Nuclear Detection: Images

GammaCam LT27 - Technology to Enhance Worker Safety

1. HOMELAND SECURITY - WHAT YOU CAN'T SEE, CAN HURT YOU
As shown below, our GammaCam enables operators to locate and characterize hidden sources of radiation in closed vehicles, stacked containers, etc.

2. REACTOR HEAD

Prior to this image being captured, the Utility was unaware of the large plane source emanating from the lead screws. This source was contributing to additional general area exposure during refuel operations. This source was subsequently eliminated with a refuel maintenance procedure modification (lower lead screws behind shielding). Capturing this image resulted in a maintenance procedure change and an estimated 2 Rem exposure savings per refuel.

3. LET DOWN HEAT EXCHANGER ROOM

A shielding package was installed and surveyed using conventional means. Work in this area was about to commence when it was decided to image the area to determine shielding effectiveness. The captured image discovered two unshielded sources missed during conventional survey of the shielding installation. A lead blanket was installed and the area was reimaged to verify shielding effectiveness. The captured image resulted in 3 Rem of savings.

 

4. SURPRISE SOURCE
This area was imaged to confirm a known source at the control valves. The image captured however shows a 150 mR/hr hot spot above the valves. This hot spot was previously not identified.

 

5. SEEING IS BELIEVING
The primary source in this area was believed to be in the vertical run of the piping down stream of the elbow. Imaging showed that the primary source was actually in the horizontal piping upstream of the elbow.

Site Characterization Using EDO's GammaCam at the former Soviet Naval Nuclear Training Facility at Paldiski, Estonia.

Under a service contract from the U.S. Department of Energy, our GammaCam recorded gamma-ray images of several areas in the former Soviet Naval Nuclear Training Facility at Paldiski, Estonia. During the expedition, the GammaCam efficiently localized the key radiological contributors in waste storage cells. With minimal operator exposure the GammaCam operated in a very high radiation area, >60 R/hr, and produced images that will be used in the planned site remediation. An example of the radiation images obtained is shown in the photograph below. The image is of a storage cell within the Solid Waste Storage building. As can be seen, the system localized two major contributors to the radiological conditions within the cell. This information will be used to plan the cell's remediation. The location of the radiation sources was verified by Swedish members of the site characterization team through use of a gamma spectrometer. It has been recommended that once these higher radioactive materials are removed, a second image should be taken to determine the presence or absence of any lower level contributors. The GammaCam finds the highest strength gamma radiation source so that it can be removed quickly with maximum safety.

Imaging High Level Rad-Waste
The figure below illustrates the GammaCam placement in another cell at the Solid Waste Storage Building. In this scenario the GammaCam was utilized to (1) take a gamma ray picture and (2) make a source flux (radiation field emanating from the source) estimation of the activated portion of reactor control rods. The radiation at the base of the control rods is so strong that it would be fatal for any person in the immediate area that stays for as short a time as 5 minutes. After being lowered into cell opening 3, the GammaCam acquired and displayed the image below in less than one minute. Operators and observers were outside of the cell and at a safe distance from the cell openings during the entire process. This deployment of the GammaCam demonstrated that this system identifies the highest source of gamma radiation from a safe standoff distance.

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