Nuclear Grade Air TrapTM - (NGATTM)

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 fluid systems.

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.

What is the NGAT ?
NGAT Benefits and Features
How the NGAT works
NGAT Cycle Animation Video
-150 Schematic Diagram

What is 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 components

  • Design allows for easy retrofit of existing conventional vents

  • 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

  • Available as:

    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)

How the NGATTM works:

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.

NGATTM Cycle Animation Video: An animation of the NGAT-150 can be found here.

NGATTM Downloads: (Left-Click to View, Right-Click to Download)

NGATTM-150 Schematic Diagram

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.


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