At Catawba Nuclear Station, we also trip
the reactor if more than 1 rod drops.
For beginning of cycle reactor startup including
low power physics testing and for mid-cycle reactor startups, our requirement
is to reinsert rod banks if a single rod drop occurs. For BOC,
requirement applies as long as we are in the test procedure for low power
physics testing. For other reactor startups, we have a test procedure for
approach to criticality (in addition to the normal operating procedure).
The requirement to reinsert rod banks if a single rod drop occurs is applicable
while we are in the test procedure for reactor startup.
In both cases once we are out of the test
procedure for reactor startup and back into the normal operating procedure for
unit startup, there is no shutdown requirement for a single dropped rod.
Effectively, our definition of startup for the purposes of response to single dropped
rod is “while in test procedure for reactor startup/physics testing”
The transition from test procedure to
operating procedure occurs at approximately 10-8 amps on
intermediate range, about a decade below point of adding heat.
Other potential definitions of reactor startup
with respect to single dropped rod could be:
Except for physics testing, the time spent
in mode 2 during reactor startup is usually so small that it doesn’t make
much difference which definition you use. I do not think it is necessary
to extend definition of reactor startup into mode 1.
Dan Wellbaum
Reactor Engineering
Catawba Nuclear Station
From:
pwrrm@retaqs.com
Subject: [Pwrrm] Definition of
When Startup is Complete
FCS has
two requirements regarding a dropped rod. First, if we drop more than one rod
at power, we trip the reactor. Second, if we drop a single rod during startup,
we trip the reactor. What we don't have is a definition of when startup is
considered complete, with regards to a dropped rod.
Do other plants have similar requirements and do
you have a definition of when startup is complete with regards to a dropped
rod?
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Joseph E. Willett, P.E.
Principal Reactor Engineer-Fuel
Nuclear Operations Division
E-mail: jwillett@oppd.com
Omaha Public Power
District Phone: (402) 533-7213
Fort Calhoun Station
Pager: (402) 561-3899
9610 Power Lane
FAX: (402) 533-6747
Blair, NE 68008
Mail Station: FC-1-1
Plant
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