NRC Meeting On North Anna – Text of Live Blogging The Meeting
Below is the liveblogging log of the NRC North Anna nuclear plant meeting today. Complete with misspelling and fumble fingered typing. I will put some notes in red where clarification can be added for better understanding. Parts of the meeting moved quickly so grabbing things like the names of those speaking was difficult.
by lillymunster 7:00 PM – Do 08 Sep 2011
NRC meeting is starting
Bob Martin talking Meting between NRC and Dominion requested by Dominion to do a presentation on the seismic event and Dominions opinion. Meeting is category 1, public comment allowed at end of meeting
Meeting announced 7th, NRC going over short notice, public feedback procedure during the meeting.
Jean Greycheck from Dominion talking, in charge of regulatory response
Talking about work being done, effects of earthquake on the plant. Bringing quake analysis, current findings at the plant. Schedule for their planned restart.
NRC stating this meeting will give NRC idea how they will approach evaluations on N Anna going forwrd
NRC review in early stages. Plant staff claim no major damage at plant. But must receive NRC approval to restart including Dominion must state under oath the findings
Doing introductions, can’t keep up with names. Various NRC and Dominion staff in attendance
Sequence of events then seismic data. “will show that the velocity demonstrates a low enough “cAV” value to not have serious damage” Dominion rep
CAV is a type of analysis standard I was unable to get additional definition through the meeting. It seems to be cumulative absolute velocity
Map of the plant vs. epicenter – 11 miles sw of NA (North Anna). at 100% power during quake. Quake, 11 seconds later both tripped negative rate flux trip. Then transformers tripped. 8 seconds later all emergency deisels started
The negative rate flux trip is a sensor in the reactor, this tripped the reactor into emergency shutdown.
Schematic of NA power station. how reserve supply powers emergency systems. SBO deisels. Shift manager kicked in emergency action plan based on loss of offsite power and quake.
SBO = Station Black Out
Emerg diesels inspection – 48 seconds in, one had coolant leak so they shut it. 15 min. later declared alert, due to 1 power supply
Trying to establish offsite power, addressed transformers for faults, and safety testing.
Transformers tripped due to sensors that saw sloshing of oil inside
cool down unit 1 as lead unit to get seismic plate data in unit 1 location.
The seismic sensors are located in unit 1, unit 2 has none.
Had to depressurize and cool down unit and depressurize containment to get the plate
1am next morning aftershock, emergency action levels and checks. Started unit 2 to hot shutdown. In hot 2 residual heat removal and steam generator to remove heat.
Retrived plates and sent to vendor. Got back info on 26th and validated it.
Had exceeded design basis in some areas.
NRC asking question: abt results on scratch plate data from auxiliary building on 8-26 that gave them design basis determination
Showing slides of findings. NRC asks what caused negative flux rate trip. Dominion says they are still figuring out.
negative flux rate trip is in reactor. NRC asks for list of seismic equipment and location
Annuciator or control panel did not show beyond design basis event at time of quake
Slide of demineralization tanks on top floor of building. Base of vessel, chipped concrete base on a tank. Damaged said pedestal
Interior wall inside containment crack horizontal in wall. Says quake is usually vertical cracks. Claims crack was along a grout line for concrete pour joint.
Inspection of dry casks. Pad 1 – 115 tons each. Pad 1 – 27 casks. 25 shifted, up to 4.5 inches. Describing the inner cask safety measures to keep sealed. no radiation spikes in the area. 6 pairs of casks no longer 16 feet apart for radiation heat dissipation.
Aftershocks, follow up pad inspection, evaluating 2 casks that moved a second time. Checking measurments to be sure.
1st quake they marked each cask for future aftershock movement. Last cask
was installed 2007.
cask storage pad #2 concrete bunker horizontal storage. no damage to pad, gaps in roof blocks for the casks an non structural damage
no radiation spikes in the bunker area. 26 bunkers, 13 casks in pad 2. Showing new gaps in the roof blocks of the modular cask system of the tongue and groove joint. The movement was on empty units.
Bunkers for convective cooling and shielding. NRC asking significance of this movement per the objective of the bunker safety
Cracking, swelling concrete on pad 2 bunker building vents
– 7:30 PM
Roof vent screening to keep peoople and animals out, held in place with anchor bolts was pulled out – slide shows a large chunk missing.
Hendrickson speaking for dominion. they consider these to be most significant of all the damage at the plant.
NRC question on tanks, no shearing of anchor bolt, how was that tested. Dominion admits they did not inspect the anchor bolts.
NRC asks any anchor bolt inspections to see if failing. Dominion states only visual inspection from outside so no further bolt inspection
Seismic monitoring panel explanation. Passive system and a panel system with alarms to control room. seismic trigger actuates the tape playback unit. 2 – seismic switch set to design basis, switch goes off. Playback device looks at 2 locations
Dominion later admits there is no seismic devices in unit 2, only in unit 1. Only one is connected to a control panel alarm.
Ingdal system is passive, recorder and graphs and sets alarms in control room. Amber OBE, Red DBE – design basis. Also scratch plates. Kinemetrics system unit 1 containment basement floor, trigger, switch and playback cassette unit on top of containment. Ingdal system is throughout plant w/ sensors with scratch plates.
OBE = operating basis exceeded DBE = design basis exceeded
X-Y_Z planes for the scratch plates with frequency recording devices like a pendulum. 12 frequencies for acceleration and scratches an arc on the plate. This gets high magnitude recording.
OBE= values and DBE= values. OBE & DBE horizontal and vertical on containment.
NRC asking about Ingdall alarms in the control room. These did not record anything. The panel lost power for 8 seconds and lost function of the Ingdal panel
Ingdal panel does not have battery back up. Alarms didn’t trip in the control room. Dominion has no clear explaination why the ingdal system didn’t trip alarms
Seismic trigger worked on other unit and started tape recorder, it had battery backup. This gave no alarm to control room. They have now added a UPS power supply to the Ingdal unit
NRC talking about why the instruments the operators depend on didn’t function as they should have. Expressing concern to dominion that these items didn’t work right.
Horizontal basemat of containment readings. IP-EEE external events evaluation study. Discussing horizontal and vertical acceleration and numbers of maximum design velocity.
GI-199 less than 1g 25htz – this is a design basis estimate
North anna had 1.5g 25 htz
For north anna 3 they used the GI-199 standards. Now debating and confusion about what standards are being used to establish design basis and acceleration.
Quoting GI-199, how curve for NA was obtained. More debating about seismic basis standards. Nobody seems to know what standards are used to compare to plant.
Dominion trying to use a 2004 seismic model. Core damage frequency estimations from the 2004. They don’t have new or current spectrograph siesmic standard etc. IP-EEE has not been done yet.
A calculated “CAV” value for NA. 3 vendors did this. They estimated they exceeded design value horizontally in north-south direction.
Duration of the strong motion of the quake. 3 values for this: 3 sec. North-South. 1.5 sec for vertical. 1 sec east-west direction
– 8:00 PM
NRC questioning the graphs and readings. The strong duration tells how long the harsh part of the quake was. NRC questioning that the north-south time and acceleration are different of the other directions.
Looking at seismic margins. .3g is the number used. Most components can withstand .3g. They had already improved some equipment to meet this .3g level.
Shut down equipment supposedly can handle more than design basis accidents per Dominion. Questions – who read the tape? A: Kinimetrics read the tape. Same person asking why nobody on site can read these tapes. Dominion engineer claiming that it was available but they could not interpret the data but Kinimetrics could turn analog to digital and interpret it.
Someone again asking about why Dominion could not read their own data. That they could have known that day if they exceeded design basis right away and that sending data to vendor makes no sense.
Kinimetrics says design exceeded horizontal and vertical. Other that acceleration exceeded and 3rd test also shows exceeded design.
The CAV design theory applies to regular buildings not industrial building per Dominion as reason they exceeded CAV values but it isn’t damaging. More questions why they are saying above OBE and yet below it.
.26g is what was found for acceleration, questioner asked about this, dominion agreed this was acceleration. Wondering why talking about CAV rather than numbers against design basis and why Dominion is using these CAV standards.
Comparing the readings from instruments plus a free field reading but they don’t have free field seismic equipment at north Anna. They estimated the free field reading
NRC structural engineering office rep talking. Correlation between soil motion and foundation motion, not all buildings are rock founded. Only containment is rock founded at NA.
Based on exceeding OBE, DBE and CAV, using NRC guidelines on evaluations, flowcharts for handling such an event.
Inspections after seismic event focus on critical areas for damage. Have they exceeded OBE or found damage. Said they exceeded OBE but didn’t find any damage they thought was severe enough. NRC – if you exceeded OBE you need to do the inspections per NRC.
Question on “no damage found” on visual only? Some testing is planned beyond visual only. Not done yet. More questions on underground pipes, tanks, sensors, inspections? No they have not completed yet.
NRC says may increase inspection of underground pipes.
Trip procedure, look for changes not anticipated. Wondering about the flux rate reactor change that tripped the reactor. Talking about how license renewal and aging management include seismic analysis and systems. NRC asks why did flux go down in core. Rod control or series of rod control to drop seem to be due to flux. Diverse and redundant trips coming in at once in control room
transformers and flux relays didn’t operate as expected.
NRC asks if grid power itself had quake related problems Dominion didn’t have clear answer
Focus inspections on seismic event vulnerable equipment first by Dominion. No indicators found then did expanded inspections, looking at 100% of inspections. Civil walk down inspections, electrical inspections. Independent inspectors were in looking at damage.
Walk down every “line” in the plant. Structural walkdown by civil engineers. Claiming they are at “damage 0”
NRC questioning EPRI guidelines and actions to take. Dominion says still considering long term actions after startup. Still in damage accessment and inspection stage.
– 8:31 PM
4 steps, data collection, research, asessment, analysis. In process of getting 3rd party reviews of analysis. 3 of 4 3rd parties agree with Dominion. Kennedy expert says no reason why dominion can’t restart and is seismically as safe as it was before quake
Dam also examined by Dominion. Surveillance testing, calibration of equipment and instruments, trips, functional tests, pump testing, kinds of tests they are doing beyond damage assessment. Dry cask storage pads, containment and spent fuel pool assessment. NRC asking question – more about the evaluation of the core fuel vs. inspections. What are you actually going to look at? Dominion – inspection plan to look at fuel in pool, new fuel racks, core, core detailed inspections in offload, visuals. Sampling of the fuel not all and only in one reactor, not both. Would not look at unit 1 fuel until spring 2012 next outage.
General overview, visual inspections, sampling video inspections up and down rods. NRC questioning that visual only inspections. NRC saying – fuel and control rods. Confirm no distortions of rods or control rods and guides, mixing veins also a concern. NRC thinks these should also be done. NRC wants to know if mixing veins are damaged from event. NRC concerns about control rods and drive mechanism safety. Has seismic data been sent to fuel supplier for them to check their design envelope.
NRC – coolant chemistry tests, temp, pressure changes in core, this information would be good. Wants pre-post quake. NRC wants core physics data due to the flux trip.
Dominion – says they plan to do these in their inspections.
NRR accident inspector – latent damage in reactor? Dominion – looking at weak links, vibration data, long term damage to materials. We have not finished these tests.
Snubbers – how will those be evaluated? Dominion – tested a couple that had low fluid levels in past. Now some oil hanging off some snubbers. NRC again says concerned about non visual damage. NRC asks about hydraulic mechanical testing on snubbers.
Spent fuel team NRC rep – boraflux used in spent fuel pool? Dominion – no, using patterning for control. NRC – evaluations of fuel storage, what kinds of inspection on racks in pool, pool liner? Dominion – some inspections so far of video on racks, comparing to 2001 video. Visual no deformation. NRC – cranes, loading and fuel handling equipment inspections? Dominino – fuel handling maybe done, cranes not
NRC div. of engineering – What did you take from the KK event, how did you incorporate that into your plant in places like welds? I see nowhere you incorporated any lessons learned from international events.
Dominion – We did visual, inspections of welds at unit 2. NRC – they had
hidden damage at KK and this is not being addressed.
KK is Kashiwazaki Kariwa, this plant had quake related damage in 2007
Dominion – we might pick up high risk welds. working on non safety components as indicators of other damage.
Dominion – all inspections will be documented. To document everything so traceable. inspections, evaluations, repairs to be done will present this to facility safety review committee. To demonstrate our ability to restart. 1000 “pairs of eyes” at plant and engineering inspections.
Dominion – going to install a free field seismic device. The time it takes to purchase and install a problem. Reinstalled the building seismic device with battery back up.
Dominion engineer – inspections have not found damage that challenges safety and structures. Initial inspections are done. Rating of “0”. Do more detailed inspections to cover all plant systems and structures.
Inspections being done, pipe on drawing, highlight it on a document as done. Identifying all deficiencies quake or non quake related. 80% of system walk downs done. Inspections ongoing for normal electrical equipment. NRC asks about generator will coolant leak, what kind of leak? Dominon – radiator closed cooling system with a tank. Shut down, won’t give a reason to NRC for shut down.
97% structure inspections done. Including dams. NRC asks – how much of containment was inspected. Dominion – all accessible.
Not all inspection has been done on unit 2 yet. Leak tests were 5 years ago for both units. #2 refueling they will leak test.
NRC asks if fans and gas treatment being inspected? Dominion claims other systems will detect problems.
– 9:03 PM
Dominion – concluded we exceeded DBE. Getting systems back operable is goal. Schedule where we feel the plant will be. 9-16 final engineering evaluation done, 9-19 to 20 safeguard and tests not required and complete post event testing, startup assessment. Unit 2, 9-12 plan to have systems tested and inspected. 9-12 to 15 reactor dissasembly for refueling. 9-16 offload core and do visual inspections. 9-16 final technical evaluations to committee. 10-1 reload and 10-6 engineered testing and post even testing. Containment closeout. 10-13 ready for restart. NRC – unit 2 evaluations on 16th does that include fuel inspections. Dominion, no inspections would follow it. Engineering evaluations do not include fuel inspections.
NRC – were any core components declared inoperable? Dominion – did not declare any of those but plan on inspecting during refueling. All declared inoperable because of design basis.
NRC – refueling outage are you going to put new fuel in? Dominion – yes new fuel is on site, did visual inspection of it.
NRC – after #2 inspection findings would have to get put into refueling restart and new fuel.
NRR engineer – asking about pipe testing spectral development. Dominion – evaluation would be long term only.
NRC – do you plan to test pipe spectra analysis before restarting? Raising concerns about un-analyized incidents. Debate between dominion and engineer between visual vs. other inspections
Dominion claims – no damage to more vulnerable items means entire plant is in good shape. Visual inspections are sufficient. Past design basis but plant can handle more (my synopsis of longer statement). Dominion wants to delay in depth piping inspections. Claims they are positively proving no damage. NRC questions this.
Dominion Says installing field seismic and a battery back up to one recording system proves improvement at plant.
Dominion claims reactors ready for restart and will ask for such.
NRC – design basis accident should be infrequent, unique situation at NA. Not clear what we need from Dominion. Thorough evaluation will be done, a summary will not do. Just due to all the questions a series of meetings will be needed on this issue. The meetings will develop expectations for a document. Restart date same day as AIT exit, NRC will not be ready and dominion will not be ready by then either.
Question public – wanting to know difference between safety and non safety side of the plant. Portions of plant only to standard building code such as water systems in non safety areas. – not answered, deferred question.
Question public – reluctance to do inspections of systems with less margin. Are you going to do those? Dominion – those are going to get done those are listed components to do.
Question – long term actions installing monitors, instruments with power back up, site more confidence in kinemetrics rather than ingdal system,. IF no confidence in Ingdal system will you replace?
Dominion – the UPS power back up solves that. Will still rely on scratch plates
Question – equipment only in unit 1 – no equip in unit 2 so you rely on unit 1 for all seismic alarm.
Dominion – at higher elevations, hard to say if DBE or OBE is exceeded in other buildings. Will look at our seismic monitoring and maybe modern equipment. Systems with scratch plates are old.
Question – license renewal, nothing about the licensee will consider during long term evaluations, the degraded cross section of properties will be considered for end of license period. Cross sections of properties of for example a pipe cross section and rates of what it would be like at end of license period. Wear rates for equipment and component thicknesses. How this will impact seismic rates, standards. You can’t just walk through the plant, 90% will be “nice looking” but areas such as cross sections of things are important.
– 9:31 PM
Question – New equipment, what kind of spectrum analysis will you look for future equipment?
no answer, NRC closing statements. Lots of work going forward. Need to continue to dialogue and regulatory space and licensing documents. Lack of experience in this area. Figure out way through this correctly. Will have to do it in public forum. NRC will be sending people down to site.
Closing of the meeting!
Thanks to everyone for putting up with my typos and clogging up the page today to document the meeting for those who couldn’t use the video. Let me know if you have suggestions on what to do with all this information.
This article would not be possible without the extensive efforts of the SimplyInfo research team
Join the conversation at chat.simplyinfo.org
© 2011-2023 SimplyInfo.org, Fukuleaks.org All Rights Reserved Content cited, quoted etc. from other sources is under the respective rights of that content owner. If you are viewing this page on any website other than http://www.simplyinfo.org (or http://www.fukuleaks.org) it may be plagiarized, please let us know. If you wish to reproduce any of our content in full or in more than a phrase or quote, please contact us first to obtain permission.