Nuclear Plant Journal, September-October 2014 NuclearPlantJournal.com
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request, the Nuclear Energy Industry
(NEI) Flooding Task Force conducted
an industry poll which indicated
that production of Flooding Hazard
Reevaluation Reports (FHRRs) took
approximately 2,600 utility man-hours
with an additional 6,100 man-hours
performed by vendor/consultants, (i.e.
8,700 man-hours).
The NEI Flooding Task Force poll
also addressed the industry’s estimates
of the effort to be taken to prepare the
Integrated Assessments not including
any new construction. The average effort
to be performed by the utilities and their
vendor/consultants was estimated to be
11,360 man-hours for plants requiring
protection and mitigation. The cost for
new protection features would be in
addition to this and was not estimated in
this polling.
To process the required FHRRs
in a timely manner, the NRC divided
licensed facilities into three groups and
staggered their submittal deadlines.
Members of the first group were required
to submit their evaluations, or reschedule
their submittals, by March 12, 2013.
There were reportedly six requests for
extensions that were granted by the NRC.
At the time of this article there has been
one reported finalized/completed NRC
staff assessment of an FHRR returned
to the licensee. The NRC has mentioned
a dozen more will be forthcoming by
November 2014. It should be noted that
the Integrated Assessments will need to
incorporate the NRC staff assessments
of the FHRRs. In this initial group,
18 of the 22 plants found their FHRR
results exceeded their Current Licensing
Basis (CLB) or that the CLB itself was
missing an element, such as Local
Intense Precipitation (LIP), which was
called for in the 50.54(f) Letter. These
18 plants are now required to perform
Integrated Assessments within two years
of their FHRR submittal, typically by
March 2015 if no extension was granted
by the NRC. The Integrated Assessments
must include and address the NRC staff
assessments of the FHRRs.
The FHRR submittals for the second
group of 24 plants were due March 12,
2014, and there were 11 extensions
granted by NRC. In this second group,
16 of the 24 plants found their FHRR
results exceeded their CLB. These 16
are now required to perform Integrated
Assessments within two years of
their FHRR submittal, typically by
March 2016. Again, these Integrated
Assessments may necessitate plant
modifications—e.g. watertight doors
for certain compartments, or moving
essential equipment to higher ground or
other mitigation processes as mentioned
above.
The third and final group of 19
plants have their FHRR submittals due
on March 12, 2015. There is no collected
group information yet to report on how
many will be moving into the Integrated
Assessment process. If that number is
consistent with the first two groups, 74%
(i.e. 48) of the 65 nuclear power plants
will proceed into Integrated Assessments.
Note that the precipitation amounts
from Hurricane Katrina and Hurricane
Sandy, shown in Figures 1 and 2
respectively, are significantly below the
minimum levels used in FHRR models or
required as a basis for protection levels
during Integrated Assessment.
A significant portion of the US
nuclear fleet will be subject to Integrated
Assessment with associated flood hazard
protection and mitigation requirements.
No estimate is yet available for the
costs associated with the protection
and mitigation measures to be taken.
However, the costs may easily run into
tens of millions of dollars. Whatever costs
are incurred under the current guidance
will be incurred without regard to the
potential frequency of the flooding events
against which plants are being protected
– since no probabilistic risk assessment is
approved for use at this time.
Contact: Peggy Striegel, Striegel &
Associates, telephone: (918) 740-5584,
email:
Figure 1.
Figure 2.
