Help | Contact Us
NukeWorker.com
NukeWorker Menu reactors

Author Topic: reactors  (Read 32209 times)

0 Members and 1 Guest are viewing this topic.

wlrun3@aol.com

  • Guest
reactors
« on: Mar 05, 2009, 08:59 »

   ...boiling water reactors...
      control rod blades incrementally withdrawn to control reactivity
     
   ...pressurized water reactors...
      boron concentration adjusted to control reactivity

   ...reactor operator and electrical dispatcher balance reactivity with electric demand (load) to maintain turbine at 1800 rpm...

   ...am i right?



     
       

Offline Creeker

  • Moderate User
  • ***
  • Posts: 112
  • Karma: 607
  • Gender: Male
Re: reactors
« Reply #1 on: Mar 05, 2009, 09:31 »
I can't speak to the BWRs... The PWRS do operate with rods all the way out, and we adjust boron every couple of hours (depending upon time in life) to adjust reactivity.  The rods are manipulated in and out a few steps every month or so to minimize fretting (undue wear in a single spot on the rod coating), but this has minimal reactivity affect.  Beginning of life, we borate, as burnable poisens loaded in the core burn up, but then we begin to dilute, to compensate for fuel burning up.

As for the reactivity balance... You're a little off.  It's pretty easy, and takes relatively little steam/power to rotate a turbine to 1800 RPM.  So, we spin it up, and then let a speed control circuitry take over to maintain turbine speed.  What is actually balanced is the load in MW on the turbine.  The more load, the more counter force is placed on the turbine, and the more steam it takes to keep pushing it at 1800 RPM.  That's a little simple, but your balancing MW with reactor power in order to keep things going, and ideally, 100% power is matched to 100% turbine output, so you're neither wasting fuel, or not getting the most out of your turbine. 

Bill

Offline Preciousblue1965

  • Very Heavy User
  • *****
  • Posts: 687
  • Karma: 524
  • Gender: Male
  • "It is good for you, builds character"
Re: reactors
« Reply #2 on: Mar 05, 2009, 10:17 »
I can't speak to the BWRs... The PWRS do operate with rods all the way out, and we adjust boron every couple of hours (depending upon time in life) to adjust reactivity.  The rods are manipulated in and out a few steps every month or so to minimize fretting (undue wear in a single spot on the rod coating), but this has minimal reactivity affect.  Beginning of life, we borate, as burnable poisens loaded in the core burn up, but then we begin to dilute, to compensate for fuel burning up.

As for the reactivity balance... You're a little off.  It's pretty easy, and takes relatively little steam/power to rotate a turbine to 1800 RPM.  So, we spin it up, and then let a speed control circuitry take over to maintain turbine speed.  What is actually balanced is the load in MW on the turbine.  The more load, the more counter force is placed on the turbine, and the more steam it takes to keep pushing it at 1800 RPM.  That's a little simple, but your balancing MW with reactor power in order to keep things going, and ideally, 100% power is matched to 100% turbine output, so you're neither wasting fuel, or not getting the most out of your turbine. 

Bill

And that's how nuclear power works.....
"No good deal goes unpunished"

"Explain using obscene hand jestures the concept of pump laws"

I have found the cure for LIBERALISM, it is a good steady dose of REALITY!

Offline Gamecock

  • Gold Member
  • *
  • Posts: 1202
  • Karma: 2367
  • Gender: Male
  • "Perfection is the enemy of good enough."
Re: reactors
« Reply #3 on: Mar 05, 2009, 10:28 »
And that's how nuclear power works.....

I thought it worked like this....

Magic Hot Rock....

Make Steam....

Makes Boat Go!!

 :P :P :P
“If the thought police come... we will meet them at the door, respectfully, unflinchingly, willing to die... holding a copy of the sacred Scriptures in one hand and the US Constitution in the other."

Fermi2

  • Guest
Re: reactors
« Reply #4 on: Mar 05, 2009, 10:33 »
I can't speak to the BWRs... The PWRS do operate with rods all the way out, and we adjust boron every couple of hours (depending upon time in life) to adjust reactivity.  The rods are manipulated in and out a few steps every month or so to minimize fretting (undue wear in a single spot on the rod coating), but this has minimal reactivity affect.  Beginning of life, we borate, as burnable poisens loaded in the core burn up, but then we begin to dilute, to compensate for fuel burning up.

As for the reactivity balance... You're a little off.  It's pretty easy, and takes relatively little steam/power to rotate a turbine to 1800 RPM.  So, we spin it up, and then let a speed control circuitry take over to maintain turbine speed.  What is actually balanced is the load in MW on the turbine.  The more load, the more counter force is placed on the turbine, and the more steam it takes to keep pushing it at 1800 RPM.  That's a little simple, but your balancing MW with reactor power in order to keep things going, and ideally, 100% power is matched to 100% turbine output, so you're neither wasting fuel, or not getting the most out of your turbine. 

Bill

Simple and extremely incorrect.

Mike

Offline Creeker

  • Moderate User
  • ***
  • Posts: 112
  • Karma: 607
  • Gender: Male
Re: reactors
« Reply #5 on: Mar 05, 2009, 10:36 »
Quote
Simple and extremely incorrect.

Ouch...  I'll beat a hasty retreat and go back to studying EMGs.

Bill

wlrun3@aol.com

  • Guest
Re: reactors
« Reply #6 on: Mar 05, 2009, 11:09 »
Simple and extremely incorrect.

Mike

   ...here is an example of the type of generalization i was looking for...

   ...20,000 years ago, Paleolithic Era, first humans develop foraging technology...

   ...10,000 years ago, Agricultural Era, rates of innovation insufficient to overcome rates of population increase causing recurrent Malthusian collapses...

   ...200 years ago, Industrial Revolution, rates of innovation exceed rates of population increase causing recurrent economic collapses...

   ...i am seeking simple and correct...


wlrun3@aol.com

  • Guest
Re: reactors
« Reply #7 on: Mar 05, 2009, 11:11 »
Ouch...  I'll beat a hasty retreat and go back to studying EMGs.

Bill

   ...thankyou for the reply...

   ...what's an EMG...



dirac

  • Guest
Re: reactors
« Reply #8 on: Mar 05, 2009, 11:13 »
   ...boiling water reactors...
      control rod blades incrementally withdrawn to control reactivity
     
   ...pressurized water reactors...
      boron concentration adjusted to control reactivity

   ...reactor operator and electrical dispatcher balance reactivity with electric demand (load) to maintain turbine at 1800 rpm...

   ...am i right?



     
       

More correct to stay steam demand to balance rectivity.

Offline Creeker

  • Moderate User
  • ***
  • Posts: 112
  • Karma: 607
  • Gender: Male
Re: reactors
« Reply #9 on: Mar 05, 2009, 11:56 »
Quote
...what's an EMG...

EMG's are the procedures that guide us when things go from wrong to very wrong.  They are symptom based, meaning you don't really have to diagnose the problem to know where to go.. You have a common entry point, which directs immediate actions, and then either directs you to a common trip procedure, or takes you to a safety injection procedure, and then you go from there, based upon your symptoms.  (Of course, there are many branches and transitions that can be made along the way, but that's a simple explanation).. Hopefully, simple and correct.  EMG's are studied in license class around the half way point.  First you do general fundamentals, then systems, then OFNs (Off Normals) then EMGs and finally take the audit exam and the NRC exam.  6 months to go!

Bill

Offline NuclearBob

  • Very Lite User
  • *
  • Posts: 7
  • Karma: 58
  • Tell Recruiters to use NukeWorker.com
Re: reactors
« Reply #10 on: Mar 05, 2009, 12:59 »
For a BWR we actually control power with both control rods and recirculation flow (coolant) through the fuel.  By adjusting the flow of coolant we can change the moderating properties (void fraction) in the core causing power to increase or decrease.  We also adjust control rods to maximize fuel efficiency.  The Main Turbine is slaved to the reactor in a BWR.  It maintains a desired pressure setpoint and speed (1800 rpm).  The reactor power output drives the turbine output.

Hope this helps to answer your questions.

wlrun3@aol.com

  • Guest
Re: reactors
« Reply #11 on: Mar 05, 2009, 01:31 »
For a BWR we actually control power with both control rods and recirculation flow (coolant) through the fuel.  By adjusting the flow of coolant we can change the moderating properties (void fraction) in the core causing power to increase or decrease.  We also adjust control rods to maximize fuel efficiency.  The Main Turbine is slaved to the reactor in a BWR.  It maintains a desired pressure setpoint and speed (1800 rpm).  The reactor power output drives the turbine output.

Hope this helps to answer your questions.

   ...what are some power change situations when you would choose one over the other option...

   ...thankyou for the reply...




number41

  • Guest
Re: reactors
« Reply #12 on: Mar 05, 2009, 07:10 »
Not qualified yet, but BWR's change power based upon grid load demand, so if the dispatcher requests a change and we can support, then we will.  Usually we use recirc pump speed to control void fraction to control Rx power and thus pressure and therefore generator power (this is the really simple version of a really complex interaction between the turbine control system and physical conditions in the reactor).  But the method used to change power is dependent on a lot of factors including procedure requirements and about 80 other things.  The magnitude of the required power change will often determine whether rods or recirc pumps are used.  Other times we would change power involve maintenance situations or control rod improvements or sequence exchanges........which is another huge discussion.  Anyway, you're actually asking for a simple explanation of something that is VERY complex in a BWR. Somebody correct me if I'm missing something.

Offline Preciousblue1965

  • Very Heavy User
  • *****
  • Posts: 687
  • Karma: 524
  • Gender: Male
  • "It is good for you, builds character"
Re: reactors
« Reply #13 on: Mar 05, 2009, 07:34 »
Not qualified yet, but BWR's change power based upon grid load demand, so if the dispatcher requests a change and we can support, then we will.  Usually we use recirc pump speed to control void fraction to control Rx power and thus pressure and therefore generator power (this is the really simple version of a really complex interaction between the turbine control system and physical conditions in the reactor).  But the method used to change power is dependent on a lot of factors including procedure requirements and about 80 other things.  The magnitude of the required power change will often determine whether rods or recirc pumps are used.  Other times we would change power involve maintenance situations or control rod improvements or sequence exchanges........which is another huge discussion.  Anyway, you're actually asking for a simple explanation of something that is VERY complex in a BWR. Somebody correct me if I'm missing something.

and that too is how nuclear power works.......I think?
"No good deal goes unpunished"

"Explain using obscene hand jestures the concept of pump laws"

I have found the cure for LIBERALISM, it is a good steady dose of REALITY!

wlrun3@aol.com

  • Guest
Re: reactors
« Reply #14 on: Mar 05, 2009, 07:43 »


   ..."The magnitude of the required power change will often determine whether rods or recirc pumps are used."

   ...that was what i was looking for...

  ...rods, rough control, pumps, fine control...
 
  ...i apologize for the naive requests for simplicity...

  thankyou


thenuttyneutron

  • Guest
Re: reactors
« Reply #15 on: Mar 05, 2009, 08:41 »
I know that I have to watch my plant.  She will pull rods to maintain a set load on the Main Turbine, and Tave at 582.  She will balance the secondary heat balance between her 2 massive steam generators all by herself.  If she gets to 103% on the highest NI, she stops pulling and yells at me.  If there is a problem, she can sometimes lower power on herself to correct it.  If she does yell at me, I know how to make it right and make her happy again.

The girl is old, but she is nimble.  Once I have her excited, I can bring her up and down at 10% per minute just by adjusting two things and standing back to watch.  She can move even faster when lowering power at 20% per minute if I need her to.  Listening to her steam driven feed pumps sing brings a smile to my face.  I have the magic touch with this mistress of mine.  I wish I could operate my wife with such ease.
« Last Edit: Mar 05, 2009, 08:58 by The Nutty Neutron »

B.PRESGROVE

  • Guest
Re: reactors
« Reply #16 on: Mar 05, 2009, 09:56 »
Nutty, now there is a man who is so in touch with his plant all he has to do is listen to it and know what to do.  Almost brings a tear to my eye.  Karma to you my friend.
« Last Edit: Mar 05, 2009, 09:57 by B.PRESGROVE »

thenuttyneutron

  • Guest
Re: reactors
« Reply #17 on: Mar 05, 2009, 11:18 »
I can handle her yelling at me with that 1970's era game show buzzers. 

When she trips from 100% power herself, she roars so loud through her mainsteam safety valves that the gates of hell will rattle.  I then know I am in serious trouble with her daddy the OPS manager.

Offline zilla

  • Light User
  • **
  • Posts: 13
  • Karma: 16
  • Tell Recruiters to use NukeWorker.com
Re: reactors
« Reply #18 on: Mar 05, 2009, 11:19 »
   ...what are some power change situations when you would choose one over the other option...

   ...thankyou for the reply...


99% of the time recirc flow is changed to adjust power.  Since we're pretty much all baseload plants.... you're just adjusting for fuel burnout or poison burnout, depending on where you are in the cycle.  Rods are moved from time to time (sequence exchanges) to alter the rod pattern to burn out fuel in the optimum pattern. (although rod density does go down over core life -- this is taken care of during the sequence exchanges)   The only times you would use rods for power adjustment would be during a need for a rapid power drop (for loss of vacuum, AOPs, etc...) and then you would first run back recirc to some minimum or low value to get a rapid decrease in power, followed by insertion of rods to get back to within your allowed operating bands.  This could be done with normal rod insertion or insertion of cram rods that wouild be driven in individually, fully.

wlrun3@aol.com

  • Guest
Re: reactors
« Reply #19 on: Mar 06, 2009, 08:04 »
 

   ..."99% of the time recirc flow is changed to adjust power"...



   ...boiling water reactor...
         recirculation pump flow is used to change reactivity

   ...pressurized water reactor...
         boron concentration is used to change reactivity


   ...thankyou, very much...

   ...what can i generally and correctly say about the relationship between the reactor operator and the electric dispatcher...




 

   

Offline retired nuke

  • Family Man
  • Very Heavy User
  • *****
  • Posts: 1508
  • Karma: 3538
  • Gender: Male
  • No longer a nuke
Re: reactors
« Reply #20 on: Mar 06, 2009, 09:52 »
 

   ..."99% of the time recirc flow is changed to adjust power"...



   ...boiling water reactor...
         recirculation pump flow is used to change reactivity
I believe in some BWRs, the pump speed remains constant..and the flow is adjusted by a valve (GGNS/BWR-6??) a minor additional detail, if I remember correctly

   ...pressurized water reactor...
         boron concentration is used to change reactivity


   ...thankyou, very much...

   ...what can i generally and correctly say about the relationship between the reactor operator and the electric dispatcher...




 

   
Remember who you love. Remember what is sacred. Remember what is true.
Remember that you will die, and that this day is a gift. Remember how you wish to live, may the blessing of the Lord be with you

Offline Creeker

  • Moderate User
  • ***
  • Posts: 112
  • Karma: 607
  • Gender: Male
Re: reactors
« Reply #21 on: Mar 06, 2009, 10:28 »
Quote
...what can i generally and correctly say about the relationship between the reactor operator and the electric dispatcher...

For my plant (PWR) we run at 100% thermal reactor power, with all rods out, and the turbine runs at 100% power output, with all control valves (that control steam flow) fully open.  So, the electrical operator (called BOP-Balance of Plant) can't really put much more real load on the reactor, however, should he take it off, the effects would immediately be reflected on the reactor side, with temperature/pressure/pressurizer level increasing initially, then settling down to lower values (except pressure, which would return to NOP) 

If we had a major downpower, then we would have to borate to minimize how far we would have to insert rods to lower Tave, so we didn't exceed our rod insertion limits.  (Our Tave is adjusted up with turbine power increasing so we have increasing S/G pressure, and down when turbine power decreases) 

If we were steady state, and the RO were to lower Tave a bit, it would result in lower S/G pressure, and lowering MW output. 

So, both sides affect each other, and must coordinate with each other for any reactivity changes.

wlrun3@aol.com

  • Guest
Re: reactors
« Reply #22 on: Mar 06, 2009, 10:54 »
For my plant (PWR) we run at 100% thermal reactor power, with all rods out, and the turbine runs at 100% power output, with all control valves (that control steam flow) fully open.  So, the electrical operator (called BOP-Balance of Plant) can't really put much more real load on the reactor, however, should he take it off, the effects would immediately be reflected on the reactor side, with temperature/pressure/pressurizer level increasing initially, then settling down to lower values (except pressure, which would return to NOP) 

If we had a major downpower, then we would have to borate to minimize how far we would have to insert rods to lower Tave, so we didn't exceed our rod insertion limits.  (Our Tave is adjusted up with turbine power increasing so we have increasing S/G pressure, and down when turbine power decreases) 

If we were steady state, and the RO were to lower Tave a bit, it would result in lower S/G pressure, and lowering MW output. 

So, both sides affect each other, and must coordinate with each other for any reactivity changes.

   ...when the offsite electric dispatcher requests more or less power does he talk to the electric balance of plant operator in the control room...




Offline Creeker

  • Moderate User
  • ***
  • Posts: 112
  • Karma: 607
  • Gender: Male
Re: reactors
« Reply #23 on: Mar 06, 2009, 11:12 »
Quote
...when the offsite electric dispatcher requests more or less power does he talk to the electric balance of plant operator in the control room...

There are plants out there which are load followers, and thank goodness we are not one.  We operate at a steady 100% real power output from end of outage to start of outage. (Called a breaker to breaker run, with the very occasional forced outage)

However, system ops, which is out electrical dispatcher, will call the control room, and speak to the Control Room Supervisor, asking to adjust reactive load by however many MVars, and the BOP operator will adjust the generator field current to adjust MVar output.  It's a very quick evolution, and typically, we'll keep system ops on the line, make the adjustment, and ask them if that adjustment was adaquate.  They (about 60 miles away) will instantly see the change, and tell is if it was or not.

Offline HydroDave63

  • Retired
  • *
  • Posts: 6295
  • Karma: 6629
Re: reactors
« Reply #24 on: Mar 06, 2009, 11:39 »
However, system ops, which is out electrical dispatcher, will call the control room, and speak to the Control Room Supervisor, asking to adjust reactive load by however many MVars, and the BOP operator will adjust the generator field current to adjust MVar output. 

On rare occasion, if a unit is making a major change to reactive load, one might see a slight change to MW output, depending on exciter temps and H2 pressure.

wlrun3@aol.com

  • Guest
Re: reactors
« Reply #25 on: Mar 06, 2009, 01:12 »


     "There are plants out there which are load followers,"

   ...what makes a load follower...design, size, location...please give some examples...

      "and thank goodness we are not one.  We operate at a steady 100% real power output from end of outage to start of outage. (Called a breaker to breaker run, with the very occasional forced outage). However, system ops, which is out electrical dispatcher, will call the control room, and speak to the Control Room Supervisor, asking to adjust reactive load by however many MVars,"

   ...what is an MVar...

      "and the BOP operator will adjust the generator field current to adjust MVar output."

   ...what is happening to reactivity as this adjustment to generator field current is made...

      "It's a very quick evolution, and typically, we'll keep system ops on the line, make the adjustment, and ask them if that adjustment was adaquate.  They (about 60 miles away) will instantly see the change, and tell is if it was or not."

   ...your posts are outstanding...again, thankyou...




wlrun3@aol.com

  • Guest
Re: reactors
« Reply #26 on: Mar 06, 2009, 01:27 »

   ..."If we had a major downpower, then we would have to borate to minimize how far we would have to insert rods to lower Tave, so we didn't exceed our rod insertion limits."

   ...what happens if you exceed the rod insertion limits...


Offline Creeker

  • Moderate User
  • ***
  • Posts: 112
  • Karma: 607
  • Gender: Male
Re: reactors
« Reply #27 on: Mar 06, 2009, 02:25 »
Quote
...what makes a load follower...design, size, location...please give some examples...

Nuclear plants as a whole are not load followers... We all supply power to our section of the grid, which is a chunk of the US electrical power distribution network.  There are many supplies to every part of the grid, all hooked up in parallel, and loads attached to the grid... As you can imagine, depending upon time of day, and time of year, the load demand placed upon the grid varies greatly.  A balance must be maintained between supply and demand, and as demand increases or comes off, system ops has to control the supply to meet demand.  Commercial nuclear plants generally are not used to follow the load.. they're the backbone, steady state power suppliers, and we use coal plants, windfarms, gas turbines to adjust upwards and downwards to ensure the the grid is stable and supplying the desired load.  This is for several reasons. 

First, Nuclear plants are on an 18 month schedule (or 12, or 24) for refueling.  When we shutdown, we have access to containment, and can do lots of maintenance and modifications that can't be done at any other time.  The planning and coordination to accomplish all we have to in a month of outage is considerable... Then factor in all the outside help that is required, HP's, vendors of every type, and that those outside folks are working a schedule going from outage to outage with other plants...  So, outages are on a fixed schedule, and to begin one early always causes many problems.  But, the fuel we buy, and install, is engineered for 18 months.  (or 12, or 24)... So, if your plant runs at 80% capacity for it's 18 months between outages, then you've wasted a lot of fuel, (Fuel is $$$$), without getting the income from your MW output.  Not good economics.
So, when you hear some idea from Cali about running Nukes as a backup only when the wind energy is maxed out, it doesn't make very good sense from the utilities standpoint.

Next, Commercial power plants don't like rapid power changes.  I've heard comparisons that navy plants are Ferraris, while commercial plants are dump trucks.  Takes a while to get up to speed, and takes a while to stop.  That's a simple comparison, but from my limited simulator time here, it is a pretty big deal to take power down 20%... Lots of coordination between the BOP, RO, boration...   It's not nearly as easy as shutting the throttles a couple of turns used to be.

I'm sure there are other reasons... I don't know of any nuke plants that are load followers, but I'm sure there are some out there.

Mvars are Mega-Vars, which is the unit of reactive power, or power which isn't really used for doing real work, but rather is stored in inductive and capacitave components and returned to the circuit.  The 3 types of power are real (Watts) reactive (Vars) and Apparent (VA's).  Apparent is the total of voltage and current output, and is the vector sum of the other 2, but that gets a little hard to discuss without drawing power triangles.  (Google power triangle)

Oops, out of time for now...  Hope that helps,

Bill

thenuttyneutron

  • Guest
Re: reactors
« Reply #28 on: Mar 06, 2009, 09:26 »
   ..."If we had a major downpower, then we would have to borate to minimize how far we would have to insert rods to lower Tave, so we didn't exceed our rod insertion limits."

   ...what happens if you exceed the rod insertion limits...



Refer to Tech Specs.

Fermi2

  • Guest
Re: reactors
« Reply #29 on: Mar 06, 2009, 10:16 »
If your Control Rods are past their insertion limit you have to Emergency Borate (start a boration at a specific flow rate with a certain concentration of boron) until the Rods are withdrawn past their insertion limit. Basically an insertion limit is for any given power the control Rods have to be withdrawn a certain amount in order to ensure on a Reactor Trip they can supply sufficient negative reactivity to shutdown the reactor. Think of it this way, a commercial PWR could theoretically generate considerable power with the Rods fully in. If you did it this way there'd be no way to rapidly shutdown the reactor. When raising power you increase steam demand, then either dilute or withdraw control rods to maintain Tave at a given program. For a Westinghouse 4 Loop PWR Tave raises a bit over 31F from Zero Power to 100% Power.
Referring to Tech Specs was an ignorant answer. In the event of an Insertion Limit Violation if you take time to read the TS you're already violating it as it's an immediate action TS to Emergency Borate.
It's also a misnomer that Commercial Reactors aren't designed to move quickly. A Westinghouse PWR is designed to move 10% instantaneously or at 5%/Min. Either is a bit hairy but it can be accomplished.
BWR's by the way don't have the issue with Rod Insertion Limits as their Control Rods are designed to keep the reactor SD with one rod withdrawn down to 68F.

Mike

wlrun3@aol.com

  • Guest
Re: reactors
« Reply #30 on: Mar 07, 2009, 07:55 »

   ..."an insertion limit is for any given power the control Rods have to be withdrawn a certain amount in order to ensure on a Reactor Trip they can supply sufficient negative reactivity to shutdown the reactor."

   ...i've noticed that you type very fast...

   ...since i'm collecting/copying all good responses like this for use in future book/s that i hope to write, may i alter this...



   ...an insertion limit, for any given power level, is the amount the control rods have to be withdrawn in order to ensure that sufficient negative reactivity can be supplied to shutdown the reactor...


   ...if i use anything i've collected on this forum over the years i will request verification and permission...


Fermi2

  • Guest
Re: reactors
« Reply #31 on: Mar 07, 2009, 10:56 »
You know what a handy source is. The Standard Tech Specs Web Page on the NRC Website. They have a generic set for all types of US Reactors. The Bases are INCREDIBLE.
One error I made, I never considered Davis Besse may be using Standard TS vice the old style that Sequoyah uses. I came from a plant that used STS (I LOVE STS by the way) and had to revert to the old style. In STS Emergency Boration is a 1 hour action vice an Immediate one.

http://www.nrc.gov/reactors/operating/licensing/techspecs/current-approved-sts.html

Mike

wlrun3@aol.com

  • Guest
Re: reactors
« Reply #32 on: Mar 07, 2009, 12:44 »
You know what a handy source is. The Standard Tech Specs Web Page on the NRC Website. They have a generic set for all types of US Reactors. The Bases are INCREDIBLE.
One error I made, I never considered Davis Besse may be using Standard TS vice the old style that Sequoyah uses. I came from a plant that used STS (I LOVE STS by the way) and had to revert to the old style. In STS Emergency Boration is a 1 hour action vice an Immediate one.

http://www.nrc.gov/reactors/operating/licensing/techspecs/current-approved-sts.html

Mike

   ...had no idea this existed...thankyou...


Fermi2

  • Guest
Re: reactors
« Reply #33 on: Mar 07, 2009, 02:11 »
Bases ate STS are great because it's just like reading a design analysis. KEEP in mind the plants version maybe a bit different. BUt for the most part most of the basis will be the same.

thenuttyneutron

  • Guest
Re: reactors
« Reply #34 on: Mar 07, 2009, 04:31 »
I also have to disagree with Mike about refering to the Tech Specs as being ignorant.  I don't think it is a good idea to jump straight to an action UNLESS it is an immediate action.  Rod insertion limits do not have immediate actions at my plant.  Very few TS have action statements that have to be met in under an hour let alone immediately while in Mode 1.  I can promise you that taking actions that are wrong in regard to TS will get you a one way ticket out the door.  You must refer to the Tech Specs rather than relying on memory. 

From the Bible (TS book)

"IMMEDIATE When "Immediately" is used as a Completion Time, the Required Action
COMPLETION TIME should be pursued without delay and in a controlled manner."

Where is the controlled manner if you are not even reading/refering to your Tech Specs?

The actions for TS 3.2 LCO 3.2.1 Action C

"Regulating rod groups
inserted in unacceptable
operational region."

 requires

"Initiate boration to restore
SDM to within the limit
specified in the COLR."

Within 15 minutes.  If I am only in the Operation Restricted Region, I may not even get here.

Just because you are in violation of a restricted operational region for rod insertion limit does not mean you are in violation of the TS for Shutdown Margin.  The Restricted Operational region for Rod Insertion Limits are more restrictive than the limits for Shutdown Margin.  This is important to know because YOU SHOULD NEVER be in a situation of having a Shut Down Margin less than 1% Delta K per K.  If I don't have that SD margin, I would be in a LCO with a 15 minute action statement. 

The rod insertion limits are not only for SD margin.  It also can affect your QPT, imbalance, DNBR, and hot channel factors. 

When my plant is in a rapid shutdown, it is possible for my plant to cut the corner of operational region for rod insertion limits for a small amount of time.  I do agree that adding Boron on the way down is a good idea, but not reading your TS will get you screwed.

This is off NRC site.

http://www.nrc.gov/reactors/operating/licensing/techspecs/current-approved-sts.html  go to the Babcock and Wilcox Plants


« Last Edit: Mar 07, 2009, 04:51 by The Nutty Neutron »

Fermi2

  • Guest
Re: reactors
« Reply #35 on: Mar 07, 2009, 06:50 »
How long have you had your SRO License Son? If you are in a 15 minute or less LCO the NRC Expects. NO DEMANDS immediately initiate the action without referral to TS. There have been plenty of NRC Violations for not doing so. When you get an SRO license then maybe, just maybe you can challenge a 9 year SM on this. Controlled manner means you have it captured in a procedure and that procedure is trained upon frequently enough that it can be accomplished without referring to the TS or even the procedure. if you don't meet your Rod Insertion Limits you STILL have SD Margin, just NOT your required SD Margin.

Mike

Nuclear Renaissance

  • Guest
Re: reactors
« Reply #36 on: Mar 07, 2009, 08:04 »
How long have you had your SRO License Son? If you are in a 15 minute or less LCO the NRC Expects. NO DEMANDS immediately initiate the action without referral to TS. There have been plenty of NRC Violations for not doing so. When you get an SRO license then maybe, just maybe you can challenge a 9 year SM on this. Controlled manner means you have it captured in a procedure and that procedure is trained upon frequently enough that it can be accomplished without referring to the TS or even the procedure. if you don't meet your Rod Insertion Limits you STILL have SD Margin, just NOT your required SD Margin.

I understand violations for delay on taking actions even within the LCO completion time, when the operator fully knows that the LCO is not and will not be met, but I have never heard that you have to take action from memory upon discovery of a non-immediate action. Where is this guidance?

Also, calling someone with a dissenting opinion "son" is one of the biggest **** moves a guy can make, and that would take things to a very personal level with me regardless of your docket # or years of service.
« Last Edit: Mar 07, 2009, 08:05 by Nuclear Renaissance »

Nuclear Renaissance

  • Guest
Re: reactors
« Reply #37 on: Mar 08, 2009, 12:49 »
If your Control Rods are past their insertion limit you have to Emergency Borate (start a boration at a specific flow rate with a certain concentration of boron) until the Rods are withdrawn past their insertion limit.

In STS Emergency Boration is a 1 hour action vice an Immediate one.

Broadzilla, I pasted the below directly from Sequoyah's Tech Specs. It seems that SPECIFICALLY for the case of exceeding a rod insertion limit, Sequoyah Tech Specs state a 2 hour completion time for rod insertion limit restoration and/or power reduction. Sequoyah's immediate boration action is in a separate spec and appear to be *only* dependent on whether shutdown margin is 1.6%.

Everything Nutty Neutron stated appears correct per the B&W STS, including the 15 minute emergency boration LCO.


REACTIVITY CONTROL SYSTEMS
CONTROL ROD INSERTION LIMITS
LIMITING CONDITION FOR OPERATION
3.1.3.6 The control banks shall be limited in physical insertion as specified in the COLR
APPLICABILITY: Modes 1* and 2*#.
ACTION:
a. With the control banks inserted beyond the above insertion limits, either:
1. Restore the control banks to within the limits within two hours,
or
2. Reduce THERMAL POWER within two hours to less than or equal to
that fraction of RATED THERMAL POWER which is allowed by the
group position using the insertion limits specified in the COLR
« Last Edit: Mar 08, 2009, 06:31 by Nuclear Renaissance »

number41

  • Guest
Re: reactors
« Reply #38 on: Mar 08, 2009, 06:23 »
Or, if you wanted to change reactive loading, you could connect to the 230KV bus capacitor banks which will add or remove 86 MVars of reactive loading.........Brunswick is a weird animal by the way.

Fermi2

  • Guest
Re: reactors
« Reply #39 on: Mar 09, 2009, 11:25 »
You've only posted the Insertion Limit TS. Sequoyah uses Insertion Limits to derive SD Margin. When we bust the insertion limit spec we also bust the SD Margin Spec. Therefore you IMMEDIATELY emergency borate at a minimum of 35 GPM. Where did I ever say I was in the Rod Inserion Spec?
The bottom line here is the NUB tried to say when you're in an IMMEDIATE Action TS you get out the Spec and read it. The NRC Says no. You are expected to take action IMMEDIATELY.
Example, at Fermi if both Recirc Pumps Tripped in Mode 1 the TS said IMMEDIATELY Trip the Reactor. If you took time to get out the Spec you might find the core already damaged.
In the BWR world if you enter the SCRAM Region of the P/F Map by TS you IMMEDIATELY SCRAM the Reactor, if you enter the Exit Region you IMMEDIATELY take action to exit that region, thus BWRs have Rods designated to start inserting.
Two BWRs got into serious trouble for
1: Getting out the Spec after a Dual Recirc Pump Trip at 11 % Power then tripping the reactor.
2: Entering the Exit Region, getting out the Spec then inserting their CRAM Array.

The reason: The NRC said don't you understand your own TS well enough to know what are the IMMEDIATE actions? IMMEDIATELY or within 15 minutes means the situation is grave enough or so deep in your accident analysis you address it.

McLovin: Sequoyah's Switchyard is so complicated it still amazes me. We use a combination of loading the generators OR adjusting an Intertie Transformer between the 500 and 161 KV Swyd OR placing Cap Banks in and out. Plus the Nomenclature is backwords. To me if you're going to adjust a parameter so it increases whatever you're adjusting should be manipulated in the UP direction. Not the Intertie. Hearing the Operators say Tapping Down in order to increase VARS is still weird to me.

20 Days then it's outage time!

Mike

Offline HydroDave63

  • Retired
  • *
  • Posts: 6295
  • Karma: 6629
Re: reactors
« Reply #40 on: Mar 09, 2009, 11:41 »

McLovin: Sequoyah's Switchyard is so complicated it still amazes me. We use a combination of loading the generators OR adjusting an Intertie Transformer between the 500 and 161 KV Swyd OR placing Cap Banks in and out. Plus the Nomenclature is backwords. To me if you're going to adjust a parameter so it increases whatever you're adjusting should be manipulated in the UP direction. Not the Intertie. Hearing the Operators say Tapping Down in order to increase VARS is still weird to me.


The operators might be tapping a load tap changer down on the plant side to maintain voltage on the high voltage side, depends on your local procedures for maintaining switchyard voltage. NERC Std. NUC-001-1 is there to make sure the wires side folks maintain voltage at the plant side by written procedures, to help the plant side meet General Design Criterion (GDC) 17. Depending on how the cap banks and MVARs are being used that day in the rest of your network, might account for LTCs being moved or (rarely) asking your plant to change voltage output on the TG.

Fermi2

  • Guest
Re: reactors
« Reply #41 on: Mar 09, 2009, 11:56 »
That's exactly what they're doing. This is the first Line Side Tap Changer I've ever seen.
The other major difference has to do with the System. TVA's System is HUGE and extremely integrated. DTE's was a small system I bet we have more breakers on the SQN SWYD than Edison had in their entire system. . You never changed VARS and the unit without having permission from the Load Dispatcher because they used Fermi to control system voltage. The only limit was the MVAR limit on the generator (Which in retrospect isn't good for the system).
Here if certain lines go down you have MVAR limits on the Generator and in any event the Operators can change MVARs more or less when they please. Also, verifying the TS Operability of Offsite Power at Fermi was as simple as verifying the position of a few breakers and taking two voltages. Here I have to call someone offsite and they tell me if I'm operable or not, which is unsettling as in the middle of the day, without me having done anything this same person can call me up and say Hey Mike, both your sources of Offsite or Inoperable. (Yes it happened!)

Mike

number41

  • Guest
Re: reactors
« Reply #42 on: Mar 09, 2009, 08:41 »
Quote
McLovin: Sequoyah's Switchyard is so complicated it still amazes me

Mike, I've heardd that.  No specifics, but I've heard that it's a monster to learn and even worse to operate.  Brunswick may not be quite as convoluted, but we are at "the end" of the grid, if you will.  We are so remote from most of the grid that we have to enable part-time load shedding and LOCA load shedding to dump chillers, condensate pumps, circ water pumps, and some other various loads to keep grid/DG voltage high enough to meet design requirements following a trip.  Hopefully these new capacitor banks will help remedy some of this craziness!

wlrun3@aol.com

  • Guest
Re: reactors
« Reply #43 on: Mar 13, 2009, 12:38 »
You know what a handy source is. The Standard Tech Specs Web Page on the NRC Website. They have a generic set for all types of US Reactors. The Bases are INCREDIBLE.
One error I made, I never considered Davis Besse may be using Standard TS vice the old style that Sequoyah uses. I came from a plant that used STS (I LOVE STS by the way) and had to revert to the old style. In STS Emergency Boration is a 1 hour action vice an Immediate one.

http://www.nrc.gov/reactors/operating/licensing/techspecs/current-approved-sts.html

Mike

   ...i found this to be very valuable...

   ...any further advice of this nature would be extremely helpful...


 


NukeWorker ™ is a registered trademark of NukeWorker.com ™, LLC © 1996-2024 All rights reserved.
All material on this Web Site, including text, photographs, graphics, code and/or software, are protected by international copyright/trademark laws and treaties. Unauthorized use is not permitted. You may not modify, copy, reproduce, republish, upload, post, transmit or distribute, in any manner, the material on this web site or any portion of it. Doing so will result in severe civil and criminal penalties, and will be prosecuted to the maximum extent possible under the law.
Privacy Statement | Terms of Use | Code of Conduct | Spam Policy | Advertising Info | Contact Us | Forum Rules | Password Problem?