All the drama and buildup to Hurricane Irma, surrounding the threatened nuclear reactors at Turkey Point, but the real news happens after the hurricane.Sequence of NRC reports:
NRC Friday Event Notifications
Turkey Point (3,4) 52952
Thursday 23:14 – NWS Hurricane Warning issued
Friday 00:06 – Notification – Emergency Declared/Offsite Notification
Friday (no time specified) 'Updated' – no indication of what was updated
(Convenient notification Friday at 00:06 ensures it won't be seen by public until Monday)
NRC Monday NRC notifications
Turkey Point (3,4) 52952
Identical notification appears again
Turkey Point (4) 52960
Sunday 18:55 Reactor only running at 88% for some unknown reason
- failure of loop 4C Steam Generator main feed regulating valve
- Loop 4C S/G [Steam Generator] water levels drop
- Emergency Operating Procedures initiated
- Manual trip of reactor from 88% PWR (?)
- Auxiliary Feed Water initiated as designed [normal response]
- restored S/G water level
- Emergency Operation Procedures exited
- returned to General Operating Procedures
- Reactor at 0% PWR; in Hot Standby
For the textually challenged (me) here's a diagram:
http://www.nucleartourist.com/images/rcs-c2.jpg
The blue juice in one of the 4 steam generators go too low, so they pumped more in. The red juice got angry at all the commotion so the operators shut the reactor down. The reactor operators don' t like it when the red juice wants to leave the containment building and comes to visit them.
Unusual that reactor was at 88% – something else was happening that they're not saying.
Either the manual scram (if unplanned, i.e., not part of planned shutdown) or the activation of the steam generator aux. feedwater system would have required reporting.
The steam generator main feedwater valve is stuck/closed/secrewed up, so they can't run steam through the turbines, cool it down and pump it back into the steam generators through that valve like normal. That'e the normal route for the secondary steam loop. Instead, they're pumping auxiliary water into the steam generator thorough a different valve, and then just dumping the steam produced into the air outside the plant. That steam/water *shouldn't* be radioactive like the primary loop steam/water, but isn't completely radiation-free, either.
In any case, the reactor doesn't care as long as the steam generators are removing enough heat from the primary loop reactor water. That's the red loop in the diagram that goes in/out the 4 steam generators' U-tubes.
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At Browns Ferry they have 3 reactors, and they lost their cooling towers, not good. But they appear to keep running at 100% even though the operation is a critical portion of the safety system, and if one other component failed, they would have a radiation release.
| MECHANICAL DRAFT COOLING TOWER FANS DECLARED INOPERABLE
"At 1000 EDT on September 9, 2017, the Division 2 Mechanical Draft Cooling Tower (MDCT) fans were declared inoperable due to failure of the over speed fan brake inverter. The brakes prevent fan over speed from a design basis tornado. The MDCT fans are required to support operability of the Ultimate Heat Sink (UHS). The UHS is required to support operability of the Division 2 Emergency Equipment Cooling Water (EECW) system. The EECW system cools various safety related components, including the High Pressure Coolant Injection (HPCI) system room cooler. An unplanned HPCI inoperability occurred based on a loss of the HPCI Room Cooler. Investigation into why the Division 2 MDCT fan over speed brake inverter failed is in progress. This report is being made pursuant to 10CFR50.72(b)(3)(v)(D) as a condition that at the time of discovery could have prevented the fulfillment of a safety function needed to mitigate the consequences of an accident based on a loss of a single train safety system." The licensee entered two (2) LCO Action Statements (AS); 14-day LCO AS 3.5.1 for ECCS (HPCI Inoperable) and 72-hour AS 3.7.2 for UHS. The licensee has two spare inverters on-site. After replacement and successful post-maintenance testing the licensee expects to exit both AS before 72-hours. The NRC Resident Inspector has been notified. |
| Power Reactor | Event Number: 52959 |
| Facility: BROWNS FERRY Region: 2 State: AL Unit: [1] [2] [3] RX Type: [1] GE-4,[2] GE-4,[3] GE-4 NRC Notified By: ANTHONY ALSUP HQ OPS Officer: STEVE SANDIN |
Notification Date: 09/10/2017 Notification Time: 20:45 [ET] Event Date: 09/10/2017 Event Time: 11:51 [CDT] Last Update Date: 09/10/2017 |
| Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(3)(v)(A) - POT UNABLE TO SAFE SD 50.72(b)(3)(v)(B) - POT RHR INOP 50.72(b)(3)(v)(C) - POT UNCNTRL RAD REL 50.72(b)(3)(v)(D) - ACCIDENT MITIGATION |
Person (Organization): ERIC MICHEL (R2DO) |
| Unit | SCRAM Code | RX CRIT | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
| 1 | N | Y | 100 | Power Operation | 100 | Power Operation |
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
| 3 | N | Y | 100 | Power Operation | 100 | Power Operation |
http://www.world-nuclear-news.org/RS-Nuclear-units-weather-Hurricane-Irma-1109177.html
Two nuclear units at St Lucie were able to continue operating as Hurricane Irma made landfall in Florida. One unit at Turkey Point was shut down as a precaution in advance of the storm as nuclear operators and regulators put storm preparation procedures into action, while the other shut down automatically because of a valve-related issue.
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Mining Awareness always does good work. He/She picked up on this story and ran with it.
https://miningawareness.wordpress.com/2017/09/13/update-to-hurricane-irma-nuclear-power-mysteries-us-nrc-contradicts-itself-on-second-turkey-point-nuclear-reactor-shutdown-defective-parts-and-more/
Turkey Point is a PWR. Steam is from non nuclear secondary side. The MSIVs opening is very loud, so operating staff need hearing protection in the viscinity. The steam is non radioactive since a PWR has isolated primary and secondary side unless a major catastrophic failure of a SG, thats one reason for msivs. The reactor is allready shut down when MSIVs open under the conditions noted. Not a big deal. Report to NRC at lowest level.
ReplyDeleteAh, but you miss the main points:
Delete1) plant was running at 88% prior to "manual scram", which I believe to be an automatic SCRAM but they wanted to pretend they were in control
2) This is coincidental with the hurricane and shutdown of the other reactor. This is suspicious of a more important underlying problem
3) FPL made it a point to have NRC state there are no know major problems with the steam generators. Which makes me think the lady doth protest too much...why belabour this point, unless of course there was leakage, and therefore cross contamination and thus radiological release. The original steam generators only lasted 8 years, they were replaced around 1982, so the new set is now 35 years old. hmmmmmmm
https://inis.iaea.org/search/searchsinglerecord.aspx?recordsFor=SingleRecord&RN=15025575
Also FPL's 2014 attempt to cover up a steam leak on this aging plant is duly noted. They pretended their shutdown was a "pre-planned evolution"
https://www.1776channel.com/2014/12/03/earth/aging-turkey-point-nuclear-reactor-near-miami-in-hot-standby-mode-following-steam-leak-and-shutdown/
Pressure to max out profits from this aging plants are clear cut as shown by the 2008 outage...
David Hoffman, a nuclear supervisor at Turkey Point, resigned over the incident and was subsequently sued by Florida Power and Light for return of a bonus. Hoffman countersued, claiming he was pressured to restart the reactors while they were in a condition which in his judgment made it unsafe to do so. Upper management wanted the reactors restarted during xenon dead time, which would have led to the operators at the controls having to continuously step control rods to safely manage reactor output.
https://en.wikipedia.org/wiki/Turkey_Point_Nuclear_Generating_Station
Also operation of Aux feed is a reportable condition. I read the LER and these things bloat the notification process since redundant SGs provide plenty of margin. One of the lessons learned from TMI was that feedwater from the secondary side and B&Ws unique once-through SG was vulnerable to these dryout situations on the secondary shell side and thats why primary coolant pressure increased. A stuck open PORV resulted in a loss of ore coolant but operators didnt recognize isenthalpic temperature through the valve. All pkants regardless had to monitor feed flow and valve indicationaa a lesson learned. For our plant, the feedwater flow indicators were up ob a mezzanine, near the SG outlet to the turbine. There was a waterhammer event that slammed into a check valve up on the mezzanine, and had i been up there at the time, woukd have been killed by superheated, nonradioactive steam. Superheated steam killed 9 at a coal plant in Laughlin Nevada that year and it didnt get much news.
ReplyDeletePeople dont realize for a PWR, outside containment, downstream from the msivs its no different than any other steam plant.
Its a non safety related incident. Usually antinukes read these reports and assume the sky is falling. They take what little information they have and assume no real knowledge of actual conduct of operations or conops. Its important to understand the concept of conops, a Navy nuclear term. Many ops staff come from the nuclear navy.
ReplyDeleteBrowns Ferry is a BWR (GE). PWR and BWR primary-secondary isolation systems are apples and oranges.
ReplyDeleteMy suspicion was correct, it was an automatic SCRAM from 88%. If they wanted a more controlled manual SCRAM they would have taken it to 30% or so.
Deletehttp://www.world-nuclear-news.org/RS-Nuclear-units-weather-Hurricane-Irma-1109177.html
Two nuclear units at St Lucie were able to continue operating as Hurricane Irma made landfall in Florida. One unit at Turkey Point was shut down as a precaution in advance of the storm as nuclear operators and regulators put storm preparation procedures into action, while the other shut down automatically because of a valve-related issue.
Reactors can scram safely from 100%. Ive witnessed it up close in the control room.
DeleteOf course they can scram from 100%, but it creates wear and tear, thermal shock, stress, maybe things break, valves get jammed, crap gets knock loose, shroud bolts get sucked into pumps....that type of thing.
DeleteYet its part of the design basis. Afterall, its meant to scram at 100% for a reason. Reactor shutdown at 100% is not preferred but its also not a situation that makes the plant less safe.
ReplyDeleteYou miss the point. They were at 88% scrambling for a solution to a serious plant problem, not trying to slowly safely take the plant down, but a hail mary pass to try not to have to shut down the plant, which failed.
DeleteWhat is the real story, is the story? Why do you think they would be at 88%
Sorry didnt see your reply. 88% probably is an imposed generator load limit. Reactor follows turbine in these plants. The reactor side is more reliable than the BOP side. Heck I almost was killed on the steam side. Very dangerous. Nuclear side much safer.This the normal rank and file doesnt know or get. They read and think what they read in press is correct. The press doesnt know
ReplyDeleteI hear of valves failing all the time on the "hot" side" the nuke side. This stuff is getting old, you cannot inspect quality into an old part.
DeleteIf all the replacements that should be done, were done, it would bankrupt the rest of the US fleet.