See my responses below.  Some of these are good topics for our meeting in July in Philly.

 

Ed McVey

 

 

During our transition to the use of the PWROG RM event coding, several questions arose and we’d like to get some feedback on how others are handling similar issues.  Specifically…

 

1.       For multi-unit sites, if there is an issue generic to all units (e.g., vendor core design analysis method error), are you applying the “hit” to all applicable units equally?  Most definitely.

2.       For those sites with dry storage (or event multi-unit sites with dry storage), how are you addressing issues with cask transport to dry storage (e.g., while transporting a cask the trailer/transporter breaks)? Is this an issue of less than adequate fuel handling equipment performance while handling fuel or control component (no fuel/component damage), L5? If so, for multi-unit sites, which unit would get the RM hit based on dry storage?  We don’t really address that very well.  That may be an item for clarification in the next revision.  I would take your pick on the unit.  Probably, if only one unit’s fuel is involved, then use that unit (like you do in 3 below).  Otherwise, either would suffice.

3.       ONS has a shared fuel pool between Unit 1 and 2. For fuel handling practices / equipment issues, we are proposing to apply any RM hit against the unit to which the specific fuel assembly or control component last operated. As far as we can tell, there is no “hit” if the fuel bridge or other equipment fails when fuel is not being handled, therefore, there will always be a unit that can be associated with the event.  That sounds appropriate to me.

4.       ONS Fuel Damage Event (SEN-280) has been classified as L4 based on fuel handling that results in damage to fuel assembly or control component. While the RM level isn’t indicative of the organizational significance of the event, this is the classification we came up with. Any comment or insights into how others might classify this event? (While we weren’t “handling fuel” at the time, we conservatively said it met the intent.)  Note that there was no specific RM impact in the event (again, this was a big event for ONS but we’re specifically focusing on RM for this question.)  This is definitely a weakness in the PWR RM PI.  The PWR PI puts a fuel failure at Level 4 versus the BWR PI puts it at Level 3.  Also, the BWR PI would also have gotten you to Level 3 in that an emergency core redesign due to fuel damage, would also have gotten you to Level 3.  You could also call it a Level 2 since technically you could argue that it failed due to “operational” issues.  I can tell you that my discussions with INPO on classification of an event like this as a Level 4 would cause them serious heartache.  That was one of the major issues that they had with the PI, was how could fuel handling damage be considered so low.  That’s why it got elevated in the BWR PI.  Not sure why the PWR team arrived where they did on that one.  I think the only justification you have is that it does not necessarily reflect the health of your RM program.  Although, someone else might argue that could be because you haven’t gotten the right sensitivity in the entire organization to ensure all personnel realize their potential impacts to Reactivity Management and Fuel Integrity.  If you look at the standard philosophy of Reactivity Management (see below for Exelon’s which was taken from other industry documents), you are suppose to operate fuel such fuel failure does not occur.  In your event, a maintenance activity caused the fuel to fail.  That has to be more than a Level 4 event.  If you can’t bin it under a standard example, then use management discretion to elevate.  The examples that we have couldn’t think of all the possibilities of things happening, but I’m pretty sure that had we thought your event was possible, it would have been binned under something higher than Level 4.

 

“

 

Thanks in advance for all the feedback!

Carl

 

Carl D. Fago

Reactor Engineering Supervisor

Oconee Nuclear Station

Duke Energy Carolinas

Phone:  (864) 873-3047

Fax:  (864) 873-3374

Email:  Carl.fago@duke-energy.com