With regard to the delta between
the BWROG and PWROG for fuel failures, as I recall from the meeting in
Pittsburgh, the basis was that a fuel failure for PWRs is potentially
significantly less RM impact than a fuel failure for BWRs. Since PWRs don’t
suppress failures, only certain cases do failures impact RM in any way. Thus,
those that do should be treated the same as SL3 events but those that don’t
are either not RM at all (say low power grid-to-rod fretting failures) or a
lower event level (L4 for fuel handling issue that results in damage).
The other issue that needs to be
discussed in Philly is that RM needs to be just that, RM. Not all fuel issues
are RM-related. There are really big deals that are not RM big deals. (ONS fuel
damage event for instance). If INPO wants to encompass all fuel issues in any
way, shape or form, within RM then INPO 06-06 and SOER 07-1 need to change to
reflect that. Currently they don’t encompass what I hear second hand that
INPO wants. My management has also pushed back on some of the PWROG criteria
based on the issue not being RM per the definition and I’ve asked them to
provide that feedback to INPO.
On a different note, another
example just to make sure we’re implementing consistently…
·
An error in the core
cycle design calculations for a current operating cycle that either does not
result in any change to the COLR or the design deliverable document used at the
plant for managing the operating core. (Say, a conservative error in the
analysis for a non-limiting event … thus the AO, rod insertion or tilt
limits are not changed.)
-
SL4 as a technical
error in an RM product after implementation but no impact to operation? (it’s
been implemented, though, so the information has been “used”)
-
SL3 does not seem to
apply since the error does not impact operation.
-
Or is it even lower
than SL4 since the site documents (COLR, etc.) did not have an error …
only the basis calculation did?
Thanks!
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
From: pwrrm@retaqs.com
[mailto:pwrrm@retaqs.com] On Behalf Of edward.mcvey@exeloncorp.com
Sent: Tuesday, April 06, 2010 2:04 PM
To: pwrrm@retaqs.com
Subject: Re: [Pwrrm] PWROG RM Coding Questions
See my responses below. Some of these are good topics for our
meeting in July in Philly.
Ed McVey
From: pwrrm@retaqs.com
[mailto:pwrrm@retaqs.com] On Behalf Of Fago, Carl D
Sent: Tuesday, April 06, 2010 11:59 AM
To: pwrrm@retaqs.com
Subject: [Pwrrm] PWROG RM Coding Questions
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
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