Nuclear Grade Air TrapTM
Our flagship product is the patented Nuclear Grade Air Trap(TM) -
or simply just called the NGAT (pronounced: En-Gat). First
introduced a the VC Summer station, this 2012 TIP Award
winning ("Top Industry Practice") technology is now being installed in
a wide variety of locations in numerous utilities.
In order to ensure the continued safe
operation of power generating stations, the NRC issued Generic Letter GL08-01 which instructs every U.S. power
station to ensure that there is "no air" in any of their safety related
Air (gas voids or "air pockets") has the ability to render the Emergency Core
Cooling System (ECCS) and other safety systems inoperable. If a gas void
within a pipe enters a pump, the pump could fail - and thus the nuclear
plant's emergency cooling system could fail.
To address this critical problem, NUCCORP
designs and manufactures the NGAT(TM.
The NGAT(TM) is an
innovative device that accumulates, measures and allows nuclear plant
operators to eliminate unwanted air/gases in otherwise liquid-filled
safety-related fluid systems.
the NGATTM ?
The NGATTM consists of a vertically mounted stainless steel chamber into
which a seismically qualified and specially designed Titanium, magnetic
float is inserted. A magnetic indicator, external to the pressure boundary,
is attached to the chamber. The indicator follows the magnetic field
produced by the float, thereby providing constant indication of the
air/water level interface. Also, there are specially designed static
components internal to the chamber which properly direct flow inside the
chamber and serve as travel stops for the float and also serve as datum
points, which allows for the minimum required indicated level to be
determined via calculation. The determination of the minimum allowed
indicated level sets the initial plant conditions which must be maintained
to ensure the air/water level stays above the main piping, following
postulated plant design events (i.e., LOCA, etc.). When actual level in the
chamber is above the minimum allowed, during normal plant operations, then
that portion of the subject system, associated with the local high point
where the NGATTM is installed, is “full”, by definition.
NGATTM Benefits and Features:
Provides a means for showing continuous,
literal compliance with station Technical Specifications regarding ECCS
Systems being “full”
Allows for removal of air/gas before it has a
chance to enter main safety-related piping
Eliminates need for periodic, random venting
by providing a continuous indication of air/gas
Indication can be local, remote or both
Eliminates labor and time-intensive UT
inspections and promotes ALARA principles
Air/gas can be removed without elevated
platforms or scaffolding
Simple and reliable passive design. No Active
Design allows for easy retrofit of existing
Designed and built to each utilities needs an
a per location basis
Two Years of flawless operation in the field
with ZERO need for UT
Built under an exacting ASME NQA-1 program to
ensure highest quality is achieved in each design and each unit
NGAT - Non-Stamped, Safety-Related Nuclear Grade Air Trap
Available in 150, 300, 600, 900 and 1500 lb "Flange Class" sizes
NGAT-XL - Large Volume, wall-mounted tank (ASME N-Stamped)
is intended to be installed at local high-points in ECCS and other ESF
systems If, or as, air/gas accumulates at these local high points, air
rises into the chamber. The water is displaced back to the RWST or VCT as
is the case. When this occurs, the water level and thus the float drops.
When a predetermined low level is reached, the operator will open the vent
valve, which vents off the air/gas while filling the chamber with water.
Then, the indicators are checked periodically, according to the operator
rounds. When air/gas accumulation is detected, a "tracking"
condition-report can be entered into the plant's corrective action program
and then the NGATTM can
be vented and filled to ensure continued OPERABILITY.
Video: An animation of the NGAT-150 can be
Downloads: (Left-Click to View, Right-Click to Download)
The NGATTM-150 shown above can also be configured with a goose-neck
arrangement to route the vent valve to a convenient lower location.
With such an arrangement, a minimum required solid-stream flow is
required during venting to ensure vertical portion of
goose-neck remains water-solid. This allows for a more lenient minimum
allowed indicated level to be calculated.