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Easter Sunday and Arkansas Nuclear One

Victor Dricks
Senior Public Affairs Officer, Region IV
 

As the eyes and ears of the NRC, resident inspectors never know when they might have to respond to an emergency at the plants anothey monitor. Fred Sanchez, Arkansas Nuclear One Senior Resident Inspector, was preparing to attend Easter services with his family when he got a call shortly before 8 a.m. Sunday informing him that a 600-ton component was dropped from a crane while being moved out of the turbine building at Unit 1.

He drove to the plant to survey the damage and phoned reports back to Region IV staff all day.

The industrial accident resulted in eight injuries and one fatality. Of the injured workers, six were treated and released from a local hospital; two remain hospitalized.

At the time of the event, Unit 1 was in a refueling outage with all of the fuel still in the reactor vessel, safely cooled. The accident damaged some electrical equipment that supplies off-site power to the plant. The plant’s emergency diesel generators started and power was quickly restored to the decay heat removal systems.

Unit 2, which was operating at full power, automatically shut down when power was lost to a reactor coolant pump due to electrical equipment that was damaged when the component fell. At 9:22 a.m. offsite power to one electrical bus was lost because water from a fire main broken by the falling component caused a short circuit. An emergency diesel generator started up and is supplying power to key safety systems. Unit 2 is cooling down using natural circulation.

Both plants are in stable shutdown condition. There was no radiological release or danger to the public.

Entergy Operations, Inc., which operates the plant, declared a Notice of Unusual Event, the lowest of four NRC emergency classifications, at 10:44 a.m. because the accident damaged some electrical equipment. The Unusual Event was terminated at 6:21 p.m. after the licensee took corrective actions to stabilize the plant’s power supplies.

Two additional inspectors have been dispatched to ANO to assist the resident inspectors and conduct follow-up reviews of the licensee’s response to the event. NRC’s Region IV also plans to conduct an inspection to review the circumstances contributing to the event.

61 responses to “Easter Sunday and Arkansas Nuclear One

  1. Weight Down May 31, 2013 at 9:50 am

    This job was critical path for the outage, so it was going to happen when everything in the schedule lined up.
    why the stator dropped??

  2. Orange Restoration (@orangesd) May 28, 2013 at 5:19 pm

    It is just terrible when disasters like this happen, especially so close to the holidays. I don’t think its good to harp on whose fault it was, but rather we should focus on how to avoid an event like this in the future. I work for a restoration company and if something goes wrong we try and focus on how we could change it rather than whose fault it was in the first place.

    Moderator Note: A link has been removed from this comment.

  3. Pave Way IV April 8, 2013 at 11:55 pm

    Victor – I noticed that the word ‘SCRAM’ was almost completely absent from media reports on the ANO accident. Media reports of ANO-2 automatically ‘shutting down’ from a breaker explosion without mentioning a SCRAM implies – to me – some kind of uncontrolled shutdown. I know that wasn’t the case and Unit 2 is now in Mode 3 – Hot Standby. I thought SCRAM had a pretty distinct meaning and was expecting to see it somewhere in media reports. The Event Report (48869) confuses me more when it states “…On Unit 2, all rods inserted during the trip…” but the SCRAM code is ‘N’ and RX CRIT is ‘Y’. If Unit 2 tripped, doesn’t that mean it has been SCRAMed and is no longer critical?

    Has there been any change in the way NRC responds to media inquiries to avoid that term, or am I just confused about *what* it means?

    • David Andersen. April 9, 2013 at 10:47 am

      The term SCRAM dates back to the beginnings of nuclear reactors and meant Shutdown Control Rod Ax Man because a man was literally stationed with an ax to cut the rope holding the control rod. The term carried over but the Ax Man didn’t. Several other terms are now also used such as Reactor Trip,and Automatic Shutdown, they mean the same thing. I’m not sure why we don’t use a standard term but it would be nice if we did to avoid confusion.

    • Moderator April 9, 2013 at 11:03 am

      We try to avoid use of the term SCRAM because it is jargon. Instead we usually say a reactor shut down automatically in a controlled fashion designed to protect equipment and public health and safety. Regarding Event Report 48869, you are correct and there is an error when it shows that Unit 2, which was critical and operating at full power, did not SCRAM as a result of the breaker malfunction. It did and the box should indicate a “Y” rather than an “N.” We’re notifying Entergy so they can fix the error. The box correctly shows a “Y” for RX CRIT indicating the reactor was critical at the time of the event.

      Victor Dricks

      • acehoffman April 9, 2013 at 11:07 am

        I prefer “plunk go the rods”

      • Gerhard LANGguth ANO_u2 RO August 1987! April 9, 2013 at 11:22 am

        FYI inforMation, more than likely the mini-seizmic event busted breaker mounts on switch gear at Elevtion 372 (none safety) and either that (loss of 4160/6900 3oAC) to the RCPs OR the main turbine vibration sensor probably intiated a full blown WTF response. Once the main “Christmas Tree” lights come on who cares whether A,B,C or Z#101 actually caused the trip. We are talking Milli and uMicroSeconds not even Minutes

      • Gerhard LANGguth ANO_u2 RO August 1987! April 9, 2013 at 11:26 am

        Thanks for your Careful moderation. That could be a Boron joke but lets kNote go there. April fools was 04/01/13 in English or 01.04.2013 in Y2K Deutsch. I speak all three and sometime get MY acro_nyms or even dat(ah)s or DtC (NiST=DateCodes) mixed up. Sorry for too much info when or if Silence is the best option currently available. My FuSimy comnts are at WP=GLsword

      • Pave Way IV April 9, 2013 at 1:22 pm

        Thanks, Victor – that makes sense. I understand why one should avoid using jargon, but reporters seem to have been fond of tossing SCRAM somewhere in their articles. The ones that still have jobs today are probably too young to have any idea what it means.

        For what it’s worth, I wasn’t nitpicking on the inconsistent SCRAM code to imply that you or Entergy should do something about the event report – I was honestly confused. There really isn’t any point in Entergy fixing it now. There’s only (apparently) about six or seven of us that actually read them and no Entergy employees. Maybe they have the NRC web site blocked in their firewall?

    • Gerhard LANGguth ANO_u2 RO August 1987! April 9, 2013 at 11:41 am

      I suggest that SCRAM be reserved to Manually intiated human responses to WTFs going on. And only that. Automatic shutdown Rabot (international-sic) responses try Robotic instead sound much better and are fair/balanced reporting VS sensational none Seismic events.

  4. John Weigler April 5, 2013 at 6:39 pm

    Anonymous, excellent show of courage. You explained my point exactly. “The schedule” takes priority over everything. The culture of nuclear power has changed dramatically over my nuclear career. Scheduled outages have been reduced from 100 days to less than 30 days. Many of those changes I agree with. However, the disregard of a power greater than ourselves and the manipulation of people to accomplish these schedules is horrible to me. I am not saying that is what happened here. I truly do not know what happened here. I know a stator was dropped and people were hurt. One person was killed. I also know night-shift thought the lift was unsafe. Day-shift came in and tried the lift, the rest is history. Lets just say replacement power is 1 million dollars a day. How many days will this set the outage back? What will the lawsuit cost? How much is a life worth? I know my management and the management in other plants wants everyone to go home the way they came in. Would it hurt anything to acknowledge God and observe the holiday? At least put off enormous evolutions until all were thru the holiday. I have seen that done before. We even schedule planned outages around big holidays. It is better for our people and better for the plant.

  5. Gerhard April 4, 2013 at 9:00 am

    I am a former worker at this place but not necessarily a blind nuclear advocate. Accidents of all types happen. Honest, hard working people drop torpedos on their own submarines and those weigh much less than 12 hundred-thousand pounds. Reading the open and reasonably fair press coverage of this incident, I am impressed by the plant operators (Entergy’s) response and willingness to be forth coming. The NRC is doing even better.

    It is my assessment from all public accounts that there are some tough questions that must be asked … but there was and IS less danger to the public from this “Industrial Accident” than most 18 wheeler (only 80 thousand pounds mind you) accidents that happen along Interstate 40 from Memphis TN to Fort Smith AR.

    Lets give these folks some room to breath, debrief and recover BEFORE drawing conclusions. If the radiation sirens go off, that is the time to duck and cover. And Fear or Panic should not in your minds even then. BTW: when was the last time you checked the batteries in your emergency weather radio?

    • LillyMunster April 4, 2013 at 9:51 am

      Nice risk PR song and dance. You used the playbook line by line.

      This really is sort of two problems. One being the industrial accident with the lift crane. The other being that the plant still has a loss of offsite power and apparently still a loss to the ultimate heat sink. Neither the NRC or Entergy are being up front or clear about the status of either of these situations. This is a problem and the public deserves clear answers.

      • Mike April 4, 2013 at 11:12 am

        There is no loss to the “ultimate heat sink.” The service water pumps, on Unit 1, automatically restarted on restoration of power to the vital buses after the diesel generators automatically tied on to the buses. The service water system is cooling plant systems, including the decay heat removal systems and the spent fuel cooling system. At least, that’s the way it is designed to work and I’ve seen nothing that makes me think otherwise. (I don’t work for anyone, so have nothing vested in this, other than knowledge.)

      • Gerhard April 4, 2013 at 1:09 pm

        If you would just read the local newspaper(s) and ask honest question instead of spouting non-sense, we would all be better informed. The “ultimate heat sink” either the emergency cooling pond or Lake Dardanelle are there and as long as there is diesel fuel NOTHING has been lost except the normal offsite shutdown power supply(ies).

        Or more precisely -read the actual incident report as it was written and shown on this dot.gov portal- The connections between a triple redundant power grid outside the Unit and the fully functional and redundant safety supplies inside is broken. However EACH safety bus is being powered by its own diesel powered generator with enough fuel on site for at least a few month of shutdown cooling and safety related operations.

        Now IF you have some information that contradicts THAT propoganda then lets hear it here. I do no longer work for Entergy or toe the NRC line. Obviously they allowed you to challenge their version of the facts. So go ahead challenge or better yet correct mine. All the information I have comes from public sources. If I was still a Licensed Reactor Operator (try Unit 2 back in the 1980s), I would probably be there doing my job.

        Instead I am “following” this and keeping myself, neighbors and friends (who ask me questions) informed as best as I can. If for one second I thought there was a clear and present danger Id be packing my bags. But to the best of my knowledge all there is is a bunch of mangled garbage and it will take a week or so to get -the electric- traffic going again. In the mean time, you just sit tight, turn up the radio and let Entergy/NRC/OSHA do their jobs.

  6. Andrew Castle April 4, 2013 at 1:56 am

    “The NRC and the Occupational Safety & Health Administration will conduct inspections on this failure, which will be documented in inspection reports that will be made public in the future.”
    Mr. Dricks, when these reports become available where can the public find them?

    • Gerhard April 4, 2013 at 9:54 am

      The Arkansas Tech Univ library is a federally funded repository for most microfiche/paper copies and reports. This blog site and/or the NRC Web site will likely have or link to online versions. The local papers (Russellville-Courier and Little Rock-Arkansas Democrat) usually provide adequate coverage so most people can find the stuff.

      However, just like NTSB (National Transportation Safety Board) crash reports it may take years of research and pain staking reconstruction before We The People and our appointed officials can fully understand what went wrong.

    • Moderator April 4, 2013 at 10:16 am

      NRC resident inspectors, assisted by two additional inspectors sent to the site, are currently reviewing the event. Their findings will be documented in a quarterly inspection report. All NRC inspection reports are posted to the NRC web site at: http://www.nrc.gov/NRR/OVERSIGHT/ASSESS/listofrpts_body.html#wc

      Victor Dricks

  7. Mike April 3, 2013 at 5:30 pm

    This job was critical path for the outage, so it was going to happen when everything in the schedule lined up.

    Restoration of decay heat in 3 minutes and 50 seconds is a good thing. They had two different procedures that they had to implement at the same time to accomplish this: Loss of Decay Heat and Degraded Power. These guys had 1.2 MILLION pounds drop 40 feet to the train bay floor, and then all the lights in the control room except for emergency lighting went out until the diesel generators started and tied onto their respective buses. The last loss of offsite power at ANO was April and June of 1980. Both of those events involved both units and were caused by events away from the site. The sound of this event was heard by residents outside the exclusion area. I suspect it was extremely loud in the control room and that the operators felt the resultant shock.

    That 1.2 million pounds, along with large pieces fell in a bay. From the pictures, I can see that there is structural damage just above that area.

    I am a retired, previously licensed SRO on ANO Unit 1

    Note: Some sensitive site-specific information deleted.

  8. LillyMunster April 3, 2013 at 1:35 pm

    In looking at the various reports beyond the limited information the NRC has provided it seems that the electrical system for unit 2’s intakes was wired over on the #1 side, causing the loss of power on the #2 side and loss of the intake pumps. It a multi unit plant shouldn’t the power systems for each side of the turbine building be wired independently and ON that side of the building rather than passing both through one side of the turbine building? This mirrored and separate systems makes sense from a design and safety standpoint and appears to not have been the case, causing an additional problem on top of the accident.

    Has power been restored to unit 2’s intakes yet? Yes or no?
    When will offsite power be restored to both units? The public deserves some clear answers on these two issues. These seem to be the only outstanding safety related issues.

    As others have mentioned this could have been worse. Someone asked me if the rail pit the stator fell into is on concrete slab? If this equipment had failed elsewhere it could have gone through multiple floors. I hope there are some follow up reports on this as more is found out about the extent of building damage etc.

    The whole incident is very unfortunate and I am sure is very hard on those working at the plant but the failure seems to maybe just be one of those freak things that can happen.

    • Moderator April 4, 2013 at 10:16 am

      The plant is designed with separate electrical power systems to minimize the possibility that an accident at one plant would affect another. On Sunday, it was the physical impact of the 600-ton component that affected both units, not electrical interconnections. When the component fell on the turbine deck it damaged part of the electrical distribution system for Unit 1, causing a loss of offsite power for Unit 1. The crash of the stator was sensed by a reactor coolant pump for Unit 2, which protectively responded by shutting down, causing the reactor, which was operating at full power, to shut down.

      In answer to your questions: Unit 1 is still using an emergency diesel generator; Unit 2 is not. Offsite power has been fully restored to Unit 2.

      Victor Dricks

    • Mike April 4, 2013 at 10:43 am

      The loss of power was to the non-vital electrical systems. The stator fell in the train bay, which is between the non-vital bus areas on both units, providing physical separation between the non-vital electrical buses. There are no interconnections between the electrical buses of the two units. Provisions are available to potentially supply one unit from the other under very unusual emergency conditions, but it takes specific operator actions to make that happen.

      I’m reading this from the outside, just like everyone else. I haven’t been inside the plant for several years, but I’ve walked the areas this occurred in many,many times.

    • hiddencamper April 4, 2013 at 2:41 pm

      Some references for class 1E power systems (vital power systems) in nuclear power plants: IEEE 384, separation criteria for class 1E power systems in nuclear power facilities. IEEE 308, standard for class 1E power systems in nuclear power facilities. IEEE 379, standard for application of single failure criteria to class 1E power systems.

      As nuclear plants were designed to these standards, they may provide the insight you are looking for. Additionally, note that these are only for the class 1E power system. The non 1E power system (non-vital busses) don’t behave in this way.

  9. Jwags23 April 3, 2013 at 12:32 pm

    My heart and prayers go out to the family members and the injured in this tragedy. It has been all long time since nuclear power plants regarded Easter and Christmas as sacred holidays. Maybe it is time. Greed is a poor reason to disregard them.

    • Anonymous April 4, 2013 at 9:21 am

      These comments about Easter are perplexing. Outage work is done to a schedule, and the schedule is modified as the work progresses. So if the stator lift comes up on Easter sunday morning, that’s when the crew doing the lift will be there to do their work. It may be hard for regular 9 to 5’ers to understand, but some parts of our world (like making electricity) go on 24 – 7 and the people who work in these industries just do it.

  10. Crack Fickerson April 3, 2013 at 1:45 am

    I saw the same lift executed at another plant. the same type equipment was used (including the brand name on the lift equipment). sometimes, in the process of making these big equipment changes to a plant, a small decision can lead to catastrophic events. It’s quite sad that a loss of life has occurred. However, this event was on the BOP side of the house, not in the Reactor side. To say the plant was distressingly close to a meltdown is not well informed and making harsh assumptions, including sensationalism. The plant operators reacted in accordance with procedures and shut the running unit down. The diesel generators are a normal backup to off-site power, and while the risk was raised by reducing the redundant systems in operating the diesels, they performed as designed. I am sure the thorough investigation will reveal errors and industry will react to ensure it doesn’t happen again. It is a tragic loss and prayers go to the families of the victims. And hopefully the anti-nuke people will feel the same way.

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