”Dominion Virginia Power’s four nuclear units produce more than 40 percent of the electricity used by the company’s nearly 2.4 million customers.
| Power Reactor | Event Number: 50457 |
| Facility: NORTH ANNA Region: 2 State: VA Unit: [ ] [2] [ ] RX Type: [1] W-3-LP,[2] W-3-LP,[3] M-4-LP NRC Notified By: PAGE KEMP HQ OPS Officer: JOHN SHOEMAKER |
Notification Date: 09/15/2014 Notification Time: 14:54 [ET] Event Date: 09/15/2014 Event Time: 09:00 [EDT] Last Update Date: 09/15/2014 |
| Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(3)(ii)(A) - DEGRADED CONDITION |
Person (Organization): SCOTT SHAEFFER (R2DO) |
| Unit | SCRAM Code | RX CRIT | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
| 2 | N | N | 0 | Refueling | 0 | Refueling |
Event Text
| FAILED FUEL ASSEMBLY IDENTIFIED DURING CORE OFF-LOAD
"With North Anna Unit 2 in Mode 6 during a scheduled refueling outage, discharged assembly 4Z9 was identified as a failed fuel assembly by In-Mast Sipping. The fuel assembly was located in core location B11. Initial inspection of the fuel assembly identified two (2) visibly split fuel pins of eight (8) to ten (10) inches long with visible damage to the top of the pins. The internals of the affected pins are visible and the springs from the top of each pellet stack are touching the top nozzle. The fuel assembly has been placed into its designated location in the Spent Fuel Pool. No abnormal increase was noted on any radiation monitor either after or during fuel assembly movement. This fuel assembly had been used during three (3) previous operating cycles and is not scheduled for reuse. "On September 15, 2014, at 0900 [EDT], subsequent video inspection of the fuel assembly identified that the top springs of the two (2) fuel pins were dislodged. Video inspection of the reactor vessel identified debris that has the potential to be fragments of fuel pellets resting on the core plate. Additional investigations are in progress. "Due to the fact that the failure exceeded expected conditions, this event is being reported per 10 CFR 50.72(b)(3)(ii)(A), as any event or condition that results in the condition of the nuclear plant, including its principle safety barriers, being seriously degraded." The licensee has notified the NRC Resident Inspector and will notify local county authorities. |
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