POWER March 2022 - 25

NUCLEAR
Holtec's Credentials
Holtec is a vertically integrated technology
and services supplier to the global
power industry. Holtec International has
13 major operations centers in eight
countries plus manufacturing capabilities
in Pennsylvania and Ohio. The company
also has a combined advanced manufacturing/research
and development center
in New Jersey. Corporate headquarters
are in Jupiter, Florida. Increasingly,
Holtec has focused on providing specialized
technology and service solutions for
the commercial nuclear and solar sectors.
The HDI subsidiary functions as
the licensed owner/operator for Holtec's
fleet of shuttered NPSs.
In 2018, Holtec International and Canada-based
global engineering and procurement
contractor, SNC-Lavalin, joined
forces to create the Comprehensive Decommissioning
International (CDI) joint
venture. CDI serves as the general contractor
for HDI's fleet of shuttered nuclear
plants. The joint venture leverages Holtec's
expertise in storing and transporting spent
nuclear fuel and SNC-Lavalin's decommissioning
and project engineering expertise.
Holtec's Site Services group, in turn,
contracts to nuclear plant licensees
around the world to support their fuel
transfer campaigns and other specialized
activities. At Pilgrim, for example, Holtec
Site Services personnel have been transferring
spent nuclear fuel from wet to dry
storage under contract since 2014.
Holtec's Accelerated
Decommissioning Approach
While the individual tasks would take approximately
the same amount of time to
perform, the DECON approach enables
decommissioning to be completed up
to 50 years sooner than if the deferred
SAFSTOR approach was used. That said,
Holtec appears to be striving to further
compress the time envelope, with plans
to complete the Pilgrim decommissioning
in just eight years.
To this end, the company leverages
Holtec-developed technology, tooling,
and best practices, and-at Pilgrim at
least-transitioned to double shifts
during the most recent fuel campaign.
Holtec's NRC-licensed HI-STORM 100
system (Figure 2) is designed to both
simplify and speed the process of
safely transferring spent nuclear fuel to
dry storage while " providing an impregnable
barrier against radiation release to
the environment. "
According to a company spokesperson
at Pilgrim, accelerated decommissioning
will benefit the Town of Plymouth by enabling
the bulk of the 1,600-acre property
to be repurposed, helping replace the tax
revenues lost when the plant shut down.
It could also benefit Holtec financially
since it would enable the company to collect
any monies remaining in the decommissioning
trust fund, valued at over $1
billion at the time of license transfer.
Securing the Spent Nuclear Fuel
The more critical portions of the fuel
transfer process at Pilgrim are performed
under water using remote-guided equipment
in the reactor building's spent fuel
pool. Holtec's HI-TRAC Transfer Case
represents a key element in this process.
First, a heavy-duty lift at ground level
2. Holtec's robustly constructed Hi-Storm
100 system was designed to provide an impregnable
barrier against radiation release to
the environment. Courtesy: Holtec Decommissioning
International (HDI)
March 2022 | POWER
slowly raises a transfer case with a HISTORM
100 Multi-Purpose Cannister
(MPC) inside to the spent fuel pool on the
upper level of the reactor building. After
being lowered into the pool, the individual
fuel rods are carefully inserted into the
MPC basket and the assembly is raised
onto the adjacent fuel transfer floor. Here,
Holtec-developed equipment dehydrates
the MPC, backfills it with inert helium gas,
permanently seals the cannister, and slips
the loaded MPC from the transfer case
into a HI-STORM dry storage overcask.
The cask is then lowered back down to
ground level for transport to the ISFSI.
The transfer case will also come into play
in the future when it's time to transfer the
loaded MPCs to a different overpack for
transport to an offsite consolidated dry
storage facility, possibly via either barge
and rail or truck and rail.
Made from 1/2-inch thick stainless
steel, the cylindrical HI-STORM 100 MPCs
are sealed at the top with a fully welded
9.5-inch-thick stainless steel lid. Each
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3. Site personnel loading HI-STORM 100
cask on upper Independent Spent Fuel Storage
Installation (ISFSI) pad. Courtesy: HDI
MPC holds 68 fuel assemblies in Holtec's
neutron-absorbing baskets. Once loaded
(Figure 3), the robust, 27-inch-thick concrete
and steel overpack is sealed with
a 19.5-inch-thick concrete and steel lid.
A fully loaded Holtec dry storage cask
weighs approximately 180 tons.
The overpack is designed to provide
both physical protection and additional
radiation shielding. According to Holtec,
the overpack's external steel structure ensures
that the cask will not degrade even
under extreme environmental conditions.
The NRC's Atomic Safety & Licensing
Board has reviewed and validated analysis
indicating that the system could hypothetically
withstand the impact of a
tornado-driven automobile, earthquakes
stronger than previously experienced in
the continental U.S. (and at least five
times stronger than the one that hit Fukushima
in Japan), impact by a fuel-laden
F-16 fighter jet, or a raging brush fire
around the storage facility. In addition,
an Electric Power Research Institute report
validated that a direct hit by a Boeing
767 aircraft traveling at 350 miles
per hour would not result in a release of
radioactive material.
Fleet Management Model Helps
'Multiply Knowledge'
In parallel with its decommissioning activities
at Pilgrim, HDI has acquired and is
decommissioning Exelon's Oyster Creek
NPS in New Jersey and Entergy's Indian
Point NPS in New York state. In December
2021, the company also received
NRC approval to acquire and decommission
the Palisades NPS in Michigan.
While this type of fleet-wide approach
could easily overwhelm a single organization's
resources, Holtec believes
that it allows the company to multiply
knowledge, standardize governance and
oversight across sites, adjust for unique
situations, and enable sites to share best
practices to enhance efficiencies. In addition
to helping reduce costs and save
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POWER March 2022

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